The City of Lincoln proposes removing and replacing the existing two-way, two-lane road McBean Park Bridge (Bridge No. 19C0254) at McBean Park Drive (formerly State Route 193) over the Auburn Ravine in Lincoln, California. The Project includes demolition of the existing 148-foot-long, 43-foot-wide bridge, construction of the replacement bridge to approximately 220 feet long by 68 feet wide with three 12-foot traffic lanes, two 8-foot shoulders, and two 6-foot sidewalks, relocation of utilities, temporary installation of water diversion structures, sediment removal and fill, and removal of vegetation and trees. Street improvements connecting to McBean Park Bridge will also include portions of intersecting Ferrari Ranch Road and East Avenue.
The existing bridge is categorized as an “on-system” bridge and is determined to be hydraulically inadequate with a history of frequent flooding events. Due to the poor integrity of the deck and superstructure, the bridge has a sufficiency rating of 67.6 when Caltrans Structures Maintenance and Investigations Division completed a routine inspection report for this bridge (Caltrans, 2021a).
The following issues have been noted in this report:
• This bridge has an NBI 113 Scour code of 3 (Scour Critical).
• Bridge foundations determined to be unstable for calculated conditions.
• There is one soffit crack in Bay 3 and one in Bay 4 in Span 2. There is also one
soffit crack in Bay 3 and one in Bay 4 of Span 3.
• There is a longitudinal crack in the AC. The crack is less than 0.25 inches wide.
• There are vertical cracks in the girders of the original structure. Most of the
cracks are about 0.015 inches wide and spaced about 3 feet on center near
midspan. There is one larger vertical crack with a few edge spalls in Girder 2 of
Span 3 in the original portion of the bridge. The crack is up 0.04 inches wide
and approx 3 feet in length, is located near midspan and is reflected on both
sides. Twenty feet of the girders are affected by cracks significant enough to be
in Condition State 2.
The purpose of the project is to replace the hydraulically inadequate McBean Park Bridge to provide reliable general and emergency vehicle access, along with other local pedestrian and automotive activities, on McBean Park Drive with the intersections of Ferrari Ranch Road and East Avenue. The project will enhance the seismic integrity of the bridge, support hydraulic conveyance to improve access during emergencies, and mitigate flooding events.
Construction of the proposed project is anticipated to commence in the summer of 2024, and the anticipated project duration is two construction seasons. Construction activities would be permitted Monday through Friday between 7:00 a.m. and 7:00 p.m., with evening construction prohibited. However, extended work periods and weekend operations may be necessary. If extended work periods are necessary, work would be permitted on Saturdays and Sundays from 8:00 a.m. to 7:00 p.m.
Typical construction equipment would include backhoes, excavators, dump trucks, graders, mulcher, crane, drill rig, hoe ram, boom and cement truck, vibrating roller, forklift, air compressors, loaders, smooth wheeled roller, asphalt paver, striping truck, cutting torch and saw, jackhammers, and chipping guns. Construction Staging Area
The proposed project contains 0.93 acres of staging areas within the project limits (Figure 2-3). The selected staging area will be needed for the duration of construction activities to store equipment and materials, and the staging area will also provide parking areas for construction workers. The temporary staging area will comply with the same requirements and mitigation measures as the project and will be restored to preconstruction conditions after project completion.
Construction activities will proceed in the following general sequence within the project area limits:
1. Clearing and Grubbing: The banks of Auburn Ravine will be cleared and grubbed to accommodate the new bridge, remove a portion of the constricting easterly abutment fill prism, and widen roadway approaches. This work includes removing above-ground material, including all vegetation, non-salvageable trees, and debris. A Revegetation Plan will be established in conformance with City specifications and regulations as required by the PCCP, CARP, USACE, CDFW, NMFS and USFWS.
2. Water Diversion: To remove portions of the existing bridge and widen or construct the new bridge piers, it will be necessary to temporarily dewater the construction site and divert creek flows through the construction area (bridge site). A Fish Passage Plan will be established in conformance with City specifications and regulations as required by the PCCP, CARP, USACE, CDFW, NMFS and USFWS. The containment dam will be constructed within the channel banks within the project limits upstream and possibly downstream of the construction activities. Materials to construct the diversion would likely consist of pipes to convey anticipated flows, sandbags, and plastic sheeting to construct a containment dam or use of bladder dams upstream and downstream of the site and within the proposed project limits.
3. New Bridge Construction: A longer multi-span bridge would replace the existing shorter multi-span bridge. The bridge will be constructed in two phases to accommodate maintaining traffic on McBean Park Drive during construction. It is anticipated that drilled piles would be utilized for the abutment foundations. The bridge will require pile placement, abutment construction with wing walls, superstructure construction, followed by construction of the bridge sidewalks and barrier rails. The new bridge will be approximately 220 feet long by 68 feet wide. This will include three 12-foot traffic lanes, two 8-foot shoulders, and two 6-foot sidewalks.
4. Remove Existing Bridge: Traffic would be shifted to the constructed portion of the new bridge, and the original bridge would be removed. The demolition will remove the bridge railing and then strip the asphalt concrete (AC) overlay from the existing bridge deck. The channel flow below would be protected in the clear water diversion system as described above. This will be followed by removing the bridge deck edges through saw cutting and jackhammering into manageable sections. The existing bridge will be tested for hazardous materials before demolition, and the bridge deck edges will be dismantled and disposed of in proper landfill facilities based on the finding of the hazardous materials study.
5. Construction of the Roadway Approach: The roadway will be raised by approximately five feet over Auburn Ravine to better accommodate the design flood to allow for the maximum flood flow to pass without damage or serious threat to the stability of the bridge structure. The excavated soils will be used for the fill prism of the roadway approach to accomplish the elevated roadway profile, and some soil import will be required for roadway approach fill. Once the roadway is excavated, and the fill prisms are placed and graded, the roadbed will be constructed consisting of an asphalt concrete wearing surface on top of an aggregate base over compacted subgrade. The western approach begins at East Avenue, and the eastern approach terminates approximately 1,200 feet east of Ferrari Ranch Road.
6. Erosion Protection Installation: Rock slope protection and or soft armoring would be installed in front of the bridge abutments on the sloped banks to a point approximately 10 feet from the abutments and along the ravine invert/thalweg upstream and downstream of the bridges approximately 40 feet, and to a height on the sloped creek bank approximately three feet below the roadway surface.
7. Utility Relocation: An existing underground natural gas line, aerial and underground electrical and telecommunication facilities are contained within the McBean Park Drive right-of-way and across the existing bridge.
• The natural gas line that exists on the westerly roadway approach to the bridge
and may require vertical relocation to account for the additional overburden
which would be placed to raise the roadway profile over Auburn Ravine.
• The aerial electrical and telecommunications will be relocated to accommodate
the new roadway slight realignment.
• The underground electrical and telecommunications facilities are supported by
the existing bridge and will be relocated with the construction of the new bridge.