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You searched for +publisher:"McMaster University" +contributor:("Razaqpur, A. Ghani"). Showing records 1 – 2 of 2 total matches.

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McMaster University

1. D'Souza, Clinton. Shear Strengthening of RC Beams Using Externally Bonded and Anchored FRP U-wraps.

Degree: MASc, 2016, McMaster University

Externally bonded FRP U-wraps are a common shear strengthening configuration for RC beams, however premature debonding of the wraps is a major problem, which limits the effectiveness and efficiency of the FRP strengthening. In this investigation a new π-shape carbon anchor was used to fasten the FRP U-wraps to the concrete in an attempt to prevent/delay debonding of the wraps and increase their effectiveness. Fourteen large scale rectangular beams with a 1900 mm span, 400 mm height, and 170 mm width were tested in three-point bending with various configurations of FRP shear strengthening. Shear pre-cracks were introduced in the beams at angles of 30 and 45 degrees in an attempt to control the inclination angle of the shear crack and determine its effect on the FRP shear resistance. The FRP shear strengthening configurations included un-anchored U-wraps, U-wraps with anchors, U-wraps with horizontal strips, and full wraps. The results showed that the use of a variable shear crack inclination angle in the CSA S806-12 (2012) standard led to overestimated shear resistance predictions for beams with a single shear crack, therefore a conservative 45 degree shear crack inclination is recommended for design. The use of the proposed carbon anchors resulted in a 74% increase in shear strength over the un-anchored U-wrapped beams, while only using half the amount of FRP. The use of the anchors also resulted in a 286% increase in the ultimate FRP strain over the un-anchored U-wraps, and allowed the FRP wraps to achieve 58% of their rupture strain. The use of horizontal strips provided similar results to the anchors and may be used as a less labour intensive alternative, but this issue needs further investigation.

Dissertation

Master of Applied Science (MASc)

Damaged or older reinforced concrete structures can be rehabilitated by using externally bonded fibre-reinforced polymer (FRP) sheets, which are bonded to the concrete surface using an epoxy adhesive. For the case of shear strengthening of beams, it is common for FRP sheets to be wrapped around the sides and bottom of the beam, resembling a U-shape. The problem with this configuration is that under high levels of load the FRP sheets tend to peel off the concrete surface (debonding). This limits the effectiveness of the rehabilitation and results in the inefficient use of the FRP. A new method for anchoring the FRP sheets to the concrete surface is investigated in this research study. The use of a new in-situ π-shape anchor shows promising results, as it delays debonding and provides a large increase in strength with less FRP needed.

Advisors/Committee Members: Razaqpur, A. Ghani, Civil Engineering.

Subjects/Keywords: FRP; U-wraps; Shear strengthening; Anchor; Reinforced concrete

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

D'Souza, C. (2016). Shear Strengthening of RC Beams Using Externally Bonded and Anchored FRP U-wraps. (Masters Thesis). McMaster University. Retrieved from http://hdl.handle.net/11375/19289

Chicago Manual of Style (16th Edition):

D'Souza, Clinton. “Shear Strengthening of RC Beams Using Externally Bonded and Anchored FRP U-wraps.” 2016. Masters Thesis, McMaster University. Accessed October 15, 2019. http://hdl.handle.net/11375/19289.

MLA Handbook (7th Edition):

D'Souza, Clinton. “Shear Strengthening of RC Beams Using Externally Bonded and Anchored FRP U-wraps.” 2016. Web. 15 Oct 2019.

Vancouver:

D'Souza C. Shear Strengthening of RC Beams Using Externally Bonded and Anchored FRP U-wraps. [Internet] [Masters thesis]. McMaster University; 2016. [cited 2019 Oct 15]. Available from: http://hdl.handle.net/11375/19289.

