预应力混凝土连续梁桥桥面爆炸荷载模型试验

Load Model Experiment of Prestressed Concrete Continuous Girder Bridge Subjected to Explosion Above the Deck

预应力混凝土连续梁桥是中国公路工程中应用最广泛的桥型之一,尚未经过抗爆防护设计,一旦发生爆炸荷载作用,有可能造成重大的人员伤亡和财产损失。进行了2×8 m两跨预应力混凝土连续T梁桥模型的野外爆炸试验,结合数值模拟的方法,研究了爆炸冲击波与预应力混凝土连续T梁桥的相互作用,分析了爆炸荷载(冲击波超压、冲量)在桥面的分布特点。结果表明:桥面上方爆炸超压和冲量沿纵(横)桥向呈非线性分布,横桥向和纵桥向超压分布基本一致,横桥向桥面冲量相比纵桥向偏小;爆心高度不变的情况下,随着比例距离的减小,桥梁整体受到的爆炸荷载急剧上升;比例距离不变时,随着炸药当量的增大,爆心正下方位置超压峰值不变,但桥面其他位置的超压峰值都显著增大;建立了适用于桥面爆炸荷载模型的超压峰值公式,可供梁桥桥面抗爆设计参考。

Prestressed concrete continuous girder bridge is one of the most widely used bridges in China’s highway engineering,No anti-explosion protection design was conducted.Once the explosion load occurs,it will cause heavy casualties and property loss.A scaled model of 2×8 m two span prestressed concrete continuous T-girder bridge was designed and constructed,and the field explosion testing was carried out.Combined with the numerical simulation method,the interaction between the explosion shock wave and the prestressed concrete continuous T-girder bridge is studied,and the distribution characteristics of the explosion load(shock wave overpressure&impulse)over the bridge deck were analyzed.It can be concluded that the explosion overpressure and impulse over the bridge deck show nonlinear distribution along the longitudinal&transverse direction.The overpressure distributions along the transverse and the longitudinal directions are basically consistent,and the impulses over the bridge deck along the transverse direction is smaller than that of the vertical direction.When the height of the blast core is constant,the explosion load of the bridge increases sharply with the decrease of the proportion distance.When the proportion distance is constant,with the increase of the explosive equivalent,the overpressure peak value at the bottom of the core is unchanged,but the peak values of the overpressures at the other positions on the bridge deck significantly increase.The overpressure peak value formula for the bridge deck blasting load model is proposed,which can provide reference for the anti-explosion protection design of girder bridge.