Re-entrant corners are corners that point into a slab. For example, if one were to pour concrete around a square column, you would create four re-entrant corners. Because the concrete cannot shrink around a corner, the stress will cause the concrete to crack from the point of that corner (See Figure 1). Crack widths, but also leads to a conceptually clear method of design. For the D-regions of reinforced concrete structures such as the re-entrant corners, the strut-and-tie model (Schlaich et al., 1987) is a very powerful tool for visualizing the internal flow of forces and for arranging the steel bars and concrete struts. Re-entrant corners will usually cause cracking. Proper planning of the joint pattern to eliminate re-entrant corners will correct this problem. Even though you isolate the column box as shown here the slab will still develop uncontrolled cracks. When slab is unrestrained, its corners will tend to lift up under UDL. However, if the slab is restrained at its edges and corners, it experiences bending moment at the corners which should be resisted by reinforcement.
This paper examines cracks which occurred at the re-entrant corners at the dapped ends of bulb tee girders used on the MIA Mover APM System at Miami International Airport. Cracks were initially identified during load testing at the precast yard, although typically they did not occur until the beams were erected. The load test and crack mechanism is described herein. Post-erection cracking is compared with that observed under load test conditions and differences are discussed. FDOT criteria were applied in determining the appropriate protection strategy.
- Record URL:
- https://doi.org/10.1061/41193(424)14
- Availability:
- Find a library where document is available. Order URL: http://worldcat.org/isbn/9780784411933
- Supplemental Notes:
- Copyright © 2011 ASCE
- Authors:
- Leverenz, David G.
- Davidson, Thomas E.
- Conference:
- Location: Paris , France
- Date: 2011-5-22 to 2011-5-25
- Publication Date: 2011
Language
- English
Media Info
- Media Type: Web
- Monograph Title: Proceedings of the Thirteenth International Conference on Automated People Movers and Transit Systems, 2011
Subject/Index Terms
Re Entrant Corner Crack Filler
- TRT Terms: Load tests; People movers; Precast concrete
- Identifier Terms: Miami International Airport
- Uncontrolled Terms: Bulbtee girders
- Geographic Terms: Florida
- Subject Areas: Maintenance and Preservation;
Filing Info
Reentrant Corner
- Accession Number: 01365047
- Record Type: Publication
- ISBN: 9780784411933
- Files: TRIS, ASCE
- Created Date: Nov 29 2011 3:00PM