综合施加预应力法加固钢筋混凝土板桥理论及试验

Theory and Experiment of Reinforced Concrete Slab Bridges Reinforced by Comprehensive Method of Post-tensioned and Pre-tensioned Prestressing

为了降低加固钢筋混凝土板的成本,提出一种综合采用后张法和先张法加固钢筋混凝土板桥的新方法。通过对砂浆层施加预压应力,可采用低廉的普通高强水泥砂浆代替高强聚合物砂浆。阐明了该方法的加固思想、设计理论及施工工艺;并通过钢筋混凝土板的模型试验,对试验测试值与理论计算值进行了分析,验证了该方法的可行性。结果表明:该方法的加固理论正确,能够在覆盖钢丝的砂浆层中建立起预压应力,并依靠结合面上界面剂的粘结作用,确保砂浆不剥离,施工工艺可行,加固成本大幅降低,覆盖砂浆所需的预压应力取决于加固后荷载对计算截面砂浆层边缘产生的拉应力及砂浆层与构件结合面的剪切强度两者中的较小值,而且截面受力性能更好。

In order to reduce the cost of reinforced concrete slabs, a new method of comprehensive post-tensioning and pre-tensioning was presented for strengthening reinforced concrete slabs withparallelly laid prestressed steel wire. The method also preloaded stress in mortar layer with common high-strength cement mortar of low cost instead of high-strength polymer mortar. Thereinforcement idea, design theory and construction techniques of the method were elaborated, and through model test of a reinforced concrete slab, the test values and the design values had beenanalyzed to verify the feasibility of this method. The results show that the reinforcement theory of the method is correct and the preloaded stress can be set up in the mortar layer covering steelwire, which relies on the bonding effect of the interface agent on joint surface to ensure that mortar does not peel. The construction method is also feasible. Through the method, commonhigh-strength cement mortar can reduce the cost greatly and the required pre-stress of mortar layer depends on the smaller value of the tensile stress of mortar layer generated by the load afterreinforcement, and the shear strength of the joint surface of mortar layer and the component, andthe mechanical properties of cross-section will be better.