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Volume 18 (2022): Issue 1 (June 2022)

Volume 17 (2021): Issue 2 (December 2021)

Volume 17 (2021): Issue 1 (June 2021)

Volume 16 (2020): Issue 2 (December 2020)

Volume 16 (2020): Issue 1 (June 2020)

Volume 15 (2019): Issue 2 (December 2019)

Volume 15 (2019): Issue 1 (June 2019)

Volume 14 (2018): Issue 2 (December 2018)

Volume 14 (2018): Issue 1 (June 2018)

Volume 13 (2017): Issue 2 (December 2017)

Volume 13 (2017): Issue 1 (June 2017)

Volume 12 (2016): Issue 2 (December 2016)

Volume 12 (2016): Issue 1 (May 2016)

Volume 11 (2015): Issue 2 (December 2015)

Volume 11 (2015): Issue 1 (May 2015)

Volume 10 (2014): Issue 2 (December 2014)

Volume 10 (2014): Issue 1 (May 2014)

Journal Details
Format
Journal
eISSN
2199-6512
First Published
30 May 2014
Publication timeframe
2 times per year
Languages
English

Search

Volume 17 (2021): Issue 2 (December 2021)

Journal Details
Format
Journal
eISSN
2199-6512
First Published
30 May 2014
Publication timeframe
2 times per year
Languages
English

Search

35 Articles
Open Access

A Generating - Absorbing Boundary Condition Applied to Wave - Current Interactions Using the Method of Fundamental Solutions

Published Online: 09 Dec 2021
Page range: 343 - 352

Abstract

Abstract

The purpose of this work is to study the feasibility and efficiency of Generating Absorbing Boundary Conditions (GABCs), applied to wave-current interactions using the Method of Fundamental Solutions (MFS) as radial basis function, the problem is solved by collocation method. The objective is modeling wave-current interactions phenomena applied in a Numerical Wave Tank (NWT) where the flow is described within the potential theory, using a condition without resorting to the sponge layers on the boundaries. To check the feasibility and efficiency of GABCs presented in this paper, we verify accurately the numerical solutions by comparing the numerical solutions with the analytical ones. Further, we check the accuracy of numerical solutions by trying a different number of nodes. Thereafter, we evaluate the influence of different aspects of current (coplanar current, without current, and opposing current) on the wave properties. As an application, we take into account the generating-absorbing boundary conditions GABCs in a computational domain with a wavy downstream wall to confirm the efficiency of the adopted numerical boundary condition.

Keywords

  • Wave-current interactions
  • Method of fundamental solutions
  • Generating-absorbing boundary conditions
Open Access

Measurements Result Analysis of Deformation Characteristics of Transition Zones on the Modernized Line Púchov – Považská Teplá

Published Online: 09 Dec 2021
Page range: 353 - 360

Abstract

Abstract

The current trend in Europe and worldwide is to support the development of so-called green transport, characterized by lower energy consumption and lower CO2 emissions. Rail transport meets these conditions and therefore considerable funding is being spent not only on the construction of high-speed lines but also on the modernization of existing railways, especially those forming part of the trans-European corridors.

Three corridors of the basic TEN-T network pass through the territory of the Slovak Republic. In the Žilina Region, there are two corridors, Balt – Adriatic and Rhine – Danube, with a common section Púchov – Žilina, which is currently being modernized. It is a known fact that railway lines often show a greater degree of degradation in the transition zones between the earthwork and the structures of sub-ballast layers. Since every railway infrastructure management aims to minimize maintenance costs, while ensuring the safety and comfort of passengers, it is necessary to pay increased attention also to transiton zones. In this context, the presented paper deals with the analysis of values of deformation characteristics on the modernized line section Púchov – Považská Teplá, which is characterized by several bridge structures and tunnels. The values were obtained within the quality inspection of work in transition zones located between the earthwork and the structures of sub-ballast layers.

Keywords

  • Railway track
  • Railway line modernization
  • Transition zone
  • Deformation resistance
  • Static modulus of deformation
Open Access

Urban Heat Island: Summer Outdoor Climate Measurement Within the University Campus and City

Published Online: 09 Dec 2021
Page range: 361 - 370

Abstract

Abstract

Work of researchers from various areas is focused on problematics of urban heat islands. Its importance is rising with the global climate change. The difference of the air temperatures within the area can be also caused by the measurement error. Usual error is not the accuracy of the sensor, but the radiation shield or location of the weather station. In this case, averaged difference can be up to 80 %. Difference of temperatures between the weather stations within the analyzed area can vary from 0.2 up to 6 °C. Difference depends usual on the size of the city and the location influenced by the surrounding geomorphology. In this paper three different radiation shields are compared which influenced the measurement and analyzed are also the results from four different weather stations, two of them are within the University of Zilina campus. One of them is placed on the roof, which is a usual location for the solar radiation measurement; the second one is placed on the grass land at the end of the campus. Other two stations belong to the national weather institute. Comparison is made for two very hot days of August 2020. Averaged difference was 0.3 °C for the whole month and 0.5 °C for selected days.

Keywords

  • Climate change
  • Mitigation
  • Urban heat island
  • Weather station
  • Radiation shield
Open Access

Developing A Mathematical Model for Planning Repetitive Construction Projects By Using Support Vector Machine Technique

Published Online: 09 Dec 2021
Page range: 371 - 379

Abstract

Abstract

Each project management system aims to complete the project within its identified objectives: budget, time, and quality. It is achieving the project within the defined deadline that required careful scheduling, that be attained early. Due to the nature of unique repetitive construction projects, time contingency and project uncertainty are necessary for accurate scheduling. It should be integrated and flexible to accommodate the changes without adversely affecting the construction project’s total completion time. Repetitive planning and scheduling methods are more effective and essential. However, they need continuous development because of the evolution of execution methods, essentially based on the repetitive construction projects’ composition of identical production units. This study develops a mathematical model to forecast repetitive construction projects using the Support Vector Machine (SVM) technique. The software (WEKA 3.9.1©2016) has been used in the process of developing the mathematical model. The number of factors affecting the planning and scheduling of the repetitive projects has been identified through a questionnaire that analyzed its results using SPSS V22 software. Three accuracy measurements, correlation coefficient (R), Root Mean Square Error (RMSE) and Mean Absolute Error (MAE), were used to check the mathematical model and to compare the actual values with predicted values. The results showed that the SVM technique was more precise than those calculated by the conventional methods and was found the best generalization with R 97 %, MAE 3.6 %, and RMSE 7 %.

Keywords

  • Project management
  • Repetitive constriction project
  • Support Vector Machine
  • Planning and scheduling
Open Access

Application of Compact Piping Sedimentation Unit as Pretreatment for Ultrafiltration Plant

Published Online: 09 Dec 2021
Page range: 380 - 386

Abstract

Abstract

The study aimed to create a compact pretreatment unit before the ultrafiltration modules. This unit targeted to improve the inlet water quality to meet the average values of the feed water quality required for the ultrafiltration plants according to the manufacturer. The used unit in this study was a pipe worked as a sedimentation unit with inclined plates to apply the plate settler technology. The suitability of using this unit was determined by using varied water sources with different Total Suspended Solids (TSS) concentrations and different retention times. The removal efficiencies for the low TSS water source reached 96.47 %, 82.94 %, 64.80 % & 30.59 % with retention time 30 minutes, 15 minutes, 5 minutes & 20 seconds respectively. For the medium TSS water source at the same retention times, the removal efficiencies reached 97.33 %, 92.87 %, 86.10 % & 63.89 %. For the high TSS water source, the removal efficiencies reached 98.64 %, 93.86 %, 87.51 % & 76.23 %. These results make the sedimentation unit able to work as an effective pretreatment unit for the ultrafiltration units for all water sources.

Keywords

  • Water treatment
  • Sedimentation
  • Plate settler
  • Pretreatment
  • Ultrafiltration
Open Access

A Waste Bank Based on the 3R Concept: Student Interest in Waste Management at the Department of Economics, University of Brawijaya

Published Online: 09 Dec 2021
Page range: 387 - 394

Abstract

Abstract

The establishment of a waste bank could be a social engineering tool for changing the mindset of students. This waste bank can be managed and made useful via the so-called “3R” concept (reduce, reuse, and recycle), which is the main principle used by waste banks. This study aimed to determine students’ interest in managing waste. The sample comprised three classes of students who are enrolled in natural resource economics courses from the Economics and Business Faculty of the University of Brawijaya. Each class has 31 students. Quantitative multivariate research was performed using a Likert scale. Validity and reliability tests were performed for behavioral control and to manage waste variables. Data analysis was used Multivariate analysis, and Bartlett’s test of sphericity was used for significance of the data. Results show that the behavioral control variable was positively correlated with and was influenced by the intention to manage waste or the interest in managing waste. We suggested that waste bank systems—in which waste can be exchanged for food or other products—could be applied in campus environments and that a waste bank should be established in the Faculty of Economics and Business of the University of Brawijaya.

Keywords

  • 3R concept
  • Interest in managing waste
  • Social engineering
  • Waste bank
Open Access

The Renewable Energy Sources for Municipal Wastewater Processes in Thailand: A Case Study of the Nonthaburi Wastewater Treatment Plant

Published Online: 09 Dec 2021
Page range: 395 - 400

Abstract

Abstract

There are 101 municipal wastewater treatment plants in Thailand supplied with electricity and cannot collect wastewater treatment fees. Alternative sources of energy for municipal wastewater treatment would reduce the electricity costs and future fossil energy uses. The Nonthaburi wastewater treatment plant (WWTP) is located in the Northwest of Bangkok and selected due to its available data. The solar energy source is applied to the Nonthaburi WWTP due to the light intensity and the area to install. By comparing to the wind and the biogas sources, the wind speed and the sludge production are not sufficient, respectively. Besides the estimated installation cost of the solar-cell panels among three companies, the NPV of 25 years and the IRR of three percent rate, the area required for installation is an affecting factor for the plant consideration.

Keywords

  • Biogas
  • Net present value
  • Internal rate of return
  • Solar panel
  • Wind energy
Open Access

Estimation of Mechanical Properties and Mass Density of Al-Malwiya Masonry

Published Online: 09 Dec 2021
Page range: 401 - 408

Abstract

Abstract

This paper presents the first estimation for the mechanical properties and the mass density of the masonry of Al-Malwiya heritage minaret. Many approaches are investigated in order to estimate the modulus of elasticity, shear modulus, Poisson’s ratio, and the mass density for this historic masonry. The mechanical properties are estimated by using empirical formulas and analytical equations, while the mass density is estimated after carrying out experimental tests for the extracted samples of the historic mortar. The estimated properties showed relatively low values compared with the newly constructed masonries, but they were interpreted as reasonable for such a historic construction.

