Modeling of Moisture Migration in an FRP Reinforced Masonry Structure

Prof. Mark Lin

Department of Mechanical and Aerospace Engineering
University of Alabama in Huntsville

November 8, 2002
202 Madison Hall
3:00 PM (Coffee and Cookies at 2:30)

Abstract

Many building structures constructed by unreinforced masonry (URM) walls in the U.S. are located in moderate to high seismic zones and do not meet current seismic building codes. It is necessary to update these structures through retrofitting to improve their strength and ductility. One contemporary method for retrofitting URM wall structures uses fiber reinforced polymer (FRP) composites. FRP composites have many outstanding properties suitable for upgrading URM wall application, including easy to apply, immune to corrosion, capable of being formed to non-planar surfaces. Though many studies have demonstrated the effectiveness of FRP reinforcements for masonry walls, little has been done to understand their impact on the building envelope. Proper characterization of the building envelope requires an understanding of environmental temperature and moisture effects on the FRP reinforcement and the FRP/masonry interface. It is of particular interest to model the moisture migration in an FRP/URM wall structure, since the adhesive interface between the FRP laminate and the host masonry can be susceptible to moisture entrapment that often results in interface damages.

In this talk, a theoretical formulation and its finite element implementation for modeling the transient moisture migration in a layered structure will be presented. Theoretical and finite element results for a one-dimensional FRP/URM model will be shown. In addition, the results of moisture induced stresses on an FRP/URM wall structure obtained by coupled hygro-mechanical analysis using finite element approach will also be discussed. The moisture transport model presented will provide the basis for a generalized hygro-thermo-mechanical model that will track moisture and temperature transport across dissimilar building materials.