Strength and Serviceability Design of Reinforced Concrete Deep Beams

Technical Report Documentation Page 1. Report No. FHWA/TX-09/0-5253-1 2. Government Accession No. 3. Recipient’s Catalog No. 4. Title and Subtitle Strength and Serviceability Design of Reinforced Concrete Deep Beams 5. Report Date December 2008, Rev. 2009: March, April 6. Performing Organization Code 7. Author(s) David Birrcher, Robin Tuchscherer, Matt Huizinga, Oguzhan Bayrak, Sharon Wood, and James Jirsa 8. Performing Organization Report No. 0-5253-1 9. Performing Organization Name and Address Center for Transportation Research The University of Texas at Austin 3208 Red River, Suite 200 Austin, TX 78705-2650 10. Work Unit No. (TRAIS) 11. Contract or Grant No. 0-5253 12. Sponsoring Agency Name and Address Texas Department of Transportation Research and Technology Implementation Office P.O. Box 5080 Austin, TX 78763-5080 13. Type of Report and Period Covered Technical Report 9/1/2005 – 8/31/2008 14. Sponsoring Agency Code 15. Supplementary Notes Project performed in cooperation with the Texas Department of Transportation and the Federal Highway Administration. 16. Abstract An experimental study was conducted in which 37 reinforced concrete deep beam specimens were tested. The specimens are some of the largest deep beams ever tested in the history of shear research. The data from the experimental program and from a database of 179 deep beam tests in the literature were used to address eight tasks associated with the strength and serviceability design and performance of deep beams. The effects of the following variables were evaluated: distribution of stirrup legs transversely through the web, triaxial confinement via concrete of CCC and CCT nodal faces, quantity of web reinforcement, member depth, and a/d ratio. A new strut-and-tie design method was proposed that is simpler and significantly more accurate than the provisions in AASHTO LRFD (2008) and ACI 318-08, yet just as conservative. Also, it was shown that the discrepancy in shear strength calculated using STM and sectional shear provisions in AASHTO LRFD (2008) at an a/d ratio of 2 is greatly reduced with the use of the proposed STM procedure. A recommendation was made on the amount of minimum web reinforcement needed for strength and serviceability considerations. A simple service-load check was proposed for the purpose of limiting diagonal cracking under service loads. Lastly, a chart was created to aid in the distress evaluation of a diagonally-cracked bent cap in the field. 17. Key Words Bent Caps, Deep Beams, Strut-and-Tie Modeling, Crack Widths, Diagonal Cracking, Serviceability 18. Distribution Statement No restrictions. This document is available to the public through the National Technical Information Service, Springfield, Virginia 22161; www.ntis.gov. 19. Security Classif. (of report) Unclassified 20. Security Classif. (of this page) Unclassified 21. No. of pages 400 22. Price Form DOT F 1700.7 (8-72) Reproduction of completed page authorized

Strength and Serviceability Design of Reinforced Concrete Deep Beams

Documents

bent caps

deep beams

strutandtie modeling

crack widths

diagonal cracking

serviceability