ROUTE 6/DEPOT RD. BRIDGE RECONSTRUCTION
Harwich, Massachusetts
The Mid-Cape Highway (Route 6) carries approximately 24,000 vehicles where it passes through Harwich on it way to Cape Cod’s many beaches and attractions. The Depot Road Bridge is a three-span reinforced concrete deck on steel stringers supported by two concrete-filled decorative steel pillar piers. Its location at the beginning of a two-lane section of the expressway is critical to highway safety in the area. When the Massachusetts Highway Department found the sufficiency of the existing deck to be substandard, C&C Consulting Engineers was assigned to provide engineering services for the rehabilitation project.
As a part of the project, a safety upgrading of the bridge rails and associated approach guardrail was to be included in the construction. Originally, it was anticipated that additional safety upgrading and re-paving would occur for a significant stretch of the highway surrounding the bridge, but a later administrative decision postponed the roadwork. The existing steel bridge railings were scheduled for replacement with a concrete barrier shape that prevents snagging and typically re-directs errant vehicles without sending them into the oncoming traffic lane.
Our pre-design inspection revealed that in addition to the concrete deck, the stringers were in need of replacement to bring the bridge into conformance with current loading standards. We recommended replacement with similar, but stronger materials, and called for a phased traffic management plan to allow the busy bridge to remain in service during the estimated twelve-month construction time frame. We recommended construction be curtailed during June, July and August to avoid problems with the summer tourist season traffic.
The Traffic Management Plan involved reconstruction of the bridge in three phases, with traffic maintained in eleven-foot lanes with no offset or shoulders between the lanes. Recognizing the tight dimensions considering the actual travel speeds in the area, we specified the use of Kwik-Curb, a movable plastic “traffic island” onto which plastic delineators can be mounted, to separate the opposing lanes of travel.
This bridge was returned to full service in the summer of 2003, and we are currently awaiting information for the preparation of record plans.
Client: Massachusetts Highway Department
