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International Concrete Abstracts Portal

Showing 1-5 of 30991 Abstracts search results

Document: 

MNL17M21

Date: 

September 4, 2024

Author(s):

American Concrete Institute

Abstract:


2-VOLUME SET


The ACI Reinforced Concrete Design Handbook provides assistance to professionals engaged in the design of reinforced concrete buildings and related structures. This edition is a major revision that brings it up-to-date with the approach and provisions of “Building Code Requirements for Structural Concrete” (ACI 318-19). The ACI Reinforced Concrete Design Handbook provides dozens of design examples of various reinforced concrete members, such as one- and two-way slabs, beams, columns, walls, diaphragms, footings, and retaining walls. For consistency, many of the numerical examples are based on a fictitious seven-story reinforced concrete building. There are also many additional design examples not related to the design of the members in the seven-story building that illustrate various ACI 318-19 requirements. Each example starts with a problem statement, then provides a design solution in a three-column format—Code provision reference, short discussion, and design calculations—followed by a drawing of reinforcing details, and finally a conclusion elaborating on a certain condition or comparing results of similar problem solutions. In addition to examples, almost all chapters in The ACI Reinforced Concrete Design Handbook contain a general discussion of the related ACI 318-19 chapter. Keywords: anchoring to concrete; beams; columns; cracking; deflection; diaphragm; durability; flexural strength; footings; frames; pile caps; piles; post-tensioning; punching shear; retaining wall; shear strength; seismic; slabs; splicing; stiffness; structural analysis; structural systems; strut-and-tie; walls.


Document: 

24-043

Date: 

September 3, 2024

Author(s):

Yongjae Yu, Cheska Espanol, Elias I. Saqan, and Oguzhan Bayrak

Publication:

Structural Journal

Abstract:

Design codes such as ACI 318-19 and AASHTO LRFD (2020) have permitted the use of high-strength steel in specific provisions. Particularly, reinforcing bars with a yield strength of 100 ksi and a size as large as No. 11 are permitted for use in tension lap splices. However, the amount of test data using larger-diameter bars, especially No. 11 high-strength bars, is limited. In this study, four large-scale reinforced concrete beams with No. 11 bars were tested in four-point bending. The beams were grouped in two groups, one utilized Grade 60 steel while the other utilized Grade 100 steel. Within each group, one beam had continuous bars, while the second beam had spliced bars. Test results showed that splicing No. 11 high-strength reinforcing bars had adequate load-carrying capacity; however, the crack width may not be adequate. Therefore, test results indicate that using No. 11 high-strength reinforcing bars in tension lap splice applications should be used with caution.

DOI:

10.14359/51742243


Document: 

23-047

Date: 

September 1, 2024

Author(s):

Muhammad Masood Rafi and Muhammad Saad Khan

Publication:

Structural Journal

Volume:

121

Issue:

5

Abstract:

This paper presents the details of the analyses which were conducted to study the effects of steel reinforcing bars with unintended high strength on the behaviors of reinforced concrete (RC) columns. The influence of these bars on the column strength and strength-reduction factors were investigated. The former was studied with the help of column axial load-moment interaction diagrams, while a reliability analysis was carried out for the latter. Four different column cross sections reinforced with reinforcement ratios varying from 1 to 4% were included in the analysis. Other variables included concrete compressive and reinforcing bar yield strengths. The effects of the aforementioned variables were also considered on the development length of the reinforcing bars in tension and compression. It was found that the use of reinforcing bars with unintended high strength could change column behavior to compression-controlled at a lesser axial load level, which is accompanied by a reduction in the curvature capacity. Modifications have been suggested to control the negative effects of unintended high strength of bars on the column behavior and bar development length. Strength-reduction factors for RC sections ranging from compression-controlled to tension-controlled regions have also been proposed, which differ from those suggested by the prevalent code of practice.

DOI:

10.14359/51740852


Document: 

23-082

Date: 

September 1, 2024

Author(s):

Jianhui Si, Yuan Zhou, Zhaobao Zeng, Kai Li, Jiannan Hu, Zewei Liu, and Xinchao Ding

Publication:

Structural Journal

Volume:

121

Issue:

5

Abstract:

Strictly following the similarity principle of specimen size, eccentricity, and carbon fiber-reinforced polymer (CFRP) strengthening layers, three groups of reinforced concrete square columns with different scales were designed. Experimental studies on eccentric compression of unstrengthened columns and CFRP-strengthened columns were carried out. The failure characteristics of specimens of various sizes were obtained, as well as the bearing capacity, ductility coefficient, lateral deflection, CFRP, and steel bar strain were analyzed. The test results showed an improved ductility, stiffness, and bearing capacity of eccentrically compressed reinforced concrete columns, strengthened with CFRP. However, the strengthening effect is inversely proportional to the size of the specimen and has a more obvious size effect.

DOI:

10.14359/51740854


Document: 

23-143

Date: 

September 1, 2024

Author(s):

Jingshuang Zhang, Ruihan Qin, Fei Lv, Yonghua Shu, and Yanqing Wu

Publication:

Structural Journal

Volume:

121

Issue:

5

Abstract:

In this paper, uniaxial tensile testing of semi-grouted sleeve connectors was carried out by controlling the amount of expansive agent in the grout material. The effects of different steel bar diameters and anchorage depths on the failure mode, bearing capacity, and surface strain of sleeve connectors were studied. It is found that there are three failure modes in the specimens—namely, steel bar pullout failure, steel bar slip failure, and screw thread failure. The expansion characteristics of the grout material can partially compensate for the lack of compressive strength. Based on the analysis of the ultimate bearing capacity of different specimens, a design method to prevent the slip failure of the semi-grouted sleeve is proposed. The addition of 5 to 11% expansive admixture can reduce the circumferential strain of the casing from the steel bar anchorage location to the grouting end by 28.57 to 125.30%, with no impact on the longitudinal strain variation pattern. As the depth of steel bar anchorage increases, the expansive effect of the steel bar anchorage and casing longitudinal strain gradually surpasses the shrinkage effect, while the shrinkage effect at the grouting end of the casing gradually outweighs the expansive effect. With an increase in steel bar diameter, the longitudinal strain at the grouting end of the casing only decreases by 1.75% and 2.10%, essentially having no significant impact.

DOI:

10.14359/51740856


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