Seismic Performance Analysis Of Bridge Structure Based On Energy Balance

Bridge is a key part of lifeline engineering which plays an extremely important role in earthquake relief and post-disaster restoration and reconstruction. By evaluating the existing bridge seismic performance to grasp wholly the destruction process of bridge structure, the weak parts of the structure may be found so that we can formulate corresponding measures to strengthen. Estimating the bridge will provide necessary basis for the selection of priority of bridge reinforcement and structure reliability analysis. At present, Pushover method is widely used to bridge seismic performance evaluation. The static elastic-plastic method based on energy balance is a new method of seismic performance evaluation which introduces the concept of energy balance to the Pushover method. This method has already been used in the construction field, but it is still lack of research in the field of bridge. Taking the Reinforced concrete bridge as object, this paper investigates further the Pushover method based on energy balance in order to this method can be applied to engineering practice more conveniently and more accurately. The main research contents cover the following aspects:(1) Double column pier model is set up which is carried on the traditional Pushover analysis. Earthquake damage shows that bridge piers under earthquake are generally entering to the stage of plasticity. So first of all, Mander concrete constitutive model is introduced and finite element model of bridge pier is established in SAP2000. Then, the results of nonlinear dynamic response analysis are compared to three traditional Pushover methods using linear distribution, the uniform distribution and basic vibration mode distribution. It shows that the results obtained from the traditional Pushover method using uniform distribution are less similar to the results from the nonlinear dynamic response analysis, but the other two are more similar.(2) Pushover analysis of the double column pier based on energy balance. In order to obtain the demand curve based on the energy, T-R-? relationship firstly was calculated by seismic nonlinear analysis software Bispec. Then, basing on the results of nonlinear dynamic response analysis, traditional Pushover methods using linear distribution and basic vibration mode distribution were compared to the corresponding Pushover based on energy balance. It shows that the results obtained from this method are more similar to the results from the nonlinear dynamic response analysis. The accuracy of the calculation results is greatly improved.(3) IDA analysis was carried out on the double column pier. Carrying out IDA analysis for the model under three typical earthquake ground motions and 10 strong ground motion records. Statistical analysis is carried out on the curves and getting different quantile IDA curves. Using IDA curve as a standard to evaluate the effectiveness of Pushover method based on energy balance.(4) To evaluation the seismic performance of double column pier. Quantized performance levels are used to evaluate the seismic response of bridge structure. The estimation results of damage state of two methods are uniform. Therefore, Pushover method based on energy balance can be used effectively to estimate the seismic response of bridge structure.