Reliability study of derrick frame in formwork support system based on stochastic finite elements

DOI：10.7511/dllgxb201801012

 作者 单位 陆征然,郭超,张茂胜,李帼昌

扣件是模板支撑体系核心构件，其工作特性对体系承载性能具有显著影响．基于蒙特卡罗法基本原理，利用Python脚本驱动ABAQUS进行模板支撑体系非侵入式随机有限元分析，得出在井字架结构的任意位置上，随机出现不同数量的扣件失效对体系承载力可靠性的影响．结果表明，扣件失效概率增大将导致其屈曲承载力下降的幅度及概率显著增加．当扣件失效概率为0.183时，井字架结构的屈曲荷载比例系数超过0.8的概率为90%．当扣件失效概率达到0.199时，其屈曲荷载比例系数超过0.8的概率仅为50%．上述成果进一步说明基于所有扣件完好条件下的模板支撑体系确定性分析不符合实际，且偏于不安全．此外，当扣件失效数量服从二项分布时，模板支撑体系井字架结构的屈曲荷载比例系数λ服从正态分布．

The fastener is the core component of the formwork support system and its working characteristic has a significant influence on the bearing capacity of the system. The non-intrusive stochastic finite elements analysis of formwork support system is conducted through Python script process driving the ABAQUS main progress based on the Monte Carlo theories. The influence of random occurrence of fastener failure with different number at any position on the reliability of system is obtained. The analysis results show that the increase of the failure probability of the fastener will lead to a significant increase in the magnitude and probability of the decrease of the buckling capacity. When the failure probability of the fastener is 0.183, the probability of the buckling load scaling coefficient of the derrick frame reaching more than 0.8 is 90%, and that probability will reduce to 50% if the failure probability of the fastener is 0.199. The above results also illustrate that the deterministic analysis of formwork support system based on the integrity of all fasteners is not practical and unsafe. When the distribution of the fastener failure number obeys binomial distribution, the buckling load scaling coefficient λ of the derrick frame in formwork support system will obey normal distribution.