Mathematical Modeling for Lateral Displacement Induced by Wind Velocity Using Monitoring Data Obtained from Main Girder of Sutong Cable-Stayed Bridge

Gao-Xin Wang,You-Liang Ding

doi:10.1155/2014/723152

Abstract

Based on the health monitoring system installed on the main span of Sutong Cable-Stayed Bridge, GPS displacement and wind field are real-time monitored and analyzed. According to analytical results, apparent nonlinear correlation with certain discreteness exists between lateral static girder displacement and lateral static wind velocity; thus time series of lateral static girder displacement are decomposed into nonlinear correlation term and discreteness term, nonlinear correlation term of which is mathematically modeled by third-order Fourier series with intervention of lateral static wind velocity and discreteness term of which is mathematically modeled by the combined models of ARMA(7,4)and EGARCH(2,1). Additionally, stable power spectrum density exists in time series of lateral dynamic girder displacement, which can be well described by the fourth-order Gaussian series; thus time series of lateral dynamic girder displacement are mathematically modeled by harmonic superposition function. By comparison and verification between simulative and monitoring lateral girder displacements from September 1 to September 3, the presented mathematical models are effective to simulate time series of lateral girder displacement from main girder of Sutong Cable-Stayed Bridge.

Highlights

Nowadays, long span cable-stayed and suspension bridge structures are commonly constructed at home and abroad
Based on monitoring data from main girder of Sutong CableStayed Bridge, time series of lateral girder displacement effect are mathematically modeled by methods of fitting Fourier series and Gaussian series, combined models of ARMA(7,4) and EGARCH(2,1), and harmonic superposition function
(1) Scatter plots between lateral static wind velocity and lateral static displacement present apparent nonlinear correlation, which is similar to quadratic parabolic curve, and time series of lateral dynamic displacement contain obvious stable power spectrum density with no variation by time

Summary

Introduction

Long span cable-stayed and suspension bridge structures are commonly constructed at home and abroad. According to aerostatic response analysis on Sutong Cable-Stayed Bridge by Xu et al, the lateral displacement response from main girder can approach 1.2 m under strong wind velocity 40 m/s with attack angle 0∘ [1]; and research results from buffeting response analysis on Golden Gate Bridge by Vincent showed that extreme buffeting amplitude from main girder can reach 1.7 m under strong wind velocity 31 m/s [2]. Such large amplitude can definitely threaten comfort and safety of the whole bridge structure. By comparison and verification between simulative and monitoring lateral displacements from September 1 to September 3, mathematical models are feasible and effective to simulate time series of lateral girder displacement from main girder of Sutong CableStayed Bridge

Bridge Monitoring and Sample Analysis

Modeling for Static Girder Displacement

Modeling for Dynamic Girder Displacement

Model Test and Evaluation

Conclusions