密集横隔板UHPC箱梁桥面板双向受力性能试验

Bidirectional Mechanical Behavior Experiment of UHPC Box-girder Bridge Deck with Dense Diaphragms

针对一种超大跨径单向预应力超高性能混凝土(UHPC)连续箱梁桥,为探讨其具有密集横隔板构造的桥面板在局部轮载作用下的双向受力性能,开展了1∶5缩尺模型试验和有限元数值模拟,并以此为基础,对桥面板的轮载双向分配与控制截面内力计算问题进行了初步推导与计算。结果表明:5.5倍设计车轮局部荷载作用下,试验工况桥面板仍处于线弹性受力阶段;具有密集横隔板构造的UHPC箱梁桥面板属双向受力构件,纵桥向成为主受力方向;线弹性受力阶段,最不利正弯矩工况下桥面板轮载纵横桥向分配比在疏隔板侧约为1∶0.64,在密隔板侧约为1∶0.53,轮载分配趋于均匀,桥面板受力效率提高;桥面板负弯矩以横隔板支承处纵桥向弯矩为控制值,现行规范的内力算法应用于该桥面板尚存在一定偏差。

Aiming at probing into a super-long span continuous box-girder bridge composed of one- way prestressed ultra-high-performance concrete （UHPC）, the bidirectional mechanical behavior of the bridge deck with dense diaphragms under local wheel loads was discussed. Meanwhile, test study and finite element simulation of a model diminished in scale of 1 ： 5 were performed. On this basis, the bidirectional distribution of the wheel loads and the internal forces of controlling sections were deduced and calculated preliminarily. The results show that the bridge deck is still in the linear elastic loading stage when carrying 5.5 times of the designed local wheel loads under test condition. Besides, the UHPC box-girder bridge deck with dense diaphragm structures behaves as a bidirectional load member, with a main loading direction of deck＇s longitudinal direction. During the linear elastic loading stage, the distribution ratio of the wheel load in longitudinal direction to that in horizontal direction is 1 ： 0.64 at the side of sparse diaphragms and 1：0.53 at the side of dense diaphragms under the most unfavourable positive bending moment. This proves that the wheel load distribution of the bridge deck tends to be uniform andthe load negative still hay carrying efficiency of the bridge deck is of the bridge deck at the position of bending moment; the calculation meth e certain deviations. repro iaphr ds of ed. Furthermore, the longitudinal bending gm serves as the controlling value of the nternal forces in the current design criteria