部分预应力混凝土梁按使用性能的设计

The Design of Partial Prestressed Concrete Beam According to the Behaviour in Service

本文根据部分预应力混凝土梁正截面极限强度要求,引入预应力度β和总配筋指标q_o概念,导出了计算预应力和非预应力钢筋截面积和开裂截面各项应力基本公式。对部分预应力混凝土梁提出了一种合理的分析方法和计算步骤,便于在桥梁设计中应用。通过对30米标准跨径梁桥的主梁计算,结果表明,按本文公式计算的部分预应力混凝土梁,与全预应力混凝土相比,既节约了高强钢筋,改善了结构的性能,减少了反拱度,又能满足裂缝宽度和各项应力条件的要求。

Based on the reqirements of ultimate strength for partial prestressed concrete beam, the degree of prestressed force β and the total allocating-steel quata q_o will be introduced into the analysis. The expressions of ma gnitude of the prestressed-steel, the nonprestressed-steel and the stress in the cracked cross-section have been developed in this paper. The reasonable analysis method and the computing steps are presented for partial prestressed concrete beam-bridges. By means of calculating the prestressed concrete T-beam-bridge on which the standard span is equal to 30 metres, the result shows that the partial prestressed concrete bridges can be economical in the use of high-tensile steel wires, improve the behaviors of structure and meet the reqirements of cracked width and the stress conditions.