Damage grades of reinforced concrete bent structures against blast
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摘要: 为了研究钢筋混凝土排架结构在大当量爆炸冲击波下的破坏规律,依据最大TNT当量为3 t的爆炸试验,对排架主体结构的抗爆破坏等级进行数值模拟研究。通过量纲分析得到1/2缩比模型的荷载参数和结构尺寸。基于Abaqus有限元软件,利用CONWEP方法实现爆炸加载,分别计算装药0.5 t爆距33 m和装药3 t爆距33 m两种工况下排架结构的破坏形态,并与试验结果进行对比。进一步通过控制药量和距离,计算不同超压和冲量下缩比模型的破坏形态。研究结果表明,排架的关键破坏特征为中间承重柱的倾覆转动;数值计算与试验破坏形态吻合较好,特征位移和特征转角的最大相对误差分别为5.6%和4.6%。以承重柱的倾覆角作为划分依据,将计算结果分为3种破坏等级,拟合得到的超压-冲量曲线和药量-距离曲线可用于厂房安全距离和仓库容量设计以及意外爆炸下的破坏程度预估。Abstract: To study the failure law of reinforced concrete bent structures under large equivalent explosions, the damage grades of the bent structures against blast were numerically calculated based on the explosion test with the maximum equivalent of 3 t TNT. The load parameters and structural dimensions of the 1/2 scaled model were obtained through dimensional analysis. Based on the Abaqus finite element software, the CONWEP method was used to achieve the blast loading. The failure modes of the structures, under the explosion loads with TNT equivalent 0.5 t and blast distance 33 m as well as TNT equivalent 3 t and blast distance 33 m, were calculated, respectively, and compared with the test results. Further, the failure patterns of the scale model under different overpressures and impulses were calculated by controlling the TNT equivalent and blast distance. The research results show that the middle column of the bent structure is prone to damage in the form of overall overturning under a lateral blast load; the calculated failure morphologies are in good agreement with the experimental ones, and the maximum relative errors of the characteristic displacements and characteristic corners are 5.6% and 4.6%, respectively. The overturning angle of the load-bearing column was used as the basis for the damage-grade division, and the calculated results were divided into three damage levels. The fitted overpressure-impulse and equivalent-distance curves can be used in the design of safety distance and warehouse capacity and the estimation of the damage degree of accidental explosion.
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Key words:
- reinforced concrete bent structure /
- blast /
- damage grade /
- overpressure-impulse curve /
- scaled model /
- CONWEP
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表 1 Q235B钢的弹塑性参数
Table 1. Elastoplastic parameters of steel Q235B
ρ/(kg·m−3) E/GPa μ A/MPa B/MPa n m C $ {\dot{\mathrm{\varepsilon }}}_{0} $/s−1 7835.5 200.6 0.259 314 527.5 0.436 0.757 0.02 0.001 表 2 HRB400钢的弹塑性参数
Table 2. Elastoplastic parameters of steel HRB400
ρ/(kg·m−3) E/GPa μ A/MPa B/MPa n m C $ {\dot{\mathrm{\varepsilon }}}_{0} $/s−1 7766 200.5 0.241 476.2 719.8 0.44 0.757 0.014 0.001 -
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