Infrastructure Research Institute Projects

Principal Investigators


David Darwin daved@ku.edu
Deane E. Ackers Professor of Civil Engineering and Director of the Structural Engineering and Materials Laboratory

Andres Lepage alepage@ku.edu
Associate Professor of Civil, Environmental, & Architectural Engineering

Rémy Lequesne rlequesne@ku.edu
Assistant Professor of Civil, Environmental, & Architectural Engineering

Adolfo Matamoros adolfo.matamoros@utsa.edu
Peter T. Flawn Distinguished Professor
University of Texas at San Antonio

Steve McCabe mccabe@ku.edu
Professor Emeritus of Civil, Environmental, & Architectural Engineering

Matt O'Reilly oreilly3@ku.edu
Assistant Professor of Civil, Environmental, & Architectural Engineering

Graduate Research Assistants


Rex Donahey
Shraddhakar Harsh
Zhenjia Shen
Barie Brettmann
Wisam Altowiaji
Oan Chul Choi
Hossain Hadje-Ghaffari
Cynthia Hester
Shahin Salamizavaregh
Ebenezer Graham
Emmanuel Idun
Michael Tholen
Jun Zuo
Michael Briggs
Shelby Miller
Jeffrey Peckover
Nate Searle
Samir Al-Yasso
Michael DeRubeis
Jayne Sperry
Krishna Ghimire
Yun Shao
Ali Ajaam
Muna Hano

Research Links


Donahey, R., Darwin, D., “Bond of Top-Cast Bars in Bridge Decks” ACI Journal Vol. 82, No. 5, January-February 1985, pp. 57-66. Download pdf

Brettmann, B., Darwin, D., Donahey, R., "Bond of Reinforcement to Superplasticized Concrete," ACI Journal Vol. 83, No. 12, January-February 1986, pp. 98-107. Download pdf

Altowaiji, W., Darwin, D., Donahey, R., "Bond of Reinforcement to Revibrated Concrete," ACI Journal Vol. 83, No. 94, November-December 1986, pp. 1035-1042. Download pdf

Harsh, S., Shen, Z., Darwin, D., "Strain-Rate Sensitive Behavior of Cement Paste and Mortar in Compression," ACI Materials Journal Vol. 87, No. 55, September-October 1990, pp. 508-516. Download pdf

Choi, O., Hadje-Ghaffari, H., Darwin, D., McCabe, S., "Bond of of Epoxy-Coated Reinforcement: Bar Parameters," ACI Materials Journal Vol. 88, No. 26, March-April 1991, pp. 207-217. Download pdf

Darwin, D., McCabe, S., Idun, E., Schoenekase, S., "Development Length Criteria: Bars Not Confined by Transverse Reinforcement," ACI Structural Journal Vol. 83, No. 94, November-December 1992, pp. 709-720. Download pdf

Darwin, D., McCabe, S., Idun, E., Schoenekase, S., "Development Length Criteria: Bars Without Transverse Reinforcement," SL Report 92-1 University of Kansas Center for Research, Inc., Lawrence, Kansas, April 1992, 68 pp. Download pdf.

Hester, C. J., Salamizavaregh, S., Darwin, D., and McCabe, S. L., “Bond of Epoxy-Coated Reinforcement:  Splices,” ACI Structural Journal, Vol. 90, No. 1, Jan.-Feb. 1993, pp. 89-102. Download pdf

Hadje-Ghaffari, H., Choi, O., Darwin, D., McCabe, S., "Bond of Epoxy-Coated Reinforcement: Cover, Casting Position, Slump, and Consolidation," ACI Structural Journal Vol. 83, No. 7, January-February 1994, pp. 59-68. Download pdf

Darwin, D., Tholen, M., Idun, I., Zuo, J., "Splice Strength of High Relative Rib Area Reinforcing Bars," ACI Structural Journal 93-10, January-February 1996, pp. 95-107. Download pdf

Darwin, D., Zuo, J., Tholen, M., Idun, E., "Development Length Criteria for Conventional and High Relative Rib Area Reinforcing Bars," ACI Structural Journal Vol. 83, No. 32, May-June 1996, pp. 1-13. Download pdf

Darwin, D., Zavaregh, S., "Bond of Strength of Grouted Reinforcing Bars," ACI Structural Journal Vol. 83, No. 94, July-August 1996, pp. 486-495. Download pdf

Tholen, M., Darwin, D., "Effects of Deformation Properties on the Bond of Reinforced Bars," SM Report No. 42 University of Kansas Center for Research, Inc., Lawrence, Kansas, September 1996, 395pp. Download pdf.

Wright, J., McCabe, S., "The Development Length and Anchorage Behavior of Headed Reinforcing Bars," SM Report No. 44 University of Kansas Center for Research, Inc., Lawrence, Kansas, September 1997, 154 pp. Download pdf. 5.38MB

Tholen, M., Darwin, D., "Effect of Reinforcing Bar Deformation Pattern on Flexural Ductility," ACI Structural Journal Vol. 83, No. 4, January-February 1998, pp. 37-42. Download pdf

Zuo, J., Darwin, D., "Bond Strength of High Relative Rib Area Reinforcing Bars," SM Report No. 46, University of Kansas Center for Research, Inc., Lawrence, Kansas, January 1998, 377 pp. Download pdf.

