爆炸作用下高层框架结构倒塌分析与设计建议  

Collapse analysis and design recommendations of high-rise frame structures under blast loadings

作　　者：吕晋贤 吴昊 方秦 LU Jinxian;WU Hao;FANG Qin(College of Civil Engineering,Tongji University,Shanghai 200092,China;Army Engineering University of PLA,Nanjing 210007,China)

机构地区：[1]同济大学土木工程学院,上海200092 [2]陆军工程大学,江苏南京210007

出　　处：《建筑结构学报》2023年第11期114-128,共15页Journal of Building Structures

基　　金：国家自然科学基金项目(52078379)。

摘　　要：爆炸荷载作用是建筑结构倒塌的重要诱因之一,拆除构件法作为中、美等国规范推荐的建筑结构抗倒塌性能评估与设计方法,但其未考虑在爆炸冲击波作用下被拆除构件的残余承载力及周围构件的不同损伤程度。为此,针对爆炸作用下高层RC框架结构抗倒塌性能评估与设计,提出建筑结构混合单元建模和任意拉格朗日-欧拉(ALE)爆炸荷载施加方法相结合的高精度有限元分析方法,并得到典型RC框架结构爆炸试验和Murrah联邦大楼爆炸倒塌事故的验证。根据美国联邦应急管理署规定的恐怖爆炸袭击类型,进一步开展不同爆炸位置,不同炸药当量爆炸作用下典型高层RC框架结构的数值仿真研究。分析了爆炸波传播及其与结构相互作用,以及建筑结构损伤破坏和关键柱柱顶竖向位移,考察了中国T/CECS 392—2021《建筑结构抗倒塌设计标准》(简称“CECS规范”)和美国UFC4-023-03、GSA规范(简称“DoD/GSA规范”)对于爆炸作用下结构抗倒塌性能评估与设计的适用性。根据建筑结构不同设防等级和区域,给出了拆除构件法的三类使用建议:该方法对于紧凑型轿车炸弹(227 kg TNT当量)和普通轿车炸弹(454 kg TNT当量)外部爆炸较为适用,建议进一步考虑荷载调整系数;对于小型货车炸弹(1 814 kg TNT当量)外部爆炸及汽车炸弹内部爆炸偏于危险,不建议采用拆除构件法进行设计;箱包炸弹(23 kg TNT当量)对结构整体的破坏较为有限,可不采用拆除构件法进行设计。Explosion is one of the triggering events for collapse of building structures.As an anti-collapse assessment and design method recommended in the codes of the United States,China and other countries,alternative path method(APM)ignores the residual bearing capacity of the removed structural members and the different damage degrees of adjacent members under blast loadings.For the assessment and design of collapse resistance of high-rise RC frame structures under blast loadings,a high-fidelity finite element analysis(FEA)approach,i.e.,combination of hybrid modelling approach for building structures and arbitrary Lagrangian-Eulerian(ALE)method for blast loadings,was proposed and verified by a typical explosion test on RC frame structure and the blast-induced collapse of Murrah Federal Building.Based on the possible design basis threats specified by the Federal Emergency Management Agency,numerical simulation of typical high-rise RC frame structures under explosions was conducted considering different detonation locations and different charge weights.Furthermore,the propagation of blast wave,its interaction with structures,the damage modes of building structures,and vertical displacements of critical columns were analyzed.The applicability of Chinese T/CECS 392—2021“Standard for anti-collapse design of building structures”(CECS code),American UFC4-023-03 and GSA codes(DoD/GSA codes)for the evaluation and design of collapse resistance under blast loadings was assessed.Three recommendations for APM are proposed based on the designed explosive threats and zones:APM is applicable to the scenarios of external explosion of compact sedan and sedan bombs(227 kg and 454 kg of TNT equivalence),and load adjustment coefficient can be further considered;the prediction underestimates the damage degree caused by external explosion of cargo van bombs(1814 kg of TNT equivalence)and internal explosion of vehicle-borne improvised explosive devices,and thus APM is not recommended for design;suitcase bombs(23 kg of TNT equivalence)c

关 键 词：高层框架结构 爆炸荷载 连续性倒塌 拆除构件法 数值模拟 抗倒塌性能 

分 类 号：TU375[建筑科学—结构工程] TU318