Lateral vibration analysis of continuous bridges utilizing equal displacement rule

Abstract

The application of equal displacement rule simplifies the evaluation of lateral displacement demand forSDOF system. For complex multi-degree-of-freedom (MDOF) structures such as continuous bridge systems, however, it requires more investigations. In this paper, a comprehensive parametric study of the ratio of maximum inelastic displacement to maximum elastic displacement for typical continuous bridges is performedto advance the application of equal displacement rule to MDOF systems. Particurlarly for the bridges with long periods, this adapted methodlogy is further simplified. It is concluded that equal displacement rule of MDOF is applicable to continuous bridges when the periods of the main modes are no less than the limiting period, which usually serves as an indication to the level of inelastic deformation for a bridge subjected to an earthquake. Key wordsEqual displacement rule, limiting period, continuous bridges, simplified seismic analysis, displacement demand Lateral vibration analysis of continuous bridges utilizing equal displacement rule INTRODUCTIONThe performance-based seismic design philosophy has been sufficiently developed to design a structure system to withstand a pre-defined level of damage under a pre-defined level of earthquake intensity. Displacement-based seismic design is an efficient and accurate method to achieve the performance-based seismic design philosophy, and it has been proposed and developed in recent years (Kowalsky, 2002;Jameel, Islam, Hussain, et al., 2013). In this methodology, the displacement demand of the designed structure should be close to the target displacement, which reflects the predefined level of damage of earthquake intensity. Therefore, to obtain the displacement demand of structure is an important step. Although analytical methods are widely utilized to calculate the displacement demand of structure, the analysis processes of currently available methods are relatively complex (Chopra and Goel, 2002;Wei, 2011;Akhaveissy, 2012). Hence, it is desired to develop a simplified method herein to obtain the displacement demand to facilitate displacement-based seismic design.

Modified generalized pushover analysis for estimating longitudinal seismic demands of bridges with elevated pile foundation systems

“…The adaption included "the selection of the appropriate control point, the way a pushover curve is bilinearized before being transformed into a capacity curve, the use of the capacity spectrum for defining the earthquake demand for each mode and then combining modal responses, and the number of modes that should be considered in the case of bridges". Biao Wei et al have applied equal displacement rule to continuous bridges with long periods (Wei, 2014). Their work is mainly on applying MPA in the transverse direction of a curved bridge.…”

Parameter optimization of damper-friction isolation systems using concave friction distribution

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