Darwin, D., Idun, E. K., Zuo, J., and Tholen, M. L., "Reliability-Based Strength Reduction Factor for Bond," ACI Structural Journal, Vol. 95, No. 4, July-Aug. 1998, pp. 434-443. Download pdf

Idun, E., Darwin, D., "Bond of Epoxy-Coated Reinforcement: Coefficient of Friction and Rib Face Angle," ACI Structural Journal Vol. 96, No. 68, July-August 1999, pp. 609-616. Download pdf

Fei, J., Darwin, D., "Fatigue of High Relative Rib Area Reinforcing Bars," SM Report No. 54, University of Kansas Center for Research, Inc., Lawrence, Kansas, July 1999, 76 pp. Download pdf

Azizinamini, A., Darwin, D., Eligehausen, R., Pavel, R., and Ghosh, S. K., “Proposed Modifications to ACI 318-95 Tension Development and Lap Splice for High-Strength Concrete,” ACI Structural Journal, Vol. 96, No. 6, Nov.-Dec., 1999, pp. 922-926. Download pdf

Zuo, J., Darwin, D., "Bond Slip of High Relative Rib Area Bars under Cyclic Loading," ACI Structural Journal Vol. 97, No. 2, March-April 2000, pp. 331-335. Download pdf

Zuo, J., Darwin, D., "Splice Strength of Conventional and High Relative Rib Area Bars in Normal and High-Strength Concrete," ACI Structural Journal Vol. 97, No. 65, July-August 2000, pp. 630-641. Download pdf

Darwin, D., Barham, S., Kozul, R., Luan, S., "Fracture Energy of High-Strength Concrete," ACI Materials Journal Vol. 98, No. 45, September-October 2001, pp. 410-417. Download pdf

Miller, G., Kepler, J., Darwin, D., "Effect of Epoxy Coating Thickness on Bond Strength Reinforcing Bars," ACI Structural Journal Vol. 100, No. 34, May-June 2003, pp. 314-320. Download pdf

Bournonville, M., Dahnke, J., Darwin, D., "Statistical Analysis of the Mechanical Properties and Weight of Reinforcing Bars," SL Report 04-1, University of Kansas Center for Research, Inc., Lawrence, Kansas, December 2004, 194 pp. Download pdf

Darwin, D., Lutz, L., Zuo, J., "Recommended Provisions and Commentary on Development and Lap Splice Lengths for Deformed Reinforcing Bars in Tension," ACI Structural Journal Vol. 102, No. 91, November-December 2005, pp. 892-910. Download pdf

Seliem, H. M., Hosny, A., Rizkalla, S., Zia, P., Briggs, M., Miller, S., Darwin, D., Browning, J., Glass, G. M., Hoyt, K., Donnelly, K., and Jirsa, J. O., “Bond Characteristics of High-Strength ASTM A1035 Steel Reinforcing Bars,” ACI Structural Journal, Vol. 106, No. 4, July-Aug. 2009, pp. 530-539. Download pdf

Peckover, J., Darwin, D., "Anchorage of High-Strengh Reinforcing Bars with Standard Hooks: Initial Tests," SL Report 13-1 University of Kansas Center for Research, Inc., Lawerence, Kansas, January 2013, 55 pp. Download pdf

Searle, N., DeRubeis, M., Darwin, D., Matamoros, A., O'Reilly, M., and Feldman, L., "Anchorage of High-Strength Reinforcing Bars with Standard Hooks - Initial Tests," SM Report No. 108, The University of Kansas Center for Research, Inc., Lawrence, KS, February 2014, 120 pp. Download pdf

​Farshadfar, O., Ajaam, A., Hano, M., O'Reilly, M., Darwin, D., "Bond Strength of Reinforcing Bars with Deformation Spacings that Exceed Maximum Specified in ASTM A615," SL Report 14-2, The University of Kansas Center for Research, Inc., Lawrence, KS, August 2014, 26 pp. Download pdf

Sperry, J., Al-Yasso, A., Searle, N., DeRubeis, M., Darwin, D.,  O'Reilly, M., Matamoros, A., Feldman, L., Lepage, A., Lequesne, R., and Ajaam, A.,  "Anchorage of High-Strength Reinforcing Bars with Standard Hooks," SM Report No. 111, The University of Kansas Center for Research, Inc., Lawrence, KS, June 2015, 266 pp. Download pdf

Sperry, J., Darwin, D., O'Reilly, M., and Lequesne, R., "Anchorage Strength of Conventional and High-Strength Hooked Bars in Concrete," SM Report No. 115, The University of Kansas Center for Research, Inc., Lawrence, KS, December 2015, 281 pp. Download pdf

