基于灰色理论对桥梁荷载试验的控制

Bridge Load Test Based on the Grey Theory

目的为了避免在桥梁检测中由于加载过大造成桥梁结构的损伤,研究基于函数cos(x^2)变换的灰色预测模型,提供一种预测桥梁在加载过程中产生内力的方法,并以此作为控制加载的一个途径.方法以斜拉桥混凝土箱梁的最大负弯矩工况的分级加载为例,采用基于函数cos(x^2)变换的灰色模型对该工况的箱梁内力进行预测.加载试验分为5级加载,整理前4级加载时的混凝土箱梁产生的内力值数据,再采用基于函数cos(x^2)变换的灰色模型对其分析,并对第5级加载时的混凝土箱梁产生的内力值进行预测,将预测值与实际值进行对比,验证其预测精度.结果预测的每一级的数值的预测精度都在97%以上,达到预测精度的要求.结论采用基于函数cos(x^2)变换的灰色模型对加载时的混凝土箱梁内力值的预测比较准确;基于函数cos(x^2)变换的灰色模型预测桥梁加载时的内力值的方法可行.

In order to avoid the damage of bridge structure caused by excessive loading in bridge detection, the grey forecasting model based on function cos（X^2） transform is studied to predict the internal force of a bridge during the loading process. The intemal force of box girder is predicted based on function cos （X^2 ） transformation when the concrete box girder of cable stayed bridge is in the maximum negative moment. The loading test is divided into 5 stages. The internal force value of the concrete box girder in the last stage loading is predicted by the grey model based on function cos （X^2） transform after the values of the first 4 levels predicted. The forecast accuracy is verified by comparing the predicted value with the actual value. The prediction accuracy of each level is a- bove 97 %. So it is feasible to predict the internal force value of bridge loading by the grey model based on function cos （ X^2 ） transform, which can be used as a useful way to control the loading process in the static load test.