CMS 9906404<br/>PI: Nabil F. Grace<br/>Development and Evaluation of Innovative FRP Braided Fabric for Strengthening<br/>Infrastructures<br/><br/>The use of fiber reinforced polymer (FRP) sheets and strips as strengthening<br/>materials for concrete structures has been gaining the interest of many<br/>researchers and a few contractors during the last two decades. However, the<br/>lack of ductility in these materials and the corresponding catastrophic<br/>failures of strengthened structures reported in several research investigations<br/>have contributed to the lack of confidence in composite materials for<br/>structural engineering and the subsequent delay in using them for the<br/>strengthening/stiffening of concrete structures in the United States. It has<br/>become impossible to convince practicing structural engineers to recommend the<br/>use of these materials to their clients. This is to be expected, since<br/>structural engineers are very conservative and are accustomed to structures<br/>that dissipate considerable energy before failure. Since ductility, combined<br/>with the safety of occupants, is the basic ingredient of any successful<br/>strengthening/stiffening project, only a handful of contractors has considered<br/>the use of FRP materials. As a result, the use of currently available FRP<br/>materials in strengthening or stiffening applications in industrial facilities<br/>and highway bridges has been very limited in the United States.<br/><br/>To solve this problem, an innovative design of new FRP sheets needs to be<br/>introduced and evaluated in both laboratory and field. This will require<br/>extensive collaboration among: (1) FRP fabricators (i.e., composite industry<br/>that includes both producers of carbon, aramid, and glass fibers and epoxy<br/>adhesives), (2) contractors (construction industry), (3) academia, and (4) end<br/>users (structural engineers). The proposed study will be conducted with<br/>collaboration among Lawrence Technological University (LTU), DFI Pultruded<br/>Composites (DR), Baker Concrete Technologies Ind. (BCT), and Ohio Department of<br/>Transportation (ODOT).<br/><br/>The study will consist of four phases. The first phase will address the<br/>development of an innovative threeaxis braided FRP fabric that will be<br/>fabricated using a combination of carbon, aramid and glass fibers oriented in<br/>three different directions. These sheets will differ from the currently<br/>available, ineffective unidirectional and woven single fiber-type sheets, which<br/>have been evaluated at LTU and found to lack the necessary energyabsorbing<br/>capability. The developed fabrics will provide ductile rather than brittle<br/>failure of strengthened structures. The interlocking mechanisms between the<br/>braided carbon, aramid, and glass fibers in the three axes will ensure<br/>redistribution of the flexural and shear loads. This phase will also include<br/>the determination and optimization of the mechanical properties of the braided<br/>sheets and a selected epoxy adhesive. This phase will be completed by DFI and<br/>LTU.<br/><br/>The second phase will deal with the construction, instrumentation and<br/>strengthening of simple, continuous, and cantilever test beams. The developed<br/>FRP braided fabric and the selected epoxy adhesive will be used for<br/>strengthening these beams. This phase will be completed by collaboration<br/>between the FRP producer, LTU, and the contractor. In the third phase, the<br/>strengthened test beams will be transported to the Structural Testing Center<br/>(STC) at LTU and the research team will conduct various environmental/loading<br/>tests. During phase four, results from the first three phases will be deployed<br/>into a practical application in the state of Ohio by ODOT.<br/><br/>This collaboration will be extended to teaching and seminar activities. The FRP<br/>producer, strengthening contractor, and state engineers will be guest lecturers<br/>at LTU. The university research team and the industrial partners will provide<br/>seminars at the annual meetings of the Associated General Contractors of<br/>America (AGC) and at meetings of the Great Lakes DOTs Consortium. Collaboration<br/>between university and industry will result in the development of an innovative<br/>FRP material for strengthening deficient concrete structures. The level of<br/>confidence achieved by these activities win lead to the widespread use of this<br/>stateofthe art technology.
GOALI: Development and Evaluation of Innovative FRP Braided Fabric for Strengthening Infrastructures