预应力后张和先张法联合加固受弯板试验研究

采用预应力钢丝平铺布置加固混凝土受弯板时,若用高抗拉强度的复合砂浆覆盖钢丝成本太高.针对这种情况,提出用普通高强水泥砂浆代替前述砂浆,采用预应力钢丝后张法和先张法联合加固的新方法施加预压应力,使板受拉区混凝土及覆盖砂浆均产生预压应力.详细阐明了该方法的原理和实施工艺,通过钢筋混凝土受弯板的加固试验研究和数值计算分析,表明该方法的加固原理和施工工艺是可行的.其关键是需要在结合面喷涂环氧类界面剂,以保证结合面不产生剥离破坏.从而无需使用昂贵的高抗拉强度复合砂浆,降低加固成本,且经加固处理后截面受力性能更好.

Experimental Study of the Strengthening Concrete Bending Slab Using Prestressed Post-tensioning and Pre-tensioning Combined

When a parallel arranging prestressed steel wire is used to strengthen concrete bending slabs,the cost is too high if the steel wire is covered with high tensile strength composite mortar.Aiming at this,a new strengthening method was proposed,in which was combined with pre-tensioning prestressing steel wire,and common high-strength cement mortar was used to replace post-tensioning the former mortar.This method can prestress on the tension zone of the concrete slab and cover the mortar layer.And the feasibility of the strengthening principle and construction technology were demonstrated by strengthening the experimental study and numerical analysis about the model test of a reinforced concrete bending slab,which shows that the premise is to spray epoxy interface agent on the joint surface in order to ensure that the joint surface does not produce detachment of the destruction.So this method can avoid using expensive high tensile strength composite mortar,the strengthening cost can be reduced,and the mechanical properties of cross-section after reinforcement can be enhanced.