爆炸荷载在圆截面桥梁墩柱上的分布规律

墩柱是桥梁结构的主要承载构件，研究爆炸荷载在墩柱上的分布规律是分析爆炸荷载作用下桥梁结构动态响应的前提。以圆截面桥梁墩柱为研究对象，基于LS-DYNA软件建立了桥梁墩柱的有限元模型，综合考虑炸药当量、爆心高度、爆炸距离和墩柱直径等影响因素，基于数值模拟得到爆心高度低于0.3倍墩柱高度，比例距离为0.5～2.1 m/kg1/3和墩柱直径为0.15～1 m时，爆炸荷载冲量沿墩柱高度和横截面方向上的分布。结果表明:沿墩柱高度方向，地面爆炸或爆心高度为0.1倍柱高时，墩柱前表面冲量近似“单线性”分布，当爆心高度距地面0.2和0.3倍柱高时，墩柱前表面冲量近似“双线性”分布；沿横截面方向的平均净冲量与其前表面冲量之比为常数。基于上述爆炸荷载冲量分布规律，进一步提出了爆炸荷载作用在桥梁墩柱上总净冲量的计算方法，从而为桥梁墩柱抗爆响应分析与设计提供一定的理论基础。

Blast loading distributions on the circular sectional bridge columns

Column is the main bearing member in bridge. It is the premise for analyzing the dynamic response of the bridge under blast loading to study the distribution law of blast load acted on bridge columns. Circular sectional bridge column has been selected as the research object, and the corresponding finite element models have been built by using the LS-DYNA software. When the height of burst is less than 0.3 times of the column height, the scaled distance is 0.5?2.1 m/kg1/3 and the column diameter is 0.15?1 m, the distributions of the blast loading impulse along column height and cross-section direction are obtained through numerical simulations. The influential parameters, e.g., the explosive equivalent, height of burst, explosion distance and sectional diameter, have been considered. It is derived that, along the column height, when the contact burst and the height of burst is 0.1 times of the column height, the blast loading impulse on the column front surface approximately follows the " Single linear” distribution. When the height of burst is 0.2 and 0.3 times of the column height, the blast loading impulse approximately follows the " Double linear” distribution. Along the cross-section direction, the ratio of the average net blast loading impulse to the blast impulse on the column front surface is a constant. Furthermore, the resultant net blast loading impulse of bridge column has been obtained, which can put some theoretical basis for blast-resistant analysis and design of bridge columns.