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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: 

SP327-19

Date: 

November 1, 2018

Author(s):

Jaime Gonzalez-Libreros, Cristian Sabau, Lesley H. Sneed, Carlo Pellegrino, and Gabriel Sas

Publication:

Symposium Papers

Volume:

327

Abstract:

Fiber reinforced cementitious matrix (FRCM) composites have gained popularity for strengthening of concrete structures due to their capacity to overcome some drawbacks of fiber reinforced polymer (FRP) composites, mainly related to the use of epoxy resins. Research on the topic has shown that FRCM composites can increase the axial, flexural, shear, and torsional capacity of concrete elements. However, experimental studies are still limited, and an important effort is required to develop accurate and reliable design models to predict the contribution of the system to the capacity of strengthened elements. In this paper, a quantitative review of experimental studies of axially loaded concrete elements confined with FRCM composites is presented. The influence of selected variables on the increase in axial capacity of the strengthened specimens is evaluated. Three available design models for predicting the increase in axial capacity of FRCM-strengthened concrete are assessed using a database compiled by the authors. Results show that confinement with FRCM composites can provide a significant increase in axial strength for both cylindrical and prismatic concrete specimens. Further efforts are needed to improve the performance of models to predict the axial strength and behavior of FRCM-confined concrete.

DOI:

10.14359/51713340


Document: 

SP327-15

Date: 

November 1, 2018

Author(s):

Enrique del Rey Castillo, Jason Ingham and Michael Griffith

Publication:

Symposium Papers

Volume:

327

Abstract:

The use of Externally Bonded Fiber Reinforced Polymer (EBR-FRP) systems is an established technique for the structural improvement of existing buildings but the technique features disadvantages. Premature FRP-to-concrete debonding has been commonly highlighted as one of the main problems, together with the difficulty of fully wrapping the structural element when the structure presents complex geometries. FRP straight anchors are used to transfer the forces from the FRP sheet into the structural element, ameliorating these two problems, but a comprehensive design method for FRP anchors has not yet been established despite the increased use and research attention given to FRP anchors. A research project was undertaken involving monotonically testing single-anchors in tension to investigate the behavior and capacity of isolated FRP anchors. However, a number of factors that may have a significant influence on the capacity of the anchors could not be investigated such as the behavior of the anchors when subjected to tension-compression cycles and the effect of dynamic loads. To address some of the aspects not covered within the single-anchor tests, six full-scale reinforced concrete columns were tested using pseudo-static loading, with the aim being to verify that the peak moment developed during testing was forecasted accurately.

DOI:

10.14359/51713336


Document: 

SP327-05

Date: 

November 1, 2018

Author(s):

Akram Jawdhari and Issam Harik

Publication:

Symposium Papers

Volume:

327

Abstract:

Fiber reinforced plastics (FRPs) have become a first choice for strengthening/repairing concrete members deficient in shear, flexure or torsion. However, oftentimes, the desired increase in capacity of FRP repaired/strengthened member is not achieved due to premature failures that occur at loads lower than the loads associated with failure of constituent materials (concrete, steel, FRP). Examples of premature failures in FRP retrofitted concrete applications include (1) plate-end debonding, (2) intermediate crack induced debonding (ICID), and (3) concrete cover separation (CCS). This paper present three-dimensional finite element (FE) models developed mainly to demonstrate the capability of FE models in predicting such failures, and to serve as reference for future FE studies concerning the behavior of RC members bonded to FRP reinforcement. Five RC beams, tested in previous experimental study by the authors, are modeled. The beams include a control beam; beam strengthened with spliced CFRP rod panel, beam strengthened with spliced CFRP rod panel, anchored at panel’s ends with CFRP wraps; beam strengthened with one (full-length) CFRP laminate, and beam strengthened with lap-spliced CFRP laminate system. Results, including load mid-span deflection response, strain profile along FRP length, and failure modes, showed that the presented FE models can replicate the experiments and predict the various premature failures oftentimes observed with FRP retrofitted concrete members.

DOI:

10.14359/51713325


Document: 

SP327-37

Date: 

November 1, 2018

Author(s):

Sina Khodaie and Fabio Matta

Publication:

Symposium Papers

Volume:

327

Abstract:

This paper demonstrates a meso-scale numerical model to simulate the mechanical response of glass fiber-reinforced polymer (GFRP) reinforced concrete (RC) structures in two instances where fracture and friction phenomena play an important role, namely: (1) four-point bending load testing of scaled slender RC beams without stirrups; and (2) static push-over load testing of a RC railing post-deck connection. The Lattice Discrete Particle Model (LDPM), a meso-scale concrete model that accounts for concrete heterogeneity, and fracture and friction behavior, is considered. The RC structural models include GFRP bar elements whose interface with the surrounding concrete is described by a nonlinear bond-slip model. For GFRP-RC beams, the results of numerical simulations provide accurate estimates of load-midspan displacement response, failure load and crack pattern irrespective of beam depth up to 292 mm. This outcome highlights the promise held by this modeling approach to enable research to advance the understanding of shear force transfer mechanisms and related size effect. For the case of a representative GFRP-RC post-deck connection, the numerical simulations yielded accurate results on strength and failure mode. This outcome highlights the potential of LDPM-based numerical modeling for screening candidate designs prior to expensive crash testing.

DOI:

10.14359/51713358


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