Structural Mechanics Solutions for Butt Joint Seals in Cold Climates

摘要

An effective, formed-in-place joint seal will respond with elastic orviscoelastic behavior over a reasonable design life to any large movement of the joint without adhesive or cohesive failure. For a given joint movement, seals with lower stiffness are most able to deform without cohesive or adhesive failure of the seal or of the structure to which it is bonded. It is in recognition of this desirable response feature that lower-modulus, rubber-based elastomeric materials have been formulated and promoted as joint sealants. For a seal formed from an elastomeric sealant, it should generally be expected that the modulus of elasticity will depend upon temperature and loading rate, such that the modulus increases (sometimes dramatically) with a reduction in temperature and an increase in loading rate, and it should be expected that the seal stiffness will depend upon the material modulus and the shape of the seal. Measurements from testing techniques that are routinely used to evaluate the temperature and rate-dependent mechanical properties of rubber-like materials, together with simple structural mechanics solutions for the load vs. deflection behavior of rubber in the configuration of rectangular shaped joint seals, allow these dependencies to be modeled, and form the basis of a practical analysis technique that could be used by civil and mechanical engineers for sealant selection and seal design.