无粘结部分预应力砼梁裂缝宽度的试验研究  

Research on Calculation of Crack Width of Unbonded Partially Prestressed Concrete Beams

作　　者：赵国藩[1] 文明秀 

机构地区：[1]大连理工大学

出　　处：《建筑结构学报》1991年第3期24-34,共11页Journal of Building Structures

摘　　要：本文报告了33根矩形截面直线配筋和2根T形截面配置曲线预应力筋的无粘结部分预应力砼梁的裂缝宽度的试验研究成果。试验表明,在无粘结预应力砼梁中配置普通有粘结筋对梁在开裂后的裂缝分布有重要影响。本文分析了影响裂缝宽度的主要因素,根据预应力筋与周围砼无粘结而可互相滑动的特点,提出了将预应力筋对砼的预压力作为截面上的纵向压力,求解与弯矩共同作用下普通有粘结筋的应力(?),而后引用普通钢筋砼构件裂缝宽度的公式计算普通钢筋(?)水平处的裂缝宽度和近似计算预应力筋(?)。水平处的裂缝宽度。用本文33根矩形截面梁的裂缝宽度试验数据及文献[2]的数据对所建议的计算方法进行了校核,符合程度较好。此外用本文报告的2根6m跨长配置曲线预应力筋的无粘结部分预应力砼T形梁进行了补充验证,得出最大裂缝宽度的计算值略大于试验值而偏于保守。最后对最大裂缝宽度允许作了讨论。This paper presents the test results of the crack widths of 33 unbonded partially prestressed concrete beams with rectangular cross-sections and linear prestressed reinforcement as well as 2 unbonded partially prestressed concrete beams with T-shaped cross-sections and curved prestressed reinforcement. Test results show that th'e additional nonprestressed reinforcement significantly affects the crack widths of unbonded partially prestressed concrete beams. This paper also studied the main factors that affect the crack widths of unbonded partially prestressfed concrete beams. As the prestressed steel can move freely in the unbonded prestresed concrete beams, the prestressing force can be considered as an eccentric co-mpressive loading acting on the cross-section in calculating the crack width. Therefore the crack width of unbonded partially prestressedconcrete beams can be calculated using the formulas propos- ed for ordinary reinforced concrete members in which the stress of additional nonprestresscd steel under the combined action of pre-stressingforce and characteristic moment is integrated. The crack widths calculated by this proposed method agree well with the test results of the 33 beams and these given in Ref. [2]. The calculated maximum values of crack widths for the tested T beams with a span of 6m are somewhat greater than the test values, the latter being rather conservative in practical design. Finally the allowable maximum crack width was also discussed in the paper.

关 键 词：无粘结 预应力 混凝土 梁 裂缝 

分 类 号：TU378.203[建筑科学—结构工程]