Title:
Performance of Ledges in Inverted-T Beams
Author(s):
David B. Garber, Nancy Larson Varney, Eulalio Fernández Gómez, and Oguzhan Bayrak
Publication:
Structural Journal
Volume:
114
Issue:
2
Appears on pages(s):
487-498
Keywords:
inverted-T beams; ledge behavior; ledge design; strut-andtie models
DOI:
10.14359/51689451
Date:
3/1/2017
Abstract:
Researchers have not extensively studied the behavior of inverted-T (IT) beams experiencing ledge failures. The work described in this paper aims to fill that gap in knowledge by providing data from tests conducted on full-scale IT beams. To the authors’ knowledge, this study was part of one of the largest experimental studies conducted on full-scale IT beams. While the focus of the overall study was the design of IT deep beams, the diversity of specimen geometries led to failure of several ledges. The findings from the behavior and failure of these ledges led to an investigation of the load spread and engagement of ledge and hanger reinforcement (approximately 45 degrees from the edge of bearings), different failure mechanisms of ledges (punching shear, ledge flexure, and ledge shear friction being most critical), and the ability of current design procedures (empirical ledge approach and strut-and-tie method) to estimate the behavior.
Related References:
1. Mirza, S. A., and Furlong, R. W., “Serviceablity Behavior and Failure Mechanisms of Concrete Inverted T-Beam Bridge Bentcaps,” ACI Journal Proceedings, V. 80, No. 4, July-Aug. 1983, pp. 294-304.
2. Larson, N.; Gomez, E. F.; Garber, D.; Bayrak, O.; and Ghannoum, W., “Strength and Serviceability Design of Reinforced Concrete Inverted-T Beams,” The University of Texas at Austin Technical Report 0-6416-1, Austin, TX, 2013, 234 pp.
3. American Association of State Highway and Transportation Officials (AASHTO), “AASHTO LRFD Bridge Design Specification, Customary U.S. Units, 6th Edition,” Washington, DC, 2012, 1661 pp.
4. ACI Committee 318, “Building Code Requirements for Structural Concrete (ACI 318-14) and Commentary (ACI 318R-14),” American Concrete Institute, Farmington Hills, MI, 2014, 519 pp.
5. Birrcher, D.; Tuchscherer, R.; Huizinga, M.; Bayrak, O.; Wood, S. L.; and Jirsa, J. O., “Strength and Serviceability Design of Reinforced Concrete Deep Beams,” The University of Texas at Austin FHWA/TX-09/0-5253-1, Austin, TX, 2009, 400 pp.
6. Reineck, K. H., ed., Examples for the Design of Structural Concrete with Strut-and-Tie Models, SP-208, American Concrete Institute, Farmington Hills, MI, 2002, 242 pp.
7. Reineck, K. H., and Novak, L. C., eds., Further Examples for the Design of Structural Concrete with Strut-and-Tie Models, SP-273, American Concrete Institute, Farmington Hills, MI, 2010, 278 pp.
8. Birrcher, D. B.; Tuchscherer, R. G.; Huizinga, M.; and Bayrak, O., “Minimum Web Reinforcement in Deep Beams,” ACI Structural Journal, V. 110, No. 2, Mar.-Apr. 2013, pp. 297-306.
9. Varney, N. L.; Fernández-Gómez, E.; Garber, D. B.; Ghannoum, W. M.; and Bayrak, O., “Inverted-T Beams: Experiments and Strut-and-Tie Modeling,” ACI Structural Journal, V. 112, No. 2, Mar.-Apr. 2015, pp. 147-156. doi: 10.14359/51687403