M.Tech. (Civil Engineering) / Recoverable anchor screws are widely used in the construction of massive concrete structures such as dams, channels, tunnels and multi-story buildings to fix temporary cantilever forms. Attempts have been made before to quantify the failure capacities of recoverable anchor screws. However, such tests were conducted and reported on more than 25 years ago and were limited to a small number of tests on concrete strengths not exceeding 20 MPa, whereas most concrete constructions now exceed such strengths. The aim of this dissertation was to review the existing theories on the use of concrete anchors in practice and to apply the appropriate theories to recoverable anchor screws. In doing so, the overall shear strength of these screws was determined by considering existing theoretical standards and norms, and by testing the tensile capacity in the laboratory. The failure behaviour of recoverable anchor screws in various concrete strengths and construction applications is reviewed and is discussed based on both theory and the laboratory results obtained. The empirical formulas derived for the practical use of recoverable anchor screws are presented in standard form. These formulas provide an easy reference for engineering professionals in practice to determine the load capacity of recoverable anchor screws in various concrete strengths and construction applications. In conclusion, the required future research on recoverable anchor screws is presented.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:uj/uj:11221 |
| Date | 29 May 2014 |
| Creators | Liebenberg, Willem Adriaan |
| Source Sets | South African National ETD Portal |
| Detected Language | English |
| Type | Thesis |
| Rights | University of Johannesburg |
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