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Showing 1-5 of 1335 Abstracts search results

Document: 

SP-360_20

Date: 

March 1, 2024

Author(s):

Emmanuel Ferrier, Laurent Michel, Andrea Armonico

Publication:

Symposium Papers

Volume:

360

Abstract:

This paper presents the crack monitoring of reinforced concrete beams strengthened with fiber reinforced polymer (FRP) sheets. Emphasis is placed on the development of a smart FRP bonded material that can measure the crack opening of a reinforced concrete beam strengthened by FRP. The reliability measured by a conventional digital image correlation (DIC) and by the proposed smart FRP is employed to assess the contribution of the FRP to control the crack. The monitoring process is based on a large set of experimental database consisting of 19 test beams. The effect of FRP to control the crack opening is studied depending on the steel ratio, FRP ratio and the level of damaged of RC beams when FRP is applied. The results were compared with the theoretical values of crack width and spacing predicted using the Eurocode 2 (EC2) formula, calibrated for non-strengthened RC elements. The corresponding results were compared in order to clarify the effect of external bonded FRP on the cracking behaviour of RC beams.

DOI:

10.14359/51740632


Document: 

SP-360_13

Date: 

March 1, 2024

Author(s):

Girish Narayan Prajapati, Shehab Mehany, Wenxue Chen, and Brahim Benmokrane

Publication:

Symposium Papers

Volume:

360

Abstract:

This paper presents an experimental study that investigated the physical and mechanical properties of the helical wrap glass fiber-reinforced polymer (GFRP) bars. The physical tests are conducted to check the feasibility and quality of the production process through the cross-sectional area and evaluation of the fiber content, moisture absorption, and glass transition temperature of the specimens. While the mechanical tests in this study included testing of the GFRP specimens to determine their tensile properties, transverse shear, and bond strength. Four bar sizes (#3, #4, #5, and #6), representing the range of GFRP reinforcing bars used in practice as longitudinal reinforcement in concrete members subjected to bending, are selected in this investigation. The GFRP bars had a helical wrap surface. The tensile failure of the GFRP bars started with rupture of glass fibers followed by interlaminar delamination and bar crushing. The bond strength of the GFRP bars satisfied the limits in ASTM D7957/D7957M. The test results reveal that the helical wrap GFRP bars had physical and mechanical properties within the standard limits.

DOI:

10.14359/51740625


Document: 

SP-360_04

Date: 

March 1, 2024

Author(s):

Ali Alatify and Yail J. Kim

Publication:

Symposium Papers

Volume:

360

Abstract:

The serviceability and ultimate limit states of a concrete member are reliant upon the bond of reinforcement. The performance of glass fiber reinforced polymer (GFRP) reinforced concrete structures is influenced by multiple parameters and one of these parameters is the bond length of GFRP rebars. The scope of the present research is to experimentally study the effects of fully and partially bonded rebars on the load-bearing capacity and cracking of GFRP-reinforced concrete beams. The beams with partially bonded reinforcement show reduced capacities compared with those with fully bonded reinforcement, and the former reveals localized cracks. The partially bonded beams fail as a result of concrete splitting, while their fully bonded counterparts fail by concrete crushing.

DOI:

10.14359/51740616


Document: 

SP-360_19

Date: 

March 1, 2024

Author(s):

Huifeng Qian, Wendell Harriman II., P.E.

Publication:

Symposium Papers

Volume:

360

Abstract:

Fiber reinforced polymer (FRP) composite rebar is a non-metallic concrete reinforcement alternative that has been successfully deployed in hundreds of structural applications globally. The increasing demand for FRP rebar as a metal alternative is driven by its unique value proposition, including lightweight, high strength, magnetic transparency, and most significantly, corrosion resistance. FRP rebar is fabricated through pultrusion, a high throughput composite fabrication process in which, resin-impregnated fiber undergoes rapid cure when pulled through a heated furnace. Considering the open nature of the open pultrusion process, expansion of production capacity for FRP rebar manufacturing demands the use of advanced resins that are free from Volatile Organic Compounds (VOCs), enable high throughput production, and deliver an outstanding translation of fiber properties following cure. In this work, we will present an epoxy system that is inherently VOC Free and is tailored to enable high throughput manufacturing of glass fiber reinforced polymer (GFRP) rebar at scale. Furthermore, the rapid formation of highly crosslinked structures achieved with this resin system during pultrusion is found to enable outstanding fiber property translation resulting in high modulus (>70 GPa) and corrosion resistance (>80 % tensile strength retention without load) that exceeds existing standards such as ASTM D7957.

DOI:

10.14359/51740631


Document: 

SP-360_23

Date: 

March 1, 2024

Author(s):

Raphael Kampmann, Tim Rauert, Niklas Pelka, und Bastian Franzenburg

Publication:

Symposium Papers

Volume:

360

Abstract:

Corrosion of reinforcement steel is a major issue for many structural concrete components, because it leads to strength reduction and may significantly reduce the service life. For this reason, fiber-reinforced polymer rebars (FRP rebars) have been developed, as they represent a viable alternative that may replace reinforcing steel for structures that are particularly susceptible to corrosion issues. However, structural design philosophies for these new materials are still in development and further research is needed to implement FRP rebars properly and safely in design codes but also to ensure that design calculations properly predict the actual behavior and performance of FRP reinforced structures.

This study was conducted to evaluate the strength and structural deformation behavior of flexural beams that were designed according to Eurocode 2 and, for comparison, according to different design methods pro-posed for FRP reinforced structures. With regard to the development of a uniform design concept for alternative reinforcement materials existing in Germany/Europe, different bending design concepts includ-ing the serviceability limit state were evaluated. In addition, the theoretically calculated and predicted strength/deformation were compared to the experimentally obtained measurements. A total of 15 flexu-ral beams, with ans overall length of 4.5 m (177 in.), a width of 200 mm (7.8 in.), and a height of 400 mm (15.8 in.), were cast; three of these beams (designed according to Eurocode 2) featured traditional steel rein-forcement, to serve as control group. The remaining 12 flexural beams were evenly allocated to capture the two alternative reinforcement materials, while generating three different reinforcement distribution patterns with comparable reinforcement ratios (equivalent cross-sectional areas). Thus, a total of six subgroups –three with GFRP and three with BFRP – each with two specimens, were analized. To test all beam in pure bending and to eliminate the influence from shear forces, two equally increasing loads were applied at the (longitudinal) third-points of the beams. Both deflections and loads were measured at several points to evaluate the structural performance of the FRP reinforced structural members.

The results showed that the deflection of the glass fiber reinforced bars at the design load capacity measured twice as much as the deflection of the control group. Almost three times as much deflection (at the same load) was observed for the concrete beams reinforced with basalt fiber rebars. In addition, it was observed that the concrete beams with glass and basalt fiber reinforcement bars showed a nearly elastic-elastic behavior up to the point of failure, whereas the steel-reinforced concrete beams showed an elastic-plastic behavior. However, the deformational behavior differed between the various beam types. While the prevailing equations properly captured the post-cracking performance of traditionally reinforced concrete beams, they do not adequately predict the deflections of FRP reinforced concrete beams. From the measurements and analyses, it was concluded that the serviceability limit state (SST) is more critical than the ultimate limit state (LTS) for the design of concrete flexural beams reinforced with FRP rebars.

DOI:

10.14359/51740635


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