مقاله انگلیسی پیش بینی ظرفیت فروریزش لرزه ای SMRF های مجاور
Highlights
Abstract
Keywords
1. Introduction
2. Description of theoretical aspects
3. Results of analysis
4. Modification factors
5. Conclusions
CRediT authorship contribution statement
Declaration of Competing Interest
References
Abstract
Severe damages of adjacent structures due to structural pounding during earthquakes have emphasized the need to use some seismic retrofit strategy to enhance the structural performance. The purpose of this paper is to study the influence of using linear and nonlinear Fluid Viscous Dampers (FVDs) on the seismic collapse capacities of adjacent structures prone to pounding and proposing modification factors to modify the median collapse capacity of structures considering the effects of pounding. The factors can be used to predict the collapse capacity of structures in pounding condition. A seismic retrofit strategy employs FVDs installed in 3-, 6- and 9-story Special Moment Resisting Frames (SMRFs). The SMRFs were assumed to have different values of separation distance according to the seismic code. To model pounding phenomenon, linear viscoelastic contact elements were used in the OpenSees software. Furthermore, to determine the seismic collapse capacities of each structure, the proposed algorithm was applied to remove the collapsed structure during the incremental dynamic analysis. The results of the analyses illustrate that the existence of FVDs can substantially improve the seismic behavior of structures having a significant influence on the collapse capacities of colliding structures. Moreover, considering the adjacent SMRFs in one or two sides of the main structure can significantly affect the median collapse capacity of the main structure itself. Finally, the proposed modification factors can be successfully used to estimate the effects of pounding on the collapse capacities of adjacent structures.
1. Introduction
Different investigations show that adjacent structures with inappropriate separation distance between them may interact one with another during earthquakes, resulting in significant damage [1]. Although nowadays it is a usual procedure to consider a minimum separation distance during the design of concrete or steel structures, many existing structures were constructed with insufficient in-between gap size since it was allowed due to old seismic codes. This insufficient separation distance, which may lead to impacts between adjacent structures during earthquakes, can significantly influence the seismic structural behavior as well as the collapse capacity. Therefore, improving the seismic performance of existing structures is often challenging because such external circumstances can affect the structural behavior. In this respect, there are two strategies: first, increasing the capacity of structural members, for instance using friction devices into beam to column joints, and second, installing passive energy dissipation devices such as dampers or adding dissipative metal shear panels (see for instance [2], [3], [4], [5], [6], [7], [8], [9], [10], [11], [12]). The first approach is more convenient for low-rise buildings, whereas the second one can be more effective and affordable for all types of structures. Furthermore, the strengthening option for structures may interfere with the architectural plans, while the installation of seismic dampers can play a positive role. Although previous studies were mainly focused on the strengthening option, the idea of using linear and nonlinear Fluid Viscous Dampers (FVDs) for retrofitting structures is not new. Among different passive energy dissipation systems, FVDs have some performance advantages for their ability to reduce both displacements and accelerations, which can be very important for the structures with sensitive components.