This project examined various methods of innovative bridge design and construction techniques to expedite construction. The following methods have been identified as possible method of reducing the time needed for bridge construction: precast substructures; prefabricated composite bridge units; prefabricated superstructure units, such as adjacent boxes, which do not need a separate wearing surface; full depth precast concrete decks; stay-in-place concrete or steel forms; completely prefabricated bridges; and, rapid curing concrete materials. The first 6 items have been tried in various states and the results of these trials can be found in an AASHTO Technology Implementation Group (TIG) report at www.ashtotig.org. In order to find additional information on barriers to rapid construction, a survey of contractors was conducted. This survey showed that the main obstacle to fast bridge construction is the forming of the deck. The contractors also indicated that the best way to build bridges faster was to allow the entire bridge to be closed and the reconstruction to occur all at one time. One possible solution to the deck forming problem is the use of stay-in-place steel deck forms. A survey of states showed that approximately 34 states use stay-in-place steel forms for decks. The main concerns about using these forms are the inability to inspect the underside of the deck, trapping moisture between the concrete and the form, deterioration of the form, and additional weight due to the flutes in the forms. However, those states which use SIP steel forms contend that all of these concerns can be overcome. An attempt was made to assess the cost of implementation, but as most of the techniques are still in a pilot phase, cost information was not available.(f) From Kansas DOT Bridge Design Manual. aquot;Steel stay-in-place forms may be considered where unusual construction conditions exist. Examples are high bridges and bridges over long expanses of water where form removal would beanbsp;...
|Title||:||Innovative Bridge Design/construction Techniques to Expedite Construction|
|Author||:||Richard A. Miller (P.E.)|