Rivista e Edizione

Volume 16 (2021): Edizione 4 (December 2021)

Volume 16 (2021): Edizione 3 (September 2021)

Volume 16 (2021): Edizione 2 (June 2021)

Volume 16 (2021): Edizione 1 (March 2021)

Volume 15 (2019): Edizione 4 (December 2019)

Volume 15 (2019): Edizione 3 (September 2019)

Volume 15 (2019): Edizione 2 (June 2019)

Volume 15 (2019): Edizione 1 (March 2019)

Volume 14 (2018): Edizione 4 (December 2018)

Volume 14 (2018): Edizione 3 (September 2018)

Volume 14 (2018): Edizione 2 (June 2018)

Volume 14 (2018): Edizione 1 (March 2018)

Volume 13 (2017): Edizione 4 (December 2017)

Volume 13 (2017): Edizione 3 (September 2017)

Volume 13 (2017): Edizione 2 (June 2017)

Volume 13 (2017): Edizione 1 (March 2017)

Volume 12 (2016): Edizione 4 (December 2016)

Volume 12 (2016): Edizione 3 (September 2016)

Volume 12 (2016): Edizione 2 (June 2016)

Volume 12 (2016): Edizione 1 (March 2016)

Volume 11 (2015): Edizione 4 (December 2015)

Volume 11 (2015): Edizione 3 (September 2015)

Volume 11 (2015): Edizione 2 (May 2015)

Volume 11 (2015): Edizione 1 (March 2015)

Volume 10 (2014): Edizione 4 (December 2014)

Volume 10 (2014): Edizione 3 (September 2014)

Volume 10 (2014): Edizione 2 (June 2014)

Volume 10 (2014): Edizione 1 (March 2014)

Volume 9 (2013): Edizione 4 (December 2013)

Volume 9 (2013): Edizione 3 (September 2013)

Volume 9 (2013): Edizione 2 (June 2013)

Volume 9 (2013): Edizione 1 (March 2013)

Dettagli della rivista
Formato
Rivista
eISSN
2784-1391
Pubblicato per la prima volta
12 Apr 2013
Periodo di pubblicazione
4 volte all'anno
Lingue
Inglese

Cerca

Volume 16 (2021): Edizione 2 (June 2021)

Dettagli della rivista
Formato
Rivista
eISSN
2784-1391
Pubblicato per la prima volta
12 Apr 2013
Periodo di pubblicazione
4 volte all'anno
Lingue
Inglese

Cerca

5 Articoli
access type Accesso libero

Experimental Test on Square Concrete Columns Strengthened with CFRP Composites in Different Configurations

Pubblicato online: 26 Oct 2021
Pagine: 1 - 12

Astratto

Abstract

The shape and FRP configuration of the concrete columns can straight forwardly influence the efficiency of the FRP confinement. Most of the columns shape in concrete buildings are non-circular sections, therefore, special attention need to be given to their strengthening and rehabilitation to maintain the safety of buildings infrastructure especially, for rectangular/square sections with section depth ≥ 300mm. This paper is directed towards to this objective through an experimental investigation carried out on 8 square concrete columns having the same dimensions (300 × 300 × 1000) mm (width × depth × height respectively) with low concrete strength confined with different CFRP configurations. Two of the columns left without CFRP strengthening to be as a control specimens, two specimens were strengthened with two-layers of CFRP sheets (full confinement), two specimens were strengthened with two-layers of CFRP sheets and CFRP strips combined with CFRP anchors, in addition, one specimen was strengthened with one-layer of CFRP and CFRP strips combined with CFRP anchors, finally, the last specimen was strengthened with CFRP strips combined with CFRP anchors (partial confinement). The results revealed that CFRP composite wrapping in different confinement procedures can enhance the ultimate load capacity and ultimate compressive strength of square concrete columns having low compressive strength subjected to axial load, and the anchorage system improved based on the final failure mode of confined columns where the failure didn’t happen in the anchors zones, which was an aim of the research.

Parole chiave

  • CFRP
  • concrete column
  • square section
  • confinement
  • load carrying capacity
access type Accesso libero

Investigation of RC Beams Rehabilitated with Angle-Ply Composite Laminate Plate

Pubblicato online: 26 Oct 2021
Pagine: 13 - 21

Astratto

Abstract

This parametric study investigates the RC Beams Rehabilitated with angle-ply composite laminate plate [θn/90m]s. This work is based on a simple theoretical model to estimate the interfacial stresses developed between the concrete beam and the composite with taking into account the hygrothermal effect. Fibre orientation angle, effects of number of 90° layers and effects of plate thickness and length on the distributions of interfacial stress in the concrete beams reinforced with composite plates have also been studied.

