钢-UHPC轻型组合桥面板横向受力性能

Transversal Mechanical Behavior of Steel-UHPC Light-weighted Composite Bridge Deck System

为研究一种正交异性钢-超高性能混凝土(UHPC)轻型组合桥面结构,在局部车轮荷载作用下的横向受力性能与横向受力组成,进行了足尺模型静载试验和有限元数值模拟。静载试验对同一足尺模型分别进行了横向简支工况和横向悬臂工况的加载试验,通过边界条件的变化来模拟组合桥面板不同的受力状态,并将试验结果与有限元分析结果进行对比,验证有限元模型的正确性,而后利用有限元模型的分析结果,得到组合桥面板在局部车轮荷载下的横向受力组成。研究结果表明:组合桥面板在车轮荷载作用下,其横向受力局部效应明显,横向应力主要局限于荷载作用区域附近的两道U肋范围内;在车轮荷载影响区域内,由横肋弯曲产生的桥面板整体附加弯矩的影响很小,组合桥面受力以第3体系为主,相应截面弯矩达到了总弯矩的75%,而在其他区域,第3体系受力所占比重迅速衰减,组合桥面受力以第2体系为主;加载至300kN时,组合桥面板受力仍处于弹性阶段,UHPC层顶面最大横向应力达到11.9 MPa仍未开裂,满足设计要求。

In order to investigate the transversal mechanical behavior and the composition of transversal stresses of a light-weighted composite bridge deck system with orthotropic steel deck and ultra high performance concrete （UHPC） layer under local wheel loads, static loading test of the full-scale model and finite element numerical simulation were conducted. The static loading tests were carried out on the same full-scale model under the simply supported conditions in the transverse direction and transverse cantilever conditions, whilst the stress state of the composite deck was simulated by changing the boundary condition. The finite element analysis results were compared with experimental values to verify the correctness of the finite element model. The transverse force composition of the composite bridge deck under local wheel load was ohtained in view of the finite element analysis. The results show that the transversal stress of the composite deck under vehicle loads has an obvious local effect and the transverse stress is mainly confined to the two U-ribs near the load-bearing area. The effect of the additional bending moment of the bridge deck caused by the bend of the transverse rib is slight. Meanwhile, the primary stress of the composite deck concentrates on the third structural system, and bending moment of the corresponding section accounts for 75 % of the total. The proportion of the third structural system stress decreases rapidly out of this region and the second structural system stress becomes the major force. The composite bridge deck is still in elastic stage when the load increases to 300 kN. The UHPC layer is still not cracked, when the maximum transversal stress on top of UHPC layer is 11.9 MPa. Hence, the stress meets the design requirement.