摘要
将框架梁在张拉阶段或工作阶段时纵梁与横梁的破坏、梁的正截面与斜截面的破坏以及锚杆的破坏等主要失效模式视为串联系统,提出了框架预应力锚索的分阶段系统可靠性计算模型。在张拉阶段,将锚索力按照位移协调和静力平衡的原则分配在纵、横梁上,然后按Winkler弹性地基梁模型分别计算单片梁的内力;在工作阶段,将侧向土压力系数视为随机变量,框架梁视为土压力作用下的简支梁来计算其内力。基于各失效模式功能函数之间的相关系数矩阵,导出了预应力锚索框架的系统可靠性计算方法并编制了计算程序。对某工程实例的计算结果表明,预应力锚索框架的失效概率主要由纵梁在工作阶段和张拉阶段的正截面失效概率及锚杆的失效概率三者共同决定,而假设此3种失效模式相互独立的系统失效概率与考虑失效模式相关性的系统失效概率误差为8.1%。
The frame prestressed anchor cable computational model for system reliability is put forward basing on a series system, which is constituted with main failure modes of the frame beam destruction in tension stage or in working stage, destruction of stringers and beams, destruction of the beam in cross-section and oblique section, and anchor damage. During tensioning stage, the anchor cable force is assigned on the beams in accordance with the principles of displacement coordination and static balance; internal forces of the monolithic beam is calculated respectively by Winkler elastic foundation beam model. In the working stage, to calculate their internal forces, the lateral earth pressure coefficient is regarded as random variables, frame beams as simply supported beam under the earth pressure. Basing on the correlation coefficient matrix of the failure mode function, prestressed anchor computational model for reliability of the system and computer program are then derived. The results of an engineering example show that the probability of failure of the prestressed anchor frame is determined by three factors： cross-section failure probability of in working stage, cross-section failure probability of tensioned stage and anchor bolt failure probability. Assuming the error of three failure modes interdependent system failure probability and system failure probability considering correlation is 8.1%.
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2014年第1期217-225,共9页
Rock and Soil Mechanics
基金
国家自然科学基金项目(No.50878082)
关键词
框架锚杆
系统可靠性
Winkler弹性地基梁
侧压力系数
相关系数
frame anchor
system reliability
Winkler elastic foundation beam
lateral pressure coefficient
correlation coefficient
