This study examines the effects of various rib properties and reinforced section geometries on the splitting force distribution around tensile lapped splices. The study makes use of a test specimen which idealizes the situation that exists in a tensile lapped splice between adjacent lateral cracks. The test specimen always failed by a longitudinal splitting of the concrete cover along a predefined failure plane. During the study the Influence of relative rib area, rib profile, amount of secondary link reinforcement, lateral pressure and bar spacing within the lap on the ultimate bond strength of the lap were examined. It was found that, for hot rolled (untwisted) deformed bars with crescent shaped ribs the orientation of the ribs to the splitting plane significantly affected the ultimate bond strength of the test specimen and, whilst the relative rib area was a good measure of a deformed bars performance In bond, it could not distinguish between the different orientations used. Further, since the maximum percentage Increase In ultimate bond stress for the same bar between orientations was of a similar magnitude to that observed for a doubling of a bars relative rib area the author recommends that bar orientation be taken into account when detailing tensile lapped splices. The presence of link steel perpendicular to the splitting plane did not significantly influence the ultimate bond strength of the model test specimen although the presence of lateral pressure did. The stress in the links at the occurrence of a full length splitting crack was less than 100 N/mm2. The finite element method was used to examine the two fundamental hypotheses describing the bond action of deformed reinforcing bars and to examine the implications of the assumption that the splitting forces around the circumference of a reinforcing bar are distributed proportionally to the rib height. The finite element analysis was also used to study the effect of varying the distance between the lapped bars on the spitting force distribution around the lapped bars. The results of a linear elastic analysis showed that both rib profile and bar spacing had a significant effect on the distribution of splitting forces around a tension lapped splice
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:335641 |
| Date | January 1993 |
| Creators | Jones, Keith G. Joes |
| Publisher | Heriot-Watt University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/10399/1513 |
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