The invention contemplates a steam-surface condenser construction wherein an assembly of spaced tube sheets, associated tubes and water boxes is axially compliantly supported with respect to the condenser shell, and wherein the said assembly further includes elongate strain-proportioning mechanism extending between the tube sheets and effectively tying the water boxes to each other independently of tube-sheet connection via the tubes. The strain-proportioning mechanism may take the form of plural spaced elongate members which effectively span the assembly, these members being positioned in substantial alignment with the region of water-box connection to the respective tube sheets.