JOURNAL OF STRUCTURAL AND CONSTRUCTION ENGINEERING
Year:2015 | Volume:2 | Issue:1|Papers Count:7

For time history analysis of structures, appropriate records are needed. Due to the lack of strong-motion records from large earthquakes in some parts of Iran (e.g. Tehran region), earthquake simulation is a useful tool for studying strong-motion characteristics. In this study, a hybrid method has been used for obtaining source parameters of the 1990 Rudbar-Manjil earthquake (Mw7.3). In this simulation we assume fault plane, slip distribution and etc., then each parameter optimized after comparing simulated results with observed ones. In this hybrid method low frequency component of record obtained by the wave-number scheme that is a deterministic method and high frequency component obtained by the stochastic simulation method of Boore (2003), extended to the case of finite faults. Records from the stochastic method filtered with a high pass filter (fc=1.5 Hz) and results from the deterministic method filtered with low pass filter (fc=1.5 Hz), then the time-histories have been combined/added in the time domain. Final results have been compared with observed PSA and PSV in specified strong-motion stations. After comparing, optimized parameters have found, then based on this optimized parameters intensity contour has drawn; simulated intensity contours show good match with and observed ones. Best parameters are 2500 m/s for rupture velocity and 3 seconds for ramp function (i.e. rise time) and 36.82o N and 49.40o for earthquake epicenter. The results are important for the assessment of hazards in other seismically active parts of Alborz mountains (e.g. Greater Tehran area).

Tall buildings with Cor wall are growing in the structural industry. Generally, occurring one plastic hinge in the base of the structure is acceptable. In this research, 20, 30 and 40 story buildings are designed according to the practice and response spectrum analysis. Then, the base of the structures are modeled by inelastic elements and seven earthquake records are applied to the models. The results show that the moment demands around the mid-height of the reinforced concrete core walls are more than expected values. This matter result in more reinforcement than the amount required from respons spectrum analysis. Another approach is to use another plastic hinge in the mid-height of the core wall. Nonlinear time history analysis of the model with capability of two plastic hinge shows that the moment demand will decrease more than 30 percent for the studied buildings. A third approach is the extended plasticity in which the core wall can have plasticity in anywhere along the height of the core wall. The results show that the interstory drift of such models is not satisfactory. The behavior of the wall will be studied in each approach.

It’s for more than three decades that Steel Shear Walls are being used as lateral load resisting system. Definitely, the actual behavior of steel shear walls can be assessed using experimental results. However, solve many of phenomenon like this one should be done using mathematical and theoretical methods due to their special characteristics such as high expenses, lack of laboratory facilities and time limitations. In this study, the behavior of steel plate shear walls with openings in a one-story frame were evaluated and compared in various conditions. For this purpose, different values for the opening in shear wall was considered and exposed to lateral displacement in ABAQUS as a comprehensive finite element software. Then, the impact of FRP arrangement on shear wall was evaluated to represent the structural behavior under various conditions. Result shows that, use of FRP sheets as parallel layers on both sides of shear wall has the best response on energy absorption, so that performance of the model was better than shear wall fully covered with FRP.

In our country, concrete is commonly used for the construction of bridges deck. But the Heavy weight of concrete decks and the impossibility of making them as long-span bridges deck has caused the engineers to think a new material that besides lightness and ease of implementation can provide a good resistance against applied loads including both dead loads and dynamic loads caused by the passage of motor vehicles and also it causes to accelerate the projects implementation in compared with the specimens has made by concrete materials. Space structures due to the lightness, ease and speed of implementation, are considered a suitable replacement for deck bridges. Since the variations of members diameter and thickness can affect the behavior of structures and deflection due to dead and moving loads, so choosing an appropriate diameter and thickness for each member, in addition to impact on structures behavior and deflection of dead and moving loads, this factor has a major impact on buckling of members. Therefore, in this study by changing the member diameter, are investigate the behavior of bridges deck built with spatial structures.

Effects of propagation and scattering of high pressure waves same as blast waves are always interested for researchers. In this paper, the additional air pressure due to blast waves near topographic irregularities is considered. Regarding this study, it is clear that additional pressure from shock waves is quite different respect to the pressure in a smooth area and this pressure is involved with the weight of detonation and distance between detonation and the target point. Also in this paper, the total force s which is apply to a building in smooth location and the location near topographic irregularities is calculated and compared.

Vulnerable buildings and their rehabilitation are important problems for earthquake regions. In recent decades the goal of building rehabilitation and strengthening has gained different rehabilitation systems. However, most of these strengthening techniques disturb the occupants, who must vacate the building during renovation. Several retrofitting techniques such as addition masonry infill wall, application of buckling restrained braces and local modification of components has been studied in order to improve the overall seismic performance of such buildings. In response to many of the practical issues and economic considerations, engineers use often convergent unbuckling steel bracing frames as the lateral load resisting system during an earthquake. This kind of bracings increases the hardness and strength of concrete structures. The aim of the present study is the evaluation and comparison of seismic performance and retrofitting of an existing 7-storeys concrete structure with buckling restrained bracings and shear walls by nonlinear static procedure (NSP) and accordance with cod-361. The results show that the buckling restrained bracing, decreased drift to acceptable levels and Structure behaves on the life safety of performance level.