Design Memorandum



TO:                  All Design Section Staff

FROM:            Bijan Khaleghi
DATE:             May 18, 2007
SUBJECT:       Bridge Deck Overlay


Concrete bridge deck protection systems shall be in accordance with the requirements of BDM Section 5.7.4 for new bridge construction and widening projects. To accommodate a future deck overlay, bridges shall be designed as shown in the following table:

The effect of the future deck overlay on girder camber, "A" dimension, creep, and profile grade need not be considered.

Deck overlay may be required at the time of original construction for some bridge widening or staged construction projects if ride quality is a major concern.


Background

Vehicular traffic will generate wear and rutting on a concrete bridge deck over the life of a bridge. One option to correct excessive wear is to add a Hot Mix Asphalt (HMA) overlay on top of the existing concrete deck. This type of overlay less construction time and is less expensive compared to removing a portion of the deck and adding a modified concrete overlay. The initial bridge design needs to incorporate the future dead load.

If you have any questions regarding this issue, please contact DeWayne Wilson at 705-7214 or Bijan Khaleghi at 705-7181.


cc:   Mohammad Sheikhizadeh, Bridge Construction - 47354

       F. Posner, Bridge and Structures 47340