Keywords

  • Masonry properties
  • Masonry estimation
  • Heritage masonry
  • Empirical formulas
  • Al-Malwiya
Open Access

Impact of Turbulence Models of Wind Pressure on two Buildings with Atypical Cross-Sections

Published Online: 09 Dec 2021
Page range: 409 - 419

Abstract

Abstract

The article deals with the numerical analysis of the wind pressure distribution on a group of two high-rise buildings of different shape for different wind directions. The first building has the shape of a circular cylinder and the second was created by a combination of semicircles and a longitudinal member. The floor plan of the second building was similar to the letter S. The simulations were realized as 3D steady RANS. CFD results were compared with experimental measurements in the wind tunnel of the Slovak University of Technology in Bratislava. The results were processed using statistical methods such as correlation coefficient, fractional bias and fraction of data within a factor of 1.3, which determined the most suitable CFD model. The purpose of the present article was to verify the distribution of the external pressure coefficient on scale models at a scale of 1:350, which are located in the Atmospheric Surface Layer (ASL). In numerical modeling, the most important thing was to ensure similarity with the flow in the experimental Atmospheric Boundary Layer (ABL) and with the flow around the models. SST kω was evaluated as the most suitable turbulent model for the given type of problem. Turbulent models had a decisive influence on the overall distribution of external wind pressures on objects. The results showed that the most suitable orientation of the objects in terms of the external wind pressure coefficient is 0°, when the cylinder produced a shielding effect, with min mean cpe = −0.786. The most unfavorable wind effects were shown by the wind direction of 90° and 135° with the value min mean cpe = −1.361.

Keywords

  • Atypical cross-section
  • External pressure coefficient
  • Wind tunnel
  • Computational fluid dynamics
Open Access

Fuzzy Finite Element Analysis for Static Responses of Plane Structures

Published Online: 09 Dec 2021
Page range: 420 - 437

Abstract

Abstract

In this paper, a fuzzy finite element algorithm is investigated to determine static responses of plane structures. This algorithm concerns finite element method, fuzzy sets theory, and response surface method. Firstly, the notion of a standardized triangular fuzzy number is developed and utilized to replace original fuzzy numbers in the surrogate models. Then, the error estimations between the training and the test sets are performed to select the suitable response surface model amongst the regression models. Lastly, a good performance combination of complete and non-complete quadratic polynomial regression models is proposed to define the responses of structures. The merits of the proposed algorithm are illustrated via numerical examples.

Keywords

  • Fuzzy sets theory
  • Fuzzy finite element
  • Response surface method
  • Possibility-probability transformations
  • Generalized similarity measure
Open Access

Investigating the Critical Success Factors for Water Supply Projects: Case of Iraq

Published Online: 09 Dec 2021
Page range: 438 - 449

Abstract

Abstract

Water supply projects (WSP) requires high plan information, specialized capabilities, capable human resources, and high administrative capacity. However, in the developing countries, particularly in Iraq, these projects experience a lack of a large number of these necessities, which shows the need to identify the critical success factors (CSFs). Accordingly, the objectives of this research are to investigate the CSFs for WSP and their significance among the construction (public and private) and education sectors. To achieve this, first we have carried out a comprehensive literature review of the CSFs for WSP. Second, we administrated a questionnaire survey to 260 construction experts working in the construction and education sectors. It was found that the top five important success factors for water supply projects in Iraq were a stable political environment; sustainable construction legislation and regulation; effective risk management practices; well-organized and committed project teams; and government decisions through the project life cycle. The survey results did not indicate major differences in the perception of the experts. The findings are focused to assist construction practitioners’ gain better understanding on the important areas to achieve project set objectives.

Keywords

  • Critical Success Factors (CSFs)
  • Construction projects
  • Water supply projects
  • Infrastructure development
  • Iraq projects
Open Access

Formulation of a Basic Constitutive Model for Fine - Grained Soils Using the Hypoplastic Framework

Published Online: 09 Dec 2021
Page range: 450 - 455

Abstract

Abstract

A hypoplastic approach to constitutive modelling was developed by Kolymbas 1996 considering a non-linear tensor function in the form of strain and stress rate. However, the implicit formulation of the hypoplastic model with indirect material parameters severely limits its applicability to real-world geotechnical problems. In many cases, the numerical analysis of geotechnical problems relies on simple elastoplastic constitutive models that cannot model a wide range of soil response aspects. One promising paradigm of constitutive modelling in geotechnics is hypoplasticity, but many of the hypoplastic models belong to advanced models. In the article, we present the simple hypoplastic model as an alternative to the widely used Mohr-Coulomb elastoplastic model.

Keywords

  • Constitutive modelling
  • Hypoplasticity
  • Soil stiffness
  • Finite element method
  • Foundation settlement
Open Access

Modelling of Traffic Noise Along Urban Corridor: A Case Study of Amman

Published Online: 09 Dec 2021
Page range: 456 - 464

Abstract

Abstract

Noise became one of the main environmental indicators of the quality of urban life. The aim of this study was to develop a traffic noise model for an arterial road in Amman, the capital of Jordan, which was being subjected to a persistent increase in traffic and its related issues. The characteristics of the traffic and its relevant noise were analysed to develop a noise prediction model using an adaptive neuro-fuzzy inference system (ANFIS). A geographic information system (GIS) was then implemented to model the current noise along the arterial road. The results of ANFIS model showed that traffic delays and the percentage of heavy vehicles were the main causes of traffic noise generation within the urban area. However, the developed ANFIS model can simulate traffic noise with a relatively low root mean square error. Furthermore, this study will help to improve the perception about traffic noise and its development along arterial roads.

Keywords

  • Bus line noise
  • Noise measurement
  • Noise modelling
  • Noise pollution
  • Traffic impacts
Open Access

Evaluating Flexural Strength of RC Beams Strengthened by CFRP using Different Analytical Models

Published Online: 09 Dec 2021
Page range: 465 - 475

Abstract

Abstract

This paper deals with reinforced concrete beams strengthened by CFRP in flexure. The debonding between CFRP and the surface of the beam is the main problem. Many researchers around the world have made extensive efforts to study the phenomenon of debonding for efficient applications. Based on these efforts and different related field applications, code previsions and various models have been proposed for predicting debonding failure. Two code previsions and three typical models are presented in the current study. ACI-440.2R 17, CNR-DT 200 R1/2013, Said and Wu, Lu et al., and Teng et al. have been used to estimate the flexural strength of RC beams strengthened by CFRP with and without grooves. Test results of eleven flexural beams strengthened by CFRP sheet/laminate using externally bonded reinforcement (EBR) and externally bonded reinforcement on grooves (EBROG) methods were used in the current paper. The performance and accuracy of each model were evaluated based on these test results. Most of the prediction models that used in this study give a closer prediction of the flexural strength of beams strengthened by EBR compared to that of the beams strengthened by EBROG. Finally, the prediction results of CNR-DT 200 R1/2013 were the most accurate and approval with test results compared with other models in the current study

Keywords

  • CFRP
  • Strengthening
  • Analytical models
  • EBROG
  • Reinforced concrete beam
Open Access

Flexural Strength Estimation for Hollow Cross-Section Simply Supported UHPC Beams

Published Online: 09 Dec 2021
Page range: 476 - 484

Abstract

Abstract

The hollow structural elements occupy a great deal of researchers’ interest due to the possibility of losing their weights and maintaining or developing their resistances especially when increasing both compressive and tensile strength of modern materials. The flexural strength based on the forces balance and stain compatibility was derived. Nine beams of Ultra High Performance concrete (UHPC) and conventional reinforced steel bars were casted. Several parameters were taken which are the thickness of the concrete top flange, thickness of the concrete bottom flange, depth of the longitudinal hollow and the ratio of the longitudinal reinforcing steel. By comp aring the practical and theoretical results, the proposed flexural strength provided a safety factor of one-fifth against the experimental collected data. The ultimate flexural force developed up 260 % when increasing the reinforced steel area 4.6 times and 230 % comparing with the solid beam. Many aspect ratios were also mentioned that keep the strength in developing.

Keywords

  • Hollow cross-section
  • Flexural strength
  • Strain compatibility
  • Concrete flange
  • UHPC
Open Access

Mitigation Techniques for Interior Radon in Refurbishment Work in High Radiation Areas of Galicia: An Experimental Model to Test Building Solutions

Published Online: 09 Dec 2021
Page range: 485 - 499

Abstract

Abstract

Radon is a naturally occurring radioactive gas, which tends to accumulate inside built structures. It is therefore necessary to include techniques to mitigate radon concentration during refurbishing work. The aim of this study is to assess the effectiveness of a number of mitigation techniques, under real conditions, to determine which is most suitable, in each case, for use in rebuilding solutions. The methodology consisted in performing four experimental tests on mitigation strategies recommended by the Código Técnico de la Edificación (Technical Building Code) (CTE-DB-HS6) and by the Government of the Autonomous Community of Galicia, (Xunta de Galicia, 2018). The concentration was measured with three different systems: radon in soil at 80 cm, passive detectors to confirm mean concentration, and continuous monitoring by devices calibrated at the LaRUC Laboratory of the University of Cantabria, in order to compare the results of the tests. The experiments were carried out in premises located in a high radiation area in Arteixo (La Coruña, Spain). Four experimental models were designed, corresponding to each of the building solutions under study, and tested over a period of 16 days in two repeated series of trials. The results obtained show that, of the different strategies tested, pressurising the living space achieves an efficient reduction of the radon concentration with a significant simplicity of construction. This solution, compatible with the minimal intervention and reversibility principles stablished in the charters of Venice, Krakovia and Nara, is shown to be especially useful when work is carried out on structures considered to be part of protected heritage.

Keywords

  • Radon
  • Heritage
  • Mitigation
  • Refurbishment
  • Air quality
Open Access

Analysis of Geogrid Reinforced Structures with a Passive Facing System Using Different Computational Methods

Published Online: 09 Dec 2021
Page range: 500 - 512

Abstract

Abstract

The article deals with designing and analysing a wrapped geogrid reinforced structure (GRS) with a passive facing system. The analysis has been done using analytical calculation and numerical modelling. The analytical calculations were executed using FINE Geo5 geotechnical software, and numerical modelling was executed using Plaxis 2D software. The analysis is focused mainly on comparing tension forces in geogrids and the stability of the reinforced embankment determined using both computational methods. The deformation analysis was done only using numerical modelling. The numerical modelling allowed for a more detailed analysis of the wrapped GRS. Each construction phase was modelled step by step according to an actual construction procedure. Two complex road embankments supported by GRS were modelled and analysed. The first model consisted of three GRS, which not affected each other. In the second model, the GRS at each side of the embankment influenced each other. The analysis results showed that tension forces in geogrids, determined using both computational methods, can differ significantly from each other. The stability of the reinforced embankment determined using numerical modelling was within the range of 0.87 – 1.22 of the stability determined using analytical calculation. The numerical modelling results showed that the final horizontal deformation of the passive facing is about 2.8 – 3.8 times smaller than the deformation of the wrapped GRS, which occurs during the construction of the embankment.

