Effects of longitudinal reinforcement discontinuities on the seismic response of structural walls
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Effects of longitudinal reinforcement discontinuities on the seismic response of structural walls Ying Wang1 · Santiago Pujol2 Received: 22 April 2020 / Accepted: 16 September 2020 © Springer Nature B.V. 2020
Abstract Lap splices and bar cutoffs introduce reinforcement discontinuities in reinforced concrete structures. A two-step approach was used to investigate the effect of longitudinal reinforcement discontinuities on the seismic performance of reinforced concrete structural walls. In the first step, six cyclic tests on small-scale reinforced concrete structural walls were conducted to study the effect of bar cutoffs. Three of the six specimens had web longitudinal reinforcement cutoffs to simulate the effects of a retrofit practice used in Japan. The test results indicated that this discontinuity resulted in approximately 50% increase in the unit tensile strains in the longitudinal reinforcing bars in boundary elements. Larger unit tensile strains caused an increase in permanent strain accumulation, increasing the likelihood of bar buckling. In the second step, the mentioned test results were combined with test results from previous tests (that investigated discontinuities related to lap splices) to calibrate equations for estimating drift capacity of structural walls with and without reinforcement discontinuities. Keywords Reinforced concrete structural walls · Web reinforcement · Drift capacity · Discontinuity · Seismic response · Cyclic loading List of symbols Asc Gross sectional area of longitudinal bars in compression Ast Gross sectional area of longitudinal bars in tension c Length from most compressive fiber to neutral axis C Estimated compressive force used in Table 3 C0 Coefficient related to restraint of bar ends in buckling equation db Bar diameter E Elastic modulus Et Tangential modulus fc Concrete compressive strength fy Yield strength of reinforcing bar hw Height of wall * Ying Wang [email protected] 1
College of Civil Engineering, Fuzhou University, Fuzhou, Fujian, China
2
Civil and Natural Resources Engineering, University of Canterbury, Christchurch, New Zealand
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Vol.:(0123456789)
Bulletin of Earthquake Engineering
l Unsupported length of bar Lp Plastic hinge length Mcr Moment at cracking Mmax Maximum moment Mn Flexural strength based on moment–curvature analysis N Applied axial load rb Bar radius s Spacing of transverse reinforcement t Width or thickness of boundary element in compression Vcr Shear force at cracking Vmax Maximum shear force Vn Nominal shear strength based on Eq. 21-7 of ACI 318-08 (2007); α = constant in Eqs. (5–6) θcr Drift ratio at cracking θy Drift ratio at yielding θ@Vmax Drift ratio corresponding to maximum shear force θu Drift capacity ε Strain ε0 Coefficient in Eqs. (5–6) εi Initial strain at beginning of half cycle εlimit Limiting concrete compressive strain εmax Maximum tensile strain εy Strain at yielding ρbl Longitudinal reinforcement ratio in boundary element of structural wall ρwl Longitudinal reinforcemen
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