Seismic Performance of Steel Fiber Reinforced High-Strength Concrete Beam-Column Joints.

Ke Shi,Li Li,Pengfei Li,Tao Zhang,Mengyue Zhang,Junpeng Zhu

doi:10.3390/ma14123235

Abstract

In high–strength concrete, the reinforcement concentration will cause some problems in the beam–column joints (BCJs) due to a large amount of transverse reinforcement. Hence, the main object of this paper is to prevent the reinforcement concentration and reduce the amount of transverse reinforcement in the BCJs through the ideal usage of steel fibers and reinforced high–strength concrete. Pseudo–static tests on seven specimens were carried out to investigate and evaluate the seismic performance of beam–column joints in steel fiber reinforced high–strength concrete (SFRHC). Test variables were steel fiber volume ratio, concrete strength, the stirrup ratio in the core area, and an axial compression ratio of the column end. During the test, the hysteresis curves and failure mode were recorded. The seismic indicators, such as energy dissipation, ductility, strength, and stiffness degradation, were determined. The experimental results indicated that the failure modes of SFRHC beam–column joints mainly included the core area failure and the beam end bending failure. With the increase in stirrup ratio, volume ratio of steel fiber, and axial compression ratio in the core area, both the ductility and energy consumption of beam–column joints increased, while the opposite was true for concrete strength.

Highlights

Under the earthquake load, the beam–column joints (BCJs) of frame structures are prone to brittle shear failure due to the comprehensive action of compression, bending, and shear
This paper presents an experimental investigation on the seismic behavior of steel fiber reinforced high–strength concrete (SFRHC) beam–column joints by conducting seven tests
With the change in axial compression ratio of column end, concrete strength, the stirrup ratio in the core area, and volume ratio of steel fiber, two modes of the joint– shear–failure area exist in the core area and beam–end–bending failure;

Summary

Introduction

The beam–column joints (BCJs) of frame structures are prone to brittle shear failure due to the comprehensive action of compression, bending, and shear. As the BCJs are the key part of the frame structure, their failure will lead to the collapse of the whole structure. To meet the requirements of “strong joints”, more shear reinforcement is usually required in practical engineering, which will lead to serious casting blockage and construction difficulties of concrete [4,5,6] This may lead to the use of larger column and beam sections or the use of more small–diameter steel bars to meet the minimum anchorage length requirement through the joint core area, which may worsen casting blockage and construction difficulties of concrete. How to design the beam–column joints better is a key issue

Objectives

Results

Conclusion