Keywords

  • Geogrid reinforced structure
  • Wrapped facing
  • Passive earth system facing
  • Reinforced earth structure
  • Mechanically stabilized earth wall
Open Access

Effects of Induction-Furnace Slag on Strength Properties of Self-Compacting Concrete

Published Online: 09 Dec 2021
Page range: 513 - 527

Abstract

Abstract

Indiscriminate waste disposal poses a severe environmental challenge globally. Recycling of industrial wastes for concrete production is currently the utmost effective way of managing wastes for a cleaner environment and sustainable products. This study investigates the strength characteristics of self-compacting concrete (SCC) containing induction furnace slag (IFS) as a supplementary cementitious material (SCM). The materials utilized include 42.5R Portland cement, induction furnace slag as an SCM ranging from 0 to 50 % by cement weight at 10 % interval, river sand, granite, water and superplasticizer. The fresh properties were tested for filling ability, passing ability and segregation resistance, the strength characteristics measured include compressive strength, splitting tensile strength, flexural strength and Schmidt/rebound number. The oxide compositions and microstructural analysis of SCC were investigated using x-ray fluorescence analyser (XRF) and scanning electron microscopy equipped with energy-dispersive x-ray spectroscopy (SEM-EDS), respectively. Empirical correlations were statistically analyzed using MS-Excel tool. The filling ability characteristic was determined via both the slump flow test and the T50cm slump flow time test. Moreover, the passing ability characteristic was determined using L-Box test. The segregation resistance characteristic was determined using V-funnel at T5minutes test. The results of the fresh properties showed a reduction in the slump flow with increasing IFS content. On the other hand, the T50cm slump flow increased with increasing IFS content. Furthermore, the L-Box decreased with higher IFS content. On the contrary, the V-funnel at T5minutes increased considerably with greater IFS content. The strength test results revealed that the strength properties increased to 20 % IFS, with a value of 66.79 N/mm2 compressive strength at 56 days, giving a rise of 12.61 % over the control. The SCC microstructural examinations revealed the amorphous and better interface structures with increasing IFS content in the mix. The empirical correlations revealed that linear relationships exist among the measured responses (fresh and strength properties). Ultimately, IFS could be utilized as a sustainable material in producing self-compacting concrete.

Keywords

  • Self-compacting concrete
  • Concrete
  • Strength
  • Induction furnace slag
  • Supplementary cementitious materials
Open Access

The Effect of External Blinds on Selected Parameters of the Indoor Environment of an office Building

Published Online: 09 Dec 2021
Page range: 528 - 541

Abstract

Abstract

This contribution focuses on the indoor environmental quality in summer due to overheating of the interior of a west-facing office, since buildings designed in passive standard do not have a problem in the winter heating season but have a problem with cooling in the summer season. Therefore, the article focuses on the effect of external blinds on the indoor environmental parameters.

Keywords

  • Office building
  • External blinds
  • Thermal comfort
  • Indoor temperatures
  • Summer measurements
Open Access

Green Building Materials Based on Waste Filler and Binder

Published Online: 09 Dec 2021
Page range: 542 - 548

Abstract

Abstract

This study is aimed at the application of alternative binder (AB) into bio-aggregate-based composite. The technically important parameters (density, thermal conductivity, water absorption and compressive strength) of 28, 60 and 90 days hardened green composites containing chemically and physico-chemically modified hemp hurds (HH) with AB compared to the Portland cement (PC) are presented. Testing of two reference bio-composites with original HH confirmed higher values of compressive strength and thermal conductivity unlike water absorption for all hardened specimens based on alternative binder (MgO-cement) compared to conventional PC. Changes in the final properties of hardened bio-composites were affected by treatment process of organic filler and alkaline nature of MgO-cement. The combination of purified HH by ultrasound treatment and AB appears to be promising for preparation of bio-based composite material with better properties compared to PC. In this paper, other option of the preparation of bio-composite system based on original (non-treated) filler and binder consisting of optimal activated MgO and silica fume is presented.

Keywords

  • Green composite
  • Bio-aggregate
  • Hemp hurds
  • MgO-cement
  • Silica fume
Open Access

Analysis of a Fire in an Apartment of Timber Building Depending on the Ventilation Parameter

Published Online: 09 Dec 2021
Page range: 549 - 558

Abstract

Abstract

In modern buildings are also currently used the wooden-based construction systems. A wide range of uses the timber constructions in apartment buildings is a vision of the countries of the EU. The use of timber and the other recyclable materials in apartment buildings creates the precondition for the implementation, operation and disposal of environmental impacts of the EU 2020 Strategy. In the long term is important to transform the construction of buildings to a sustainable standard, which the application of wood in construction supports. Currently, the fire height of timber-based residential construction in most EU countries is limited to 5 storeys, provided that the timber structures are fire-protected. This paper deals with the influence of the ventilation parameter in the time and the intensity of the gas temperature during a fire in a model of an apartment building with a timber load-bearing structure. The load-bearing structure is made of CLT panels, with a mixed structural unit, i.e. with fire-resistant cladding of all load-bearing and fire-dividing structures. FDS (Fire Dynamics Simulator - PyroSim software) is used for dynamic simulations of fire in the model apartment.

Keywords

  • Fire safety
  • Timber building
  • FDS
  • Fire
  • Parametric fire
Open Access

The Correlation Between the Statistical Pass-By Index Values and the Total Number of Vehicle Passes

Published Online: 09 Dec 2021
Page range: 559 - 571

Abstract

Abstract

In this study, the traffic noise degradation in asphalt pavements was analysed using the ‘Statistical Pass-By method’. The sound levels of two surfaces were monitored during 9 and 12 years of service, respectively. By comparing the dependencies of the maximum A-weighted sound pressure level on logarithm of vehicle velocity, an increase in the sound level was found at all recorded speeds. Following an analysis of sound levels, as combined with the statistical pass-by index (SPBI) calculated versus age (expressed in vehicles), it was determined that the noise is an increasing power function of SPBI values on vehicle passes, based on an approximation of noise level adjustment to a reference temperature of 20 °C (using a coefficient of 0.06 for asphalt concrete surface AC11 and - 0.03 for mastic asphalt SMA11). The adjusted traffic noise degradation model showed that the SMA11 surface has a higher resistance to acoustic degradation than AC11 surface.

Keywords

  • Traffic
  • Noise
  • SPBI
  • Asphalt surface
  • Ageing
Open Access

Assessment of the Indoor Environment in the Intelligent Building

Published Online: 09 Dec 2021
Page range: 572 - 582

Abstract

Abstract

Currently, thermal comfort and indoor air quality are essential elements in designing modern and intelligent buildings or improving existing ones, so that they would provide proper indoor conditions. The article focuses on the thermal sensations of the students of Kielce University of Technology and determining whether the given parameters of the internal environment contributed to their well-being. 164 people aged 16 - 24 participated in the study, which was conducted with the use of a microclimate meter and questionnaires. It turned out that the temperature range from 19.3 °C – 27.6 °C is acceptable and comfortable for nearly 78% of people. As a result of further analysis, it turned out that the research group definitely prefers and feels better in colder temperatures.

Keywords

  • Thermal comfort
  • Thermal sensations
  • Relative humidity
  • Indoor environment
  • Educational building
Open Access

Role of Fly Ash on Strength Properties of Rejuvenated Soil Cement for Pavement Materials

Published Online: 09 Dec 2021
Page range: 583 - 596

Abstract

Abstract

Stabilization with cement is the most commonly used technique for the improvement of soil physical, mechanical, and engineering properties. This research reported on the properties of the rejuvenation for recycled soil cement with incorporation of fly ash (FA). The study showed that the specific gravity of Rejuvenated Soil Cement (RSC) decreased with increasing FA. The free swell ratio and linear shrinkage of RSC were significantly decreased with the increase in FA. The maximum dry unit weight of RSC increased with increasing FA up to the optimum FA content of 20 – 25 %. The optimum water content in compaction was relatively constant with the increase in FA. Particularly, the strength improvement in active zone of FA-RSC was influenced by several factors viz., compaction, packing, rehydration, and pozzolanic reaction. As a result, the unconfined compressive strength (UCS) of RSC increased with increase in FA and curing time. This research clearly showed that the rejuvenation of soil-cement with FA as additive was successful. It was also shown that the normalized UCSs of RSC at various curing times could be used to predict the UCSs at 7 and 28 days.

Keywords

  • Rejuvenated soil cement
  • Pozzolanic reaction
  • Rehydration effect
  • Unconfined compressive strength
  • Secant modulus of elasticity
Open Access

The Behavior of Strip Footing Resting on Soil Strengthened with Geogrid

Published Online: 09 Dec 2021
Page range: 597 - 609

Abstract

Abstract

The soil in Iraq has a low load carrying or bearing capacity and high deflections or settlement because of the applied loads. The use of strip footing as a foundation to support different kinds of heavy structures has become necessary nowadays through solving such problems by using geogrid. This soil improvement technique is widely used all over the world. In this paper, the bearing capacity and settlements were calculated using finite elements and analytical models for strip footing resting on different kinds of soil. The study parameters are footing rigidity, the number of layers in a geogrid, the dimension of geogrid, and spacing of geogrid layers. According to the findings, the geogrid improved the bearing ability of the footing and reduced settlement. The optimum geogrid dimension was three times the footing width, and three geogrid layers were optimum. The changing in footing rigidity also affects the stress and settlement behavior.

Keywords

  • Finite element
  • Strip footing
  • Geogrid
  • Response
  • Soil
Open Access

Investigation of Energy Recovery from Municipal Solid Waste: A Case Study of Al-Karak City / Jordan

Published Online: 09 Dec 2021
Page range: 610 - 620

Abstract

Abstract

Municipal solid waste (MSW) from Al-Karak city is monitored and characterized. The MSW is sorted into 14 different waste categories. In addition, the MSW is separated into several size fractions, followed by sorting and characterization. The average daily production rate of waste is 61.5 ton/day. The MSW generated per capita is estimated to be 0.55 kg/capita/day. The main input MSW comprised a modest proportion of organic content 38.8 %. Other combustible fractions are present in significant proportions, allowing the waste to be utilized for energy recovery. Refuse-derived fuels (RDFs) may be made from waste fractions > 100 mm and 50 – 100 mm.

