عنوان مقاله [English]
Pushover is a non-linear static process, where a lateral load defined by a different load pattern than before, which represents the inertial forces in a particular earthquake, is defined as increasing uniformly until it reaches the target displacement or destruction. In this analysis, the overall force intensity has changed, but the load pattern remains the same until the end of the analysis, so the results of the Pushover analysis are highly sensitive to the applied load pattern. In the traditional Pushover analysis, uniform distribution, the response is only considered under the influence of the first mode assuming that it does not change, if the constant force distribution cannot be used in the distribution of internal forces due to the yielding of the structure and the changes related to the vibration characteristics, including the increase the participation of higher modes in the response of the structure gives a correct estimate. Therefore, in order to develop and include the effect of higher modes, three new load pattern examples are proposed in the analysis of concrete bridge with continuous straight deck and piers of different height. The pattern of uniformly distributed lateral loads based on the FEMA-273 regulation, the upper band method, the modal spectral composition, and the second method of modal composition of the patterns used here. Based on the results of this research, in short bridges, the modal combination method, and in long bridges, the spectral modal combination method have created the closest estimation of the response parameters among other methods.