Institute for Research in Construction, N.R.C.
and PROFESSOR G. T. SUTER Carleton University, Ottawa

Climatic fluctuations in temperature create temperature differentials between the exterior and interior walls of buildings. In typical buildings of loadbearing masonry wall construction, interior crosswalls are rigidly connected to exterior walls which forces the intersecting walls to deform together under the temperature differential. Consequently, thermal stresses develop in the walls. Previous work using linear elastic finite element analysis indicated that the walls may crack or be overstressed in compression due to the environmental thermal load. This paper deals with a nonlinear finite element analysis of the thermal stresses. For increased accuracy in the current work, orthotropy of concrete block masonry was considered by developing a theoretical model. The results from the nonlinear analysis essentially substantiate those of the linear analysis. Thus, in a typical 10-storey building located in Ottawa, the exterior wall may crack in winter and be subjected to significant thermal compressive stress in summer. These cracks and overstressing in compression have both serviceability and safety implications on the building.