Strengthening of RC deep beams using glass chopped strand mat fiber

Name: Lalin, Lam

keyword: Anchors

LCSH: Reinforced concrete -- Testing

; External bonded

LCSH: Strength of materials -- Testing

; Glass chopped strand mat fiber

; Reinforced concrete deep beam

; Strengthening

Abstract: This thesis is aimed to investigate the techniques to externally strengthen the reinforced concrete deep beams by using multidirectional glass chopped strand mat (GCSM) composites. In external bonded strengthening technique, the GCSM sheet was cut and attached on the surfaces of the beam by using hand lay-up method. The behavior and the failure mode of strengthened specim ens were experimentally investigated. It was known that the failure mode of specimens strengthened with external bonded technique was mostly due to the debonding of the fiber composites from the beam surfaces, therefore, various mechanical anchors were investigated and utilized to prevent the debonding failure of GCSM fiber composites. The usage of anchors was able to improve the bond between concrete and composites, which leads to fully usage of fiber composites. The experimental program in this study was divided into three parts. The first part discusses the experimental results of six reinforced concrete deep beams strengthened in shear using external bonded technique. One beam was tested without strengthening, while the remaining five beams were strengthened using different fiber thickness and configurations. All specimens were tested under static loading until failure. The comparisons between control and strengthened specimens were made and discussed in Chapter 4. The experimental results showed that this GCSM e xternal strengthening technique enhances the ultimate loading capacity of the RC deep beam. The second part presents the experimental results of five reinforced concrete deep beams which were strengthened using external GCSM fiber composites with mechanical anchors. Different resin systems (i.e., polyester and epoxy resin) were used to fabricate and bond the GCSM composites to the beam surfaces by using hand lay-up method. The experimental results indicated that providing additional bond strength by means of mechanical anchors enhances the ultimate loading capacity of RC deep beams and leads to fully usage of the fiber composites. Epoxy resin is more effective than polyester resin since the ultimate load of specimen strengthened with epoxy-bonded GCSM fiber composites was increased up to 68% compared the control specimen. The behavior and failure mode of all specimens in this group were discussed in Chapter 5. The third part shows the series of twenty reinforced concrete deep beams which were strengthened using external bonded GCSM fiber composites with anchors. All specimens were subjected to static loading and tested up to failure. Epoxy resin system was used as the adhesive in this study. The effects of external bonded GCSM technique on the beams of diffierent concrete strengths and shear span-to-depth ratios were experimentally investigated. The GCSM fiber sheets were applied to the beam in different amounts and configurations (i.e., Side-bonded and Uwrapped scheme). Two different types of anchors (i.e., mechanical expansion anchor and epoxy anchor) were exploited. The experimental results showed that the fiber thickness has the effect on the strengthening efficiency of external bonded GCSM composites for improving the ultimate strength of reinforced concrete deep beams. The U-wrapped scheme has a significant benefits compared with side-bonded scheme. The applied load versus the mid-span deflection curves of strengthened specimen were plotted against their control specimens. The behavior and mode of failure of all tested beams were presented and discussed in Chapter 6. Chapter 7 presents the finite element analysis carried out on reinforced concrete (RC) deep beams strengthened in shear using Glass Chopped Strand Mat (GCSM) polymer composites. VecTor2 is a nonlinear finite element (FE) software which has been developed at the University of Toronto. FE program VecTor2 was used for the modeling and analysis of RC deep beams externally strengthened using GCSM fiber composites with mechanical anchors. It can be seen that the results obtained from the VecTor2 were in good accordance with the experimental results. The finite element models can predict the behavior of un-strengthened and strengthened RC deep beams. This finite element program is also capable of predicting cracks at every load steps. The crack patterns of RC deep beams observed during testing and the predicted finite lement results are compared and discussed in the following sections

Thammasat University. Thammasat University Library

Address: BANGKOK

Email: preserv@tu.ac.th

Name: Amorn Pimanmas

Role: advisor

Created: 2015

Modified: 2021-11-02

Issued: 2021-11-02

วิทยานิพนธ์/Thesis

application/pdf

DOI: 10.14457/TU.the.2015.1460

eng

DegreeName: Master of Science

Level: Master's Degree

Descipline: Engineering and Technology

Grantor: Thammasat University

©copyrights Thammasat University

ลำดับที่.	ชื่อแฟ้มข้อมูล	ขนาดแฟ้มข้อมูล	จำนวนเข้าถึง	วัน-เวลาเข้าถึงล่าสุด
1	4873lalin.pdf	4.11 MB

ใช้เวลา

0.029996 วินาที