Overview
As a subcontractor to Stantec, Modjeski and Masters, Inc. (M&M) was selected by the MassDOT-Transit Division for a contract involving design for the rehabilitation of 12 bridges. This includes assignments for two drawbridges at Boston’s North Station known as Draw 1 east and Draw 1 west. The original scope provided rehabilitation design. Inspections revealed considerable deficiencies that resulted in the the decision to move to replacement, which will be handled as a separate contract.
The two North Station bascule bridges each include a through truss bascule span and a track girder span supported on caissons. The main bascule spans of the structure are a set of twin steel Scherzer-type rolling lift bridges. Structural inspections have focused on concerns with deterioration of floor beams and the rolling track girders. Mechanical and electrical inspection focused on movable bridge elements. M&M inspected the aging electrical system in the M/E rooms mounted on the bridges, and in Tower A, the control room building.
M&M also designed and performed construction support for a new auxiliary operating system that was added to each leaf. The new system features a small HP motor that can operate via a portable generator hook-up. Operation is executed via a hand-held wireless remote unit with a dedicated frequency or optionally via hard-wired operating stations.
Bridge Geometry
| Length of Movable Span | 97 feet |
|---|---|
| Total Project Length | 147 feet |
| Tracks on Structure | two tracks |
