Structural Behavior of GFRP-Reinforced Circular HFRC Columns Under Concentric and Eccentric Loading

  • PDF / 4,750,916 Bytes
  • 14 Pages / 595.276 x 790.866 pts Page_size
  • 102 Downloads / 212 Views

DOWNLOAD

REPORT


RESEARCH ARTICLE-CIVIL ENGINEERING

Structural Behavior of GFRP-Reinforced Circular HFRC Columns Under Concentric and Eccentric Loading Ali Raza1

· Qaiser uz Zaman Khan2

Received: 19 May 2020 / Accepted: 13 August 2020 © King Fahd University of Petroleum & Minerals 2020

Abstract The previous research is rich in plain concrete columns reinforced with glass fiber-reinforced polymer (GFRP) bars, but it is deficient in GFRP-reinforced concrete columns incorporating hybrid fibers. The present study aims to explore and compare the structural behavior of steel and GFRP-reinforced concrete columns having hybrid fibers (SHFC and GHFC columns). Two types of fibers, i.e. steel fibers and polypropylene fibers, were used to develop the hybrid fiber-reinforced concrete. A total of 18 circular concrete columns (9 SHFC columns and 9 GHFC columns) having a height of 1150 mm and a diameter of 250 mm were constructed and tested under axial loading at various eccentricities. The test measurements portrayed that the SHFC columns presented a better performance in terms of axial strength (about 20% higher) and ultimate deflections. The GHFC columns presented higher ductility indices compared with SHFC columns. Both steel and GHFC columns showed similar failure modes and similar reductions in the axial strength when subjected to eccentricities. The newly developed empirical model for the prediction of the axial strength of GHFC columns showed a close agreement with the experimentation. Thus, the comparative study solidly substantiates the application of the proposed empirical model. Keywords GFRP · Columns · Hybrid fiber-reinforced concrete · Hoops · Ductility · Empirical model

List of Symbols E FRP  f co  εco dc ρt wi s f le AFRP  f cc  εcc fl

B

Elastic modulus of GFRP bars Crushing strength of unconfined concrete Axial strain of unconfined concrete at peak axial load Diameter of concrete core material Volumetric ratio of GFRP ties Clear distance between the GFRP bars Center-to-center spacing between GFRP ties Effective lateral confinement stress Cross-sectional area of GFRP long bars Crushing strength of confined concrete Axial strain of confined concrete at peak axial load Lateral confinement pressure of GFRP ties

Ali Raza [email protected] Qaiser uz Zaman Khan [email protected]

1

Department of Civil Engineering, Pakistan Institute of Engineering and Technology, Multan 66000, Pakistan

2

Department of Civil Engineering, University of Engineering and Technology, Taxila 47050, Pakistan

ke s f fv ρl

Confinement effectiveness coefficient Clear vertical spacing between GFRP ties  Stress in GFRP ties at f co Reinforcement ratio of long GFRP bars

1 Introduction The corrosion of steel reinforcement in the reinforced concrete (RC) structures causes the large maintenance costs and decreases the functioning of structural components. Fiberreinforced polymer (FRP) composites are the sound and viable alternatives for the steel reinforcement [1]. These composites are obtaining the acceptance and trust of the regulatory