非加劲钢板剪力墙结构分析等代模型研究

RESEARCH ON ANALYTICAL MODELS FOR UNSTIFFENED STEEL PLATE SHEAR WALLS

非加劲钢板墙等代模型Strip Model(SM)由Thorbur在1983提出,并被加拿大国家标准CAN/CSA S16-01及美国AISC推荐。但前人研究发现,应用SM模型获得的极限承载力和初始侧移刚度总是不同程度低于试验包络线。为弥补上述缺陷,加拿大Alberta大学于2005年提出了修正的等代模型Modifided Strip Model(MSM)。尽管如此,SM和MSM的具体适应范围始终未能界定。该文的分析表明,当墙板较厚时,SM的计算结果过于保守,MSM则未能弥补SM的关键缺陷,也不是合理的等代模型。一般厚度的非加劲墙板,除拉力场效应外,还应包括一部分剪切作用,SM获得的结果偏保守之主要原因在于完全忽略了墙板的剪切部分。为此,该文提出了适于用任意墙板厚度(厚板、中厚板及薄板)的统一等代模型Unified Strip Model(USM),该模型由剪切和拉力场两部分组成,针对墙板厚度的变化,二者的比例相应调整。结果显示,与SM相比,USM大幅提高了初始侧移刚度和框架内力的准确度,克服了滞回曲线过度的捏缩现象,消除了等代模型如SM适用范围不明确的问题。

One of the analytical models,namely the Strip Model（SM） developed by Thorburn in 1983,was recommended to analyze unstiffened steel plate shear walls（USPSW） in CAN/CSA S16-01 and AISC.Some results showed that the SM tended to underestimate both the ultimate capacity and the initial stiffness.In order to obtain a more accurate prediction of the overall behavior of USPSW,the SM was refined and renamed Modified Strip Model（MSM） by Alberta University in 2005.However,the applicable region for neither SM nor MSM was addressed regarding the slenderness ratio of the wall.The results obtained in this paper indicate neither the SM nor the MSM can be regarded as a reasonable model since neither of them is able to well describe the behavior of the USPSW with arbitrarily varying slenderness ratio.A new analytical model,namely the Unified Strip Model（USM） considering the combination of the pure shear and pure tension fields,is proposed in this paper,and the ratios of true shear and tension field action vary in accordance to the thickness of the wall.It is then verified that the USM gives a better prediction of overall behavior,including the initial stiffness,elastic frame force and hysteresis loops for USPSW than other models,meanwhile the vagueness of applicable scopes which exists in the other models is overcame.