ACI 435.8R : 1985

Part 1 - FIELD DEFLECTION MEASUREMENTS OF REINFORCED
         CONCRETE FLAT PLATES FLAT SLABS AND BEAMS:
         A REVIEW OF LITERATURE
Investigation A - (Commonwealth Scientific and
                  Industrial Research Organization,
                  Melbourne, Australia - experimental
                  flat plate structures)
Investigation B - (Jenkins, Plowman and Haseltine -
                  Scottish apartment building)
Investigation C - (Army Engineer Waterways Experiment
                  Station, Vicksburg, Mississippi -
                  Army barracks flat plate structure)
Investigation D - (Taylor, Heiman - five Sydney area
                  buildings)
Investigation E - (Chalmers University, Goteborg Sweden -
                  two apartment houses)
Investigation F - (Jenkins - Australian flat plate
                  building)
Investigation G - (Sbarounis - multistory flat plate
                  building)
Part 2 - FACTORS CONTRIBUTING TO DEFLECTION PROBLEMS
         IN TWO-WAY REINFORCED CONCRETE SLABS
Factors Contributing to Slab Deflection Problems
Loads During Construction
Properties of Concrete at Early Ages
Creep of Concrete Loaded at Early Ages
Control of Slab Deflections
Summary and Conclusions

Covers two parts. Part I is a summary of published studies on slab deflections (3 from Australia, 1 from Scotland, 1 from Sweden, 2 from U.S.). The summary focuses on construction practices and materials quality. Comparison of deflections calculated by various methods with actual long-term deflections is made in some cases. Part II summarizes several construction problems and material deficiencies which can contribute to large long-term deflections. Focuses on large construction loads as construction loads may be considerably higher than design loads and that high construction loads cause high initial deflections because concrete has a lower modulus of elasticity when loaded at an early age. Also, concrete creeps more when loaded at an early age which causes additional high long-term deflections.