Experimental Study On Seismic Performance Of Controlled Rocking-isolated Railway Bridges

In recent years, base-isolation technology has been research focus at home and abroad for its potential favorable isolation capability. In this paper, seismic performance of controlled rocking piers with pile foundation of railway bridges is studied based on pseudo-static test method, and the seismic performance analysis of numerical simulation models of the tests are conducted through Pushover method. The main research works in this paper are as follows:(1) Development of domestic and overseas seismic design ideas is reviewed; the superiority of controlled rocking isolation is elaborated; research production in the field of controlled rocking isolation study by means of theoretical calculation, experimental study and numerical simulation by international and domestic academics are summarized, and several bridges designed or repaired with idea of controlled rocking isolation are briefly introduced.(2) Three types of test models of controlled rocking-isolated piers with pile foundation are designed, respectively are free rocking model, the model with inhibiting steel bar on the sides of pier bottom and pile caps and the model with prestressed anti-overturn steel bar at the center of pier top and pile caps bottom. The pseudo-static test program of controlled rocking-isolated pier is drawn up, and test models are made and schemes of loading process and data collecting method are confirmed.(3) Pseudo-static tests are carried out on test models, and phenomena observed during the tests are described and analyzed. Seismic performance parameters of hysteretic curves, skeleton curves, energy-dissipating curves and characteristic values of strength and stiffness are obtained by analyzing datum of pseudo-static tests. By comparing the test datum, the seismic performance of the models is compared and some useful conclusions are obtained.(4) Numerical simulations of the test models are made through finite element analysis software and Pushover analysis is carried out on the models, obtaining parameters as hysteretic curves, rocking-lifting characteristics and the elastic-plastic deformation characteristics of lift-limit devices. By comparing and analyzing the calculation results of the numerical models, the advantages and disadvantages of seismic performances of each model are concluded.(5) Reliability of numerical simulation model of controlled rocking isolated pier adopted in the calculation is verified by comparing the skeleton curves achieved from Pushover analyses and pseudo-static tests.