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TO: All Design Staff
FROM: C. C. Ruth
DATE: May 2, 1994
SUBJECT: Designing Bridges for Future Overlay

The question has been raised as the whether or not our new designs should include a future overlay. The following guidelines should be followed.

New Bridges

New bridges are not designed for future overlay


Widenings (new portion) are designed for a future overlay if the existing adjacent structures is not overlaid as part of the widening.

Since all new bridges are designed with a deck protective system (epoxy-coated rebar with 2.5" concrete cover), a future overlay is unlikely. If a future overlay is required, an "equivalent weight" portion of the 2.5" concrete cover could be removed to equalize the dead load. Any changes to the above guidelines should be approved by the Bridge Design Engineer.


cc;     M. M. Lwin

         O. R. George

         E. H. Henley

         Z. Y. Fahoum, (Bridge Design Manual)