An Alternative Design Method for the Seismic Retrofit of RC Moment Resisting Frame Buildings with Viscous Dampers

ABSTRACT

An alternative design methodology which can be conveniently adopted by practicing engineers is proposed to enhance the seismic performance of existing reinforced concrete moment resisting frame (RC-MRF) buildings by employing viscous dampers. Here, the response indicators of the unretrofitted building are calculated using nonlinear response history analysis (NLRHA); viscous damper characteristics are calculated by estimating the peak viscous damper forces in terms of supplemental viscous damping and peak story shear forces of the unretrofitted building; and currently available expressions are used for the displacement profile of the retrofitted building and the equivalent single degree of freedom (SDOF) system displacements, to calculate the supplemental viscous damping. The effectiveness of the distribution of the viscous damper constants proportional to story parameters is also investigated.

KEYWORDS:

• Distribution of damper constants
• moment resisting frame buildings
• seismic design method
• reinforced concrete
• seismic retrofit
• viscous dampers

Acknowledgments

The first author gratefully acknowledges a Monbukagakusho (Ministry of Education, Culture, Sports, Science and Technology, Japan) scholarship for graduate students. The authors are grateful to the anonymous reviewers for helpful suggestions, which have improved the manuscript.