Sharif Digital Repository

The aim of the work presented in this thesis is deal with some of the aspects in the FEM analysis of sandwich panels containing holes which comprised with foam core. It is a new topic in this field; so the activities that have been done about this case are poor with respect to its performances in engineering. The main emphasis is placed on the treatment of the foam core since the core often is the weakest part of the sandwich and therefore in many ways governs the capacity and lifetime of the whole sandwich structure. Because of increasing application including construction, aircraft and transportation, marine and etc., different load conditions are considered for the analysis and... 

Wall systems are an essential part of the buildings and their capacity should be properly considered in their design. However, the seismic behavior of building systems with in-filled walls and their interaction is a very complex issue, yet to be understood. Using the in-filled walls in the buildings without including them in the design process changes the whole behavior of the structural system as well as their failure mechanism under earthquake excitations. On the other hand, there have been extensive researches on rehabilitation of the structures with in-filled walls or designing them as the main or one of the lateral load carrying systems against seismic input. In this research, first the... 

The widespread usage of corrugated steel plates as girders and steel shear walls necessitates the need for further investigation of theseefficient structural members. Having significant initial stiffness, high capability of energy dissipation and special geometry are the fundamental reasons for this study. The nonlinear behavior of trapezoidal corrugated steel shear walls with rectangular opening has been studied in this thesis. A series of corrugated and simple shear walls with and without opening regarding different angles of corrugation and different infill plat thicknesses have been investigated. This analytical study was conducted to compare the initial stiffness, ultimate strength,... 

As steel shear walls are usually applied in the central cores of buildings (around the elevators and stairs), the use of opening as door is inevitable in steel shear wall spans. On the other hand, because of weakening the performance of steel shear walls due to the presence of these openings, it is necessary to apply stiffeners around it. The use of stiffeners around all sides of opening continued to beams and columns, is very expensive. Therefore, the necessity of studying on the effect of different arrangements of stiffeners on the behavior of steel shear walls is felt. In this research, a number of steel shear walls with different characteristics in terms of plate aspect ratio, location... 

In some cases, because of the need for installations, creating cutouts in the existing RC slabs will be necessary whereas these cutouts can cause weakness in the strength and stiffness of the slabs. Nowadays, expanding the use of FRP materials can provide the possibility of easier strengthening of such slabs. There are various methods for strengthening with FRP including Externally Bonded FRP sheets, Near Surface Mounted FRP rebars, and Mechanically Fastened FRP sheets. To select the most appropriate techniques for strengthening RC slabs with cutouts, it is essential to know different structural performance of these strengthened slabs. This research tends to model one and two-way spanning RC... 

One of the lateral-load bearing systems that has been recommended since almost 40 years ago is the steel plate shear wall (SPSW) system, which consists of a steel plate surrounded by beams and columns in each story. As for the performance of SPSWs, it is assumed that the boundary members of the wall’s plate, i.e. beams and columns, have sufficient stiffness and strength, so that they would not yield by the tensile stresses exerted due to the post-buckling behavior of the plate (tension field); and the global stability of the structure is still maintained. This assumption leads to significantly increased dimensions of the sections applied in the wall’s boundary members, particularly its... 

Reinforced concrete buildings with open ground storey are vulnerable to accumulate of large lateral displacement at the ground story. This is due to drastic reduction in the relative stiffness of the ground story compared to the upper stories, a phenomenon known as soft storey effect. Furthermore inevitable Existence of Opening in masonry infill and increasing it’s area reduces both the lateral strength and stiffness of the fully infilled RC frames so when percentage of the central opening is very high, the behaviour of the infilled frame approaches the bare frame. It is a perception about open ground storey buildings that openings in the upper stories infilled frame offset the soft storey... 

Steel shear wall is a lateral load resistance system, which has been taken into consideration in recent decades for designing and reinforcing high-rise buildings. This system is comprised of steel filler panel surrounded by frame members including beams and columns. Steel shear walls are presently fabricated in two types, stiffened and unstiffened. According to numerous conducted research, it can be stated that the stiffened type has better seismic performance. The use of stiffeners with a great number of executive details is required to spend more time and costs on the construction sector. In order to solve these problems, some experimental and numerical studies have been conducted on... 

One of the advantages of Steel Plate Shear Walls (SPSWs) is the possibility of using openings with varying sizes in the infill plates depending on a need basis. Openings are used for various reasons, such as the possibility of installing utilities and for architectural reasons. However, the latest research studies suggest that the use of large-sized openings in infill plates calls for the use of heavy stiffeners or special measures for ensuring system stability. The seismic behavior of two SPSWs with large unstiffened opening (one with a rectangular opening in the middle of the plate and the other with two oval openings on the sides of the infill plate) was studied experimentally and...