复杂桩基筏板冲切线的选取

Selection of Punching Line in Complex Pile Rafts

在高层建筑基础设计中,复杂桩基筏板的冲切线选取较无桩筏板更难以确定,可能的冲切线有很多条,但最不利的只有一条。对某超高层建筑的复杂桩基筏板共选取了四组不同形式的冲切线进行试算,得出了三道冲切线在这四组冲切线形式下的抗冲切反力,并进行了冲切计算的对比分析。结果表明,随竖向构件的直转角的冲切线(第一组)为最不利的初步结论,同时也指出各组中不利的冲切线数值差异不大,宜进行多种情况下多条冲切线的试算。在设计中,对冲切承载力预留一定的安全储备,同时配置一定的构造钢筋是有必要的。

In foundation design of high-rise buildings,selection of punching line is harder to identify in complex pile rafts than in rafts without piles.There are many potential punching lines,but only one of them is the most unfavorable.In this paper,the comlex pile rafts of an super-highrise building was tentatively calculated according to four kinds of punching lines,and the punching-resistant forces of three punching lines of those four kinds were yielded and compared.It was shown that the punching line along the right-angle of vertical members,which belongs to the first kind,is the most unfavorable,and the result of the unfavorable punching line in each kind differs slightly,so tentative calculation of more than one punching line is neccesary.It is essential to keep a safty margin to punching-resistant forces and set some constructional reinforcement.