International Concrete Abstracts Portal

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  • The International Concrete Abstracts Portal is an ACI led collaboration with leading technical organizations from within the international concrete industry and offers the most comprehensive collection of published concrete abstracts.

International Concrete Abstracts Portal

Showing 1-5 of 27360 Abstracts search results

Document: 

19-241

Date: 

July 1, 2020

Author(s):

Salaheldin Mousa, Hamdy M. Mohamed, Brahim Benmokrane, and Antonio Nanni

Publication:

Structural Journal

Volume:

117

Issue:

4

Abstract:

This paper reports on an investigation of the flexural behavior and serviceability performance of long-span square concrete members with a shear span-to-effective depth ratio (a/d) greater than 5, internally reinforced with uniformly distributed fiber-reinforced polymer (FRP) bars. The study comprised testing of four large-scale square members up to failure under four-point bending. The specimens measured 400 mm (16 in.) in width, 400 mm (16 in.) in depth, and 6000 mm (236.22 in.) in length. The test parameters included the longitudinal reinforcement ratio and the longitudinal reinforcement type, including glass FRP (GFRP), carbon FRP (CFRP), and steel bars. Test results show that the deformability of the tested FRP-reinforced concrete (FRPRC) specimens ranged between 7.0 and 10.4, which significantly exceeds the requirements of North American codes. Moreover, the nominal flexural strength of the specimen reinforced with GFRP bars was 1.9 times that of the steel counterpart specimen when the reinforcement ratios were similar. An analytical strain-compatibility model capable of predicting the flexural strength of the tested specimens was developed and compared to the experimental results. In addition, the measured crack widths and deflections were analyzed and compared at service load conditions to those predicted using models in the literature as well as in design guidelines and codes. The effect of uniformly distributed bars on the flexural strength and serviceability of square FRPRC members was also investigated, revealing that the presence of side bars significantly enhanced the serviceability performance in terms of crack width and deflection. On the other hand, the contribution of these side bars to flexural strength was minimal.

DOI:

10.14359/51723511


Document: 

18-529

Date: 

July 1, 2020

Author(s):

Hakan Yalciner and Atila Kumbasaroglu

Publication:

Structural Journal

Volume:

117

Issue:

4

Abstract:

A total of 30 full-scale reinforced concrete (RC) columns were tested to develop models for the prediction of the structural behavior of corroded RC columns. Of these, 25 RC columns were tested under cyclic loading for two different applied axial load ratios—namely, 0.20 and 0.40—at three concrete strength levels—namely, 9, 27, and 37 MPa (1305, 3915, and 5365 psi)—and at four corrosion levels. Five RC columns were loaded monotonically with an axial load ratio of 0.20 at four corrosion levels to calculate the damage index. The actual corrosion levels were obtained by breaking the concrete and extracting all the reinforcing bars. The test results demonstrated that the ductility ratios of the corroded RC columns, which were not determined in accordance with energy-based or bilateral failure criteria, could be misleading. The determined energy dissipation capacity and damage index of the columns further revealed the corrosion effects.

DOI:

10.14359/51721372


Document: 

19-309

Date: 

July 1, 2020

Author(s):

Marina L. Moretti, Susumu Kono, and Taku Obara

Publication:

Structural Journal

Volume:

117

Issue:

4

Abstract:

A database consisting of 414 reinforced concrete (RC) walls with rectangular, barbell, and flanged cross sections reported to have failed in shear was assembled. Based on the database, a number of design- and code-based sets of equations were evaluated regarding their capacity to predict the peak shear strength of walls. It is demonstrated that the design provisions studied vary considerably in functional form and have in general poor predictive capacity for walls with reinforcement detailing not in accordance with modern code requirements. New, improved empirical equations are proposed which result in better predictions with relatively smaller scatter and variation compared to test values and have no restrictions in their application; therefore, they are particularly suitable for the assessment of shear resistance of existing RC walls designed with older code principles.

DOI:

10.14359/51724668


Document: 

18-146

Date: 

July 1, 2020

Author(s):

Elias I. Saqan, Hayder A. Rasheed, and Tarek Alkhrdaji

Publication:

Structural Journal

Volume:

117

Issue:

4

Abstract:

Due to the lack of sufficient experimental studies, the subject of fiber-reinforced polymer (FRP) anchorage has not been addressed in ACI 440.2R-17 in a quantifiable sense. This study is intended to examine the seismic performance of flexural frame members strengthened with carbon fiber-reinforced polymer (CFRP) and anchored using CFRP wrapping and CFRP splay anchors. Five full-scale reinforced concrete assemblages were tested as a control, strengthened with full wraps, strengthened with two arrangements of splay anchors, and strengthened with a combination of a splay anchor and full wrap. The seismic response is traced cyclically up to 3% drift ratios. Various response parameters were extracted from the hysteresis curves of the specimens, and are presented and discussed in this paper. The dense splay anchor specimen along with the splay anchors plus full-wrap specimen provided adequate confinement/stabilization to the plastic hinge region and yielded the best seismic performance overall. The dense splay anchorage arrangement is suggested to use when access is not available to provide full wrapping at the critical plastic hinge zone.

DOI:

10.14359/51723517


Document: 

19-230

Date: 

July 1, 2020

Author(s):

Sung-Hyun Kim, Hong-Gun Park, and Hyeon-Jong Hwang

Publication:

Structural Journal

Volume:

117

Issue:

4

Abstract:

In Korea, bearing-wall structures with pilotis have been frequently used for high-rise residential buildings. In the present study, an economical load-transfer design and the reinforcing bar details were studied for bearing walls with pilotis, which are laterally supported by other vertically continuous walls. Four specimens were tested under gravity loads and cyclic lateral loading. To avoid a brittle failure of the interface between the wall and pilotis, a capacity design was applied to the design of the test specimens. The test results showed that ductile flexural yielding of the upper wall occurred without premature brittle failure of the transfer wall, columns, and the critical interface section. To confirm the test strength, a strut-and-tie model was applied to the test specimens. The strength and damage mode predicted by the strut-and-tie model agreed with the test result. Based on the test results and the strut-and-tie model used for the test specimens, a strut-and-tie model was proposed for the actual design of the prototype wall, and the relevant reinforcing bar details were proposed. The safety of the design was confirmed by nonlinear finite element analysis.

DOI:

10.14359/51723543


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