Keywords

  • Municipal solid waste
  • Waste screening
  • Waste characterization
  • Physico-chemical properties
  • RDF
Open Access

Non-Destructive Evaluation of Asphalt Concrete Materials Performance During their Life Cycle Based on Accelerated Pavement Testing

Published Online: 09 Dec 2021
Page range: 621 - 628

Abstract

Abstract

The characteristics of asphalt concrete materials (ACM) composing the surfacing layer of a bituminous pavement must fulfil a requirement to maintain a level of operational capability demanded by national standards of a given country. ACM’s are a subject to significant stress caused by traffic load and climate conditions, this leads to changes in their physico-mechanical properties. The loss of physico-mechanical properties causes deterioration of road surface characteristics. Since these changes occur throughout the ACM’s life cycle, it is necessary to know the deterioration curves related to loading and time in mathematical terms, i.e. functions describing the initiation and progression of pavement’s defect in time. Pavement Performance Models (PPM) ascertained by non-destructive testing are used to objectively express the surface properties of pavements and their deterioration. The methodology consists of an analytical method to ascertain physico-mechanical characteristics of ACM’s and the use of experimental accelerated pavement testing (APT) facilities.

Keywords

  • Degradation
  • Pavement
  • Simulation
  • Testing
  • Unevenness
Open Access

Mechanical Properties of Concrete with Recycled Plastic Waste

Published Online: 09 Dec 2021
Page range: 629 - 643

Abstract

Abstract

Plastics are a vast group of synthetic or semi-synthetic materials that are often made of polymers. Because of their plasticity, plastics can be molded, extruded, and pressed into solid objects of different sizes. Its extensive use is due to its flexibility, as well as a number of other properties such as light weight, durability, and low manufacturing costs. The high use of plastics has resulted in an increase in solid waste, with domestic waste accounting for a significant portion of it. Since this waste is not biodegradable and takes up a lot of space, it is considered a serious environmental problem. To overcome these adverse effects, recycling plastic waste and using it in concrete can be an effective way to protect the environment. In this study, an attempt was made to experimentally evaluate the mechanical properties of concrete with recycled PET plastic wastes. The effect of this type of plastic waste was investigated by adding it in three different lengths: 22 mm, 45 mm, and a combination of both lengths 22 + 45 mm. For each length of fiber, it was added in three percentages to concrete 0.1, 0.3 and 0.5 % of cement weight. Several experiments were carried out on concrete mixtures such as slump test, compressive test, splitting tensile test, flexural test, and ultrasound pulse velocity test. The findings showed that PET waste in the form of fibers could be incorporated into concrete and achieve adequate compressive strength. When the ultrasound test results were compared to the results of previous tests, it was discovered that normal concrete containing plastic waste in the form of fibers performed exceptionally well.

Keywords

  • PET fibers
  • Experimental investigation
  • Mechanical properties
  • Ultrasound pulse velocity
  • Soil contamination
Open Access

Analysis of Dowel Action in Reinforced Concrete Beams with Shear Reinforcement

Published Online: 09 Dec 2021
Page range: 644 - 653

Abstract

Abstract

The shear transfer mechanism was examined to view the contributions of different components of shear transfer such as aggregate interlocking, dowel force and uncracked compression zone. Understanding the role of various shear transfer components with transverse reinforcement provided was complex due to traditional difficulties involved in detail assessment of accompanying kinematics during the failure. In the present paper, the issue was addressed by employing sixteen specimens and grouped under two categories representing conventional beams and beams with preformed cracks and were tested under four - point bending load with a shear span to depth ratio of 1.26 by increasing the characteristic strength of concrete. From the results obtained, empirical formulas proposed were also evaluated and it was concluded that the results were consistent and contribution of shear transfer across uncracked compression zone was maximum in shear resistance with transverse reinforcement provided. Later structural behaviour was also assessed and it was concluded that beams with preformed cracks had exhibited greater stiffness thus nullifying the effect of aggregate interlocking in shear transfer.

Keywords

  • Shear transfer
  • Preformed cracks
  • Four-point bending load
  • Shear resistance
  • Structural behavior
Open Access

Fuzzy - Based Multi - Criteria Decision Support System for Maintenance Management of Wastewater Treatment Plants

Published Online: 09 Dec 2021
Page range: 654 - 672

Abstract

Abstract

Wastewater treatment plants (WWTPs) contain a large number of components, and these components in turn require a large number of maintenance activities and high costs. In this paper, a Fuzzy-based Multi-Criteria Decision Support System (FBMCDS) model was designed based on the failure mode and effect analysis FM-EA and applied to the Rustumiya Project (RP) in Iraq. Information of the RP’s components, failure modes, applied maintenance activities and costs were collected from the documented data, site visit and face-to-face interviews as well as opinions of 44 experts. Through applying the fuzzy logic to analysis the failure modes and effects, the risk priority index (FMRPI) and total intensity (FMTI) of each failure mode ware computed. Thus, maintenance priorities and weights of the RP’s failure modes were specified. In addition, the best maintenance plan was specified based on the FMRPI-FMTI diagram that shows the importance and the type of maintenance required for each failure mode. Failure of the submersible pump has the first rank in terms of priority, while the last priority was occupied by the building failure mode, where the mechanical failure modes are of the highest importance, followed by the electrical failure modes. Finally, the construction failure modes are ranked last due to the small probability of failure. The designed model is considered an efficient tool due to the similarity of the results with the reality of the situation and the ease of reading and displaying the results. In addition, this model can be applied to other projects such as water treatment plants and irrigation projects.

Keywords

  • FMCDM
  • Wastewater treatment plants
  • Failure mode and effect analysis
  • Risk priority index
  • Total intensity
Open Access

Prediction of the Delay in the Portfolio Construction Using Naïve Bayesian Classification Algorithms

Published Online: 09 Dec 2021
Page range: 673 - 680

Abstract

Abstract

Projects suspensions are between the most insistent tasks confronted by the construction field accredited to the sector’s difficulty and its essential delay risk foundations’ interdependence. Machine learning provides a perfect group of techniques, which can attack those complex systems. The study aimed to recognize and progress a wellorganized predictive data tool to examine and learn from delay sources depend on preceding data of construction projects by using decision trees and naïve Bayesian classification algorithms. An intensive review of available data has been conducted to explore the real reasons and causes of construction project delays. The results show that the postponement of delay of interim payments is at the forefront of delay factors caused by the employer’s decision. Even the least one is to leave the job site caused by the contractor’s second part of the contract, the repeated unjustified stopping of the work at the site, without permission or notice from the client’s representatives. The developed model was applied to about 97 projects and used as a prediction model. The decision tree model shows higher accuracy in the prediction.

Keywords

  • Delay
  • Construction
  • Decision tree
  • Bayesian
  • Portfolio
Open Access

The Role of Geotechnical Monitoring at Design of Foundation Structures and their Verification – Part 2

Published Online: 09 Dec 2021
Page range: 681 - 689

Abstract

Abstract

The main aim of the article is demonstrating successful design of spread foundations of a commercial centre building, where geotechnical monitoring allows us to check design efficiency and calculate reliability in comparison with real vertical deformation of building. Introduction to the case study area and building structure and foundations was done in previously published first part of the article in which engineering geological conditions were described. There was also presented a comparison of calculated vertical settlement of selected footings with the real geodetic measurement provided during construction time till the period of two years’ operation time after completion of civil works. Geotechnical engineers do not have many opportunities to evaluate their designs, especially when everything passes successfully. Our presented case study is one of the examples, which could be evaluated from the point of view of reliability index of design adjusted with real geodetic measurement. Index of reliability of selected foundations was calculated by deterministic probability methods. In order to evaluate thousands of statistical data combinations, programing tool in Python language was developed for batch processing calculation of vertical displacement of foundation in Plaxis software. Discussion part of the article contains the actual state of reliability theory in structural standards in Europe.

Keywords

  • Geotechnical monitoring
  • Reliability index
  • Batch processing
  • 3D FEM model
  • Probability of failure
Open Access

Sleep Disturbance and Noise Annoyance and Environmental Noise Exposure in Residents of Two Major Slovakian Cities

Published Online: 09 Dec 2021
Page range: 690 - 697

Abstract

Abstract

The significant growth in traffic density in Slovakia, combined with the country’s economic change, has resulted in new environmental noise issues, particularly in road traffic noise. The objective of this study was to assess and evaluate the impact of environmental noise on the psychosocial well-being of young healthy individuals in the two main Slovak cities of Bratislava and Kosice. To assess noise annoyance, interference with activities, and sleep disturbance, the ICBEN (The International Commission on the Biological Effects of Noise) anonymous validated “Noise annoyance questionnaire” was applied; noise levels were objectified by direct measurements using a sound level analyzer with a frequency analysis module. Young individuals between the ages of 20 and 30 were interviewed in Bratislava (533 respondents, 155 males) and Kosice (355 respondents, 111 males). The majority of the respondents in both cities were exposed to medium levels of road traffic noise LAeq≥ 60 dB. In Bratislava, 27.82 % of respondents resided in the higher noise exposure category LAeq≥ 70 dB, while in Kosice, 39.9 % resided in the lower noise exposure category LAeq< 50 dB. Road traffic noise annoys respondents in the higher noise exposure category in Bratislava 63.51 %, and even in the lower noise exposure category in Kosice, it interferes with reading and mental work, sleep and falling asleep 46.51 %. The study has identified traffic noise as an environmental issue in large cities, emphasizing the need for vulnerable individuals to be protected, particularly at night.

Keywords

  • Road traffic noise
  • Questionnaire
  • Young adults
  • Noise annoyance
  • Sleep disturbance
Open Access

Proportional and Structural Analysis of the Historical Truss of Church of St. Bartholomew in Mladočov

Published Online: 09 Dec 2021
Page range: 698 - 705

Abstract

Abstract

The researched truss of the Gothic Church of St. Bartholomew in the village of Mladočov is one of the examples of the use of the historical Czech length units of measurement; in this case, the Gothic and Baroque part of it. At the same time, it analyzes the proportional relationships between the individual elements of the truss. The structural analysis in relation to current standards points to the fact that the original design of the structure based on geometrical and proportional principles satisfy the reliability conditions defined by current European standards for structural design.

Keywords

  • Roof
  • Proportion
  • Historical length unit
  • Historical truss
  • Structural analysis
Open Access

Numerical Modelling of Soil-Nail and Secant Pile in Plaxis 2D: A Case Study of Tomb of Jam Nizam-al-Din Samoo, Makkli Thatta

Published Online: 09 Dec 2021
Page range: 706 - 717

Abstract

Abstract

The majority of historical heritage structures of Makli, Thatta require rehabilitation. As the Tomb of Jam Nizam-al-Din Samoo is near the slope’s edge, the settlement increased due to slope degradation. This study aims to investigate the effect of structural elements such as secant pile and structural nails on the settlement of Tomb. From this study, it was observed that with the installation of secant piles on the slope, Tomb’s settlement can be reduced considerably; moreover, the anchors did not have an appreciable role in the settlement. The secant pile of 12 m sufficient to reduce settlement. This will be economical and easy approach as compare to the retaining wall. The Factor of safety (FOS) reduced from 1.36 to 1.10 with increase of slope from 45 to 35. The FOS of slope also increased with the installation of nails from east side of slope. The will reduce the chances of slope failure and consequently the tilting/collapse of Tomb.

