Volume 67 (2022): Edition 3 (September 2022)

The paper presents the comparative analyses in terms of dynamic behavior of two scenarios of an RC frame structural system for a duplex house situated in Neamt, Romania a seismic zone with PGA 0.25g. The study shows the structural behavior in terms of vibration modes, horizontal displacements and efforts. The conclusions offer the best argument to chose the preferred structural system by owner.

There exists an interest to realize impermeable concrete, which would have many applications in bridges and water transport / storage structures, such as tanks, reservoirs, gutters and pipes. Furthermore, it would be possible to use such a type of concrete in other structures where the water pressure represents an exterior action, such as basement walls, caissons and slab foundations. However, absolutely impermeable concrete is almost impossible to be obtained, hence low – permeability concrete could be the correct technical term. In the current article, several samples of such concrete (containing active admixtures) are detailed and relevant conclusions are drawn.

Given the current context at national and European level in terms of reducing skilled labour force in constructions, as well as the high level of density and traffic in large cities, there is an increasing emphasis on the possibility of shortening the duration of building the structural frames on site, reducing the number of workers or even reducing the level of noise pollution. Thus, the introduction of precast technologies in the case of office buildings and residential buildings, with multi-storey frame structure, is becoming an increasingly pressing and topical issue.

The purpose of this paper is to enable structural engineers, architects and potential investors to consciously choose the type of optimal structure, taking into account a number of technical and economic aspects.

In this sense, in order to highlight the main advantages and disadvantages of using multi-storey precast reinforced concrete frame structures, a comparative case study will be carried out between a precast frame structure and a monolithic frame structure, respectively.

The bio-cementation repairing technique consists in using a bio product which precipitates in a porous environment and thus, filling the internal voids. In the construction industry, there is a series of applications for this repairing technology, mainly for cementitious materials. In this respect, the calcium carbonate-based materials are considered to be the most suitable bio products since they are compatible with a wide range of concrete mixes.

This paper presents a method of manufacturing a calcium carbonate bio product, using a device designed and manufactured exclusively for this experimental work. In order to design a bio product with an unique set of properties, various preliminary samples, obtained by varying the material quantities, the preparation time and working temperatures, have been tested. The bio product analyzed in this work may increase the impermeability of mortar and concrete elements, by continuous sealing of microcracks that can occur throughout the life cycle of the members. Thus, since this bio product was meant to be a component of the mortar/concrete mixture, the mechanical properties were determined by testing several mortar samples made with different cement-bio product ratios.

This research aimed to analyze the effects of using tuff and limestone as supplementary pozzolanic materials on the permeability of a classic C12/15 concrete composition. There were designed two types of concrete compositions with different degrees of permeability, namely P₈¹⁰ and P₁₂¹⁰ as reference concrete compositions and eight experimental concrete compositions with tuff in 6% and 10% of the cement quantity and with limestone in the same proportions. According to results, the tuff and limestone led to the decrease of concrete permeability, the best values being registered in the case of using 10% tuff in the concrete composition with P₈¹⁰ class of permeability.

Quality is a requirement of the 21st century, ranging from education to construction. Hence, this paper aims to treat in a theoretical but especially in an applied manner the set of concepts which lead to the achievement of quality in construction.

The article is structured in five sections, followed by the resulting conclusions at the very end. The first section deals with the introductory elements of this article.

The second section refers to the definition of the concept of quality in construction. The third section concerns the definition of the concept of planning in construction, as a necessity to reach the quality level required by the Romanian legislation. The fourth section deals with the elements of a database design for a construction project, its stages and the information that is processed. The fifth section refers to the case study that presents the elaboration of the project plan and the logical matrix of a project.

For the last five years, image processing using artificial neural networks (ANN) got several researchers interested in the field of Civil Engineering. As the artificial neural network, which consists of several neurons may not be able to extract features from the image due to the required computing power, the Convolutional Neural Network (CNN) was created. CNN is a machine learning algorithm that uses the image as input, attributing the importance of different aspects (objects in the image) to allow their differentiation. The results recorded in Civil Engineering domain show a real success.

As time goes on, the majority of the countries face the issue of a large number of old and/or decommissioned buildings that need rehabilitation/consolidation measures to be put in, to be further used in structural safety circumstances.

The work presents an analysis in terms of the efficiency of rehabilitation techniques that aim to improve and strengthen the structure individually or as a whole. The purpose of this study is to investigate rehabilitation methods specific to reinforced concrete columns. From a functional point of view, the rehabilitation of a structural element refers to the restoration of its active state, by restoring some of its capacities damaged due to various causes. The study presented was carried out in an old technical-administrative building that later changed its destination to an office building.

The solution proposed and adopted, as well as the action/intervention program derived from it, has as essential purpose the obtaining of innovative responses, in accordance with the new concepts.

The paper presents aspects related to the verification of the general stability of the bridge superstructures on circular arches with rigid vertical hangers, bridges of open-type or free-standing, without upper bracing.

A numerical worked analysis is carried out for a single-track railway bridge with a span of 30 m, which is based on the normative SR EN 1993-2:2007. Eurocode 3: Design of steel structures. Part 2: Steel Bridges (EC3-2).

The worked analysis carried out can be useful in deepening the knowledge of the procedure presented in the normative, as well as in the designing of the structures on arches in the field of bridges or other types of metal structures.

This paper deals with multi-story buildings erected mostly in interwar period in seismic areas and designed for gravitational actions only. The typical structural system is reinforced concrete frames and masonry infills. A usual multi-story interwar structure was chosen in order to evaluate its seismic resilience. There were made in situ measurements for its dynamic characteristics. The numerical model was calibrated according to in situ measurements. There were proposed two methods of increasing the seismic resilience. First method consists in improving the resilience by reshaping without reinforcing. The second method is additional to the first. It consists in reinforcing infilled frames in order to take over seismic loads.