中文摘要：

为了解竖向接缝对预应力混凝土箱梁桥抗剪性能的不利影响及改进措施,以七里坪 湘江大桥预应力混凝土梁为原型,设计制作4片预应力混凝土模型梁进行跨中单点加载试验,分析 各模型梁在试验过程中的裂缝发展情况、破坏形态和抗剪承载力,研究交界面粗糙度和普通钢筋配 筋率对抗剪性能的影响.结果表明：各模型梁的裂缝发展过程基本相似,破坏形态均为弯剪破坏; 带竖向接缝梁的抗裂性能比整体浇筑梁差,但各梁的抗剪承载力相差不大;带竖向接缝梁的刚度低 于整体浇筑梁的刚度;增加接缝处混凝土交界面粗糙度和普通钢筋配筋率可以提高带竖向接缝梁 的抗裂性能和刚度.

英文摘要：

T o in v e s t ig a te th e ad v erse inf lu en ces of th e v ert ic al jo in ts on th e sh e a r b eh av io r of prest ressed concrete （PC） box girder and the related improvement measures against the influences, the PC box girder of the Qiliping Xiangjiang River Bridge was taken as the prototype, 4 model PC box beams were designed, prepared and the tests of the single point loading at the midspans of the beams were made. The crack propagat ion, fai lure modes and shear bear ing capacity of the model beams in the tests were analyzed and the inf luences of the concrete inter face roughness and the common reinforcement rat ios on the shear behavior of the beams were studied. The results show that the crack propagat ion processes of the various model beams are basically simi lar and the fai lure modes are all the bending shear fai lure. The cracking behavior of the beams wi th the vert ical joints is poorer than that of the monol ithically cast beams, but the shear bearing capacity of the beams does not dif fer great ly. The r igidi ty of the beams wi th the vert ical joints is lower than that of the monol ithically cast beams and the increase of the concrete inter face roughness and the common re-inforcement rat ios at the vert ical joints can improve the cracking behavior and r igidi ty of the beams wi th the ver t ical joints.