RESEARCH ARTICLE
Seismic Retrofit of an Existing Reinforced Concrete Building with Buckling-restrained Braces
Massimiliano Ferraioli1, *, Angelo Lavino1, Carmine Molitierno2, Gennaro Di Lauro1
Article Information
Identifiers and Pagination:
Year: 2021Volume: 15
First Page: 203
Last Page: 225
Publisher ID: TOCIEJ-15-203
DOI: 10.2174/1874149502115010203
Article History:
Received Date: 17/10/2020Revision Received Date: 20/11/2020
Acceptance Date: 9/12/2020
Electronic publication date: 14/07/2021
Collection year: 2021
open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: https://creativecommons.org/licenses/by/4.0/legalcode. This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Abstract
Background:
The seismic retrofitting of frame structures using hysteretic dampers is a very effective strategy to mitigate earthquake-induced risks. However, its application in current practice is rather limited since simple and efficient design methods are still lacking, and the more accurate time-history analysis is time-consuming and computationally demanding.
Aims:
This paper develops and applies a seismic retrofit design method to a complex real case study: An eight-story reinforced concrete residential building equipped with buckling-restrained braces.
Methods:
The design method permits the peak seismic response to be predicted, as well as the dampers to be added in the structure to obtain a uniform distribution of the ductility demand. For that purpose, a pushover analysis with the first mode load pattern is carried out. The corresponding story pushover curves are first idealized using a degrading trilinear model and then used to define the SDOF (Single Degree-of-Freedom) system equivalent to the RC frame. The SDOF system, equivalent to the damped braces, is designed to meet performance criteria based on a target drift angle. An optimal damper distribution rule is used to distribute the damped braces along the elevation to maximize the use of all dampers and obtain a uniform distribution of the ductility demand.
Results:
The effectiveness of the seismic retrofit is finally demonstrated by non-linear time-history analysis using a set of earthquake ground motions with various hazard levels.
Conclusion:
The results proved the design procedure is feasible and effective since it achieves the performance objectives of damage control in structural members and uniform ductility demand in dampers.
