新型波形钢腹板组合箱梁桥动力性能分析

Dynamic analysis of new corrugated steel web composite box girder bridge

对一种新型波形钢腹板组合箱梁桥结构开展了动力特性及抗震性能分析;以鄄城黄河大桥跨中箱梁段为例,建立组合箱梁桥的多尺度有限元模型,并与实测值进行了对比,验证了多尺度模型的有效性;基于此设计了该新型波形钢腹板组合箱梁的截面参数,采用多尺度建模方法研究了各参数变化对箱梁动力特性的影响规律,通过地震反应谱法分析了该结构在各向地震作用下的结构响应。结果表明:箱梁横隔板的数量和厚度是结构动力特性的敏感参数,对结构的扭转刚度影响很大;增大波形钢腹板厚度可有效提高结构刚度,且刚度增大对频率的影响程度大于质量增大对频率的影响,建议腹板厚度宜设为20~30 mm;槽形钢板可有效提高截面的抗弯刚度,尤其对结构竖向弯曲模态影响较大;横向地震作用对混凝土顶板和横隔板应力的影响最大,纵向地震力对波形钢腹板应力的影响最大,竖向地震力对混凝土底板和槽形钢板的应力影响较大。

The dynamic characteristics and seismic performance analysis were conducted on a new type of corrugated steel web composite box girder bridge structure.Taking the mid-span box girder section of the Juancheng Yellow River bridge as an example,a multi-scale finite element model of the composite box girder bridge was established and compared with the measured values,and the effectiveness of the multi-scale model was verified.Based on this,the cross-section parameters of the new type of corrugated steel web composite box girder were designed,and the influence of parameter changes on the dynamic characteristics of the box girder was studied using a multi-scale modeling method.The structural response of the structure under muti-directional seismic action was analyzed using the seismic response spectrum method.The results show that the number and thickness of box girder diaphragms are sensitive parameters of structural dynamic characteristics,which have a significant impact on the torsional stiffness of the structure.Increasing the thickness of the corrugated steel web can effectively improve the structural stiffness,and the impact of stiffness increase on frequency is greater than that of mass increase.It is recommended to set the web thickness to 20-30 mm.Groove steel webs can effectively improve the bending stiffness of the cross-section,especially have a significant impact on the vertical bending mode of the structure.The transverse seismic action has the greatest impact on the stress of the concrete top plate and diaphragm,the longitudinal seismic force has the greatest impact on the stress of the corrugated steel web,and the vertical seismic force has a greater impact on the stress of the concrete bottom plate and groove steel plate.