جستجوی مقالات مرتبط با کلیدواژه "لرزه" در نشریات گروه "عمران"

Reinforced concrete connections are one of critical points in concrete frames due to changing in concrete characteristics in high temperatures and cyclic loads. In present study the residual capacity of concrete connections was evaluated under seismic and fire loads with push-over analysis. The ABAQUS software was used for parametric study and the experimental results were used for verification of numerical study. In present study the compressive strength of concrete and the area of longitudinal reinforcement of column are considered as variable parameters. The modeled connections were loaded under seismic loads at ambient temperature, so, the temperature analysis was done to evaluate the loading capacity, ductility, stiffness and wasted energy of model under fire situation. The results show that by increasing the compressive strength of concrete from 25 to 45 MPa, the wasted energy and stiffness of connection were increase 10% and 35%, respectively, and the ductility was decreases 8%. Also, with increasing the area of longitudinal reinforcement of column from 1% to 8%, the wasted energy and stiffness of connection were increase 190% and 50%, respectively, and the ductility was decreases 290%. The connections were stable up to 200℃, but, the lateral resistance, ductility and stiffness of connections decrease 55%,60% and 60%, respectively, at 600℃ and 80%, 80% and 340%, respectively, at 1000℃.

Given that bent steel bending frames are one of the load-resisting systems such as earthquakes and winds, the role of bonding resistance in these frames will be crucial. The purpose of this study was to investigate the behavior of semi-conductive welded steel joints on the seismic behavior of 3D steel frames. The results of this study show that with the decrease in the number of structural classes, in this project the reduced formability of the structures decreases the IDA curves to a lower IM level, indicating that with increasing Structural plasticity can be achieved by higher computations in structures at the same earthquake level. Also, the coating curves corresponding to the structures with less ductility are at a higher level, that is, the coating curve is lower at higher level, with increasing formability in nonlinear static analysis. In other words, with increasing rigidity of the joints, the structures behave more rigidly and their bending curves are higher and the structures with higher plasticity become horizontal at lower seismic intensity levels. And the rigid structures are at a higher level, which is also reflected in the results of nonlinear static analysis, and by decreasing the rigidity of the joints, the effective alternation time of the asymmetric structure increases and the spectral acceleration decreases. Also with decreasing joint rigidity, the contribution of higher modes increased, so in semi-rigid joints the number of effective mods in the structures is higher than the rigid state. This issue can play an important role in the design of the structure. According to the findings of this study, little work can be done to investigate this method in the country, although research on the behavior of welded steel joints has so far been studied.