Yuan, J., O'Reilly, M., Matamoros, A., and Dawrin, D., "Effect of Preexisting Cracks on Lap Splice Strength of Reinforcing Bars," ACI Structural Journal, Vol. 113, No. 1, July-August 2016, pp. 901-812. Download pdf

Shao,Y., Darwin, D., O'Reilly, M., Lequesne, R.D., Ghimire, K., Hano, Muna, "Anchorage of Conventional and High-Strength Headed Reinforcing Bars, " SM Report No. 117, The University of Kansas Center for Research, Inc., Lawrence, KS, August 2016, 234 pp. Download pdf

Sperry, J., Yasso, S., Searle, N., DeRubies, M., Darwin, D., O'Reilly, M., Matamoros, A., Feldman, L.R., Lepage, A., Lequesne, R.D., and Ajaam, A., "Conventional and High-Strength Hooked Bars - Part 1: Anchorage Tests," ACI Structural Journal, Vol. 114, No. 1, January-February 2017, pp. 255-342. Download pdf.

Sperry, J.,  Darwin, D., O'Reilly, M., Lequesne, R.D.,Yasso, S.,  Matamoros, A., Feldman, L.R.,and Lepage, A., "Conventional and High-Strength Hooked Bars - Part 2: Data Analysis," ACI Structural Journal, Vol. 114, No. 1, January-February 2017, pp. 267-314. Download pdf

Yasso, S., Darwin, D., and O'Reilly, M., "Anchorage Strength of Standard Hooked Bars in Simulated Exterior Beam-Column Joints," SM Report No. 124, The University of Kansas Center for Research, Inc., Lawrence, KS, April 2017, 330 pp. Download pdf

Ajaam, Ali, Darwin, D., and O'Reilly, M., "Anchorage Strength of Reinforcing Bars with Standard Hooks," SM Report No. 125, The University of Kansas Center for Research, Inc., Lawrence, KS, April 2017, 372 pp. Download pdf

PROJECT SUMMARY:

Bond, Development, and Anchorage of Reinforcement to Concrete

Research Programs: Reinforcing steel must be anchored to and act in concert with the surrounding concrete for reinforced concrete to perform as an effective structural material. The University of Kansas has long been involved in research in the field of bond, development, and anchorage of reinforcement to with projects covering the effects of construction procedures, member geometry, coatings, reinforcement geometry, bar stresses, concrete strength, aggregate properties, cyclic loading, and anchorage method (hooks and headed bars). Notable work includes development of the ASTM A944 Beam-End test procedure, recognition of the role deformation geometry, as characterized by bar relative rib area, on bond strength, and the development of the ACI Committee 408 equations for bond strength, and development length and splice design of straight bars in tension. The ACI 408 equations have been shown to accurately characterize bond and development strength for concretes with compressive strengths up to 16,000 psi (110 MPa) and bars loaded to stresses in excess of 120 ksi (830 MPa).

Current active projects: Anchorage of High-Strength Reinforcing Bars with Standard Hooks: The study will develop basic data on the anchorage of hooked high-strength reinforcing bars and use those results to formulate design criteria for reinforced concrete structures. The results of this study will be used by the design profession, code writers, and ultimately throughout concrete construction industry. The goal of the experimental phase of the study is to gain a firm understanding of the variation in hook strength as a function of bar size, concrete strength, member geometry, and transverse reinforcement. Emphasis will be placed on No. 5, No. 8, and No. 11 hooked bars tested at bar stresses of 60, 80, and 100 ksi (410, 550, and 670 MPa). A limited number of bars will be tested at stresses as high as 120 ksi (670 MPa). Concrete compressive strengths of 5000, 8000, 12,000, and 15,000 psi (35, 55, 83, and 105 MPa) will be used. The ranges in steel stress and compressive strength are needed to establish the performance of hooked bars across a broad range of material properties to help ensure that applications are not limited, as they now are, by a lack of data as a function of steel or concrete strength. The test results will be used to establish reliability-based design provisions.

 

Use of Headed Reinforcing Bars to Develop High-Strength Reinforcing Steel: The study will develop basic data on the anchorage of high-strength headed reinforcing bars and use those results to formulate design criteria for reinforced concrete structures. The study will include configurations and material properties that, while being necessary or advantageous for construction, are not addressed by the current design codes due to a lack of experimental results. Tests will include high-strength reinforcing bars, high-strength concrete, a broader range of head geometries than tested to date, group effects, and the effects of staggering the heads. Emphasis will be placed on No. 5, No. 8, and No. 11 hooked bars tested at bar stresses of 60, 80, and 100 ksi (410, 550, and 670 MPa). A limited number of bars will be tested at stresses as high as 120 ksi (670 MPa). Concrete compressive strengths of 5000, 8000, 12,000, and 15,000 psi (35, 55, 83, and 105 MPa) will be used. The test results will be used to establish a reliability-based design expression for the development length of headed bars and recomm


 

 


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