Council of Science Editors:

D'Souza C. Shear Strengthening of RC Beams Using Externally Bonded and Anchored FRP U-wraps. [Masters Thesis]. McMaster University; 2016. Available from: http://hdl.handle.net/11375/19289


McMaster University

2. Makhmalbaf, Elyas. A GFRP Bar Bond Stress and Strength: Comparison of Beam-bond and Pullout Tests Results.

Degree: MASc, 2015, McMaster University

Four beam-bond test specimens, two in accordance with RILEM TC-RC5 recommendation, labelled as RILEM and two based on a modified form of the ACI 208 beam-bond test method, labelled as Notched, were tested in four-point bending to investigate the bond stress distribution and values along the bar embedment length of a 15 𝑚𝑚 nominal diameter GFRP rebar. The beams experienced failure through the rupturing of the longitudinal GFRP tensile reinforcement. In addition, two Modified and ten Standard pullout specimens were tested using the same bar. The beam-bond and the Modified pullout specimens had embedment length of 600 𝑚𝑚 while the Standard pullout specimens had, in accordance with CSA S806, 60 𝑚𝑚 embedment, or four times the bar nominal diameter. The first Modified pullout specimen experienced concrete splitting failure and as a result, the second was lightly confined and failed by GFRP bar rupture. All ten Standard pullout specimens failed due to bar pullout. It was determined that the actual bond stress distribution as a function of the embedment length is practically parabolic and can be described by the derivative of a modified form of the logistic growth function used to approximate the strain distribution along the embedment length. Furthermore, the maximum bond stress location progressively moves from the loaded-end towards the unloaded-end as the bond continues to deteriorate with increasing GFRP stress levels. The development length recommendations by ACI 440.1 and to a lesser degree, CSA S806 and CSA S6 are quite conservative compared to that which is required. It is observed that pullout tests alone cannot provide sufficient knowledge regarding the bond behaviour of FRP reinforcement; consequently, the results of beam-bond testing are more appropriate. Standard pullout tests may be incorporated into quality assurance programs with the understanding that they cannot provide valuable information regarding bond stress distribution and required development length in real structural elements with large embedment lengths. In terms of the beam-bond test method, the RILEM TC-RC5 design recommendation appears to be superior since it eschews severe stress perturbation caused by incidence of flexural cracks at beam midspan. As a result, it produces stability in the terms of the data gathered from the strain gauges placed on the GFRP bar. This benefit outweighs the ease of constructability of the Notched beams as well as their resemblance to real beams.

Thesis

Master of Applied Science (MASc)

The force that bonds a reinforcing rod to concrete is determined using three test methods. Each method is recommended by some design standards, but it is unclear how the results of these tests compare to each other. To shed light on the issue, a 15 𝑚𝑚 fibre glass rod was tested using three well-known test methods. It was discovered that two of the methods give results that are reasonably close while the third gives variable results that generally do not agree with the results of the other two. It was also discovered that…

Advisors/Committee Members: Razaqpur, A. Ghani, Civil Engineering.

Subjects/Keywords: GFRP bond stress distribution; GFRP bond; GFRP embedment/development length; Beam bond and pullout test method for a GFRP bar

Record DetailsSimilar RecordsGoogle PlusoneFacebookTwitterCiteULikeMendeleyreddit

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Makhmalbaf, E. (2015). A GFRP Bar Bond Stress and Strength: Comparison of Beam-bond and Pullout Tests Results. (Masters Thesis). McMaster University. Retrieved from http://hdl.handle.net/11375/17237

Chicago Manual of Style (16th Edition):

Makhmalbaf, Elyas. “A GFRP Bar Bond Stress and Strength: Comparison of Beam-bond and Pullout Tests Results.” 2015. Masters Thesis, McMaster University. Accessed October 15, 2019. http://hdl.handle.net/11375/17237.

MLA Handbook (7th Edition):

Makhmalbaf, Elyas. “A GFRP Bar Bond Stress and Strength: Comparison of Beam-bond and Pullout Tests Results.” 2015. Web. 15 Oct 2019.

Vancouver:

Makhmalbaf E. A GFRP Bar Bond Stress and Strength: Comparison of Beam-bond and Pullout Tests Results. [Internet] [Masters thesis]. McMaster University; 2015. [cited 2019 Oct 15]. Available from: http://hdl.handle.net/11375/17237.

Council of Science Editors:

Makhmalbaf E. A GFRP Bar Bond Stress and Strength: Comparison of Beam-bond and Pullout Tests Results. [Masters Thesis]. McMaster University; 2015. Available from: http://hdl.handle.net/11375/17237

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