Title:
Behavior of Fasteners Loaded in Tension in Cracked Reinforced Concrete
Author(s):
Rolf Eligehausen and Tamas Balogh
Publication:
Structural Journal
Volume:
92
Issue:
3
Appears on pages(s):
365-379
Keywords:
anchors (fasteners); control joints; cracking (fracturing); failure; loads (forces); studs; tension; Structural Research
DOI:
10.14359/1137
Date:
5/1/1995
Abstract:
Many reinforced concrete structures are designed under the assumption that the concrete is cracked due to external loads or restraint of imposed deformations (e.g., due to creep, shrinkage, temperature variations, or support settlement). Research shows that fasteners will attract cracks or even induce cracking. Therefore, the behavior of different types of fastener in cracked reinforced concrete has been studied extensively. Fasteners suitable for use in cracked reinforced concrete such as cast-in situ headed studs or headed anchors, post-installed undercut anchors, and specially designed torque-controlled expansion anchors show a reduction of the concrete cone failure load of about 25 to 35 percent compared to uncracked concrete when located in or close to cracks with a width 0.3 to 0.4 mm (0.012 to 0.016 in.). This crack width can be expected in typical concrete members designed with ordinary crack control provisions. The failure load of ordinary torque-controlled expansion, deformation-controlled expansion, and bonded anchors is more influenced by cracks and may be unpredictable, especially if installation inaccuracies that might occur on site are taken into account. Fasteners used in zones with potential concrete cracking must be suitable for this application. A test program to check the effective functioning of fasteners in cracked reinforced concrete is described in technical guides by UEAtc and EOTA, a basis for the proposed ASTM specification.