预应力混凝土框架结构的侧向约束分析

ANALYSIS OF LATERAL RESTRAINTS OF PRESTRESSED CONCRETE FRAME STRUCTURES

在预应力混凝土框架结构梁中张拉预应力筋时,柱侧向约束将造成梁中设计预加轴力的损失,梁中达不到设计预加应力值,同时也会在柱中产生次剪力和次弯矩,并进一步在梁中产生次剪力和次弯矩作用。对于有明显侧向约束的超长超宽多跨预应力混凝土框架结构,若不合理考虑侧向约束对预压力传递的影响,不仅裂缝控制得不到满足,而且承载力计算也是偏于不安全的。建立了不同张拉顺序下次内力计算模式并推导出了计算公式,提出了设计、施工运用中注意的问题,为合理进行结构设计提供了依据。

When prestressed tendons were being tensioned in prestressed concrete frame structures, lateral restraints of columns brought about the loss of designed pre-added axial force, the loss induced designed pre-added axial stress not to be reached in beams,and would result in secondary shear and secondary moment in columns, and in beams too. In over-long and over-wide prestressed concrete frame structures with obvious lateral restraints, if the influence of lateral restraints of columns on the transfer of pre-compressive force in beams was not thought over rationally, not only the control of cracks could not be satisfied, but also the computation of carrying load capacity was not safe. Computational models of secondary interior force were built up for different tensioning order, and computational formulas were derived. Some methods were put forward for rational structural design.