Strength of Lapped Splices in Concrete Beams Using Hooks

摘要

The investigation was concerned with determining what splice strengths could be developed by using lapped hooks. A series of eight tests were performed using No. 8 bars only. The beam width, depth, and length for each test were constant. One beam was tested using a straight lapped splice. The remaining beams were tested using spliced 180-degree hooks, 135-degree hooks, and 90-degree hooks. Primary results obtained were steel stress and bond stress developed under pure flexural loading. An analysis of the data reveals that spliced hooks develop about as much steel and bond stress as a straight splice of comparable length. However, it was found that a higher steel and bond stress can be developed with the 180-degree hooks when using a higher concrete strength. It was also found that the splice strength could not be appreciably increased by placing transverse bars on the inside radii of the 180-degree hooks. It is felt that the type of hook splices used in the investigation cannot be used to any advantage over the 1963 Code designed straight splice. (Author)