نشریه آنالیز سازه - زلزله
سال شانزدهم شماره 1 (بهار 1398)

Application of dampers as means of attenuation of earthquake energy is one of the most significant approaches and viscose damper is the most popular one. The aim of this paper was to investigate the effect of viscose dampers on decreasing the vulnerability of tall structures at earthquake and selection of the optimal arrangement of dampers in these structures. so, two types of concrete special moment frames with central cores with 26 floors were designed with SAP2000 software. Then, they were applied to five earthquake records and their vulnerabilities were investigated according to non-linear timehistory dynamic analysis. Then, dampers were erected into the structure and modeled. To do so, the dampers were horizontally positioned in the structure and the models were evaluated again using non-linear timehistory dynamic analysis. The results obtained by investigating three parameters of maximum Floor displacement, base shear, and structure Acceleration verified signified decrease in all three parameters. In such a way that the displacement of the structure, between 10 to 25 percent,the base shear 15 percent, as well as the acceleration of the input to the structure, to about 17 to 20 percentage reduction.

The large bridges of the new Meyaneh - Tabriz Railroad are located in a region with a high risk of a large earthquake and a slope of sloping soils, which are susceptible to landslides. Depending on the user's specific circumstances, it is simply not possible to identify malicious factors and prevent progressive failures. Regarding the daily and seasonal temperature variation cycles, imposing irreparable damage due to the creation of thermal expansion barriers between the shell and the deck is likely to occur accidentally or deliberately in the structure. Therefore, in order to detect the thermal behavior of the bridge and prevent potential destructive factors, the bridge was investigated using the CSI Bridge software and the results of the heat changes were analyzed. The results show that with increasing temperature gradually, stress, axial, shear and anchor forces increase to 60 ° C uniformly. With temperature reaching 65 ° C, the stress caused by heat changes increased by 17.7%. Applying a temperature of 800 ° C in the middle span with a sharp change in the axial and shear forces of 9833 tons and flexural anchorage of 2074 tons per meter and a displacement of 24.34 cm. were calculated.

The performance of beam – column  connection of common steel moment frames has been evaluated in a seismic discuss and progressive collapse alone. After the Northridge and Kobe earthquake, researchers found that the connections were weak. This is while the connections have a huge impact on the process of energy depletion of structure and structure behavior against unusual loads; Because if the panel zone is weak, even in the case of performing a rigid connection with resistance of more than beam which causes failure in the connection area, it causes a large deflection and resulting in a brittle fracture of connection. In this regard, in the current study, the performance Two common types of WFP bending (welded flange plate connection) and WUF-W (welded unreinforced flange-welded web connection) against a progressive coolapse phenomenon have been investigated by changing the type of steel used in plate for this purpose. The purpose of these two types of connection is once with St 37 and once with a steel alloy steel LY160, in a frame 8 steel story with different scenarios, Column removal (without remove the column, removing the column of the ground floor, third and seventh) was simulated in ABAQUS software. The results show that the DCR (criterion which is the Demand Capacity Ratio and it is also called the demand factor) value in the WUF-W connection is much lower by replacing the alloy steel.

Space structure is a rigid, lightweight, truss-like structure constructed from interlocking struts in a geometric pattern. Space structure can be covered large areas without intermediate supports.In this paper, the problem of simultaneous shape and size optimization of a three-layer paraboloid space structure is addressed. In this method, the hybrid charged system search-particle swarm is utilized as the optimization algorithm and the result is compared with the particle swarm optimization algorithm. The objective of this paper is to find optimal weight, that design variables are considered as height and cross-sectional area. For conducting this, a three-layer paraboloid space structure is designed by SAP and then optimized by using hybrid charged system search-particle swarm and particle swarm optimization algorithms. The result demonstrate the efficiency of the hybrid charged system search-particle swarm algorithm.

Considering the architectural remnants of the so-called structure of Ali-Shah in Tabriz as the last sequence of large-scale buildings during the Ilkhanid era in which it’s approximate 29-meter span had held the largest and the highest ever made arch in the Islamic World, proposing controversial technical bugs parallel to the violation of theoretical possibilities towards erecting such an arch would be the opposite point of more than half a century’s studies of historic architecture, archaeological investigation as well as historic documents in relation to the location of the Great Ali-Shah Mosque. With this pre-assumption that the U-shape structure including roughly 11 meter thickness for its walls had been considered to create a brick arch of a huge architectural project; clarifying the statically limitations of the mentioned building in terms of stability, durability, vulnerability and the impossibility of creating any kind of arch and vault in mentioned span would shed new lights towards the  interpretation of historical contexts and its connections with the Ilkhanid structure appeared in the sources.
After responding to question of statically feasibility of any kind of arch made by traditional masonry in so-called Ali-Shah Ark, besides statically analyses with no attention to historic reports and events, this project is aimed to play a vital role in reviewing the historic chronologies of Ali-Shah Mosque. According to the results, tensions result of loading due to any kind of arch would exceed the mechanical potentials of structure and will cause grossly deformation of vertical units under any condition. From this point of view, there has been no covering of arch either of vaults in this building anytime. In other words, there has been no relation between what is marked as Ali-Shah Mosque including the world’s largest brick arch, and what is known as today’s remnants of the so-called Ali-Shah Ark.

Due to the fact that many of the existing structures have been in existence for over a decade, retrofitting has become one of the greatest challenges facing structural engineers. There are several methods to retrofit that, due to the unique properties of FRP composites, their use for the repair of reinforced concrete members has become one of the most commonly used methods. One of the most important factors in the need to retrofit the shear wall is the insufficiency of the shear bending of the beam in the shear wall of the cooper. Considering the fact that the price of FRP materials is one of the limiting factors for its use in improving structures, in this study, Numerical and Laboratory Results With the help of ABAQUS Limited Components Software, 5 different FRP derivatives that reduce the use of FRP in the seismic reconstruction of the coupler shear wall fittings were introduced. The results obtained from these 5 samples were compared with the base model without FRP coating and the sample, which has a complete overlapping of FRP, and the sample, which is multiplied by drowning, was selected as the best sample, which reduces the cost of refinement The connective beam is in the wall of the shear joint.