# Seismic Performance of Precast Reinforced Concrete Beam–Column Connections with Embedded Steel Sections

## TL;DR

This study shows that adding steel sections to precast concrete beam-column connections improves their strength and resilience during earthquakes.

## Contribution

The novel use of composite steel sections in precast RC joints is shown to enhance seismic performance through experimental and numerical analysis.

## Key findings

- Composite steel joints prevent premature failure and relocate plastic hinges away from critical regions.
- The composite design significantly improves load capacity, stiffness, and energy dissipation.
- Finite-element models accurately simulated failure modes and deformation trends, validating the experimental results.

## Abstract

Precast reinforced concrete (RC) structures offer advantages in terms of construction efficiency and quality control; however, their seismic performance is governed by the behavior of the beam–column connections. This study presents an experimental investigation of the cyclic response of precast RC beam–column joints that include a composite steel connection, designed to enhance strength, stiffness, and damage control in critical regions. A composite joint specimen was tested under displacement-controlled cyclic loading, and its behavior was compared with that of a corresponding pure RC connection. Experimental results showed that the composite configuration effectively prevented premature failure at the beam–column interface, relocated plastic hinges away from the joint core, and significantly improved the load-carrying capacity, stiffness, and energy dissipation. To interpret the experimental observations and examine the internal stress transfer and evolution of damage, a three-dimensional nonlinear finite-element model was developed. The simulations reproduced the observed modes of failure, shapes of deformation, hysteretic responses, and moment distribution trends, particularly in the post-yield and strain-hardening ranges. Although the pinching effects observed experimentally were not fully captured numerically, the overall levels of agreement in the ultimate strength and plastic hinge locations were satisfactory. The combined results indicate that composite steel-reinforced precast beam–column joints represent a promising solution for improving seismic performance.