BRIDGE APPROACH PAVEMENTS, INTEGRAL BRIDGES, AND CYCLE-CONTROL JOINTS

The 1977 Final Report of the National Experimental and Evaluation Program for Watertight Bridge Deck Joint Seals documents the experiences of 40 state transportation departments for a period of 7 years. The summary contains a paragraph indicating that a number of states have shown strong interest in bridges of some length built without joints, and designs with integral abutments. Many such bridges have been built in Tennessee, according to this report, with the only evidence of movement showing in the form of a crack in the approach pavement off the structure. Those cracks are of a minor nature and do not appear to present a problem. However, as is evidenced by the bridge approach designs presently being used by a number of states, and illustrated and evaluated in this paper, some transportation departments are fully aware that the designs of approach pavements for integral bridges need special consideration and provisions if they are to survive for more than 5 to 10 years without serious distress. They are aware that the cracks described do not begin to suggest the potentially serious distress that such approaches will experience if appropriate pavement designs are not developed and employed. Additionally, the bridge approach designs presently being used suggest that some engineers are not fully aware of the great growth potential of unrestrained rigid pavement and the great pressure potential of restrained pavement, or are unable to provide an effective means to contend with such behavior. Even the most effective of the present designs appear to need improvement if they are to survive for more than 5 to 10 years without modification or repair. Finally, the functional effectiveness of these designs is becoming even more critical with the current emphasis on integral design and the development of even longer integral bridges. Although some of the current designs will be illustrated and evaluated in this paper, completely effective designs are not suggested. Such designs will depend on materials that are presently not available to the transportation profession.