25C - AGMT - ENGINEERING SRVS - Laserfiche WebLink

Home Browse Search

Fairview Street Bridge Rehabilitation Option 2 Option 2 is to widen the bridge deck 18' -0" to the west of the existing bridge to accommodate 8' -0" sidewalks, 4' -0" shoulder safety /bike lanes, and concrete barriers on both sides of the bridge (See Exhibit A). This option shifts the centerline 9' -0" west of the current bridge centerline. This alignment takes advantage of the approach curve south of the bridge to make a smooth lane shift in the northbound direction. In the southbound direction, the outside lane will be on a tangent alignment with a small shift to adjust for a wider shoulder on the bridge. The west side widening requires re- grading of two of the four OC Flood Control Department maintenance access roads and relocation of two gates. Within the river, the west widening does not impact the existing debris noses or the storm drain outlet at the northwest corner. Not needing to re- construct the debris noses represents a significant cost reduction to this project. Minimizing construction in the river has several benefits such. as ensuring nationwide permit is applicable for the streambed alteration which will speeds up environmental and permit processing tasks, and reducing the construction time which will result in lower construction bids. In order to build the widening, traffic will be shifted to the east side. This will maintain one 3' -6" walkway during construction, allowing pedestrian access across the River. Upon completion of the widening, a new sidewalk along the east side will be added. This option can be built in the shortest time possible without a winter shutdown. A key benefit of a single sided widening to the west is the reduced life cycle cost when factoring in i future &•lane widening. A future single sided 28' -0" widening of the bridge to the east will create a 6 -lane structure that matches the approaches. (See Exhibit B) This provides 8' -0" sidewalks, 5-0" shoulder /bike lanes, six 11' -0" lanes and a 4' -0" median. The overall centerline shift will be 5' -0 ",which can smoothly be shifted within the median transition on the approaches. Another benefit of this option is to be able to build ultimate sections within existing right of way. As shown in Exhibit B attached with this proposal, the existing extra wide sidewalk is narrowed from 20' -0" to about 10' -0 ", which results in less encroachment on the park across the street. The trade -off for this option is a slight encroachment into the recently improved Fairview Triangle Habitat Restoration area as opposed to a larger encroachment at a future date. REHABILITATION WIDENING Op #Bean 2 - West Rehabilitation Widening: Shift centerline 9' -0" west and do not touch debris wall. Future ultimate widening would require debris wall reconstruction. 14 1 Understanding of Need Design Services for Fairview Street Bridge Rehabilitation AT K E 25C -20