Keywords

  • Numerical modelling
  • Plaxis 2D
  • Secant pile
  • Factor of safety
  • Rehabilitation of old structure
35 Articles
Open Access

A Generating - Absorbing Boundary Condition Applied to Wave - Current Interactions Using the Method of Fundamental Solutions

Published Online: 09 Dec 2021
Page range: 343 - 352

Abstract

Abstract

The purpose of this work is to study the feasibility and efficiency of Generating Absorbing Boundary Conditions (GABCs), applied to wave-current interactions using the Method of Fundamental Solutions (MFS) as radial basis function, the problem is solved by collocation method. The objective is modeling wave-current interactions phenomena applied in a Numerical Wave Tank (NWT) where the flow is described within the potential theory, using a condition without resorting to the sponge layers on the boundaries. To check the feasibility and efficiency of GABCs presented in this paper, we verify accurately the numerical solutions by comparing the numerical solutions with the analytical ones. Further, we check the accuracy of numerical solutions by trying a different number of nodes. Thereafter, we evaluate the influence of different aspects of current (coplanar current, without current, and opposing current) on the wave properties. As an application, we take into account the generating-absorbing boundary conditions GABCs in a computational domain with a wavy downstream wall to confirm the efficiency of the adopted numerical boundary condition.

Keywords

  • Wave-current interactions
  • Method of fundamental solutions
  • Generating-absorbing boundary conditions
Open Access

Measurements Result Analysis of Deformation Characteristics of Transition Zones on the Modernized Line Púchov – Považská Teplá

Published Online: 09 Dec 2021
Page range: 353 - 360

Abstract

Abstract

The current trend in Europe and worldwide is to support the development of so-called green transport, characterized by lower energy consumption and lower CO2 emissions. Rail transport meets these conditions and therefore considerable funding is being spent not only on the construction of high-speed lines but also on the modernization of existing railways, especially those forming part of the trans-European corridors.

Three corridors of the basic TEN-T network pass through the territory of the Slovak Republic. In the Žilina Region, there are two corridors, Balt – Adriatic and Rhine – Danube, with a common section Púchov – Žilina, which is currently being modernized. It is a known fact that railway lines often show a greater degree of degradation in the transition zones between the earthwork and the structures of sub-ballast layers. Since every railway infrastructure management aims to minimize maintenance costs, while ensuring the safety and comfort of passengers, it is necessary to pay increased attention also to transiton zones. In this context, the presented paper deals with the analysis of values of deformation characteristics on the modernized line section Púchov – Považská Teplá, which is characterized by several bridge structures and tunnels. The values were obtained within the quality inspection of work in transition zones located between the earthwork and the structures of sub-ballast layers.

Keywords

  • Railway track
  • Railway line modernization
  • Transition zone
  • Deformation resistance
  • Static modulus of deformation
Open Access

Urban Heat Island: Summer Outdoor Climate Measurement Within the University Campus and City

Published Online: 09 Dec 2021
Page range: 361 - 370

Abstract

Abstract

Work of researchers from various areas is focused on problematics of urban heat islands. Its importance is rising with the global climate change. The difference of the air temperatures within the area can be also caused by the measurement error. Usual error is not the accuracy of the sensor, but the radiation shield or location of the weather station. In this case, averaged difference can be up to 80 %. Difference of temperatures between the weather stations within the analyzed area can vary from 0.2 up to 6 °C. Difference depends usual on the size of the city and the location influenced by the surrounding geomorphology. In this paper three different radiation shields are compared which influenced the measurement and analyzed are also the results from four different weather stations, two of them are within the University of Zilina campus. One of them is placed on the roof, which is a usual location for the solar radiation measurement; the second one is placed on the grass land at the end of the campus. Other two stations belong to the national weather institute. Comparison is made for two very hot days of August 2020. Averaged difference was 0.3 °C for the whole month and 0.5 °C for selected days.

Keywords

  • Climate change
  • Mitigation
  • Urban heat island
  • Weather station
  • Radiation shield
Open Access

Developing A Mathematical Model for Planning Repetitive Construction Projects By Using Support Vector Machine Technique

Published Online: 09 Dec 2021
Page range: 371 - 379

Abstract

Abstract

Each project management system aims to complete the project within its identified objectives: budget, time, and quality. It is achieving the project within the defined deadline that required careful scheduling, that be attained early. Due to the nature of unique repetitive construction projects, time contingency and project uncertainty are necessary for accurate scheduling. It should be integrated and flexible to accommodate the changes without adversely affecting the construction project’s total completion time. Repetitive planning and scheduling methods are more effective and essential. However, they need continuous development because of the evolution of execution methods, essentially based on the repetitive construction projects’ composition of identical production units. This study develops a mathematical model to forecast repetitive construction projects using the Support Vector Machine (SVM) technique. The software (WEKA 3.9.1©2016) has been used in the process of developing the mathematical model. The number of factors affecting the planning and scheduling of the repetitive projects has been identified through a questionnaire that analyzed its results using SPSS V22 software. Three accuracy measurements, correlation coefficient (R), Root Mean Square Error (RMSE) and Mean Absolute Error (MAE), were used to check the mathematical model and to compare the actual values with predicted values. The results showed that the SVM technique was more precise than those calculated by the conventional methods and was found the best generalization with R 97 %, MAE 3.6 %, and RMSE 7 %.

Keywords

  • Project management
  • Repetitive constriction project
  • Support Vector Machine
  • Planning and scheduling
Open Access

Application of Compact Piping Sedimentation Unit as Pretreatment for Ultrafiltration Plant

Published Online: 09 Dec 2021
Page range: 380 - 386

Abstract

Abstract

The study aimed to create a compact pretreatment unit before the ultrafiltration modules. This unit targeted to improve the inlet water quality to meet the average values of the feed water quality required for the ultrafiltration plants according to the manufacturer. The used unit in this study was a pipe worked as a sedimentation unit with inclined plates to apply the plate settler technology. The suitability of using this unit was determined by using varied water sources with different Total Suspended Solids (TSS) concentrations and different retention times. The removal efficiencies for the low TSS water source reached 96.47 %, 82.94 %, 64.80 % & 30.59 % with retention time 30 minutes, 15 minutes, 5 minutes & 20 seconds respectively. For the medium TSS water source at the same retention times, the removal efficiencies reached 97.33 %, 92.87 %, 86.10 % & 63.89 %. For the high TSS water source, the removal efficiencies reached 98.64 %, 93.86 %, 87.51 % & 76.23 %. These results make the sedimentation unit able to work as an effective pretreatment unit for the ultrafiltration units for all water sources.

Keywords

  • Water treatment
  • Sedimentation
  • Plate settler
  • Pretreatment
  • Ultrafiltration
Open Access

A Waste Bank Based on the 3R Concept: Student Interest in Waste Management at the Department of Economics, University of Brawijaya

Published Online: 09 Dec 2021
Page range: 387 - 394

Abstract

Abstract

The establishment of a waste bank could be a social engineering tool for changing the mindset of students. This waste bank can be managed and made useful via the so-called “3R” concept (reduce, reuse, and recycle), which is the main principle used by waste banks. This study aimed to determine students’ interest in managing waste. The sample comprised three classes of students who are enrolled in natural resource economics courses from the Economics and Business Faculty of the University of Brawijaya. Each class has 31 students. Quantitative multivariate research was performed using a Likert scale. Validity and reliability tests were performed for behavioral control and to manage waste variables. Data analysis was used Multivariate analysis, and Bartlett’s test of sphericity was used for significance of the data. Results show that the behavioral control variable was positively correlated with and was influenced by the intention to manage waste or the interest in managing waste. We suggested that waste bank systems—in which waste can be exchanged for food or other products—could be applied in campus environments and that a waste bank should be established in the Faculty of Economics and Business of the University of Brawijaya.

Keywords

  • 3R concept
  • Interest in managing waste
  • Social engineering
  • Waste bank
Open Access

The Renewable Energy Sources for Municipal Wastewater Processes in Thailand: A Case Study of the Nonthaburi Wastewater Treatment Plant

Published Online: 09 Dec 2021
Page range: 395 - 400

Abstract

Abstract

There are 101 municipal wastewater treatment plants in Thailand supplied with electricity and cannot collect wastewater treatment fees. Alternative sources of energy for municipal wastewater treatment would reduce the electricity costs and future fossil energy uses. The Nonthaburi wastewater treatment plant (WWTP) is located in the Northwest of Bangkok and selected due to its available data. The solar energy source is applied to the Nonthaburi WWTP due to the light intensity and the area to install. By comparing to the wind and the biogas sources, the wind speed and the sludge production are not sufficient, respectively. Besides the estimated installation cost of the solar-cell panels among three companies, the NPV of 25 years and the IRR of three percent rate, the area required for installation is an affecting factor for the plant consideration.

Keywords

  • Biogas
  • Net present value
  • Internal rate of return
  • Solar panel
  • Wind energy
Open Access

Estimation of Mechanical Properties and Mass Density of Al-Malwiya Masonry

Published Online: 09 Dec 2021
Page range: 401 - 408

Abstract

Abstract

This paper presents the first estimation for the mechanical properties and the mass density of the masonry of Al-Malwiya heritage minaret. Many approaches are investigated in order to estimate the modulus of elasticity, shear modulus, Poisson’s ratio, and the mass density for this historic masonry. The mechanical properties are estimated by using empirical formulas and analytical equations, while the mass density is estimated after carrying out experimental tests for the extracted samples of the historic mortar. The estimated properties showed relatively low values compared with the newly constructed masonries, but they were interpreted as reasonable for such a historic construction.

