Blast-resistant analysis and design of CFRP sheet strengthened masonry infilled walls
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摘要: 为研究爆炸作用下碳纤维增强聚合物(CFRP)布加固砌体填充墙的抗爆性能及其设计方法,首先采用商用有限元软件LS-DYNA建立砌体填充墙的简化分离有限元模型及其CFRP布加固抗爆分析模型,通过与已有9组未加固和CFRP布加固砌体填充墙的野外爆炸试验结果对比,验证了所采用的墙体简化分离建模方法、砌体和CFRP布本构模型及其参数的适用性。进一步参考GB 50608-2020标准推荐的砌体墙CFRP抗震加固方式,通过对比分析爆炸作用下CFRP布加固原型砌体填充墙的动力行为,建议优先采用对角双向加固方式,其次是垂直双向和横向满铺加固方式,不建议采用竖向满铺和混合三向加固方式。最后,以同时满足CFRP布基本保持完整、墙体中心不发生砌块飞散,以及墙体中心最大面外挠度小于墙厚为设计目标,得出典型小轿车(227 kg TNT当量)和手提包炸弹(23 kg TNT当量)在不同比例距离爆炸时,对应6~9度抗震设防等级要求的三种拉结筋布置形式(无/截断/通长拉结筋)原型墙体需要加固的比例距离范围分别为0.8~2 m/kg1/3和0.2~1.2 m/kg1/3,进一步给出了最优CFRP布加固层数建议。
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关键词:
Abstract: Aiming to investigate the performance and design approach of the carbon fiber reinforced polymer (CFRP) sheet strengthened masonry infilled walls subjected to blast loads, the commercial finite element program LS-DYNA is firstly used to develop the simplified micro-finite element model of masonry infilled walls and the corresponding blast-resistant analysis model of CFRP sheet strengthened walls. By comparing with the nine groups field explosion test results of unstrengthening and CFRP sheet strengthened masonry infilled walls, the applicability of the present simplified micro-modeling approach, as well as the material models and parameters of masonry and CFRP sheet, is verified. Furthermore, referring to the CFRP seismic strengthening methods recommended by Chinese standard GB 50608-2020, the dynamic behaviors of the prototype masonry infilled walls strengthened with CFRP sheets under blast loads are analyzed and compared. It is recommended to prioritize the diagonal two-way strengthening method, followed by vertical two-way and horizontal full-cover strengthening methods, and vertical full-cover and mixed three-way strengthening methods are not recommended. Finally, to simultaneously satisfy the CFRP is basically intact, no scattering debris and the peak central deflection less than wall thickness as the blast-resistant design goal, the ranges of scaled distance of prototype masonry infilled walls with different arrangements of tie bar (non-/cut-off/full-length tie bar) that need to be strengthened under typical sedan (227 kg equivalent TNT) and briefcase bombs (23 kg equivalent TNT) explode at different scaled distances are determined as 0.8-2 m/kg1/3 and 0.2-1.2 m/kg1/3, respectively. The suggestions for the optimal number of CFRP sheet layers for blast-resistant design are further given.
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