Statistical Inversion Approach for Stress Estimation Based on Strain Monitoring in Continuously Pre-Stressed Concrete Beams

Huibing Xie,Wutong Yan,Peng Jiang,Bing Han

doi:10.3390/app112110161

Abstract

Stress is one of the most important physical indexes reflecting the mechanical behavior of concrete structures. In general, stress in structures cannot be directly monitored and can only be estimated through an established model of stress and strain. The accuracy of the estimated stress depends on the rationality of the established model for stress and strain. As the strain measured by sensors contains creep, shrinkage, and elastic strain, it is difficult to establish an analytical model for strain and stress. In this paper, a statistical inverse method was utilized to estimate the stress in continuously pre-stressed concrete beams based on the monitored strain. Stress in the beams and the model uncertainty factors were treated as model parameters. A linear-simplified method was adopted to determine the prior distribution of the stresses. The posterior distribution of the stresses at different locations during bridge construction can be obtained by the proposed method. A continuously pre-stressed concrete beam bridge was taken as the case study to verify the effectiveness of the proposed method. Additionally, the constitution of the total strain in the different construction stages was calculated. It was concluded that the creep strain is the dominant part of the total strain.

Highlights

This study proposed a statistical inverse method to evaluate stress in concrete beams based on the monitored strain
Stage 1: Since the external load was not first applied to the beam, the monitored strain was mainly composed of the shrinkage strain
This study proposed a monitored strain-based statistic inverse analysis method for the estimation of stress in different stages of pre-stressed concrete (PC) beam bridge construction

Summary

Introduction

The structural evaluation method of bridges based on longterm monitoring and inspection data has been widely used in practical engineering [2,3,4]. It is challenging to properly evaluate the structural behavior of bridges according to the monitoring results [5,6]. De Domenico et al [1] proposed that a combined experimental–numerical method for bridge evaluation would be more effective. The monitored data from the full-scale bridge can be used for updating the model used in the numerical method. For the most commonly used structural evaluation system, the criteria used to assess the condition of a bridge structure are generally based on the stress index [7,8,9]. Stress is more direct and important for structural evaluation based on material strength

Results

Discussion

Conclusion