近场近地爆炸下建筑柱爆炸荷载分布规律及简化模型OACSTPCD

To rapidly assess the dynamic responses and failure modes of the building columns under near-field near-ground explosions,in this paper numerical simulation method is employed to investigate the distribution pattern of the shock waves that are applied on the front face of building columns under near-field near-ground blast scenarios,and a corresponding simplified blast load model is proposed.To this end,firstly,the existing experimental data of overpressure and impulse were selected to validate the numerical model for blast load.Then,a typical numerical model under near-field near-ground blast scenarios was established to study the effects of the scaled distance and the scaled height of spherical charges on the characteristic values of the shock waves acting at the building columns.Finally,formulae for the maximum reflected impulse and the representative value of the positive overpressure duration were derived based on nonlinear regression analysis,and the blast load at each location of the column front face was represented by an equivalent triangular load model.The results indicate that when the scaled height of the charge is less than 0.3 m/kg1/3,the distribution of the maximum reflected impulse along the column length can be represented as a trilinear model and a bilinear model for the scaled distance of 0.4-0.6 m/kg1/3 and 0.6-1.4 m/kg1/3,respectively.In comparison,the distribution of the shock waves in the transverse direction of a column section was approximately uniform.Moreover,under a given scaled distance and a scaled height,the peak reflected overpressure remains constant as the charge weight increases,but the maximum reflected impulse is proportional to the cubic root of the charge weight at the locations with the identical scaled height of the column.