SOME ASPECTS OF THE SERVICEABILITY OF SLAB SYSTEMS

Serviceability issues, particularly the control of deflections, is becoming an increasingly important factor in the design of slabs. This issue is addressed by a number of the authors in this seminar. A number of aspects of this problem are discussed. There is some evidence that the deflections of actual structures exceed those calculated by current methods. Recent work carried out at Cardington has shown that in very many, if not most cases, the most critical loading to which a slab may be subjected is during construction; this is generally not considered in design. The effect of this high early loading on the future performance is considered. In slabs, the accurate assessment of deflections depends to a great degree on the assessment of the effects of tension stiffening and tensile strength. This has recently been studied in a major joint research programme reported in outline in another paper in this seminar. It is pointed out that current code methods give very different answers for the deflections of many practical slab situations.

• INTRODUCTION

• CONDITIONS DURING CONSTRUCTION

• ACCURACY OF DEFLECTION PREDICTION FORMULAE

• UNCERTAINTIES ABOUT THE TENSILE STRENGTH

• CONCLUDING DISCUSSION

• REFERENCES