| Summary: | The use of headed reinforcement and hooked bars to reduce development length is restricted to bars loaded in tension only and shall not be considered effective in developing bars in compression according to the ACI-318 code. However, there are situations where a small development length in compression is required. This paper presents results of experimental study for assessing the use of dual headed bars to develop bars in compression as well as in tension. A total of 35 pullout tests and bar compression tests were performed. Parameters affecting the anchorage behavior of dual headed bars such as spacing between heads, concrete cover, concrete compressive strength, head area and confining reinforcement were studied. The results showed that bars with dual heads loaded in compression exhibited remarkable improvement in bond capacity. The parameters studied affected bond strength in compression loading in the same way as they affect bond on tension loading. No improvement is obtained for such dual headed bars loaded in tension, and even slight decrease in anchorage capacity was recorded for some specimens loaded in tension. However, the loss in anchorage capacity for bars with dual heads loaded in tension was very small in comparison to the gain attained in anchorage capacity in compression loading.
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