Fixings in cracked concrete: the probability of coincident occurrence and likely crack width (TN136)

The proposals being put forward for testing fixings require consideration of the possibility of a crack forming in the concrete through the location of the fixing. There is considerable debate about what width of crack is appropriate for the tests. To assist in establishing a reasonable test régime, a study was commissioned to try to define, from calculation, what widths of crack could actually be expected to occur in buildings. This Report considers the factors affecting the likelihood of cracks occurring in actual structures from various causes and the likely widths of cracks if they do occur. Two types of cracking are considered in detail:cracking due to applied loads and cracking resulting from the restraint to shortening of members due to shrinkage and cooling. Key words: concrete and structures, materials.