# Correlation Model of Damage Class and Deformation for Reinforced Concrete Beams Damaged by Earthquakes

## TL;DR

This study proposes a model linking damage levels and deformation in reinforced concrete beams after earthquakes, focusing on how shear strength affects performance.

## Contribution

The paper introduces a new correlation model for damage classification and deformation in earthquake-damaged RC beams based on shear strength margins.

## Key findings

- Specimens with lower shear strength margins showed more pronounced shear failure patterns and larger residual cracks.
- Shear strength margin had limited impact on seismic capacity reduction but significantly affected ultimate deformation capacity.
- A correlation model was developed to relate damage classes with deformation for RC beams of varying deformation capacities.

## Abstract

The objective of this study was to propose a correlation model of the damage class and deformation of reinforced concrete (RC) beams damaged by earthquakes with a focus on columns and walls. For this purpose, a series of full-scale RC beam specimens with different shear strength margins were tested under cyclic lateral loading to examine their deformation performance and damage states. Then, the damage class and seismic capacity reduction factor of RC beams were evaluated based on the test results. The results showed that the tendency of shear failure, such as shear crack pattern and shear deformation component, of specimens with small shear strength margins was more remarkable, and its maximum residual crack widths tended to be slightly larger and dominated by shear cracks. The results also indicated that the effect of the shear strength margin on the seismic capacity reduction factor which represents the residual seismic performance of RC beams was limited, whereas the specimen with a smaller shear strength margin exhibited lower ultimate deformation capacity. In addition, there was a difference in the boundary value of the lateral drift angle which classifies the damage class of specimens with different shear strength margins. Finally, correlation models between the damage class and deformation of RC beams with different deformation capacities were proposed.