Rebonding of Prestressed Tendons in Concrete by Internally Released Adhesives

内释放粘合剂对混凝土中预应力筋的再粘合

• 批准号: 9906283
• 负责人: Carolyn Dry
• 金额: $ 17.51万
• 依托单位: University of Illinois at Urbana-Champaign
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-10-01 至 2003-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9906283&HistoricalAwards=false
• 关键词: Rebonding; Prestressed; Tendons; Concrete; Internally

Demolishing of prestressed concrete is difficult due to the energy storedin the prestressing metal tendons which is usually up to 125,000 pounds. Inunbonded tendons the energy may be catastrophically released, threateningthe safety of people, workers and buildings. Most of all flat plateconstruction and bridge girders produced utilize tensioning of metaltendons; so the problem is large and it most improtantly it is unresolved. The objectives of this research are to develop and to test means ofrestraining or rebonding the tendons under stress for continued effectiveload transfer during use and for safe demolition. The proposed researchapproach consists of four activities. 1) We will develop information on theforces available in prestressed members and calculate the countervailingforces needed to be supplied by the release mechanism and materials. 2)Large scale laboratory testing will be done on the proposed systems.Strucutral tie downs and tensioning devices will be used. 3) Full scaleprestressed girders will be tested using the rebonding system. 4) the datawill be evaluated and disseminated.The impact on education should be large. This project should employ anestimated 25-30 different students from both undergraduate and graduatelevels. They will be active in all aspects of the project. The proportionof women gaining that experience should be high, approximately half or more.

拆除预应力混凝土是困难的，因为预应力金属筋中储存的能量通常高达12.5万磅。在无粘结的筋中，能量可能会灾难性地释放，威胁到人、工人和建筑物的安全。大多数平板结构和桥梁梁都是利用金属筋的张拉；所以问题很大，而且最即兴的是，它还没有得到解决。这项研究的目的是开发和测试在应力作用下约束或重新粘合肌腱的方法，以便在使用过程中继续有效地转移荷载，并进行安全拆除。拟议的研究方法由四项活动组成。1)我们将开发关于预应力构件可用力的信息，并计算释放机构和材料需要提供的反力。2)将对拟建的体系进行大规模的实验室测试。将使用结构系带和张拉装置。3)使用重粘结系统对足尺预应力梁进行试验。4)对数据进行评估和传播。对教育的影响应该很大。该项目应雇用约25-30名不同的学生，包括本科生和研究生。他们将积极参与该项目的各个方面。获得这种经历的女性比例应该很高，大约是一半或更多。