为研究组合梁在负弯矩作用下的混凝土开裂机理及裂缝发展规律,以提出更好地适用于钢-混凝土组合梁桥的裂缝宽度计算公式,对3根反向加载的钢-混凝土简支组合梁和3根2跨连续组合梁进行了静载试验。试验表明,混凝土板中横向钢筋间距对组合梁的裂缝间距具有较大影响。根据试验结果并结合其它的研究成果,将横向钢筋间距和配筋力比作为主要影响参数,给出了混凝土桥面板的裂缝间距计算公式,并对现行规范中的钢筋应变不均匀系数进行了修正。计算所得的裂缝宽度与试验值吻合良好,可为组合梁桥裂缝宽度验算提供参考。 In order to study the crack initiation mechanism and crack propagation law of composite beams under the action of negative moment, a formula to calculate the crack width which is better applied to the composite beam-steel-concrete composite beams is proposed. Three steel-concrete simply supported The composite beam and three 2-span continuous composite beams were subjected to static load test. The tests show that the transverse bar spacing in concrete slab has a great influence on the crack spacing of composite beams. Based on the test results and other research results, the transverse reinforcement spacing and reinforcement ratio are taken as the main influence parameters. The formula for calculating the crack spacing of concrete bridge deck is given, and the non-uniformity coefficient of reinforcement strain in current code is revised. The calculated crack width is in good agreement with the experimental value, which can provide reference for checking the crack width of the composite beam bridge.