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Concrete ground-supported floor slabs commonly incorporate a layer of steel fabric reinforcement, to assist in the control of cracking which can be caused by restraint to shrinkage movement of the concrete. Where steel fabric reinforcement is used it will not necessarily prevent the formation of all cracks, but if a crack occurs, the reinforcement will control its opening.
In strip construction, steel fabric reinforcement is normally used near to the slab´s surface with 50mm minimum cover. In large area pour construction, a nominal weight steel fabric, commonly type A142, is normally incorporated in the lower part of the slab, which facilitates construction by ´Laser Screed´ or manual methods. The reinforcement in this case is used to control and equalise the opening of the sawn groove shrinkage contraction control joints and thereby minimise the risk of random cracking from shrinkage restraint.
Traditionally the small proportions of steel fabric used in floors have not been considered in calculations of load-carrying capacity. Appendix E of Technical Report 34, Concrete industrial ground floors provides design guidance specific to steel fabric to be used in conjunction with the design equations in that document.
Acknowledgement: Concrete Society
Other references:Concrete Society Project Report 2, ´The structural use of steel fabric reinforcement in ground-supported concrete floors´, 2004.
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