预应力UHPC连续刚构桥的优化设计

为了充分发挥UHPC的材料特性,通过有限元和理论分析,从箱梁截面尺寸和体内、外预应力配置两个方面对苏通大桥辅航道桥进行优化设计,提出了体外预应力UHPC结构的抗弯强度简化计算公式,并将其静力特性和经济性与普通混凝土刚构桥进行了对比分析.结果表明,在满足规范规定强度和刚度的要求下,UHPC主梁比一般混凝土主梁的自重减轻约43%,抗弯承载力提高80%以上.上部结构的减重提高了箱梁抵抗使用阶段荷载的有效性,有利于提高预应力混凝土梁桥的经济跨径.

Optimization design for prestressed UHPC continuous rigid frame bridge

In order to give full play to the material properties of UHPC, an optimization design for the auxiliary shipping channel bridge of Sutong bridge was conducted from two aspects of the sectional dimension of box girder and the configuration of internal and external prestress through both finite element analysis and theoretical analysis. A simplified calculation formula of bending strength of UHPC structure with external prestress was proposed, and the static and economic characteristics of UHPC structure were compared and analyzed with those of an ordinary concrete rigid frame bridge. The results show that under the condition of meeting the requirements of strength and stiffness in the specification, the dead weight of main UHPC girder is approximately reduces by 43% and the bending capacity increases by over 80% than those of the general concrete girder, respectively. The weight decrease of superstructure raises the effectiveness of box girder to resist the loads in the service stage, and is beneficial to increasing the economic span of prestressed concrete beam bridge.