详情

Development of Design Recommendations for Non-Contact, Hooked Bar Lap Splices for Large Reinforcing Bars

项目名称：	Development of Design Recommendations for Non-Contact, Hooked Bar Lap Splices for Large Reinforcing Bars
摘要：	There has been an increase in the design of bridge substructures using precast elements in order to accelerate construction. Often, these designs require innovative connection methods, such as reinforcing bars spliced in closure pours between precast pieces. Making these splices using large-sized bars for the flexural reinforcement can be challenging because the development length of straight reinforcement, particularly Class B tension lap splices that must be 1.3 times the ordinary development length, can make closure pours quite large. Furthermore, failures of these connections tend to be brittle, thus adequate development is important. One strategy for reducing the closure pour length is to lap splice hooked bars in a non-contact fashion, which enables easier fit-up of members during construction. While American Association of State Highway and Transportation Officials (AASHTO) does provide limits for lap-spliced straight longitudinal bars in flexural members, there is no guidance on the maximum offset distance between hooked bars serving as a lap splice. There is also little data for non-contact lap splices or the development length of hooked bars that are larger than #6 bars. Additionally, multiple layers of spliced reinforcement in tension is not explicitly covered in AASHTO. The objective of this work will be the development of recommendations for designing non-contact, hooked bar lap splices in precast substructure elements. The scope will include large-scale structural tests to assess the need for modification factors based on: bar size, hook type, distance between lapped bars, side cover, transverse tie reinforcement, multiple layers of reinforcing, reinforcement yield strength, and concrete strength. The analysis will assess the cracking at service level stresses and the conditions of the elements at strength level and incipient failure.
状态：	Active
资金：	515532
资助组织：	Virginia Transportation Research Council
项目负责人：	Kassner, Bernie
执行机构：	Virginia Polytechnic Institute and State University, Blacksburg
开始时间：	20210801
预计完成日期：	20250531
主题领域：	Bridges and other structures；Construction；Design；Highways；Materials