Keywords

  • Masonry properties
  • Masonry estimation
  • Heritage masonry
  • Empirical formulas
  • Al-Malwiya
Open Access

Impact of Turbulence Models of Wind Pressure on two Buildings with Atypical Cross-Sections

Published Online: 09 Dec 2021
Page range: 409 - 419

Abstract

Abstract

The article deals with the numerical analysis of the wind pressure distribution on a group of two high-rise buildings of different shape for different wind directions. The first building has the shape of a circular cylinder and the second was created by a combination of semicircles and a longitudinal member. The floor plan of the second building was similar to the letter S. The simulations were realized as 3D steady RANS. CFD results were compared with experimental measurements in the wind tunnel of the Slovak University of Technology in Bratislava. The results were processed using statistical methods such as correlation coefficient, fractional bias and fraction of data within a factor of 1.3, which determined the most suitable CFD model. The purpose of the present article was to verify the distribution of the external pressure coefficient on scale models at a scale of 1:350, which are located in the Atmospheric Surface Layer (ASL). In numerical modeling, the most important thing was to ensure similarity with the flow in the experimental Atmospheric Boundary Layer (ABL) and with the flow around the models. SST kω was evaluated as the most suitable turbulent model for the given type of problem. Turbulent models had a decisive influence on the overall distribution of external wind pressures on objects. The results showed that the most suitable orientation of the objects in terms of the external wind pressure coefficient is 0°, when the cylinder produced a shielding effect, with min mean cpe = −0.786. The most unfavorable wind effects were shown by the wind direction of 90° and 135° with the value min mean cpe = −1.361.

Keywords

  • Atypical cross-section
  • External pressure coefficient
  • Wind tunnel
  • Computational fluid dynamics
Open Access

Fuzzy Finite Element Analysis for Static Responses of Plane Structures

Published Online: 09 Dec 2021
Page range: 420 - 437

Abstract

Abstract

In this paper, a fuzzy finite element algorithm is investigated to determine static responses of plane structures. This algorithm concerns finite element method, fuzzy sets theory, and response surface method. Firstly, the notion of a standardized triangular fuzzy number is developed and utilized to replace original fuzzy numbers in the surrogate models. Then, the error estimations between the training and the test sets are performed to select the suitable response surface model amongst the regression models. Lastly, a good performance combination of complete and non-complete quadratic polynomial regression models is proposed to define the responses of structures. The merits of the proposed algorithm are illustrated via numerical examples.

Keywords

  • Fuzzy sets theory
  • Fuzzy finite element
  • Response surface method
  • Possibility-probability transformations
  • Generalized similarity measure
Open Access

Investigating the Critical Success Factors for Water Supply Projects: Case of Iraq

Published Online: 09 Dec 2021
Page range: 438 - 449

Abstract

Abstract

Water supply projects (WSP) requires high plan information, specialized capabilities, capable human resources, and high administrative capacity. However, in the developing countries, particularly in Iraq, these projects experience a lack of a large number of these necessities, which shows the need to identify the critical success factors (CSFs). Accordingly, the objectives of this research are to investigate the CSFs for WSP and their significance among the construction (public and private) and education sectors. To achieve this, first we have carried out a comprehensive literature review of the CSFs for WSP. Second, we administrated a questionnaire survey to 260 construction experts working in the construction and education sectors. It was found that the top five important success factors for water supply projects in Iraq were a stable political environment; sustainable construction legislation and regulation; effective risk management practices; well-organized and committed project teams; and government decisions through the project life cycle. The survey results did not indicate major differences in the perception of the experts. The findings are focused to assist construction practitioners’ gain better understanding on the important areas to achieve project set objectives.

Keywords

  • Critical Success Factors (CSFs)
  • Construction projects
  • Water supply projects
  • Infrastructure development
  • Iraq projects
Open Access

Formulation of a Basic Constitutive Model for Fine - Grained Soils Using the Hypoplastic Framework

Published Online: 09 Dec 2021
Page range: 450 - 455

Abstract

Abstract

A hypoplastic approach to constitutive modelling was developed by Kolymbas 1996 considering a non-linear tensor function in the form of strain and stress rate. However, the implicit formulation of the hypoplastic model with indirect material parameters severely limits its applicability to real-world geotechnical problems. In many cases, the numerical analysis of geotechnical problems relies on simple elastoplastic constitutive models that cannot model a wide range of soil response aspects. One promising paradigm of constitutive modelling in geotechnics is hypoplasticity, but many of the hypoplastic models belong to advanced models. In the article, we present the simple hypoplastic model as an alternative to the widely used Mohr-Coulomb elastoplastic model.

Keywords

  • Constitutive modelling
  • Hypoplasticity
  • Soil stiffness
  • Finite element method
  • Foundation settlement
Open Access

Modelling of Traffic Noise Along Urban Corridor: A Case Study of Amman

Published Online: 09 Dec 2021
Page range: 456 - 464

Abstract

Abstract

Noise became one of the main environmental indicators of the quality of urban life. The aim of this study was to develop a traffic noise model for an arterial road in Amman, the capital of Jordan, which was being subjected to a persistent increase in traffic and its related issues. The characteristics of the traffic and its relevant noise were analysed to develop a noise prediction model using an adaptive neuro-fuzzy inference system (ANFIS). A geographic information system (GIS) was then implemented to model the current noise along the arterial road. The results of ANFIS model showed that traffic delays and the percentage of heavy vehicles were the main causes of traffic noise generation within the urban area. However, the developed ANFIS model can simulate traffic noise with a relatively low root mean square error. Furthermore, this study will help to improve the perception about traffic noise and its development along arterial roads.

Keywords

  • Bus line noise
  • Noise measurement
  • Noise modelling
  • Noise pollution
  • Traffic impacts
Open Access

Evaluating Flexural Strength of RC Beams Strengthened by CFRP using Different Analytical Models

Published Online: 09 Dec 2021
Page range: 465 - 475

Abstract

Abstract

This paper deals with reinforced concrete beams strengthened by CFRP in flexure. The debonding between CFRP and the surface of the beam is the main problem. Many researchers around the world have made extensive efforts to study the phenomenon of debonding for efficient applications. Based on these efforts and different related field applications, code previsions and various models have been proposed for predicting debonding failure. Two code previsions and three typical models are presented in the current study. ACI-440.2R 17, CNR-DT 200 R1/2013, Said and Wu, Lu et al., and Teng et al. have been used to estimate the flexural strength of RC beams strengthened by CFRP with and without grooves. Test results of eleven flexural beams strengthened by CFRP sheet/laminate using externally bonded reinforcement (EBR) and externally bonded reinforcement on grooves (EBROG) methods were used in the current paper. The performance and accuracy of each model were evaluated based on these test results. Most of the prediction models that used in this study give a closer prediction of the flexural strength of beams strengthened by EBR compared to that of the beams strengthened by EBROG. Finally, the prediction results of CNR-DT 200 R1/2013 were the most accurate and approval with test results compared with other models in the current study

Keywords

  • CFRP
  • Strengthening
  • Analytical models
  • EBROG
  • Reinforced concrete beam
Open Access

Flexural Strength Estimation for Hollow Cross-Section Simply Supported UHPC Beams

Published Online: 09 Dec 2021
Page range: 476 - 484

Abstract

Abstract

The hollow structural elements occupy a great deal of researchers’ interest due to the possibility of losing their weights and maintaining or developing their resistances especially when increasing both compressive and tensile strength of modern materials. The flexural strength based on the forces balance and stain compatibility was derived. Nine beams of Ultra High Performance concrete (UHPC) and conventional reinforced steel bars were casted. Several parameters were taken which are the thickness of the concrete top flange, thickness of the concrete bottom flange, depth of the longitudinal hollow and the ratio of the longitudinal reinforcing steel. By comp aring the practical and theoretical results, the proposed flexural strength provided a safety factor of one-fifth against the experimental collected data. The ultimate flexural force developed up 260 % when increasing the reinforced steel area 4.6 times and 230 % comparing with the solid beam. Many aspect ratios were also mentioned that keep the strength in developing.

Keywords

  • Hollow cross-section
  • Flexural strength
  • Strain compatibility
  • Concrete flange
  • UHPC
Open Access

Mitigation Techniques for Interior Radon in Refurbishment Work in High Radiation Areas of Galicia: An Experimental Model to Test Building Solutions

Published Online: 09 Dec 2021
Page range: 485 - 499

Abstract

Abstract

Radon is a naturally occurring radioactive gas, which tends to accumulate inside built structures. It is therefore necessary to include techniques to mitigate radon concentration during refurbishing work. The aim of this study is to assess the effectiveness of a number of mitigation techniques, under real conditions, to determine which is most suitable, in each case, for use in rebuilding solutions. The methodology consisted in performing four experimental tests on mitigation strategies recommended by the Código Técnico de la Edificación (Technical Building Code) (CTE-DB-HS6) and by the Government of the Autonomous Community of Galicia, (Xunta de Galicia, 2018). The concentration was measured with three different systems: radon in soil at 80 cm, passive detectors to confirm mean concentration, and continuous monitoring by devices calibrated at the LaRUC Laboratory of the University of Cantabria, in order to compare the results of the tests. The experiments were carried out in premises located in a high radiation area in Arteixo (La Coruña, Spain). Four experimental models were designed, corresponding to each of the building solutions under study, and tested over a period of 16 days in two repeated series of trials. The results obtained show that, of the different strategies tested, pressurising the living space achieves an efficient reduction of the radon concentration with a significant simplicity of construction. This solution, compatible with the minimal intervention and reversibility principles stablished in the charters of Venice, Krakovia and Nara, is shown to be especially useful when work is carried out on structures considered to be part of protected heritage.

Keywords

  • Radon
  • Heritage
  • Mitigation
  • Refurbishment
  • Air quality
Open Access

Analysis of Geogrid Reinforced Structures with a Passive Facing System Using Different Computational Methods

Published Online: 09 Dec 2021
Page range: 500 - 512

Abstract

Abstract

The article deals with designing and analysing a wrapped geogrid reinforced structure (GRS) with a passive facing system. The analysis has been done using analytical calculation and numerical modelling. The analytical calculations were executed using FINE Geo5 geotechnical software, and numerical modelling was executed using Plaxis 2D software. The analysis is focused mainly on comparing tension forces in geogrids and the stability of the reinforced embankment determined using both computational methods. The deformation analysis was done only using numerical modelling. The numerical modelling allowed for a more detailed analysis of the wrapped GRS. Each construction phase was modelled step by step according to an actual construction procedure. Two complex road embankments supported by GRS were modelled and analysed. The first model consisted of three GRS, which not affected each other. In the second model, the GRS at each side of the embankment influenced each other. The analysis results showed that tension forces in geogrids, determined using both computational methods, can differ significantly from each other. The stability of the reinforced embankment determined using numerical modelling was within the range of 0.87 – 1.22 of the stability determined using analytical calculation. The numerical modelling results showed that the final horizontal deformation of the passive facing is about 2.8 – 3.8 times smaller than the deformation of the wrapped GRS, which occurs during the construction of the embankment.

