节段预制桥梁胶接缝配筋剪力键剪切性能试验

针对节段预制桥梁胶接缝设计普遍采用剪力键作为连接形式，制作3组共计16个匹配预制的胶接缝剪力键试件，考虑剪力键键齿齿目、键齿配筋形式以及是否配有体内束3种因素，进行直剪试验研究，以得到这些因素对胶接缝的开裂荷载、极限荷载、变形、裂缝开展模式以及最终的破坏模式的影响规律。研究结果表明：与素混凝土键齿胶接缝相比，三键齿配筋的胶接缝剪力键抗剪承载力平均提高4.52%，双键齿配筋胶接缝剪力键抗剪承载力平均提高8.73%，而布置体内束的胶接缝剪力键的抗剪承载能力提高率能达到18.6%，远大于键齿配筋；剪力键键齿配筋和布置体内束可以明显提高剪力键破坏时的延性，降低开裂荷载与极限荷载的比值，改变开裂形式；键齿处配筋使得剪力键的破坏形式从原来的素混凝土键齿根部脆性破坏变为键齿配筋处的保护层脱落破坏；布置体内束，键齿中的裂缝增多，尤其是斜裂缝发展更加充分和密集。为了方便预测胶接缝剪力键的抗剪承载能力，根据胶接缝的传力机理，依据莫尔-库仑摩擦破坏准则，并结合AASHTO规范与Buyukozturk的试验研究成果，提出了预测胶接缝配筋剪力键直剪承载力的抗剪承载力计算公式，同时将分析结果与试验结果进行对比，吻合良好。

Experiment of Shear Performance of Epoxy Resin Joints with Reinforced Keys in Precast Concrete Segmental Bridge

Epoxy resin joints with shear keys are popular in the design of precast concrete segmental bridges. To investigate the effects of the number of shear keys, internal tendons, and multiple reinforced keys on the shear capacity of the epoxy resin joints of precast concrete segmental bridges, three groups of 16 full-depth male-female shear key specimens were cast and tested. The crack load, ultimate load, relative slip distance, and crack pattern of these epoxy resin joints with castellated keys were investigated in detail. The test results show that compared with epoxy resin joints with plain concrete keys, the average ultimate shear strength of epoxy resin joints with three reinforced keys, two reinforced keys, and internal tendons increased by 4.52%, 8.73%, and 18.6%, respectively. The layout of internal tendons crossing the joint and reinforcing bar in keys not only enhanced the ductility of the epoxy resin joints but also decreased the ratio of crack shear load to ultimate shear load, and even changed the crack pattern. The failure of epoxy resin joints changed from the shear keys brittle shedding to the cover of reinforcements in key stripping due to the layout of reinforcements in keys. Additional diagonal cracks also appeared and developed more deeply due to the layout of the internal tendons. Finally, according to the force transfer mechanism of epoxy resin joints and the Mohr-Coulomb principle, a formula for predicting epoxy resin joints with reinforced key is proposed by combining the American Association of State Highway and Transportation Officials code and the observed results of Buyukozturk's test, and comparison with test data showed good agreement.