The SAP Application to Precasted Segmental Bridge Column Feasibility Study
Date Issued
2009
Date
2009
Author(s)
Peng, Yu-Pang
Abstract
The use of the precast modular construction for bridge column is the way which combines the previous casting work in the factory and the mechanization method of fabrication. Due to the precast way of production, it allows bridge engineers to minimize accidents in the work zone, to reduce traffic disruptions, and to increase the speed of construction, while maintaining construction quality and minimizing the life-time cost and environment impact. Because the seismic resistance and behavior of this kind of column is still being studied, most of the applications, however, have been in low-seismicity regions. In particular, there hasn’t been any application of the segmental precast bridge column in moderate to high-seismicity regions such as the state of California in United States or Taiwan. In order to investigate the use of segmental precast bridge columns in high-seismicity regions, a cooperative research project is established between the National Center for Research on Earthquake Engineering (NCREE) in Taiwan and Multidisciplinary Center for Earthquake Engineering Research (MCEER) at University of New York at Buffalo in the United States.irst considering the application of segmental precast bridge column is still under investigated, and no relative standards or codes provide the detail guideline to design this kind of column. In order to understand the basic properties of the column before the test begun, this research takes the post-tensioned segmental precast bridge column described previously as the object and uses the developed finite element analysis software ― SAP , to develop a model which can estimate the seismic capacity and mechanical behavior of the column. According to this model, before the beginning of segmental precast bridge column tests in different sizes, design ways and figures, we can establish the SAP model to run parametric analysis, predict the effect of parameter adjustment to the model performance, and observe the behavior of the column under seismicity.he analysis results show that the finite element model of post-tensioned segmental bridge column can predict its seismic behavior well under cyclic loading, like the opening behavior, opening amplitude, curvature distribution and the initial stiffness of the column. The analysis results match the test results well, if we establish the SAP model according to the material strength, section properties, column members and the mechanical behavior of the real column in test. During the cyclic loading test, no plastic hinge is developed in the post-tensioned segmental bridge column, and the hysteretic energy dissipation of the column comes from the crush and spalling of the base segment, the friction between the tendons and tubes, and the slight relative displacement between segments. However, the SAP model can’t simulate the hysteretic behavior of the column under cyclic loading by nonlinear static analysis, but can simulate the envelope of the hysteretic loop (pushover curve); if we use the SAP model to simulate the column behavior under pseudo dynamic test by nonlinear time history analysis, we can assign the damping ratio of the model, then the simulation of the hysteretic behavior under pseudo dynamic test is better then under cyclic loading test. According to this result, we might consider the possibility of using SAP model to simulate the segmental precast column under cyclic loading by nonlinear time history analysis. Besides this research also develop the model used to simulate the specimen with energy dissipation bars (ED bars). Because of the uncertainty of the potential plastic hinge zone of segmental bridge column, we use simple method to simulate the ED bars between segments by nonlinear link.
Subjects
precast
segmental column
post-tensioned
finite element
cyclic loading
pseudo dynamic
ED bars
Type
thesis
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