Study On Load Test Of Self-anchored Suspension Bridge Based On Robust Regression Analysis

In recent years,the self-anchored suspension bridge develops rapidly,and how to evalu-ate its bearing capacity accurately,efficiently and economically is also a hot spot of many scholars.Now there are few literatures about the load test of it.Based on the robust regression analysis,the paper constructed the model to predict the reaction of structure under high load efficiency to achieve the load efficiency coefficient reduction optimization.This was not to the norms of negation.It was of great significance to classify the check coefficient of the bridge based on probability statistics and to provide reference for the evaluation of Baishi bridge bearing capacity.The paper taked Midas/Civil to establish the accurate Baishi bridge finite element model,according to the"Load Test Methods for Highway Bridge"(JTG/T J21-01-2015)to determine the static and dynamic load test scheme and implement it on site.The main research work on this paper was as follows:(1)The application of robust regression analysised in bridge engineering,the calculation theory of self-anchored suspension bridge and its nonlinear factors.The project overview and modeling ideas of Baishi bridge were introduced in detail.(2)The linear regression equation of load efficiency and structural response was estab-lished by hierarchical loading data.The structural response underη_q=0.95~1.05 could be predicted by the hypothesis testing equation.The prediction function was established with a smaller load efficiency,and the prediction error met the engineering requirements,so as to reduce and optimize the load efficiency coefficient.The correctness of this method was veri-fied by the maximum deflection of the main girder of the Zicai bridge and the maximum de-flection of the tower.(3)Based on the domestic multi-seat self-anchored suspension bridge load test literature,the probability of a partial testing coefficients was 95%confidence interval determined by the probability statistics.It was important for the procedure to establish a detailed and reasonable evaluation basis for the testing coefficient of A(superior),B(good),C(middle),D(differ-ence),and E(bad).(4)The design of Baishi bridge’s static load test was reasonably formulated.And the dynamic test scheme was determine and conductd on-site implementation.According to the test results,the actual bearing capacity and natural vibration characteristics of Baishi bridge and the impact analysis under driving were provided to offer reference for the later period maintenance.The analysis showed that the regression analysis method was feasible in the load test of self-anchored suspension bridges,and the load efficiency coefficient could be reduced to 0.7.Steel girder self-anchored suspension bridge partial testing coefficients could be established A(excellent),B(good),C(medium),D(poor),E(bad)meticulous classification criteria.The static load test of Baishi bridge showed that the working conditions of the main girder,tower column and sling were good and met the design requirements.The measured frequencies of fluctuation test were all larger than the values and the first six vibration modes were basically the same as the theoretical ones.The calculated impacted coefficient of non-obstacle driving was around 0.04 and obstacle driving impacted on the bridge significantly.It was proposed to periodically maintain the bridge deck.