Keywords

  • Geogrid reinforced structure
  • Wrapped facing
  • Passive earth system facing
  • Reinforced earth structure
  • Mechanically stabilized earth wall
Open Access

Effects of Induction-Furnace Slag on Strength Properties of Self-Compacting Concrete

Published Online: 09 Dec 2021
Page range: 513 - 527

Abstract

Abstract

Indiscriminate waste disposal poses a severe environmental challenge globally. Recycling of industrial wastes for concrete production is currently the utmost effective way of managing wastes for a cleaner environment and sustainable products. This study investigates the strength characteristics of self-compacting concrete (SCC) containing induction furnace slag (IFS) as a supplementary cementitious material (SCM). The materials utilized include 42.5R Portland cement, induction furnace slag as an SCM ranging from 0 to 50 % by cement weight at 10 % interval, river sand, granite, water and superplasticizer. The fresh properties were tested for filling ability, passing ability and segregation resistance, the strength characteristics measured include compressive strength, splitting tensile strength, flexural strength and Schmidt/rebound number. The oxide compositions and microstructural analysis of SCC were investigated using x-ray fluorescence analyser (XRF) and scanning electron microscopy equipped with energy-dispersive x-ray spectroscopy (SEM-EDS), respectively. Empirical correlations were statistically analyzed using MS-Excel tool. The filling ability characteristic was determined via both the slump flow test and the T50cm slump flow time test. Moreover, the passing ability characteristic was determined using L-Box test. The segregation resistance characteristic was determined using V-funnel at T5minutes test. The results of the fresh properties showed a reduction in the slump flow with increasing IFS content. On the other hand, the T50cm slump flow increased with increasing IFS content. Furthermore, the L-Box decreased with higher IFS content. On the contrary, the V-funnel at T5minutes increased considerably with greater IFS content. The strength test results revealed that the strength properties increased to 20 % IFS, with a value of 66.79 N/mm2 compressive strength at 56 days, giving a rise of 12.61 % over the control. The SCC microstructural examinations revealed the amorphous and better interface structures with increasing IFS content in the mix. The empirical correlations revealed that linear relationships exist among the measured responses (fresh and strength properties). Ultimately, IFS could be utilized as a sustainable material in producing self-compacting concrete.

Keywords

  • Self-compacting concrete
  • Concrete
  • Strength
  • Induction furnace slag
  • Supplementary cementitious materials
Open Access

The Effect of External Blinds on Selected Parameters of the Indoor Environment of an office Building

Published Online: 09 Dec 2021
Page range: 528 - 541

Abstract

Abstract

This contribution focuses on the indoor environmental quality in summer due to overheating of the interior of a west-facing office, since buildings designed in passive standard do not have a problem in the winter heating season but have a problem with cooling in the summer season. Therefore, the article focuses on the effect of external blinds on the indoor environmental parameters.

Keywords

  • Office building
  • External blinds
  • Thermal comfort
  • Indoor temperatures
  • Summer measurements
Open Access

Green Building Materials Based on Waste Filler and Binder

Published Online: 09 Dec 2021
Page range: 542 - 548

Abstract

Abstract

This study is aimed at the application of alternative binder (AB) into bio-aggregate-based composite. The technically important parameters (density, thermal conductivity, water absorption and compressive strength) of 28, 60 and 90 days hardened green composites containing chemically and physico-chemically modified hemp hurds (HH) with AB compared to the Portland cement (PC) are presented. Testing of two reference bio-composites with original HH confirmed higher values of compressive strength and thermal conductivity unlike water absorption for all hardened specimens based on alternative binder (MgO-cement) compared to conventional PC. Changes in the final properties of hardened bio-composites were affected by treatment process of organic filler and alkaline nature of MgO-cement. The combination of purified HH by ultrasound treatment and AB appears to be promising for preparation of bio-based composite material with better properties compared to PC. In this paper, other option of the preparation of bio-composite system based on original (non-treated) filler and binder consisting of optimal activated MgO and silica fume is presented.

Keywords

  • Green composite
  • Bio-aggregate
  • Hemp hurds
  • MgO-cement
  • Silica fume
Open Access

Analysis of a Fire in an Apartment of Timber Building Depending on the Ventilation Parameter

Published Online: 09 Dec 2021
Page range: 549 - 558

Abstract

Abstract

In modern buildings are also currently used the wooden-based construction systems. A wide range of uses the timber constructions in apartment buildings is a vision of the countries of the EU. The use of timber and the other recyclable materials in apartment buildings creates the precondition for the implementation, operation and disposal of environmental impacts of the EU 2020 Strategy. In the long term is important to transform the construction of buildings to a sustainable standard, which the application of wood in construction supports. Currently, the fire height of timber-based residential construction in most EU countries is limited to 5 storeys, provided that the timber structures are fire-protected. This paper deals with the influence of the ventilation parameter in the time and the intensity of the gas temperature during a fire in a model of an apartment building with a timber load-bearing structure. The load-bearing structure is made of CLT panels, with a mixed structural unit, i.e. with fire-resistant cladding of all load-bearing and fire-dividing structures. FDS (Fire Dynamics Simulator - PyroSim software) is used for dynamic simulations of fire in the model apartment.

Keywords

  • Fire safety
  • Timber building
  • FDS
  • Fire
  • Parametric fire
Open Access

The Correlation Between the Statistical Pass-By Index Values and the Total Number of Vehicle Passes

Published Online: 09 Dec 2021
Page range: 559 - 571

Abstract

Abstract

In this study, the traffic noise degradation in asphalt pavements was analysed using the ‘Statistical Pass-By method’. The sound levels of two surfaces were monitored during 9 and 12 years of service, respectively. By comparing the dependencies of the maximum A-weighted sound pressure level on logarithm of vehicle velocity, an increase in the sound level was found at all recorded speeds. Following an analysis of sound levels, as combined with the statistical pass-by index (SPBI) calculated versus age (expressed in vehicles), it was determined that the noise is an increasing power function of SPBI values on vehicle passes, based on an approximation of noise level adjustment to a reference temperature of 20 °C (using a coefficient of 0.06 for asphalt concrete surface AC11 and - 0.03 for mastic asphalt SMA11). The adjusted traffic noise degradation model showed that the SMA11 surface has a higher resistance to acoustic degradation than AC11 surface.

Keywords

  • Traffic
  • Noise
  • SPBI
  • Asphalt surface
  • Ageing
Open Access

Assessment of the Indoor Environment in the Intelligent Building

Published Online: 09 Dec 2021
Page range: 572 - 582

Abstract

Abstract

Currently, thermal comfort and indoor air quality are essential elements in designing modern and intelligent buildings or improving existing ones, so that they would provide proper indoor conditions. The article focuses on the thermal sensations of the students of Kielce University of Technology and determining whether the given parameters of the internal environment contributed to their well-being. 164 people aged 16 - 24 participated in the study, which was conducted with the use of a microclimate meter and questionnaires. It turned out that the temperature range from 19.3 °C – 27.6 °C is acceptable and comfortable for nearly 78% of people. As a result of further analysis, it turned out that the research group definitely prefers and feels better in colder temperatures.

Keywords

  • Thermal comfort
  • Thermal sensations
  • Relative humidity
  • Indoor environment
  • Educational building
Open Access

Role of Fly Ash on Strength Properties of Rejuvenated Soil Cement for Pavement Materials

Published Online: 09 Dec 2021
Page range: 583 - 596

Abstract

Abstract

Stabilization with cement is the most commonly used technique for the improvement of soil physical, mechanical, and engineering properties. This research reported on the properties of the rejuvenation for recycled soil cement with incorporation of fly ash (FA). The study showed that the specific gravity of Rejuvenated Soil Cement (RSC) decreased with increasing FA. The free swell ratio and linear shrinkage of RSC were significantly decreased with the increase in FA. The maximum dry unit weight of RSC increased with increasing FA up to the optimum FA content of 20 – 25 %. The optimum water content in compaction was relatively constant with the increase in FA. Particularly, the strength improvement in active zone of FA-RSC was influenced by several factors viz., compaction, packing, rehydration, and pozzolanic reaction. As a result, the unconfined compressive strength (UCS) of RSC increased with increase in FA and curing time. This research clearly showed that the rejuvenation of soil-cement with FA as additive was successful. It was also shown that the normalized UCSs of RSC at various curing times could be used to predict the UCSs at 7 and 28 days.

Keywords

  • Rejuvenated soil cement
  • Pozzolanic reaction
  • Rehydration effect
  • Unconfined compressive strength
  • Secant modulus of elasticity
Open Access

The Behavior of Strip Footing Resting on Soil Strengthened with Geogrid

Published Online: 09 Dec 2021
Page range: 597 - 609

Abstract

Abstract

The soil in Iraq has a low load carrying or bearing capacity and high deflections or settlement because of the applied loads. The use of strip footing as a foundation to support different kinds of heavy structures has become necessary nowadays through solving such problems by using geogrid. This soil improvement technique is widely used all over the world. In this paper, the bearing capacity and settlements were calculated using finite elements and analytical models for strip footing resting on different kinds of soil. The study parameters are footing rigidity, the number of layers in a geogrid, the dimension of geogrid, and spacing of geogrid layers. According to the findings, the geogrid improved the bearing ability of the footing and reduced settlement. The optimum geogrid dimension was three times the footing width, and three geogrid layers were optimum. The changing in footing rigidity also affects the stress and settlement behavior.

Keywords

  • Finite element
  • Strip footing
  • Geogrid
  • Response
  • Soil
Open Access

Investigation of Energy Recovery from Municipal Solid Waste: A Case Study of Al-Karak City / Jordan

Published Online: 09 Dec 2021
Page range: 610 - 620

Abstract

Abstract

Municipal solid waste (MSW) from Al-Karak city is monitored and characterized. The MSW is sorted into 14 different waste categories. In addition, the MSW is separated into several size fractions, followed by sorting and characterization. The average daily production rate of waste is 61.5 ton/day. The MSW generated per capita is estimated to be 0.55 kg/capita/day. The main input MSW comprised a modest proportion of organic content 38.8 %. Other combustible fractions are present in significant proportions, allowing the waste to be utilized for energy recovery. Refuse-derived fuels (RDFs) may be made from waste fractions > 100 mm and 50 – 100 mm.

Keywords

  • Municipal solid waste
  • Waste screening
  • Waste characterization
  • Physico-chemical properties
  • RDF
Open Access

Non-Destructive Evaluation of Asphalt Concrete Materials Performance During their Life Cycle Based on Accelerated Pavement Testing

Published Online: 09 Dec 2021
Page range: 621 - 628

Abstract

Abstract

The characteristics of asphalt concrete materials (ACM) composing the surfacing layer of a bituminous pavement must fulfil a requirement to maintain a level of operational capability demanded by national standards of a given country. ACM’s are a subject to significant stress caused by traffic load and climate conditions, this leads to changes in their physico-mechanical properties. The loss of physico-mechanical properties causes deterioration of road surface characteristics. Since these changes occur throughout the ACM’s life cycle, it is necessary to know the deterioration curves related to loading and time in mathematical terms, i.e. functions describing the initiation and progression of pavement’s defect in time. Pavement Performance Models (PPM) ascertained by non-destructive testing are used to objectively express the surface properties of pavements and their deterioration. The methodology consists of an analytical method to ascertain physico-mechanical characteristics of ACM’s and the use of experimental accelerated pavement testing (APT) facilities.

