Behavior of RC curved beams with openings and strengthened by CFRP laminates

Other Title(s)

سلوك الأعتاب الخرسانية المسلحة المقوسة و الحاوية على فتحات مقواة بألياف الكاربون البولمرية

Dissertant

Hamzah, Bashshar Abd

Thesis advisor

Ali, Ammar Yasir

Comitee Members

Jasim, Nabil A.
Khudayr, Jamal A. S.
Allush, Namir A.
Dawud, Mustafa B.
Nimnim, Haydar T.

University

University of Basrah

Faculty

Engineering College

Department

Department of Civil Engineering

University Country

Iraq

Degree

Ph.D.

Degree Date

2013

English Abstract

This research is devoted to investigate the behavior and performance of reinforced concrete curved beams(the curved beam and the applied loads lie in same plane) with and without openings, unstrengthened and strengthened(externally by CFRP laminates or internally by steel reinforcement).

The experimental work consisted of fabrication and testing of twelve reinforced concrete beams.

Eight of these beams had rectangular openings and four without openings.

The experimental variables considered in the test program included: curvature forces, location of opening through profile of beam, presence of internal strengthening by reinforcing steel(stirrups) or external strengthening by CFRP laminates for openings.

The beams were tested under two points loading at top edges with (hinge-roller) supports at bottom.

The experimental results showed a significant decrease in ultimate load capacity by about 38 % of that for control beam, with splitting mode failure which were registered for curved beams without confining stirrups to resist curvature forces in radial direction.

The use of CFRP laminates as external confinement at the middle sector to resist curvature forces induced between reinforcing bars and concrete cover, which gave approximately the same general response, but the ductility ratio was lesser.

The increase in load capacity for beam containing an opening at zone of excessive compressive force ( near the support) was 39% and 43% more than for zones of pure bending and combined bending, shear force and axial compressive force, respectively.

The proposed design method used in the current study for externally strengthening of opening by CFRP laminates at zones of pure bending, combined bending, shear force and axial compressive force, and excessive compressive force ( near the support) gave good results, where the enhancement of the ultimate load of strengthened beam was about 100%, 87% and 58%, respectively, when compared with unstrengthened beams that has same properties of openings, and gave conservative results when compared with solid control beam, where the ultimate load reached about 83%, 75% and 91%, respectively .

The numerical work included a three-dimensional nonlinear finite element model suitable for the analysis of reinforced concrete curved beams with or without openings and unstrengthened or strengthened by(CFRP laminates or reinforcing steel) under monotonic loading using the computer program ANSYS version 11.0.

Full bond was assumed between the CFRP and concrete surface and between the steel reinforcement and concrete.

Brick element SOLID65 and SOLID45 was used to represent concrete element and steel plate, respectively.

While LINK8 and SHEEL41 were used to represent steel reinforcement and CFRP sheets respectively.

In general, a good agreement between the finite element solutions and experimental results has been obtained concerning estimate load-deflection response, mode of failure.

And cracking and ultimate loads with average difference about 5.83% and 3.92%,respectivly.

The numerical results for the analyzed beams show that the ultimate load increases by about 17% when the length of opening decreased by 50%, and it decreases by 11% when the length of opening increased by 50%.

Also, as the depth of the opening decreases by 37%, the ultimate load increases by about 42% .

Also, the ultimate load capacity increases by about 9% and 20% when the depth/length of the opening decreased from 1:2 to 1:3 and 1:4, respectively.

Main Subjects

Civil Engineering

No. of Pages

152

Table of Contents

• APA
• MLA
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Language

English

Data Type

Arab Theses

Record ID

BIM-748135