Cracking In Bridge Decks PDF Download

Cracking in reinforced concrete bridge decks is a widespread concern in the United States. Many concrete bridge decks, regardless to the age of construction, have shown different levels and patterns of cracking. Not only does cracking of bridge decks weaken the bridge infrastructure, but also allows the inflow of corrosive agents into the reinforcement, regardless of the bridge design type, length of spans, deck thickness and concrete mixture designs. Increased cracking of concrete bridge decks all over the world poses a threat to life as well as prove extremely expensive for repair and maintenance. Thus, precautions must be taken in order to avoid and restrict bridge deck cracking, one of which is inspection of the bridge at regular intervals. The Ohio Department of Transportation's current procedure for bridge inspection offers only a qualitative assessment of the bridges inspected. In this study, a method was developed for the quantification of crack densities for twelve bridges in District 3. Two types of bridges were inspected: three structural slab bridge decks and nine stringer supported bridge decks. Crack densities for each bridge were determined based on crack maps corresponding to the surveys for each bridge deck. Results indicated that structural slab bridge decks have slightly higher shrinkage crack densities compared to the bridge decks constructed with stringer supports. However, the "structural" cracks seem to be wider than shrinkage cracks for structural slabs (greater than 0.007 inch). Particularly on bridge ASD-42-0656, which is a continuous slab bridge, there were several large "structural" cracks that were parallel to the pier beams supports. The shrinkage crack densities of the twelve bridge decks determined in this study were considerably lower than the crack densities of similar bridge decks located in other states, demonstrating that Ohio bridge decks in general have lower crack density than those in other states. The shrinkage crack densities of the bridges constructed with QC/QA type of concrete have lower values than the bridges made with other types of concrete. Also, the crack widths were determined at certain key locations and were compared with theoretical values. The measured crack widths are much larger compared to the corresponding theoretical crack widths. This is a reason for concern.