Parametric studies on the ductility of axial loaded square reinforced concrete column made of normal-strength concrete (NSC) and high-strength steel confining rebar (HSSCR) with various ties configuration

Anis Aulia Ulfa,Bambang Piscesa,Mario M Attard,Pujo Aji,Faimun Faimun,S.-J Hwang,L Comfort,I.W Segara,A Hakam

doi:10.1051/e3sconf/202015603002

Abstract

During an earthquake, Reinforced Concrete (RC) building structures should behave in a ductile manner to prevent the structures from collapse. Therefore, the column element should have sufficient ductility to sustain an axial load at the post-peak region. Ductility of the RC column can be sufficiently provided by confinement to the RC column core. Therefore, in this paper, ductility of square RC columns made of NSC and HSSCR are analyzed using three-dimensional nonlinear finite element analysis (3D-NLFEA) with various ties configurations. In total, 12 specimens for each transverse steel rebar configuration were examined. The measurement used for ductility comparisons is the I10 index (AS 3600-2018) which is compared with the concept of ductility available in the literature (for example ACI 318-14). The study found that the computed minimum transverse steel rebar diameter based on ACI 318-14 showed larger diameter than the AS 3600:2018. From the 3DNLFEA analysis found that using a confining rebar higher than 700 MPa with the same volumetric ratio shows lower ductility for the Type I RC column configuration.

Highlights

A special resisting moment frames structure should be designed based on the Strong Column Weak Beam (SCWB) concept plus specific detailing for each element
The strength and ductility enhancement of the Reinforced Concrete (RC) column are strongly affected by the confining rebar configuration and characteristics such as the volumetric ratio, the pitch spacing, the diameter, and the yield strength of the rebar [3]
For Type II RC columns which comply with the ACI 318-14 confining bar requirement, the strain ductility of the column significantly increases as the yield strength of the transverse steel rebar increases

Summary

Introduction

A special resisting moment frames structure should be designed based on the Strong Column Weak Beam (SCWB) concept plus specific detailing for each element. Plastic hinges should be designed properly to occur mainly on the beam element and at the base of the column The purpose of this is to avoid structural collapse and give people inside a building enough time to save themselves during an earthquake event. The use of high strength materials for confining reinforcing bars can result in larger pitch spacing and can increase the workability of the member during concrete casting. For each modeled RC column based on ACI 318-14 and AS 3600-2018, both the I10 ductility index and the displacement ductility level were examined and compared This investigation will show that using a confining rebar with a yield strength higher than 700 MPa and maintaining the same volumetric ratio yields a lower. I10 ductility index and lower displacement ductility level for a certain type of ties configuration

Specimen Geometry Detail

Minimum Confining Rebar Diameter

Results and Discussion

Conclusions