Accession Number:

ADA275190

Title:

Design, Development, and Testing of Advanced Bridge Structures

Descriptive Note:

Final rept. May 1990-Jun 1993

Corporate Author:

MARTIN MARIETTA LABS BALTIMORE MD

Report Date:

1993-12-23

Pagination or Media Count:

199.0

Abstract:

Three aspects of the application of adhesive bonding to lightweight bridge structures were examined producing composite surface treatments to reliably bond with epoxy adhesives, developing computer models to optimize adhesive joint design and develop design guidelines, and adapting a high- toughness, low-temperature-curing epoxy adhesive to practical use as a bridge and repair kit adhesive. New testing methods were developed in the composite surface preparation task to assess fracture toughness and environmental durability of composite-to-adhesive bonds. A wide variety of existing and novel surface treatments were examined. Simple mechanical cleaning, such as hand sanding, was shown to be highly effective in providing the basis for strong, tough, and durable bonds. Finite element models of a prototype tubular lap joint indicated that such a joint could be characterized by a few critical parameters, such as diameter, tube thickness, and joint overlap length. Design guidelines were developed using these parameters to allow a designer to determine load bearing capacity, optimum design, and stress-concentration factor a figure of merit. Design optimization studies included techniques to reduce stress concentrations and equalize load across the entire surface of the joint. Adhesive enhancement studies resulted in the development and limited production of a lower viscosity, repair-kit suitable version of a high toughness, low- temperature-curing epoxy adhesive originally developed on an earlier research program. Studies of potential sealant systems to prevent degradation of epoxy adhesives due to moisture ingress did not identify any suitable sealants. Adhesive bonding, Composite surface preparation, Finite element analysis, Adhesive joint design guidelines, Structural epoxy adhesives, Sealants, Adhesive testing

Subject Categories:

  • Adhesives, Seals and Binders
  • Laminates and Composite Materials
  • Civil Engineering
  • Couplers, Fasteners and Joints

Distribution Statement:

APPROVED FOR PUBLIC RELEASE