Haystack Bridge: Repurpose of a Bascule
(Room Sagamore 2)
19 Sep 17
2:00 PM
-
2:30 PM
Tracks:
AREMA Technical Sessions- Structures
Sonoma and Marin Rapid Transit (SMART) recently completed a unique project involving the repurposing of an existing rolling bascule superstructure. The existing bascule bridge was purchased by SMART after it was removed to make way for a larger lift span at the Port of Galveston. The bridge was purchased by SMART to provide the following improvements to this new light rail system currently under construction: The repurposed bascule would replace an aging swing bridge (built in 1915) which was in need of repair. It would increase the functionality of the river crossing by increasing the navigable width, and also shorten the duration for opening and closing the bridge for a train crossing. The existing swing bridge had to remain in active rail service until the new bridge was operational. As this is an important waterway with high traffic, the contractor was limited to only a handful of closures to marine navigation. In order to minimize impacts to the navigational channel, the contractor built the bridge in the vertical (open) position, which allowed the existing swing bridge to remain operational. After the bascule erection, there was a closure of the waterway to install the rail ties, install the rails, and perform the final balance. The bascule was supported and stabilized against its own foundations during erection. The new bridge was opened in late 2015. The presentation will discuss the condition of the existing bridge mechanical components, the design of the electrical and mechanical systems along with the scheme, methods and equipment used to repurpose the bascule from Texas to California from the perspective of Stafford Bandlow Engineering, who served as mechanical and electrical Engineer of Record; and COWI North America, who was engaged by the Contractor to develop and validate the scheme for erecting the bridge in the open position, as well designing the temporary works required to support the counterweight during erection, as well as the segmental girder.