爆炸荷载作用下悬索桥竖弯响应的数值模拟

摘要

针对大跨度悬索桥可能遭受的爆炸袭击,采用数值模拟方法研究了空中爆炸冲击波作用下悬索桥竖向弯曲响应.研究表明:悬索桥的竖弯响应过程可分为非稳态和稳态两阶段,所有构件的最大内力均发生在非稳态阶段.非稳态阶段相联构件间相互作用强烈,构件内力变化大.稳态阶段构件间的相互作用减弱,构件内力绕恒载值小幅波动.装药水平位置对加劲梁和吊杆最大内力影响显著,但对主索最大内力的影响不明显;加劲梁的最不利荷载位置在跨端,吊杆的最不利荷载位置在跨中.%Aiming at threats of explosion attack to a suspension bridge, the vertical bending response of the suspension bridge under air explosion loading was studied with numerical simulation. The results showed that the vertical bending response process can be divided into unstable phase and stable phase, and all the component members' maximum inner forces occur in the unstable phase; in the unstable phase, the interaction between jointed component members is intensive and the inner forces change greatly with time; in the stable phase, the interaction is weakened and each of the inner forces fluctuates around its mean value; the charge's horizontal position has obvious influence on the maximum inner forces of the stiffened beam and suspenders, but has little influence on that of the main cable; the most harmful loading position is at the support end of the stiffened beam and at the middle of the span of suspenders.