Parole chiave

  • Interfacial stresses
  • Concrete beam
  • Angle-ply laminates
  • hygrothermal effects
  • Fibre volume fractions
access type Accesso libero

The Fundamental Vibration Period Determination for an Existent Historical Monument Building, by Using Numerical Modelling, Empirical and Experimental (AVT) Methods

Pubblicato online: 26 Oct 2021
Pagine: 22 - 33

Astratto

Abstract

One of the most important parameters necessary in the seismic force determination is the building’s fundamental vibration period, which is also useful in “health monitoring” procedure for the existent buildings, during their exploitation. The fundamental vibration period can be determined by theoretical, empirical or experimental methods. In particular, the experimental method it is known as AVT (Ambiental Vibrations Tests) procedure, which intensively studied today. In this paper it was performed a comparative analysis between fundamental vibration periods values, determined for an existent building, by using a numerical method (finite elements program - ETABS), some direct methods (empirical formulas), and an experimental method (dynamic recordings, based on AVT), using special devices as accelerometers from KINEMETRICS brad. The existent building has “house flats” destination, and it is historic monument, located in Bucharest city, which it was built in ~1930 period, and it has basement and 4 floors. The building’s structure is done half by masonry walls with concrete slabs and half by RC frames (columns and beams), with concrete slabs. The main goal of the analysis is to emphasize the advantages and disadvantages of each studied method.

Parole chiave

  • seismic force
  • fundamental vibration period
  • analytical
  • experimental
  • historic monument
  • dynamic sensors
access type Accesso libero

Concrete Columns Strengthened with Fibre Reinforced Cementitious Matrix (FRCM)

Pubblicato online: 26 Oct 2021
Pagine: 34 - 44

Astratto

Abstract

Since concrete structures are subjected to degradation, one of the newly retrofitting system used to increase both the strength and the overall ductility is based on the Fibre Reinforced Cementitious Matrix (FRCM) composite material. FRCM system was proposed as an enhanced alternative to the traditional fibre reinforced polymer (FRP) jacketing, overcoming the limitations related with the use of organic adhesives. After a brief state of art about the FRCM system, the paper presents an analytical study on the confinement of plain concrete columns with FRCM composites. Representative analytical models are selected from the technical literature, and the predictions of the maximum compressive strength are compared with respect to the reference experimental results. Four plain concrete columns strengthened with FRCM system, which were previously tested by the authors, were used for this analytical study. Slightly different strength of concrete materials and different number of FRCM layers (one-layer and two-layer) differentiate the reference specimens. Therefore, the capability of the selected analytical models to make close predictions when changing the base material and the number of FRCM layers was evaluated. Recommendations are made based on the comparative results.

Parole chiave

  • FRCM
  • confinement
  • plain concrete column
  • analytical model
access type Accesso libero

Experimental and Numerical Study on the Influence of Mechanical Ventilation on the Survival Conditions in a Room Set on Fire

Pubblicato online: 26 Oct 2021
Pagine: 45 - 56

Astratto

Abstract

Statistics show that most fires occur in civil residential buildings. Most casualties are caused by the inhalation of hot air loaded with smoke, leading to intoxication with substances harmful to the human body. This research aims to determine the physical and chemical parameters essential for the survival of persons in the early stages of a fire in different ventilation situations: with and without a mechanical ventilation system for the extraction of hot air.

These essential parameters are indoor air temperature, visibility, oxygen concentration, and carbon dioxide concentration. Three full-scale experiments were carried out to study the burning behaviour. The experiments were used to calibrate and validate a numerical model with respect to the temperature variation at a specific control point inside the experimental stand. The model was further employed in order to understand the influence of the operations of the ventilation system on other active firefighting systems, fire evolution, and people evacuation. We found the ventilation system has mixed influences; we present here a detailed conclusion on its influence.

Parole chiave

  • fire simulation
  • temperature
  • smoke
  • visibility
  • FDS
5 Articoli
access type Accesso libero

Experimental Test on Square Concrete Columns Strengthened with CFRP Composites in Different Configurations

Pubblicato online: 26 Oct 2021
Pagine: 1 - 12

Astratto

Abstract

The shape and FRP configuration of the concrete columns can straight forwardly influence the efficiency of the FRP confinement. Most of the columns shape in concrete buildings are non-circular sections, therefore, special attention need to be given to their strengthening and rehabilitation to maintain the safety of buildings infrastructure especially, for rectangular/square sections with section depth ≥ 300mm. This paper is directed towards to this objective through an experimental investigation carried out on 8 square concrete columns having the same dimensions (300 × 300 × 1000) mm (width × depth × height respectively) with low concrete strength confined with different CFRP configurations. Two of the columns left without CFRP strengthening to be as a control specimens, two specimens were strengthened with two-layers of CFRP sheets (full confinement), two specimens were strengthened with two-layers of CFRP sheets and CFRP strips combined with CFRP anchors, in addition, one specimen was strengthened with one-layer of CFRP and CFRP strips combined with CFRP anchors, finally, the last specimen was strengthened with CFRP strips combined with CFRP anchors (partial confinement). The results revealed that CFRP composite wrapping in different confinement procedures can enhance the ultimate load capacity and ultimate compressive strength of square concrete columns having low compressive strength subjected to axial load, and the anchorage system improved based on the final failure mode of confined columns where the failure didn’t happen in the anchors zones, which was an aim of the research.

