Browsing by Author "Vermaak, Willem Jacobus"

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    Anchorage bond in concrete bases
    (1981) Vermaak, Willem Jacobus; De Kock, M O
    Five series of tests were performed to investigate the anchorage bond stresses in concrete bases. In Series I to IV concrete base specimens were loaded and column starter bar strains measured for different supporting conditions of the base. Curves indicating the distribution of steel compressive stresses and bond stresses in the columns and base slabs are given. Results from these tests indicate that the conventional design approach towards bond stresses in concrete bases is conservative and that the allowable bond stresses in BS CP110 seem to be too low while the maximum stresses specified in ACI 318-71 and the CEB-FIP Recommendations seem to be more acceptable. In Series V pull-out tests were made on 60 concrete cube specimens subjected to biaxial normal pressure. The ultimate bond strength was found to increase with applied normal pressure in proportion to the square root of the normal pressure and square root of the concrete strength. A comparative finite element stress analysis was done on a typical concrete base specimen and the results were found to be in accordance with the results of the tests in Series I to IV.