Sharif Digital Repository

Tall buildings with lightweight and low damping are vulnerable under wind load. The wind loads stimulate tall buildings in the alongwind and acrosswind direction so the wind loads should be considered in addition to the earthquake loads. Wind tunnel testing is one of the empirical testing that used to study the behavior of tall buildings under wind load besides the simulation of turbulence components of the wind field is one of the issues that have been studied by researchers. In this research we have simulated two models of tall building with different side ratio and we have surveyed wind and earthquake loads in the different loading conditions. The models have been analysis in both time... 

Seismic isolation is a method for seismic-resistant design of structures against earthquake and is one of the important control of structures technologies. Codification and publishing of codes for design of seismic isolation takes place widely since 1980s and this codification has undergone extensive evolutions during its developing process. In this project initially the developing process and fundamentals of codifying regulations of seismic design have been investigated and then the developing process of codifying regulations of seismic isolation in current important international codes like ASCE7-05, Eurocode 8, and Japanese code has also been considered. After considering these two... 

To verify most of the numerical and analytical developments in the structural and earthquake engineering techniques, experimental methods have been considered by many researchers. For instance, numerical simulations in structural health monitoring, structural control and energy dissipation systems need to be verified and compared with experimental results. Consequently, research organizations spend substantial budgets on assessing and updating these experimental methods. Many of these experimental tests are essentially conducted on the benchmark structures with specific technical characteristics; these properties should not be changed after each experiment. Therefore, the tests on these... 

There are many parameters which are utilized to obtain a more reasonable performance for structures under earthquake excitations in seismic provisions. It is well recognized that the main character to design of structures under seismic excitation is probabilistic rather than deterministic; therefore, it should be determined if the probability of structural damages is decreased when such parameters change in design of structures. In this thesis, fragility curves are developed in order to evaluate these parameters. Fragility curves are employed for various probability parameters. These diagrams are utilized to demonstrate when a coefficient or a number of parameters are used to improve... 

In the ongoing research project on tall buildings, the study of wind-induced demands is categorized as: along-wind and crosswind responses. These demands are caused by different mechanisms. Moving along the wind-induced is due to the effects of turbulence impact while the perpendicular component is related to the effects of windstorm. Along-wind response may be of special importance with respect to the comfort criteria. The loading condition on skyscrapers may differ from low-rise buildings due to the number of stories, on structures due to the high number of stories, and the importance of dynamic effects of current loading (wind). On the other hand the effect of wind load on tall structures... 

Steel shear wall systems have been introduced as a lateral load resisting system since 1970s. Based on the designer’s choice, this system can be used with or without stiffeners. Employing stiffeners prevents the elastic buckling of steel plates which can enhance the system to absorb more energy. The design code for using stiffners has not developed yet in Iran since this kind of systems is not common practice. In this study, the Response Modification Factor (R), as an important factor in the design procedures of structures, is investigated for 2 to 10-story building structures which have steel shear walls with 3 and 6 millimeters thickness with 3, 4 and 6 meters spans.To this end, the... 

Due to structural and nonstructural damage after the occurrence of Northridge 1994 and Kobe 1995 earthquakes, Seismic design basics was modified and philosophy of performance based design was suggested. In this novel solution, Predefined limitations are considered. Performance criteria were usually related to displacement or other correlated factors such as hinge plastic rotation. All the mentioned limitations are related to different damage states.Most of the codes and articles use following assumptions for assessing structural performance: 1) considering first vibrational mode for structural response to any seismic excitation regardless of seismic input acceleration records or structural... 

Sensitive equipment, are vulnerable to strong earthquakes, and failure of these equipment may result in a heavy economic loss. Recent studies have revealed that a conventional passive seismic isolation system may induce an excessive displacement when it is subjected to a near-fault earthquake that possesses strong longperiod components.
Semi-active control devices are capable of offering the adaptability of active devices and stability and reliability of passive devices that have been considered by many researchers.
Magnetorheological (MR) damper is a reliable semi-active control device which works in a wide range of temperature besides its mechanical simplicity at a modest... 

Purpose of this research is to investigate the effects of different seismic isolation techniques and effect of their location on seismic behavior of assymetric bridges and on mitigating their seismic demand. According to different types of isolators and their possible locations, a research is necessary to help to choose the optimum choice among different possible choices for isolators and their location. In this strudy, Lead-Rubber Beraing (LRB), Friction Pendulum Systme (FPS) and High Damping Rubber (HDR) isolators have been investigated and 3D bridge models are 3-span concrete box girder with 50 meters long each span and each interior piers, 7 or 14 meters long. Isolators also can be...