PULLOUT SIMULATION OF POSTINSTALLED CHEMICALLY BONDED ANCHORS

Citation
M. Mcvay et al., PULLOUT SIMULATION OF POSTINSTALLED CHEMICALLY BONDED ANCHORS, Journal of structural engineering, 122(9), 1996, pp. 1016-1024
Citations number
14
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Engineering, Civil","Construcion & Building Technology
ISSN journal
0733-9445
Volume
122
Issue
9
Year of publication
1996
Pages
1016 - 1024
Database
ISI
SICI code
0733-9445(1996)122:9<1016:PSOPCB>2.0.ZU;2-T
Abstract
Chemically bonded postinstalled anchors have seen tremendous growth ov er the past few years for retrofits, as well as new construction. Curr ently, they are designed from proprietary tables provided by adhesive manufacturers based on laboratory pullout tests. Recently, Doerr et al . (1989), Cook (1993), and Eligehausen et al. (1984) have developed eq uations to predict pullout resistance of anchors. Since chemically bon ded anchors result in the failure of both the concrete and adhesive-co ncrete interface, the equations attempt to predict the ultimate resist ance of the anchor through the sum of the contributions from the concr ete-failure cone and adhesive-concrete interface. However, this approa ch requires an estimate of both the average or maximum shear stress wi thin the adhesive bond layer and the concrete-failure cone depths. To shed more light on the development of failure for these types of ancho rs, a state-of-the art elastoplastic finite-element analysis was perfo rmed and compared to experimental results. Besides being able to predi ct pullout resistance, concrete-failure cone depths, and orientations, the analysis revealed that failure initiates as a tension zone below the concrete surface at the anchor-adhesive interface and propagates w ith load toward the surface. In the process, both the concrete and adh esive material dilate increasing the confinement and shear resistance within the adhesive layer. Once the tension zone reaches the surface, the confinement is lost, resulting in a diminished shear resistance wi thin the adhesive layer and anchor failure. After comparing a number o f proposed methods to predict resistance to the experimental data, it was found that a simplistic, uniform bond stress applied over the whol e anchor did an excellent job of predicting pullout capacity.