双面组合连续梁裂缝扩展机理与裂缝宽度研究

Study on Crack Propagation Mechanism and Crack Width of Double-side Composite Continuous Beam

钢-混凝土双面组合梁是一种新型组合结构。对3根钢-混凝土双面组合2跨连续梁模型进行加载试验和有限元数值模拟研究,测得上翼缘混凝土板裂缝扩展状况,发现其主要表现为负弯矩区上混凝土板弯曲裂缝;对裂缝扩展规律与机理进行分析探讨,得到裂缝宽度随荷载增加的变化曲线;建立模型梁平面问题的ANSYS分析模型,考虑钢梁与混凝土板、受拉混凝土与钢筋间的界面滑移以及混凝土受拉产生局部损伤直至退出工作的过程,通过测量节点位移的变化得到裂缝宽度,与试验实测结果吻合良好;通过数值计算获得最大裂缝宽度与下混凝土板厚的关系。

The steel-concrete double side composite beam is a new kind of composite structure. Three pieces of 2-span double side composite continuous beam specimens with full shear connection were tested for loading and were simulated by the finite element method. Crack propagation of the upper-flange concrete slab was meas- ured, which was mainly in the form of flexure cracks in the negative bending moment region. The crack propa gation law and mechanism were analyzed, and the curve of crack width vs load was given. The specimens were modeled as a plane problem and simulated by Software ANSYS. Considering the interface slip between steel beam and concrete slab and between tension concrete and reinforing bar and the process of tension concrete from initiation to generation of local damages and till final withdrawal from operation, changes of joint dis- placements were measured to get crack widths, which were in good agreement with the test values. The rela tionship between the maximum crack width and the lower-flange concrete slab thickness was illustrated.