approval of design exceptions by GDOT and the Federal Highway Administration (FHWA). The GDOT Design Policy Manual notes in Table 6.7 that for Urban Freeways, outside shoulders should have an overall width of 14 feet and median shoulders should have an overall width of 12 feet. The AASHTO Design Policy of Streets notes in Section 8.2.4 that Freeways of six or more lanes should have paved right and left shoulders of ten feet, and where truck traffic exceeds 250 vehicles per hour, consideration for paved shoulder widths of 12 feet should be given. The previous technical analysis proposed three construction approaches for constructing new bridge abutments on the outside shoulders to support a bridge cap over the Downtown Connector.
The three approaches are as follows: 1. Abutment Wall with Drilled Shafts
Proposes a single row of drill shaft foundations and columns located behind the existing retaining walls, which are supported during construction with shoring and then existing wall are removed.
Figure D-7: Drilled shaft abutment, replacing existing walls
2. Pile Cap Abutment with Micropiles Above Existing Walls Construct abutment cap over existing GASE wall reinforcing and support with micropiles between each existing GASE strap.
D-10
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