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. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Engineering Services for Government Infrastructure RFQ No. 07-03.(),1 -Eft behind the barrier walls, and finally an approx. 1'-1" wide aesthetic railing at the bridge coping line. The 15' width of the driving lanes is prescribed by FOOT for 175' horizontal curves radius and is needed for safe turning movements of cars and trucks. The 8' wide sidewalks are pedestrian friendly. We propose for the time being at the south bridge approach, within the available 20' easement, the construction of a 6' wide sidewalk separated by a barrier from an 11' wide driving lane for emergency vehicles. This way the path is clear for emergency vehicles at all times. Vertical Alignment: The vertical alignment presents a challenge. The challenge is caused by the U.S. Coast Guard and FOOT requirement of a 12' vertical clearance from mean high water level to the low member of the bridge structure. This pushes up the roadway profile from 174th Street to 172nd Street. One solution that we are looking at introduces a short section of roadway grade of 9% on each side of the canal, connected by a central vertical crest curve on the bridge over the canal, and two vertical sag curves, one tying into 174th Street and the other at 172nd Street (in compliance with FOOT criteria, for proper stopping sight distance). All pedestrian areas need to meet ADA requirements. At the south and north end of the project the sidewalks will start with 12: 1 grade for a distance of 30', then a horizontal landing of 5' to 8', then another 30' of 12:1 grade, and so on, until the sidewalk surface meets the bridge deck at a point where the proposed grade is 5%. Along the approach grades the sidewalk walking surface will be at a higher level than the roadway/bridge level up towards the point where the bridge grade is less than 5%. ...._r;:=~ _ /"- ~Vr L~';ll ~ .... PROFILE GRADE LINE 2.5 Possible Concept for the North Bay Road Pedestrian/Bike and Emergency Vehicle Bridge A possible concept that will be evaluated during the Bridge Development Report (BDR) consists of two (2) continuous steel box girder spans with 8 %" cast-in-place deck slab supported on single flared concrete columns for the interior support (See Inset above). The north abutment will be a stub abutment with warp-around proprietary (MSE) walls utilizing special concrete patterns and finishes to enhance the overall aesthetics in the proximity of the existing properties. The south end of the bridge will be supported on a pile bent with a CIP curtain wall meeting the pedestrian/bike/emergency vehicle ramp and closing the temporary opening from existing street and properties view. !, \ D J .. - ~ J D! .....-.-1 .L fQJ I TYPICAL BRIDGE SECT/ON - ,l In order to enhance the overall appearance of the exterior barrier and pedestrian lighting, a possible custom design of pedestrian railings with stone patterns meeting ADA requirements and integrated with custom designed pedestrian lighting can be provided (See Insets). ~~~~,