International Concrete Abstracts Portal

Showing 1-5 of 581 Abstracts search results

Document: 

SP364_11

Date: 

December 1, 2024

Publication:

Symposium Papers

Volume:

364

Abstract:

This theoretical study discusses the serviceability of reinforced concrete beams retrofitted with near-surface-mounted (NSM) carbon fiber reinforced polymer (CFRP) strips. Particularly, the research aims to understand the tension stiffening of the strengthened beams under varying degrees of steel corrosion. Five beams are modeled and analyzed, which represent different levels of deterioration up to 100 years. The effects of tension stiffening are evaluated at service and yield loads. Results show that the tension stiffening of the beams decreases as the cross-sectional area of the steel reinforcement reduces. Likewise, the yield and ultimate capacities of the beams diminish with the reduced steel reinforcement. The effective moment of inertia formula stipulated in ACI 318-19 appears to be applicable to the NSM CFRP-retrofitted beams.

DOI:

10.14359/51745463


Document: 

CI4608NExInsights

Date: 

August 1, 2024

Publication:

Concrete International

Volume:

46

Issue:

8

Abstract:

A new certificate program on “Designing Concrete Structures Reinforced with GFRP Bars Using the ACI CODE-440.11-22” is now offered online through ACI University. The program focuses on recently published ACI CODE-440.11-22: Building Code Requirements for Structural Concrete Reinforced with Glass Fiber-Reinforced Polymer (GFRP) Bars—Code and Commentary.


Document: 

SP-363-8

Date: 

July 1, 2024

Author(s):

Ali Alatify and Yail J. Kim

Publication:

Symposium Papers

Volume:

363

Abstract:

This paper presents the prediction of bond strength between ultra-high performance concrete (UHPC) and fiber reinforced polymer (FRP) reinforcing bars using an artificial neuronal network (ANN) approach. A large amount of datasets, consisting of 183 test specimens, are collected from literature and an ANN model is trained and validated. The ANN model includes six variable inputs (bar diameter, concrete cover, embedment length, fiber content, concrete strength, and rebar strength) and one output parameter (bond strength). The model performs better than other models excerpted from existing design guidelines and previously published papers. Follow-up studies are expected to examine the individual effects of the predefined input parameters on the bond strength of UHPC interfaced with FRP rebars.

DOI:

10.14359/51742111


Document: 

SP-362_01

Date: 

June 5, 2024

Author(s):

Wu and Jishen Qiu

Publication:

Symposium Papers

Volume:

362

Abstract:

Reactive magnesia cement (RMC) is an emerging class of low-alkaline and CO2-sequestering binder, which can mitigate the deterioration of GFRP reinforcements induced by a high alkaline environment, e.g., in Portland cement. This study investigated the slip behavior of GFRP rebar embedded in RMC composite, which varies with carbonation depth significantly. The variation of the interfacial bond was determined by a specially designed push-out test of the GFRP core; the variation of the carbonation degree and microstructure was examined by SEM-EDX, XRD, TGA, and acid digestion tests. Both properties demonstrated a similar trend, decreasing rapidly with increasing depth. A new finite element model that considers the depth-dependency of the matrix compositions and the rebar-to-matrix interfacial bond is established. It can predict the constitutive bond-slip behavior of a long GFRP rebar embedded in an RMC composite with non-uniform carbonation.

DOI:

10.14359/51740871


Document: 

CI4605Sicaras

Date: 

May 1, 2024

Author(s):

Victoria K. Sicaras

Publication:

Concrete International

Volume:

46

Issue:

5

Abstract:

New research funded by the ACI Foundation developed and tested retrofit techniques for diaphragms using externally bonded fiber-reinforced polymer (FRP). Key findings from the research are being translated into guidance on how to establish the effective FRP design strain and the nominal shear strength contribution of the FRP. The recommendations also address the use of intermediate and end FRP anchors and limitations on the clear spacing between sheets


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