Research On Seismic Performance Analysis Of Pier-piles Structure

In nearly half a century, the bridge construction in our country has made rapid development and suspension bridge, deep-water bridge, large span cable-stayed bridge and other various styles of bridges appear in people’s lives. Since it plays a vital role in emergency relief and reconstruction after the earthquake, the bridge structure is a key component of the lifeline system. In this paper, considered the impact of hydro dynamic pressure on a bridge to study the problem, the author established of the finite element model of the pier-pile foundation structure system. The incremental dynamic analysis method (IDA methods) and nonlinear static analysis method (on Pushover method) were used respectively to analysis of the seismic performance of the system. Using the result of the IDA method as a criterion, the paper discussed the applicability of the Pushover method in evaluating the seismic performance of the pier-pile system. Main contents included:1. Dynamic analysis of the pier-pile structure. After a detailed description of the constitutive relationship of reinforced concrete structural materials and the finite element model of the actual project by the ANSYS software, the author made a modal analysis for the structure and made a brief analysis of the first four vibration modes in the structural characteristics, which has laid the foundation for future dynamic time-history analysis. After respectively input three typical vibration records to the structure for the dynamic time history analysis, the author compared the difference of the displacement, acceleration and velocity of the pier top under different vibration records and the reactions between the nodes in the pier and those at pier top to study whether the reactions are similar.2. Pushover analysis of the pier-pile structure. Pushover method principle, the basic theory of the assumptions and analysis steps are described in detail in the paper. Because the target displacement of the structure and lateral load distribution model has a great influence on the pushover analysis results, this paper adopted triangular load mode and uniform load mode respectively to take pushover analysis for the structure. Using capacity spectrum method to determine the performance points of structure, the capacity curve and performance points of structure under rare earthquake of8degrees and9degrees are obtained to measure the seismic performance of the structure in the rare earthquake of8degrees and9degrees.3. IDA analysis of the pier-pile structure and compare the results with the results of Pushover method. Described the basic theory and implementation steps of the IDA method in detail, the author carried out IDA analysis for the model under ten original motion records and obtained multiple motion records of the IDA curve. After statistical analysis and obtained different quantile IDA curves, the paper compares the results obtained with the results of Pushover analysis such as vertex displacement, base shear, the plastic hinge distribution and proves that the pushover analysis method can be adopted to evaluate the seismic performance of the pier-pile structure.