Rebonding of Prestressed Tendons in Concrete by Internally Released Adhesives

预应力混凝土的拆除是困难的，因为预应力金属筋中储存的能量通常高达125，000磅。在无粘结的钢筋束中，能量可能会灾难性地释放，危及人员、工人和建筑物的安全。大多数的平板结构和桥梁生产利用金属筋张拉，所以这个问题很大，最重要的是它没有得到解决。本研究的目的是开发和测试在应力下约束或重新粘结钢筋束的方法，以便在使用过程中继续有效地传递荷载，并安全拆除。 拟议的研究方法包括四项活动。1)我们将开发有关预应力构件中可用力的信息，并计算释放机构和材料所需提供的抵消力。2)将对建议的系统进行大规模的实验室测试。将使用结构系紧唐斯和张紧装置。3)全尺寸预应力梁将使用重新粘结系统进行测试。4)这些数据将被评估和传播。对教育的影响应该很大。这个项目应该雇用估计25-30不同的学生从本科和研究生水平。他们将积极参与项目的各个方面。获得这种经验的女性比例应该很高，大约一半或更多。

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.