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International Concrete Abstracts Portal

Showing 1-5 of 23 Abstracts search results

Document: 

SP322

Date: 

July 1, 2018

Author(s):

Editor: Raafat El-Hacha

Publication:

Symposium Papers

Volume:

322

Abstract:

The use of Fiber-reinforced polymer (FRP) composite materials in new construction and repair of concrete structures has been growing rapidly in recent years. FRP provides options and benefits not available using traditional materials. The promise of FRP materials lies in their high-strength, lightweight, noncorrosive, nonconducting, and nonmagnetic properties. ACI Committee 440 has published several guides providing recommendations for the use of FRP materials based on available test data, technical reports, and field applications. The aim of these document is to help practitioners implement FRP technology while providing testimony that design and construction with FRP materials systems is rapidly moving from emerging to mainstream technology.

DOI:

10.14359/51710887


Document: 

SP322-21

Date: 

June 18, 2018

Author(s):

Mohamed Zawam and Khaled A. Soudki

Publication:

Symposium Papers

Volume:

322

Abstract:

An experimental study was conducted to determine the transfer length of prestressed Glass Fiber Reinforced Polymer bars. This paper is a part of a broad program that studies the long-term behaviour of GFRP prestressed concrete beams. 16 GFRP prestressed concrete beams were cast in this study. The parameters included were; prestressing level; 300 MPa (44 ksi) and 500 MPa (73 ksi), concrete compressive strength; 30 MPa (4440 psi) and 70 MPa (10000 psi), and the GFRP bar diameter;12Φ (No. 4) and 16Φ (No.5). Accurate estimation of the transfer length is necessary for elastic stress calculations at the service limit state and for the shear design of prestressed members. Strain gauges were used to measure strains on the GFRP bars and DEMEC gauges were used to measure the concrete surface strains at the level of the prestressed GFRP bar to determine the transfer length. The transfer length of 16Φ (No.5) GFRP bars in concrete with compressive strength of 30 MPa (4440 psi) was found to be about 17 db, and 14 db for prestressing levels of 500 MPa (73 ksi) and 300 MPa (44 ksi), respectively. The measured transfer length values were used to improve the transfer length estimates provided by the ACI 440.4 R-04 equation by calibrating the material coefficient factor (αt) used in the ACI equation.

DOI:

10.14359/51706972


Document: 

SP322-08

Date: 

June 18, 2018

Author(s):

Jennifer Eisenhauer Tanner, David Mukai, Jiangang Deng, and Charles W. Dolan

Publication:

Symposium Papers

Volume:

322

Abstract:

Sustainability of CFRP materials is evaluated based on their long-term capacities that can be decreased by environmental exposure. Researchers regularly accelerate this process by various forms of hygrothermal conditioning. Results of both flexural and tension tests are presented. A comparison of flexural and direct tension test methods is proposed and compared to those obtained by other investigators. In addition, a simple predictive model is introduced. Accelerated ageing tests indicate that the sustainability of carbon fiber reinforced polymer (CFRP) repair systems is impacted by the coverage rate of adhesives. Test results indicate no change in strength for specimens with 91 to 233 percent of the manufacturer’s recommended adhesive application while accelerated ageing tests show a markedly lower strength for specimens with less than the manufacturer’s recommended coverage.

DOI:

10.14359/51706959


Document: 

SP322-12

Date: 

June 18, 2018

Author(s):

Omar I. Abdelkarim, Ahmed Gheni, Sujith Anumolu, and Mohamed A. ElGawady

Publication:

Symposium Papers

Volume:

322

Abstract:

This paper describes the behavior of precast hollow-core fiber-reinforced polymer (FRP)-concrete-steel columns (HC-FCS) under combined axial and lateral loading. The HC-FCS column consists of a concrete wall sandwiched between an inner steel tube and an outer FRP tube. This study investigated two large-scale columns: the traditional reinforced concrete (RC) and the HC-FCS column. The steel tube of the HC-FCS column was embedded into the footing while the FRP tube was stopped at the top of the footing level (i.e., the FRP tube provided confinement only). The hollow steel tube provided the only reinforcement for shear and flexure inside the HC-FCS column. The FRP in HC-FCS ruptured at a lateral drift of 15.2%, while the RC column displayed a 10.9% lateral drift at failure. The RC column failed due to rebar rupture when the moment capacity dropped more than 20%. The HC-FCS failed gradually with concrete compression failure and steel local buckling followed by FRP rupture. Finite element (FE) analysis was conducted using LS-DYNA to develop a static cyclic analysis of a three-dimensional HCFCS model. The FE results mirrored the experimental results. The bending strength of HC-FCS columns could easily be calculated with a high degree of accuracy using a sectional analysis based on Navier-Bernoulli’s assumptions and strain compatibility concepts.

DOI:

10.14359/51706963


Document: 

SP322-20

Date: 

June 18, 2018

Author(s):

Donna Chen and Raafat El-Hacha

Publication:

Symposium Papers

Volume:

322

Abstract:

Experimental and analytical investigation into the performance of a special bond system was conducted on small-scale mixed-mode bending (MMB) specimens for implementation in a full-scale hybrid bridge deck system. Full-depth threaded Glass Fiber Reinforced Polymer (GFRP) rods, as a proposed replacement for commonly used GFRP shear studs, in conjunction with an epoxy bonded coarse silica sand aggregate layer, were used at the bond interface between a pultruded GFRP plate and cast-in-place Ultra-High Performance Concrete (UHPC). Findings show that the presence of the threaded GFRP rods increased the strength of the system up to 250% while utilizing 25% of the rod capacity. The full potential of full-depth threaded GFRP rods for bond and crack control can be explored in greater detail in future studies, including the application of nut tightening forces to increase initial clamping forces at the bond interface.

DOI:

10.14359/51706971


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