Dynamic Equilibrium of CFRP-RC Square Elements under Unequal Lateral Impact

Area of Science:

• Civil Engineering
• Materials Science

Background:

• Building structures require reinforcement for various reasons, including damage and functional changes.
• Carbon fiber reinforced polymer (CFRP) is a preferred material for structural reinforcement due to its high strength, light weight, corrosion resistance, and ease of construction.

Purpose of the Study:

• To investigate the dynamic response of CFRP-strengthened reinforced concrete frame elements under unequal lateral impact.
• To analyze the effectiveness of different CFRP wrapping configurations (longitudinal vs. transverse) and layer numbers on structural performance.

Main Methods:

• Experimental testing of CFRP-strengthened reinforced concrete frame elements subjected to lateral impact.
• Analysis of impact, deflection, and strain time history data.
• Development of a dynamic equilibrium principle equation based on experimental findings.

Main Results:

• Elements primarily failed in bending, with severe damage at the impact point and supports.
• Transversely wrapped elements showed more abrupt failure.
• Longitudinal wrapping and increased layer count effectively reduced damage levels.
• Wrapping mode and layer count had minor influence on impact force peaks.
• Longitudinally wrapped elements exhibited longer plateau segments in their response.
• Increased vertical wrap layers raised the plateau value and reduced impact-induced deflection.
• Longitudinal wrapping facilitated effective force transmission.

Conclusions:

• CFRP strengthening, particularly with longitudinal wrapping and multiple layers, significantly enhances the impact resistance of reinforced concrete frames.
• The study provides a validated dynamic equilibrium principle for analyzing such scenarios.
• Findings offer valuable insights for designing more resilient structures using CFRP materials.