钢-部分预应力混凝土连续组合梁内力重分布研究

Study on Moment Redistribution of Steel Partially Prestressed Concrete Composite Continuous Beams

本文报道了10榀钢-部分预应力混凝土连续组合梁和1榀钢-普通混凝土连续组合梁的极限承载力试验结果。试件为两跨连续梁,主要试验参数为负弯矩区部分预应力比PPR、综合力比Rp及栓钉连接程度。试验采用跨中单调一次加载。试验发现,在负弯矩区施加预应力的钢-部分预应力混凝土连续组合梁可产生较充分的内力重分布,其主要影响因素为截面相对受压区高度ξu和负弯矩区综合力比Rp。本文通过试验研究和理论分析,提出了钢-部分预应力混凝土连续组合梁满足承载力要求的弯矩调幅限值犤β犦的计算公式,其计算结果与试验结果吻合较好。

two span steel partially prestressed concrete composite continuous beam specimens and a two span reinforced concrete composite continuous beam specimen have been tested with several parameters examined, which include partial prestress ratio PPR, combined force ratio Rp and the connecting degree of shear connectors in the negative moment regions. The test results indicate that adequate moment redistribution may take place when the prestressing force is applied in the negative moment regions of the tested beams, which is mainly influenced by the ratio of the depth of the equivalent rectangular stress block to the effective depth of the section ξu and the combined force ratio in the negative moment regions Rp. A general equation for calculating the allowable percentage of moment redistribution, that is ductility related proportion of ultimate moment capacity, is also proposed in this paper, the theoretical predictions agree closely with the measured values.