Keywords

  • Degradation
  • Pavement
  • Simulation
  • Testing
  • Unevenness
Open Access

Mechanical Properties of Concrete with Recycled Plastic Waste

Published Online: 09 Dec 2021
Page range: 629 - 643

Abstract

Abstract

Plastics are a vast group of synthetic or semi-synthetic materials that are often made of polymers. Because of their plasticity, plastics can be molded, extruded, and pressed into solid objects of different sizes. Its extensive use is due to its flexibility, as well as a number of other properties such as light weight, durability, and low manufacturing costs. The high use of plastics has resulted in an increase in solid waste, with domestic waste accounting for a significant portion of it. Since this waste is not biodegradable and takes up a lot of space, it is considered a serious environmental problem. To overcome these adverse effects, recycling plastic waste and using it in concrete can be an effective way to protect the environment. In this study, an attempt was made to experimentally evaluate the mechanical properties of concrete with recycled PET plastic wastes. The effect of this type of plastic waste was investigated by adding it in three different lengths: 22 mm, 45 mm, and a combination of both lengths 22 + 45 mm. For each length of fiber, it was added in three percentages to concrete 0.1, 0.3 and 0.5 % of cement weight. Several experiments were carried out on concrete mixtures such as slump test, compressive test, splitting tensile test, flexural test, and ultrasound pulse velocity test. The findings showed that PET waste in the form of fibers could be incorporated into concrete and achieve adequate compressive strength. When the ultrasound test results were compared to the results of previous tests, it was discovered that normal concrete containing plastic waste in the form of fibers performed exceptionally well.

Keywords

  • PET fibers
  • Experimental investigation
  • Mechanical properties
  • Ultrasound pulse velocity
  • Soil contamination
Open Access

Analysis of Dowel Action in Reinforced Concrete Beams with Shear Reinforcement

Published Online: 09 Dec 2021
Page range: 644 - 653

Abstract

Abstract

The shear transfer mechanism was examined to view the contributions of different components of shear transfer such as aggregate interlocking, dowel force and uncracked compression zone. Understanding the role of various shear transfer components with transverse reinforcement provided was complex due to traditional difficulties involved in detail assessment of accompanying kinematics during the failure. In the present paper, the issue was addressed by employing sixteen specimens and grouped under two categories representing conventional beams and beams with preformed cracks and were tested under four - point bending load with a shear span to depth ratio of 1.26 by increasing the characteristic strength of concrete. From the results obtained, empirical formulas proposed were also evaluated and it was concluded that the results were consistent and contribution of shear transfer across uncracked compression zone was maximum in shear resistance with transverse reinforcement provided. Later structural behaviour was also assessed and it was concluded that beams with preformed cracks had exhibited greater stiffness thus nullifying the effect of aggregate interlocking in shear transfer.

Keywords

  • Shear transfer
  • Preformed cracks
  • Four-point bending load
  • Shear resistance
  • Structural behavior
Open Access

Fuzzy - Based Multi - Criteria Decision Support System for Maintenance Management of Wastewater Treatment Plants

Published Online: 09 Dec 2021
Page range: 654 - 672

Abstract

Abstract

Wastewater treatment plants (WWTPs) contain a large number of components, and these components in turn require a large number of maintenance activities and high costs. In this paper, a Fuzzy-based Multi-Criteria Decision Support System (FBMCDS) model was designed based on the failure mode and effect analysis FM-EA and applied to the Rustumiya Project (RP) in Iraq. Information of the RP’s components, failure modes, applied maintenance activities and costs were collected from the documented data, site visit and face-to-face interviews as well as opinions of 44 experts. Through applying the fuzzy logic to analysis the failure modes and effects, the risk priority index (FMRPI) and total intensity (FMTI) of each failure mode ware computed. Thus, maintenance priorities and weights of the RP’s failure modes were specified. In addition, the best maintenance plan was specified based on the FMRPI-FMTI diagram that shows the importance and the type of maintenance required for each failure mode. Failure of the submersible pump has the first rank in terms of priority, while the last priority was occupied by the building failure mode, where the mechanical failure modes are of the highest importance, followed by the electrical failure modes. Finally, the construction failure modes are ranked last due to the small probability of failure. The designed model is considered an efficient tool due to the similarity of the results with the reality of the situation and the ease of reading and displaying the results. In addition, this model can be applied to other projects such as water treatment plants and irrigation projects.

Keywords

  • FMCDM
  • Wastewater treatment plants
  • Failure mode and effect analysis
  • Risk priority index
  • Total intensity
Open Access

Prediction of the Delay in the Portfolio Construction Using Naïve Bayesian Classification Algorithms

Published Online: 09 Dec 2021
Page range: 673 - 680

Abstract

Abstract

Projects suspensions are between the most insistent tasks confronted by the construction field accredited to the sector’s difficulty and its essential delay risk foundations’ interdependence. Machine learning provides a perfect group of techniques, which can attack those complex systems. The study aimed to recognize and progress a wellorganized predictive data tool to examine and learn from delay sources depend on preceding data of construction projects by using decision trees and naïve Bayesian classification algorithms. An intensive review of available data has been conducted to explore the real reasons and causes of construction project delays. The results show that the postponement of delay of interim payments is at the forefront of delay factors caused by the employer’s decision. Even the least one is to leave the job site caused by the contractor’s second part of the contract, the repeated unjustified stopping of the work at the site, without permission or notice from the client’s representatives. The developed model was applied to about 97 projects and used as a prediction model. The decision tree model shows higher accuracy in the prediction.

Keywords

  • Delay
  • Construction
  • Decision tree
  • Bayesian
  • Portfolio
Open Access

The Role of Geotechnical Monitoring at Design of Foundation Structures and their Verification – Part 2

Published Online: 09 Dec 2021
Page range: 681 - 689

Abstract

Abstract

The main aim of the article is demonstrating successful design of spread foundations of a commercial centre building, where geotechnical monitoring allows us to check design efficiency and calculate reliability in comparison with real vertical deformation of building. Introduction to the case study area and building structure and foundations was done in previously published first part of the article in which engineering geological conditions were described. There was also presented a comparison of calculated vertical settlement of selected footings with the real geodetic measurement provided during construction time till the period of two years’ operation time after completion of civil works. Geotechnical engineers do not have many opportunities to evaluate their designs, especially when everything passes successfully. Our presented case study is one of the examples, which could be evaluated from the point of view of reliability index of design adjusted with real geodetic measurement. Index of reliability of selected foundations was calculated by deterministic probability methods. In order to evaluate thousands of statistical data combinations, programing tool in Python language was developed for batch processing calculation of vertical displacement of foundation in Plaxis software. Discussion part of the article contains the actual state of reliability theory in structural standards in Europe.

Keywords

  • Geotechnical monitoring
  • Reliability index
  • Batch processing
  • 3D FEM model
  • Probability of failure
Open Access

Sleep Disturbance and Noise Annoyance and Environmental Noise Exposure in Residents of Two Major Slovakian Cities

Published Online: 09 Dec 2021
Page range: 690 - 697

Abstract

Abstract

The significant growth in traffic density in Slovakia, combined with the country’s economic change, has resulted in new environmental noise issues, particularly in road traffic noise. The objective of this study was to assess and evaluate the impact of environmental noise on the psychosocial well-being of young healthy individuals in the two main Slovak cities of Bratislava and Kosice. To assess noise annoyance, interference with activities, and sleep disturbance, the ICBEN (The International Commission on the Biological Effects of Noise) anonymous validated “Noise annoyance questionnaire” was applied; noise levels were objectified by direct measurements using a sound level analyzer with a frequency analysis module. Young individuals between the ages of 20 and 30 were interviewed in Bratislava (533 respondents, 155 males) and Kosice (355 respondents, 111 males). The majority of the respondents in both cities were exposed to medium levels of road traffic noise LAeq≥ 60 dB. In Bratislava, 27.82 % of respondents resided in the higher noise exposure category LAeq≥ 70 dB, while in Kosice, 39.9 % resided in the lower noise exposure category LAeq< 50 dB. Road traffic noise annoys respondents in the higher noise exposure category in Bratislava 63.51 %, and even in the lower noise exposure category in Kosice, it interferes with reading and mental work, sleep and falling asleep 46.51 %. The study has identified traffic noise as an environmental issue in large cities, emphasizing the need for vulnerable individuals to be protected, particularly at night.

Keywords

  • Road traffic noise
  • Questionnaire
  • Young adults
  • Noise annoyance
  • Sleep disturbance
Open Access

Proportional and Structural Analysis of the Historical Truss of Church of St. Bartholomew in Mladočov

Published Online: 09 Dec 2021
Page range: 698 - 705

Abstract

Abstract

The researched truss of the Gothic Church of St. Bartholomew in the village of Mladočov is one of the examples of the use of the historical Czech length units of measurement; in this case, the Gothic and Baroque part of it. At the same time, it analyzes the proportional relationships between the individual elements of the truss. The structural analysis in relation to current standards points to the fact that the original design of the structure based on geometrical and proportional principles satisfy the reliability conditions defined by current European standards for structural design.

Keywords

  • Roof
  • Proportion
  • Historical length unit
  • Historical truss
  • Structural analysis
Open Access

Numerical Modelling of Soil-Nail and Secant Pile in Plaxis 2D: A Case Study of Tomb of Jam Nizam-al-Din Samoo, Makkli Thatta

Published Online: 09 Dec 2021
Page range: 706 - 717

Abstract

Abstract

The majority of historical heritage structures of Makli, Thatta require rehabilitation. As the Tomb of Jam Nizam-al-Din Samoo is near the slope’s edge, the settlement increased due to slope degradation. This study aims to investigate the effect of structural elements such as secant pile and structural nails on the settlement of Tomb. From this study, it was observed that with the installation of secant piles on the slope, Tomb’s settlement can be reduced considerably; moreover, the anchors did not have an appreciable role in the settlement. The secant pile of 12 m sufficient to reduce settlement. This will be economical and easy approach as compare to the retaining wall. The Factor of safety (FOS) reduced from 1.36 to 1.10 with increase of slope from 45 to 35. The FOS of slope also increased with the installation of nails from east side of slope. The will reduce the chances of slope failure and consequently the tilting/collapse of Tomb.

Keywords

  • Numerical modelling
  • Plaxis 2D
  • Secant pile
  • Factor of safety
  • Rehabilitation of old structure

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