BRIDGE REPAIR/REHABILITATION FEASIBILITY STUDY

The effectiveness of the counterweight to balance the operating forces is lessened when it dips in
the water at high tide and becomes somewhat buoyant, which increases the force in the operating
ropes when the bascule span is raised.
Maintenance: Replacement of the operating equipment with new operating equipment properly
sized and designed to current design standards would reduce the wear and fatigue on the wire
ropes, provide greater horsepower to overcome minor increases in load caused by ice, wind and
friction. All of these will reduce maintenance requirements. Replacement of the electrical power
and control equipment will also reduce the maintenance required to periodically repair the
electrical equipment.
Visual Impacts: The minimum recommended size for the new sheaves, pulleys and winch drums
is approximately 36” in diameter. The significantly larger sheaves, pulleys and winch drums will
be a significant visual departure from the existing equipment and thus may introduce a visual
impact. Shifting the operating equipment outward by 1’-0” may also introduce a visual impact.
4.4 Substructure
4.4.1 Concrete Abutments
NBIS Condition Rating: 5 (Fair)
Condition Description: The abutment concrete is generally sound with minimal cracking and
spalling that does not significantly reduce the integrity of the abutments. Previously installed
1/8” thick epoxy mortar applied to the exposed concrete surfaces of the abutments has cracked
and spalled in isolated areas, primarily at the locations of construction joints where the
abutments were previously modified. However, this condition is primarily cosmetic in nature.
There is a single large spall, measuring 12”x9”x6”, at the top of the East Abutment back wall
adjacent to the south sidewalk.
The timber sills (caps) are typically sound with no apparent significant decay, although the sills
contain splits and checks of a depth that permits fungal spores to access the center of the timber,
where there are no preservatives, which increases the risk for decay. Much of the preservatives
have leeched from the surfaces of the timber increasing the risk of surface decay as well.
Moisture from the roadway deck joint, as evidenced by the moisture staining, is retained on top
of the abutment breast walls adjacent to the sills, which promotes fungal decay. The backside
and underside of the timber sills adjacent to the abutment concrete and the top of the sills directly
below the timber stringers are not accessible for visual inspection, and thus the condition of these
surfaces cannot be verified. The cut ends of the sills are not sealed, and although the cut ends are
not located where water typically ponds, water running over the cut ends can absorb in to the
ends of the sills, which promotes decay.
The asphalt sidewalks along the wing walls (retaining walls) do not provide the required
minimum clear width of 3’-0” and thus to not meet accessibility requirements. The top of the
concrete wing walls is above the asphalt sidewalk surface with the height above the sidewalk
varying along the length. The steel guardrail attached to the back face of the wing walls is
Repair/Rehab. Feasibility Study March 10, 2011
Bridge No. C-07-001 (437) 33 Final Report