A parametric study of the development of transverse deck cracking

Bridges and especially bridge decks experience problems of transverse cracking and deterioration. The causes of early age cracking are mainly due to plastic shrinkage, temperature effects, autogenous shrinkage, and drying shrinkage. Many parameters can affect the development of such cracks. The cracks can be influenced by material characteristics, formwork, climate conditions, geometry, load patterns, amount of deflection, and time dependent factors. It is important to resolve the issue of transverse deck cracking otherwise several bridge decks may experience loss of stiffness and the possibility loss of function which may affect the safety of bridges. This paper examines the effect of a wide range of parameters on the development of cracking. The parameters include, the number of spans, the span length, girder spacing, deck thickness, concrete compressive strength, dead load, hydration, temperature, shrinkage, and creep. The importance of each parameter is identified and then evaluated. Also, the AASHTO Standard Specification limits live-load deflections to L/800 for ordinary bridges and L/1000 for bridges in urban areas that are subject to pedestrian use. One of the main objectives of the study is also to ensure that the current deflection limit is adequate. It is determined that the deflection limit is an important parameter to affect cracking. The current deflection limit needs to be revisited and modified. A set of recommendations to limit the transverse deck cracks in bridge decks is also presented. © Civil-Comp Press, 2012