预应力钢-混凝土连续组合梁的变形分析

对预应力钢-混凝土连续组合梁在正常使用极限状态下的变形计算进行分析。分析考虑钢与混凝土之间的滑移效应,建立简化计算模型,并在此基础上,提出混凝土支座开裂区长度以及预应力筋内力增量的计算公式,给出两跨预应力连续组合梁跨中挠度的计算图表。分析结果表明,两跨预应力连续组合梁变形计算公式计算正常使用极限状态预应力筋的内力值精度较高,不考虑预应力筋内力增量的变形计算值较试验值偏大,考虑预应力筋内力增量的变形计算值精度有明显提高,与试验结果吻合较好,可供工程设计参考。最后在两跨预应力连续组合梁变形计算公式的基础上提出预应力连续组合梁变形计算的通用方法。

Deformation analysis of prestressed continuous steel-concrete composite beams

Deformation calculation analysis is conducted for prestressed continuous steel-concrete composite beams, accounting for the slip effect between steel and concrete interface under service loads.A simplified analytical model is presented.Based on the model,formulae are derived for predicting the crack length in the region of hogging moment at interior supports of concrete slab and the increase of the prestressing tendon force.A table is also proposed for calculating the mid-span deflection of two-span prestressed continuous composite beams.It is found that the internal force of the prestressing tendon under service loads can be accurately calculated by using the proposed formula.Ignoring the increase of tendon force would make the calculated deflection over-estimated,whereas considering the increase of tendon force can significantly improve the accuracy of predictions.As the calculated values are in good agreements with the test results,the proposed formulae can be reliably applied to the deformation analysis of prestressed continuous composite beams.Based on the formulae for calculating the deformation of two-span prestressed continuous composite beams,a generally applicable method for deformation analysis of prestressed continuous composite beams is proposed.