A prestressed kevlar cable/FRP structural system: Lightweight, maintenance-free and adjustable
This dissertation investigates the proposed design and behavioral characteristics of a new, advanced composite material structural system constructed of kevlar cable and fiberglass reinforced plastic.^ Currently, the cost of maintaining and rehabilitating the nation's infrastructure is very expensive, therefore it is very important to use structural components which are durable, easily modified and lightweight. This investigation proposes to solve this problem by using a prestressed structural system constructed of kevlar cable and E-glass isophthalic polyester resin shapes which is lightweight, adjustable, and maintenance-free as well as economical in comparison to traditional building systems. These advanced composite materials have excellent corrosion resistance as well as being lightweight. The design of the system emphasizes the lightweight and adjustable stiffness characteristics obtained by using prestressing.^ The research involved an investigation into 3 major areas; materials, geometry and construction. The material study involved the determination of strength/stiffness characteristics of kevlar 49 and 149 cable and E-glass isophthalic resin tube shapes. These characteristics were found to be similar, in most cases, to manufacturer's recommended values. It also addressed the time-dependent characteristics (laboratory conditions vs. functional environment) of the materials as well as the constructed components. Creep/relaxation behavior observed for approximately 10,000 hrs. was found to be small after the initial 1000 hrs.^ The geometry investigation involved a full scale study of the proposed members of the system. This research involved over 250 tests to determine strength/stiffness characteristics of the system and to provide adequate data for the development of a computer model. A model was developed which predicted the behavior of the system (within 10%) in the linear range. Based on this information, a series of 17 full scale tests to failure were conducted at the ATLSS Center at Lehigh University to determine possible failure modes in the system. The ultimate load carrying capability achieved was 24.0 kips for a proposed member which weighed approximately.15 kip.^ Last, the construction investigation involved a series of field case studies which addressed the construction aspects of the proposed system. Field prestressing techniques, portability of components, adjustability, erection procedures, and field modifications were all evaluated. This pan of the study determined the feasibility of the proposed system for use in construction. ^
Johansen, G. Eric, "A prestressed kevlar cable/FRP structural system: Lightweight, maintenance-free and adjustable" (1995). Dissertations available from ProQuest. AAI9532212.