Seismic evaluation of existing RC frames with wide beams using an energy-based approach

Abstract

This paper investigates the seismic performance of existing reinforced concrete frames with wide beams mainly designed for gravity loads, as typically found in the seismic-prone Mediterranean area before the introduction of modern codes. The seismic capacity is evaluated in terms of the overall amount of input energy that the frame can dissipate/absorb up to collapse. This approach provides a quantitative evaluation that can be useful for selecting and designing an appropriate retrofit strategy. Six prototype frames representative of past construction practices in the southern part of Spain are designed, and the corresponding non-linear numerical models are developed and calibrated with purposely conducted tests on wide beamcolumn subassemblages. The models are subjected to sixteen earthquake records until collapse by applying the incremental dynamic analysis method. It is found that the ultimate energy dissipation capacity at the story level is markedly low (about 1.36 times the product of the lateral yield strength and yield displacement of the story), giving values for the maximum amount of energy that the frame can dissipate which are from one fourth to half of that required in moderate-seismicity regions.

Comparative Study of Seismic Design and Performance of OMRF Building Using Indian, British, and European Codes

“…However, they did not discuss issues related to reinforcement and its performance in relation to seismic events. Climent and Zahran [33] studied the seismic performance of RCC building frames with a wide beam in a seismic-prone Mediterranean area before the introduction of modern codes. However, they did not compare the results with buildings that have been designed with following present building codes; also, they considered the effect of the wide beam.…”

Proposal of energy spectra for earthquake resistant design based on Turkish registers

“…Given the similarity between the relative velocity spectra and the V D spectra and the little sensitivity of the ratio V D / V E on the period [Decanini, Mollaioli 2001;Benavent et al 2010], the proposed spectra are expected to be basically shaped as the result of multiplying the design acceleration spectra proposed by the Eurocode 8 [EN-1998[EN- 2004] by factor T / 2 π. Therefore, these spectra have three branches, corresponding roughly to the short, medium and long period ranges, respectively; the first branch is linear starting from zero, the second branch is constant, and the third branch is decreasing.…”

“…The considered nonlinear SDOF systems have an elastic-perfectly plastic behavior and, hence, they are characterized by their damping ratio ζ, by their initial (elastic) natural period T and by the displacement ductility µ. In this study, three values of ζ are considered (0.02, 0.05, 0.10) and six values of µ are considered (2,3,5,10,15,20). Obtaining the spectrum of each acceleration record for a given fixed value of µ requires performing iterative analyses in which the yield strength of the SDOF system, Q y , is varied until the resulting µ reaches the prescribed target value with 10% tolerance.…”