预应力高强软钢丝加聚合物砂浆抗弯加固性能试验与理论分析

发布时间：2018-07-29 18:31

【摘要】：为了给预应力高强软钢丝加聚合物砂浆加固方法的设计计算与施工张拉控制提供依据,首先通过5根钢丝束张拉试验提出了考虑张拉力损失、由施工扭力换算得到的钢丝束初张力设计计算公式;然后完成了2根预应力高强软钢丝加聚合物砂浆加固矩形梁和1根对比梁的抗弯性能试验,研究了加固梁的抗裂性、抗弯承载力、刚度等性能的提升效果,并探明加固梁的破坏模式;同时定义了加固梁的开裂、屈服和抗弯极限等特征状态,利用理论分析推导出加固梁的开裂、屈服、极限弯矩和开裂、屈服刚度等设计计算公式,并将理论计算结果与试验结果进行了对比。研究结果表明:混凝土梁采用预应力高强软钢丝加复合砂浆加固后,钢丝束越多、相同荷载等级下的裂缝宽度越小,说明预应力软钢丝束能较好地抑制原混凝土结构裂缝的产生和发展;与未加固梁相比,加固梁的抗裂性能提升了60.3%~101%,抗弯承载力提高了17.3%~35.8%,跨中挠度减小了10.4%~27.4%,构件的抗裂性、抗弯承载力和刚度均明显提高;钢丝束初张力设计公式、加固梁在开裂、屈服和极限状态时的特征弯矩以及开裂和钢筋屈服时跨中挠度的理论计算方法均与试验结果吻合较好,且偏于保守,能够满足工程应用的精度要求。
[Abstract]:In order to provide the basis for the design calculation and construction tensioning control of prestressed high strength soft steel wire reinforced with polymer mortar, the tensile force loss is considered through the tension test of 5 steel wire bundles. The design formula of the initial tension of steel wire bundles obtained from the conversion of the construction torsion force, and then completed the flexural performance tests of two prestressed high strength soft steel wires and polymer mortar reinforced rectangular beams and one contrast beam, and studied the crack resistance of the strengthened beams. At the same time, the characteristic states such as crack, yield and flexural limit of strengthened beam are defined, and the crack and yield of strengthened beam are deduced by theoretical analysis. The formulas of ultimate bending moment, crack and yield stiffness are designed, and the theoretical results are compared with the experimental results. The results show that the more the steel wire bundles are, the smaller the crack width of the concrete beam is under the same load grade after the prestressed high strength soft steel wire and composite mortar are used to reinforce the concrete beam. The results show that the prestressed mild steel wire bundle can restrain the crack generation and development of the original concrete structure, and compared with the unstrengthened beam, the crack resistance performance of the strengthened beam is increased by 60.33 / 101, the flexural bearing capacity is increased by 17.33.58 and the mid-span deflection is reduced by 10.4 and 27.427.427.42.The crack resistance of the members is improved. The design formula of initial tension of steel wire bundle, the characteristic bending moment of strengthened beam under cracking, yield and limit state, and the theoretical calculation method of mid-span deflection when crack and steel bar yield are in good agreement with the experimental results. It is conservative and can meet the precision requirement of engineering application.
【作者单位】：湖南大学风工程与桥梁工程湖南省重点实验室;湖南大学土木工程学院;广东省公路建设有限公司;
【基金】：广东省交通运输厅科技项目(2011-02-036) 湖南省自然科学基金项目(14JJ2046)
【分类号】：U445.72

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