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部分预应力混凝土结构的裂缝宽度控制一直是工程界和理论界所十分关注的问题,也是人们争议最多的问題之一。本文在分析前人的研究结果和实践经验的基础上,强调用限制钢筋应力增量的办法来控制裂缝宽度的合理性和重要性。针对六片无粘结部分预应力混凝土梁的静力和疲劳试验结果,分析了重复荷载作用之后裂缝宽度和普通钢筋中残余应力的发展规律,提出了考虑该残余应力的重复荷载作用N次之后的裂缝宽度计算公式,并给出了一个初步的、用于限制部分预应力混凝土梁裂缝宽度的钢筋中应力增量的限值。
Crack width control of partially prestressed concrete structures has always been a concern of engineering and theoretical circles and one of the most controversial issues. Based on the analysis of the predecessors’ research results and practical experience, this paper emphasizes the rationality and importance of controlling the crack width with the method of limiting the stress increment of reinforcement. According to the static and fatigue test results of six unbonded prestressed concrete beams, the law of crack width and the residual stress in ordinary steel after repeated loading is analyzed. The effect of repeated loading considering this residual stress is given N times The formula for calculating the crack width is given and a preliminary limit value of the stress increment in the steel bar for limiting the crack width of the partially prestressed concrete beam is given.