International Concrete Abstracts Portal

Showing 1-5 of 1240 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-363-3

Date: 

July 1, 2024

Author(s):

Megan S. Voss, Daniel Alabi, Raid S. Alrashidi, Taylor A. Rawlinson, Christopher C. Ferraro, H. R. Hamilton, Joel B. Harley, and Kyle A. Riding

Publication:

Symposium Papers

Volume:

363

Abstract:

The movement of ultra-high-performance concrete (UHPC) toward wide scale acceptance within the concrete industry has generated interest in developing improved test methods to provide quality assurance for this material. Most test methods currently used to measure the tensile behavior of ultra-high-performance concrete require specialized testing equipment that is not typically owned by precast or ready-mix production facilities. These test methods provide reliable data for quality assurance of newly developed concrete mixes, but they are impractical as quality-control tests, which would need to be performed for every UHPC placement. This paper presents the development of a simple and inexpensive test to measure tensile strength and ductility for UHPC and serve as a quality-control test. This method was developed from the double-punch test, commonly referred to as the “Barcelona test,” but has been revised to incorporate substantial changes to the loading and data collection requirements to eliminate the need for expensive, specialized equipment. It was determined that the modified test method could produce reliable results using a load-controlled testing procedure with manually recorded data points taken every 0.635 mm (0.025 inches) of vertical displacement for ductile concrete specimens. It was also determined that specimen surface grinding, loading rate, and punch alignment did not significantly influence the test results. However, the fabrication of the specimens, specifically the rate and method at which the molds were filled, had a significant effect on the results. Accordingly, any recommended standardized test method based off of this procedure should have requirements on specimen fabrication.

DOI:

10.14359/51742106


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: 

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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