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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。
In order to provide the basis for design calculation and construction tension control of the prestressed high strength soft steel wire reinforced polymer mortar reinforcement method, the initial tension of the steel wire bundle, which is calculated by the construction torque, is proposed by five steel wire bundle tension tests. Then the calculation formulas of the two beams are obtained. Then the bending tests of two reinforced prestressed high strength steel wires plus polymer mortar reinforced rectangular beams and one comparative beam are completed. The crack resistance, flexural capacity and stiffness of the reinforced beams are studied Enhance the effect and ascertain the failure mode of the reinforced beam; at the same time, define the characteristic states of the cracked, yield and flexural strength of the reinforced beam; deduce the cracking, yielding, ultimate bending moment, cracking, The calculation formula is designed, and the theoretical calculation results are compared with the test results. The results show that the prestressed high-strength soft steel wire reinforced with composite mortar, the more steel wire, the smaller the crack width under the same load level, indicating prestressed soft steel wire bundle can better inhibit the original concrete structure cracks Compared with non-reinforced beam, the crack resistance of the reinforced beam increased by 60.3% -101%, the flexural capacity increased by 17.3% -35.8%, and the midspan deflection decreased by 10.4% -27.4% Crack resistance, flexural capacity and stiffness were significantly improved. The design formula of the initial tension of steel wire bundle, the characteristic bending moment of the reinforced beam during cracking, yielding and the ultimate state, and the theoretical calculation method of mid-span deflection during cracking and yielding were The test results are in good agreement with conservative results, which can meet the accuracy requirements of engineering applications.