简支梁转变为连续梁的弯矩调幅试验研究及其简化计算方法

EXPERIMENTAL STUDY AND CALCULATION METHOD ON MOMENT REDISTRUBUTION INDUCED BY TRANSFORMING SIMPLY SUPPORTED BEAMS INTO CONTINUOUS BEAMS

  • 摘要: 提出了一种通过在负弯矩区施加预应力将简支梁转变为连续梁的方法。为深入了解连续梁的内力重分布特性,进行了2根连续梁及1根对比梁的试验研究。试验中考虑的参数为预应力钢绞线的长度、单双支座。试验结果表明,简支梁转变为连续梁后,开裂荷载、极限荷载得到了较大的提高。弯矩重分布的规律为跨中截面开裂后,跨中截面的弯矩向中支座截面传递,中支座截面开裂后,弯矩反向向跨中截面传递。在试验研究的基础上,提出了两跨连续梁的弯矩调幅分析方法。计算结果表明:提出的计算方法与试验值吻合较好,可以用来计算连续梁的弯矩调幅。

     

    Abstract: The technique to transform simply supported beams into continuous beams by prestressing in the negative moment zones was presented. Two T-shaped continuous beams and one control beam were tested to investigate the feasibility of the technique and to understand the moment redistribution. Variables considered in this experimental program included length of the steel strands, single and double supports. The test results show that the crack loads and ultimate loads increased. The mid-span moments decreased and support moments increased when the cracks appeared at mid-span. Thereafter, the support moments decreased and mid-span moments increased when the cracks appeared at the inner supports. Based on the test results, a simplified method to calculate the moment redistribution is presented. The calculated results show good agreement between the calculated and experimental results.

     

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