| The reinforced concrete (RC) pier was vulnerable to suffer serious damage by the shear-flexural coupling under seismic actions, and developing this seismic nonlinear numerical analysis model is the premise and guarantee to reveal the damage mechanism and understand the seismic performance of bridge. This paper summarizes the damage mode of RC pier in the previous earthquake at home and abroad, and the seismic numerical analysis model research progress of RC pier, restudying the seismic nonlinear numerical analysis method of RC pier under the flexural-shear coupling, and a numerical analysis model that consider flexural effect, shear effect and strain penetration is built based on OpenSees analysis platform, and the accuracy of the model is verified by comparison the tested and modeled. At last, the model was be used to analyze the seismic performance of the irregular bent pier. The main work results and conclusions are summarized as follows:1. In order to study the influence of strain penetration effect in RC pier, a seismic nonlinear numerical analysis model of RC pier that dominated by flexural mode was built based on the nonlinear beam column element and zero-length element of OpenSees software. The model have been reasonable considered the flexural and strain penetration coupling effect by modifying steel fiber and concrete fiber in zero-length section element. At last, the accuracy of the model was verified by comparison of Lehman’s hysteretic curves and deformation component of the simulated and tested, which provide effective basis for evaluation the seismic performance of the RC pier.2. The target displacement of pushover numerical analysis model by collecting the36quasi-static hysteretic curves results of circular piers failed in shear or flexural-shear modes was built based on the OpenSees numerical analysis platform, and separated the rotation of plastic hinge when the shear failure occur. A rotation formula of circular piers when the shear failure occur, was built based on multiple linear regression analysis. At last the analysis model was verified by comparing with the quasi-static test results of12nonlinear shear dominated circular bridge piers. The results indicate that the simulated hysteretic curves agreed well with the test data, and the accuracy of the model is verified.3. Based on quasi-static test results, a numerical model for seismic analysis of the unbonded prestressed RC bridge piers was built based on the OpenSees analysis platform. In which the nonlinear fiber beam column element was used to model the flexural deformation of the piers. The shear deformation was calculated by the Modified Compression Field Theory (MCFT) and modeled by the shear spring element. While the longitudinal bar slip deformation was modeled by the zero length rotation spring. Thus, flexure-shear-axial interaction of the piers under seismic action was simulated by combining the three deformation components. The simulated hysteretic curves, skeleton curves, unbonded prestressing tendon stress and residual displacement were compared with experimental results. Also, the flexural, shear and longitudinal bar slip deformations of the piers obtained by the numerical model were obtained. The results indicate that the model could be used to simulate the seismic behavior of the longitudinal unbonded prestressed RC bridge piers.4. In the background of Shui Dong Gua Shan NO.2bridge, the high way of Da li-Li jiang in Yun Nan province, from engineering applications(ignore shear effect)to the numerical analysis model before (consider shear effect), a numerical model for seismic performance analysis and nonlinear static analysis of the irregular bent pier was built based on the OpenSees analysis platform, and have studied the changes of axial compression ratio, the relationship of load-displacement and the time plastic hinge occur, etc. And the measure was provided to evaluate the seismic performance from engineering acceptable and refinement analysis method before for such bridge. |
PDF Full Text Request