Loading Rate Effect on Reinforced Concrete Walls with Low Aspect Ratios under High-Frequency Earthquake

• Published in: ACI structural journal Vol. 117; no. 6; pp. 105 - 118
• Main Authors: Baek, Jang-Woon, Yang, Hyeon-Keun, Park, Hong-Gun
• Format: Journal Article
• Language: English
• Published: Farmington Hills American Concrete Institute 01.11.2020
• Subjects: Aspect ratio; Concrete; Cracks; Dynamic testing; Earthquakes; Engineering models; Failure modes; Flexing; Friction; Lateral loads; Load distribution; Loading rate; Materials; Mechanical properties; Nuclear accidents & safety; Nuclear engineering; Nuclear power plants; Nuclear safety; Reinforced concrete; Reinforcement; Reinforcing steels; Seismic activity; Shear strength; Steel; Testing; Velocity; Walls; Yield strength; Yield stress; United States
• ISSN: 0889-3241; 0889-3241; 1944-7361
• DOI: 10.14359/51728059

In regions with high-frequency earthquakes, the safety of nuclear power plants has been re-investigated considering the high-frequency contents. In this study, cyclic lateral loading testing was performed for low-rise reinforced concrete walls with aspect ratios of 1.0 and 0.5 to investigate the loading rate effect. For direct comparison, twin specimens that were subjected to either low-rate loading (1 mm/s [0.039 in./s]) or higher-rate loading (100 mm/s [3.93 in./s]) were tested. The test parameters include failure mode and reinforcement ratio. The test results showed that under higher-rate loading, the number of concrete cracks decreased while the crack width increased. However, the failure mode ofRC walls was not significantly changed with varying strain rates (in the orders of [Please download the PDF to view the formula]. In the material test, under the higher rate loading, the yield strength of steel reinforcement was increased by approximately 3.3 to 8.3%. In the wall test, the strengths of the walls were increased by 9.9 to 12.2%, 4.0 to 17.5%, and 4.9 to 5.6% in flexure, shear, and shear-friction, respectively. The strength increase is mainly attributed to the increased yield strength of steel reinforcement under high rate loading. Keywords: cyclic loading; dynamic loading; high-frequency earthquake; low-rise walls; strain rate effect.