دانلود رایگان مقاله انگلیسی ارزیابی عملکرد لرزه ای از قاب فولادی با دیوارهای برش چوبی پیش ساخته - الزویر 2018

abstract

Steel-timber hybrid structural systems offer a modern solution for building multi-story structures with more environmentally-friendly features. This paper presents a comprehensive seismic performance assessment for a kind of multi-story steel-timber hybrid structure. In such a hybrid structure, steel moment resisting frames are infilled with prefabricated light wood frame shear walls to serve as the lateral load resisting system (LLRS). In this paper, drift-based performance objectives under various seismic hazard levels were proposed based on experimental observations. Then, a numerical model of the hybrid structure considering damage accumulation and stiffness degradation was developed and verified by experimental results, and nonlinear time-history analyses were conducted to establish a database of seismic responses. The numerical results further serve as a technical basis for estimating the structure's fundamental period and evaluating post-yielding behavior and failure probabilities of the hybrid structure under various seismic hazard levels. A load sharing parameter was defined to describe the wall-frame lateral force distribution, and a formula was proposed and calibrated by the time-history analytical results to estimate the load sharing parameter. Moreover, earthquake-induced non-structural damage and residual deformation were also evaluated, showing that if designed properly, desirable seismic performance with acceptable repair effort can be obtained for the proposed steel-timber hybrid structural system.

Summary and conclusions

A steel-timber hybrid building made of steel moment-resisting frames and prefabricated infill wood shear walls to resist later loads for multi-story buildings has been proposed. This paper presents a seismic performance assessment for these hybrid structures. The performance-based seismic design objectives under the IO, LS, and CP performance levels were discussed and defined. Nine prototype structures with three building height levels (i.e., 3-story, 6-story, and 9- story) and various infill wall configurations were designed. The infill configurations were designed based on the lateral infill-to-frame stiffness ratio, λ. FE models were developed for the steel-timber hybrid structures, and comprehensive nonlinear time-history analyses were conducted to investigate the seismic behavior of the prototype structures. The lateral stiffness ratio, λ, crucially influenced the fundamental period of the structure. Since the structure with large λ adopted stiffer and stronger infill wood shear walls, the period of the prototype structure decreased by 21.6%, on average, when λ increased from 1.0 to 2.0, and the period of the prototype structure decreased further by 15.0% when λ increased from 2.0 to 3.0. The probability of failure, with respect to a specified hazard level, was evaluated on the CDF given the performance criterion. As expected, as λ increased, the shear wall peak displacement decreased. The results demonstrated that the drift targets for the LS performance level did not control the design of the LLRS of the steel-timber hybrid structure. Thus, the performance-based design of the proposed steel-timber hybrid structural system should be focused on sizing the steel and timber members to have sufficient elastic stiffness under the IO performance level and maintaining a reasonable amount of postyielding strength and stiffness under the CP performance level.