Control of cracking in composite bridge decks in regions in biaxial tension

Deck slabs of bridges of composite construction can in places be stressed in biaxial tension throughout their thickness. Rules for control of crack width in codes such as EN 1994-2 are based on tests in uniaxial tension. Crack-width measurements are reported from tests in 1977 on slabs in biaxial tension, acting as flanges of composite beams. A theoretical model for prediction of crack width is explained, and a method is given for applying the rules of EN 1994-2 to biaxial tension. It gives results slightly more conservative than characteristic values deduced from the test results.