iel Dan

Theoretical Study on Steel Reinforced Concrete Hybrid Walls with Centered and Staggered Openings

Buildings placed in seismic areas are designed to simultaneously ensure strength, ductility and stiffness during earthquakes. In most cases the lateral resisting system is composed by shear walls. Lately for mid and high rise buildings the solution to use steel reinforced concrete shear walls, called hybrid walls, has been used. In most cases, the shear walls provided to limit the lateral displacement of the buildings, need to have openings due to architectural requirements. The existing theoretical and experimental studies presented in the literature refer to the behavior of solid/plain walls and a lack of information was identified for hybrid walls with openings. A theoretical and experimental program was developed at Politehnica University Timisoara, Romania with the aim to study the behavior of hybrid walls with centered and staggered openings. The current paper presents the results of nonlinear finite element analyses using ATENA package performed in order to assess the structural capabilities of the proposed experimental specimens with openings. Using the results obtained in one previous experimental program, consisting in tests on 1:3 scale steel-concrete composite elements, the paper presents a comparative study regarding the behavior of hybrid walls with openings versus solid walls. The study is focused on nonlinear behavior of elements with key parameters being evaluated, i.e. maximum load, deformation capacity and stiffens degradation.

LIFE CYCLE ASSESSMENT AND LIFE CYCLE COST ANALYSIS OF A NEARLY ZERO ENERGY RESIDENTIAL BUILDING - A CASE STUDY

Environmental issues have received ascending attention in recent years due to the increase of their negative effects. Greenhouse gas emission levels have experienced an exponential increase in the last decades mainly on account of the development of the building sector. Life cycle assessment (LCA) of buildings is a proper tool to analyse the full environmental impact during their designed lifespan. Inventory databases have a shortage of local parameters in some countries and need to be developed constantly. Life cycle cost (LCC) analysis evaluates the global costs of an investment. Besides the initial cost of implementing a project, usage, maintenance, repair, replacement and demolition costs are also taken into account. The goal of the research presented in this paper is to evaluate the environmental impact of a highly energy efficient residential house, built in western Romania. Life cycle assessments of buildings show that in most cases the impact of operating phase is much higher than construction phase, but in case of highly energy efficient buildings, the results are slightly different. However, energy related processes play a major role in determining the impact of buildings. A cradle-to-grave life cycle analysis, using SimaPro software, offers a complete image of the studied building s environmental impact. The main objective is to determine the fraction of each component of the building with relevant contribution to the human health and ecosystems categories.

Thermal Studies of Specific Envelope Solutions for an Energy Efficient Building

This paper presents the design and monitoring scheme of an energy efficient high school building with emphasis on the analysis of constructive and geometric thermal bridges that can affect the overall energy consumption and thermal comfort. The ANTHERM software is used to accurately assess the specific details and determine isotherms, heat flux distribution and the Psi-values (Ψ value) of the sections where different types of materials connect. A monitoring system with temperature sensors installed in the layers of the building envelope elements has been designed in order to compare the obtained values with the real time thermal performances of the envelope elements. The study highlights the influence of the type and thickness of the insulation materials used in the specific constructive details on the overall thermal performance of buildings.

Precast RC Wall Panels with Cut-out Openings Retrofitted by FRP Composites

In this paper studies made on seismic retrofitting of reinforced concrete large panels with cut-out openings are presented. There are described the horizontal and vertical loading strategies, the strengthening procedures and the experimental results of the elements strengthened in both prior-to-damage and post-damage states.

Ductility Increasing for Concrete Columns. Experimental Results

The research program presented here contains a short theoretical and experimen- tal study upon the reinforced concrete columns retrofitted using composite materials. The aim is to clarify some of the aspects regarding the ductility of these types of elements. One part of the study is that it aims to establish the type of interaction between two methods of retrofitting, namely in bending and by confinement. The actual codes present only the computational meth- ods for each individual situation, but not for the superposition of the two retrofitting methods.

High Performance Materials Used in Retrofitting Structural Masonry Walls

In this paper the studies made on the clay brick masonry walls strengthened with fibre reinforced polymer (FRP) composites are presented. In the theoretical part, the following have been determined: the distribution of the principal stresses and the crack propagation in the wall, respectively the probable failure load and the collapse mechanism. In the experimental part, five wall specimens have been tested. These were subjected to pure in-plan shear loads up to failure and then retrofitted on one side, with different types, percentages and lay-ups of fabrics. Performances of the different strengthening configurations were compared in terms of the ultimate load, strain in composite and failure mechanism. Based on the results obtained it was proven the effectiveness of using externally bonded composites for retrofitting brick masonry walls. The final conclusions and recommendations will probably be useful in the design and the execution of such retrofits.