Evaluation of seismic performance of as‐built and retrofitted reinforced concrete frame structures with LAP splice deficiencies

Abstract

Several studies have looked at the development of hinge models to simulate the hysteretic response of flexure-and shear-critical reinforced concrete (RC) beamcolumn components from damage initiation to onset of gravity collapse. However, few studies have been conducted to develop similar models for older type bond-critical beam-column components. First, using existing experimental data, this paper describes the calibration of simple and efficient hinge models to simulate the inelastic hysteretic response of as-built and retrofitted splice-deficient columns. Subsequently, to demonstrate the applicability of the hinge models, the seismic performance of as-built and fibre-reinforced polymer (FRP) -retrofitted two-and four-story nonductile RC frame buildings with splice-deficient columns are assessed using nonlinear dynamic analysis procedures. The results show that buildings with bond-critical columns may have a lower collapse potential than buildings with shear-critical columns, implying that in certain cases a longer splice length may actually worsen performance. According to the analyses, local retrofitting of the columns can significantly improve the seismic performance of the buildings. Contrary to results presented in this study, a significant U.S. evaluation methodology for RC frame buildings, FEMA P-2018, indicates that buildings with bond-critical columns have similar collapse potential as buildings with shear-critical columns. Modifications are proposed to improve the FEMA P-2018 provisions. The modelling approach presented in this paper are recommended for incorporation into ASCE/SEI 41, engineering practice and future research.

Enhancing Resilience and Self-Centering of Existing RC Coupled and Single Shear Walls Using EB-FRP: State-of-the-Art Review and Research Needs

“…RC columns might be strengthened due to deficiencies such as (i) poor ductility, compressive, shear, and flexural strength [26][27][28]; (ii) lack of lap splice and confinement [29][30][31]; (iii) poor column-beam connection [32,33].…”

“…FRP strengthening patterns.3.1.1. Columns RC columns might be strengthened due to deficiencies such as (i) poor ductility, compressive, shear, and flexural strength[26][27][28]; (ii) lack of lap splice and confinement[29][30][31]; (iii) poor column-beam connection[32,33].One of the most prevalent methods of increasing compressive strength in RC structures, especially in columns, is the use of fully wrapped EB-FRP around the perimeter of the element. This can significantly enhance the confinement (lateral pressure) on the column, thereby improving ductility, shear strength, axial strain, and load-carrying capacity[21,34].…”

Seismic fragility assessment of a RC frame considering concentrated and distributed plasticity modelling

“…However, it has an inherent limitation on its formulation that makes the simulation of the strain softening associated with rebar buckling difficult [11]. Lumped plasticity models are frequently used in structural analysis [14]- [16], since it is easier to implement [17]. When calibrated properly, it can capture degradation of strength and stiffness that is essential to collapse modeling.…”