Parole chiave

  • CFRP
  • concrete column
  • square section
  • confinement
  • load carrying capacity
access type Accesso libero

Investigation of RC Beams Rehabilitated with Angle-Ply Composite Laminate Plate

Pubblicato online: 26 Oct 2021
Pagine: 13 - 21

Astratto

Abstract

This parametric study investigates the RC Beams Rehabilitated with angle-ply composite laminate plate [θn/90m]s. This work is based on a simple theoretical model to estimate the interfacial stresses developed between the concrete beam and the composite with taking into account the hygrothermal effect. Fibre orientation angle, effects of number of 90° layers and effects of plate thickness and length on the distributions of interfacial stress in the concrete beams reinforced with composite plates have also been studied.

Parole chiave

  • Interfacial stresses
  • Concrete beam
  • Angle-ply laminates
  • hygrothermal effects
  • Fibre volume fractions
access type Accesso libero

The Fundamental Vibration Period Determination for an Existent Historical Monument Building, by Using Numerical Modelling, Empirical and Experimental (AVT) Methods

Pubblicato online: 26 Oct 2021
Pagine: 22 - 33

Astratto

Abstract

One of the most important parameters necessary in the seismic force determination is the building’s fundamental vibration period, which is also useful in “health monitoring” procedure for the existent buildings, during their exploitation. The fundamental vibration period can be determined by theoretical, empirical or experimental methods. In particular, the experimental method it is known as AVT (Ambiental Vibrations Tests) procedure, which intensively studied today. In this paper it was performed a comparative analysis between fundamental vibration periods values, determined for an existent building, by using a numerical method (finite elements program - ETABS), some direct methods (empirical formulas), and an experimental method (dynamic recordings, based on AVT), using special devices as accelerometers from KINEMETRICS brad. The existent building has “house flats” destination, and it is historic monument, located in Bucharest city, which it was built in ~1930 period, and it has basement and 4 floors. The building’s structure is done half by masonry walls with concrete slabs and half by RC frames (columns and beams), with concrete slabs. The main goal of the analysis is to emphasize the advantages and disadvantages of each studied method.

Parole chiave

  • seismic force
  • fundamental vibration period
  • analytical
  • experimental
  • historic monument
  • dynamic sensors
access type Accesso libero

Concrete Columns Strengthened with Fibre Reinforced Cementitious Matrix (FRCM)

Pubblicato online: 26 Oct 2021
Pagine: 34 - 44

Astratto

Abstract

Since concrete structures are subjected to degradation, one of the newly retrofitting system used to increase both the strength and the overall ductility is based on the Fibre Reinforced Cementitious Matrix (FRCM) composite material. FRCM system was proposed as an enhanced alternative to the traditional fibre reinforced polymer (FRP) jacketing, overcoming the limitations related with the use of organic adhesives. After a brief state of art about the FRCM system, the paper presents an analytical study on the confinement of plain concrete columns with FRCM composites. Representative analytical models are selected from the technical literature, and the predictions of the maximum compressive strength are compared with respect to the reference experimental results. Four plain concrete columns strengthened with FRCM system, which were previously tested by the authors, were used for this analytical study. Slightly different strength of concrete materials and different number of FRCM layers (one-layer and two-layer) differentiate the reference specimens. Therefore, the capability of the selected analytical models to make close predictions when changing the base material and the number of FRCM layers was evaluated. Recommendations are made based on the comparative results.

Parole chiave

  • FRCM
  • confinement
  • plain concrete column
  • analytical model
access type Accesso libero

Experimental and Numerical Study on the Influence of Mechanical Ventilation on the Survival Conditions in a Room Set on Fire

Pubblicato online: 26 Oct 2021
Pagine: 45 - 56

Astratto

Abstract

Statistics show that most fires occur in civil residential buildings. Most casualties are caused by the inhalation of hot air loaded with smoke, leading to intoxication with substances harmful to the human body. This research aims to determine the physical and chemical parameters essential for the survival of persons in the early stages of a fire in different ventilation situations: with and without a mechanical ventilation system for the extraction of hot air.

These essential parameters are indoor air temperature, visibility, oxygen concentration, and carbon dioxide concentration. Three full-scale experiments were carried out to study the burning behaviour. The experiments were used to calibrate and validate a numerical model with respect to the temperature variation at a specific control point inside the experimental stand. The model was further employed in order to understand the influence of the operations of the ventilation system on other active firefighting systems, fire evolution, and people evacuation. We found the ventilation system has mixed influences; we present here a detailed conclusion on its influence.

Parole chiave

  • fire simulation
  • temperature
  • smoke
  • visibility
  • FDS

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