Development Length Criteria for Plain and Ransome Bars
Poudyal, Umesh 1982-
Historical bars such as plain and Ransome bars were used in reinforced concrete structures until about the mid-1950s in the U.S and Canada. Bond provisions for plain and Ransome bars are not included in the current edition of Canadian and American codes. Twenty-two splice specimens reinforced with either plain, Ransome, or deformed bars were therefore tested monotonically under four-point loading as a part of a multi-year experimental investigation to develop bond provisions for plain and Ransome bars. The reinforcement was cast either in the bottom or top position. Load versus deflection behaviour, cracking patterns, and maximum load attained by all specimens are presented. Moment curvature analysis was performed for the specimens to calculate the tensile resistance of the reinforcement at the maximum load level. Reliability-based provisions for splice and development length were proposed for plain bars from a test database of splice specimens. A comparison of the proposed development length required for plain bars as compared to deformed bars, calculated in accordance with CSA A23.3, suggests that plain bars require fifty percent more development length than deformed bars when cast in the bottom position. However, when reinforcement is cast in the top position, the required development length for plain square and plain round bars is two and three times that for modern deformed bars, respectively. Similarly, reliability-based provisions for splice length were proposed for Ransome bars. A comparison of the proposed splice length of Ransome bars and that calculated for deformed bars in accordance with CSA A23.3 suggests that the bond capacity of Ransome bars closely matches to that of deformed bars when bars are cast in the bottom position. However, the required splice length for Ransome bars is around 25% more than that for modern deformed bars when cast in the top position.
DegreeMaster of Science (M.Sc.)
DepartmentCivil and Geological Engineering
SupervisorFeldman, Lisa R
CommitteeWegner, Leon D; Boulfiza, Mohamed; Alexander, John
Copyright DateJune 2018