Masters Theses

Alternative Title

Evaluation of the orientation of 90 degree and 180 degree reinforcing bar hooks


"This thesis describes test results of a study initiated to evaluate the potential influence of hook tilt angle of standard reinforcing hooks on the bond strength of concrete. The topic of the evaluation of the orientation of 90 and 180 degree reinforcing bar hooks in concrete members was identified by the Concrete Reinforcing Steel Institute (CRSI) as high-priority for the reinforcing steel industry. In this test program, a series of single bar and multiple bar specimens were designed and tested to examine bar behavior and potential group effects that may exist in wide flexural members with multiple bars, such as a slab or footing. In the beam-end specimens, 90 and 180 degree standard reinforcing hooks were placed at varying angles to compare the angle of tilt and to compare the two hook types. Twelve single bar specimens and twelve multiple bar specimens, each containing either No. 5 or No. 8 standard reinforcing bars, were tested by axially loading the reinforcing bar in tension. Measuring the bar displacement and strain at varying points along the bar, load-displacement curves obtained were utilized in the analysis of hook tilt. Based on observations of the beam-end specimens, design recommendations for tilted hooked bar anchorages were made. For No. 5 bars and smaller with concrete compressive strength, f'c, greater than 4500 psi, spacing between 0.5 and 2 times the hook length, A, and concrete cover equal to or exceeding the values used in this study, tilting reinforcing hooked bars from vertical at any angle does not compromise the structural integrity. For No. 5 bars and smaller with concrete compressive strength less than 4500 psi, spacing less than 0.5 times the hook length, A, or concrete cover less than the values used in this study, more data is needed. For bars larger than No. 5, more data is needed"--Abstract, page iii.


Sneed, Lesley

Committee Member(s)

LaBoube, Roger A.
Volz, Jeffery S.


Civil, Architectural and Environmental Engineering

Degree Name

M.S. in Civil Engineering


Missouri University of Science and Technology. Center for Transportation Infrastructure and Safety
Concrete Reinforcing Steel Institute
National University Transportation Center


Missouri University of Science and Technology

Publication Date

Fall 2011


xiii, 174 pages


© 2011 Nichole Lynn Podhorsky, All rights reserved.

Document Type

Thesis - Open Access

File Type




Subject Headings

Anchorage (Structural engineering)
Reinforced concrete -- Testing
Reinforcing bars -- Evaluation

Thesis Number

T 9939

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