International Concrete Abstracts Portal

Showing 1-5 of 55 Abstracts search results

Document: 

SP327

Date: 

November 20, 2018

Publication:

Symposium Papers

Volume:

327

Abstract:

Fiber-reinforced polymer (FRP) composite materials been widely used in civil engineering new construction and repair of structures due to their superior properties. 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 reports, guides, and specifications on the use of FRP materials for may reinforcement applications 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.

This volume represents the thirteen in the symposium series and could not have been put together without the help, dedication, cooperation, and assistance of many volunteers and ACI staff members. First, we would like to thank the authors for meeting our various deadlines for submission, providing an opportunity for FRPRCS-13 to showcase the most current work possible at the symposium. Second, the International Scientific Steering Committee, consisting of many distinguished international researchers, including chairs of past FRPRCS symposia, many distinguished reviewers and members of the ACI Committee 440 who volunteered their time and carefully evaluated and thoroughly reviewed the technical papers, and whose input and advice have been a contributing factor to the success of this volume.

DOI:

10.14359/51714460


Document: 

SP327-31

Date: 

November 1, 2018

Author(s):

Amir Mofidi, Lijuan Cheng, Omar Chaallal, Yixin Shao

Publication:

Symposium Papers

Volume:

327

Abstract:

This paper evaluates the influence of the key parameters on the shear behavior of reinforced concrete (RC) beams retrofitted in shear using near-surface mounted (NSM) fiber-reinforced polymers (FRP) laminates and rods. The commonly observed debonding failure is considered in the study. The principal bond related parameters are examined, including the FRP effective bond length, the NSM FRP to concrete bond relation and the pull-off force of NSM FRP bonded from concrete surface. It is found that unlike the beams strengthened with externally bonded (EB) FRP, the effect of the existing transverse steel shear reinforcement on the shear contribution of FRP is not significant and should not be considered by the design models. The existing experimental results in the open literature also show that the internal steel shear reinforcement and the strengthening NSM FRP do not diminish each other’s contributions to the shear resistance of the RC beam. To precisely predict the shear contribution of NSM FRP of the strengthened RC beams corresponding to the debonding failure, a new prediction method is proposed in this study to consider the most influencing factors on the shear contribution of NSM FRP (Vf). The accuracy of the proposed equations is verified by comparing the predictions with the shear strength of a series of experimentally tested RC beams from the literature. Moreover, a comparison with other existing models shows that the proposed model achieves a better correlation with the experimental data than the other existing equations.

DOI:

10.14359/51713352


Document: 

SP327-28

Date: 

November 1, 2018

Author(s):

Salah Altoubat, Abdul Saboor Karzad, Mohamed Maalej

Publication:

Symposium Papers

Volume:

327

Abstract:

This paper is part of an on-going research project on the behavior of damaged Reinforced Concrete (RC) beams repaired and strengthened with Externally Bonded Fiber Reinforced Polymer (EB-FRP). A total of seven full-scale rectangular beams; fully-damaged in a previous study, were repaired and retested to failure. The repair methodology consists of filling the cracks with epoxy, and then wrapping the beams with FRP discrete strips with two different thicknesses (1 layer and 2 layers). Out of the seven beams, four beams were strengthened using 2 layers of EB-FRP discrete strips; two beams were strengthened with 1 layer of EB-FRP; and the remaining beam was only repaired by crack injection with epoxy without wrapping with FRP. The beams were instrumented and tested to failure in three-points loading setup. The measured test parameters were the beams deflection and the maximum load-carrying capacity. Furthermore, the mode of failure was also observed and reported in this study. The test results revealed that the use of EB-FRP strips along with epoxy injection is an effective repair method that not only recovers the original strength (strength of the beams tested in previous study, considered as the reference beams), but also significantly increases their shear capacity. Comparing the shear capacity of the repaired beams to that of the reference beams, revealed that 2 layers of EB-FRP increased the shear strength by up to 95%, while the use of 1 layer of EB-FRP increased the shear strength by up to 66%. Moreover, comparison of the test results with existing predictive models (ACI 440.2R and fib TG-9.3) showed that both models reasonably predict the EB-FRP contribution to the shear strength of repaired and strengthened damaged beams.

DOI:

10.14359/51713349


Document: 

SP327-29

Date: 

November 1, 2018

Author(s):

Mostafa Yossef, An Chen and Austin Downey

Publication:

Symposium Papers

Volume:

327

Abstract:

Insulated concrete sandwich panels are composed of two concrete wythes separated by an insulation layer and connected by shear connectors. This paper develops a multifunctional photovoltaic (PV) integrated insulated concrete sandwich (PVICS) panel, which can act as a passive energy system through the insulation layer and an active energy system by harvesting the solar energy using attached thin-film solar cells. The panel features an innovative co-curing scheme, where solar cells, Fiber-Reinforced Polymer (FRP) shell, and polymer concrete are manufactured together to act as a formwork for the sandwich panel. The objective of this paper is to prove the concept of PVICS based on bending test, Finite Element (FE) analysis and analytical study. It can be concluded that the test results correlate well with those from the FE and analytical models. FRP shell can act as both shear connectors and reinforcement. The panel achieved 82% Degree of Composite Action, which can provide enough strength and stiffness. Solar cells worked properly under service load. Shear-lag effect was observed for the strains along the width of the panel.

DOI:

10.14359/51713350


Document: 

SP327-26

Date: 

November 1, 2018

Author(s):

Nader Sleiman, Ryan Barrage, Graeme J. Milligan, and Maria Anna Polak

Publication:

Symposium Papers

Volume:

327

Abstract:

The use of GFRP as main reinforcement in concrete structures is an attractive option for structures in aggressive environments. The use of GFRP reinforcement in frame corner joints may be problematic considering the weak link at the reinforcement bend, and it has not been previously studied. The presented experimental program studies the effect of reinforcement ratio and confinement stirrups on the behaviour of the joint. The failure mode was altered from bar rupture to failure of diagonal strut by increasing the reinforcement ratio, however had minimal effect on ultimate strength. The results also indicated a substantial increase in ultimate strength and maximum deflection with the addition of confinement stirrups. The finite element analyses performed suggested good model predictions for failure moments and deflections, but were unable to completely capture the concrete failure within the joint. The suspected cause is the modelling of the bond between the reinforcement and concrete.

DOI:

10.14359/51713347


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