大跨斜拉桥扁平钢箱梁的多尺度损伤分析研究

以润扬大桥斜拉桥为分析对象,提出了扁平钢箱梁结构的多尺度损伤分析方法。采用子结构方法将钢箱梁结构全尺度动力响应和细节尺度构件损伤相互衔接实现多尺度损伤分析。在此基础上对模态曲率、模态应变能、模态柔度和斜拉索索力指标的损伤识别效果进行了比较研究。分析结果表明:(1)无噪声情况下,除了模态柔度指标不能够正确识别钢箱梁腹板损伤以外,各损伤指标均能正确识别其余所有损伤工况。(2)对大多数情况,柔度指标的抗噪性最好,曲率指标和应变能指标次之,索力指标最差;(3)应变能指标和柔度指标在钢箱梁结构损伤定位上具有一定的互补性。

MULTI-SCALE DAMAGE ANALYSIS FOR STEEL BOX GIRDER OF LONG-SPAN CABLE-STAYED BRIDGES

The multi-scale damage analysis method for steel box girder is presented with respect to Runyang Cable-stayed Bridge. The full-scale dynamic responses and fine-scale local damage of steel box girder are connected by the substructure method to realize structural multi-scale damage analysis. The modal curvature index, modal strain energy index, modal flexibility index and cable tension index for damage localization of steel box girder are further comparatively investigated. The analysis results show that (i) in the absence of noise, all damage indices can properly identify structural damage cases of steel box girder except the damage case of ventral plate using the modal flexibility index; (ii) for most damage cases, flexibility index is the best of the four indices in anti-noise and the cable tension index is the worst; (iii) modal strain energy index and modal flexibility index are complementary to each other in damage location identification for steel box girder.