Discover how New York State Department of Transportation’s debut of SpaanSpan® marked a milestone in bridge design for the Route 159 bridge over the CSX Railroad in Rotterdam, NY, achieving a 130-foot span with minimal structural depth. Through the integration of precast, pre-tensioned concrete deck slab units supported by longitudinal edge girders and the use of spliced girders for efficient shipping and onsite assembly, Fort Miller Precast played a crucial role in introducing this revolutionary new technique in the state of New York.
Project Background
The driving force behind selecting the SpaanSpan® bridge system for the Route 159 bridge over the CSX Railroad in Rotterdam, NY, was to increase the under clearance for the railroad without increasing the profile of the approaches. SpaanSpan®, which is a low-profile through girder bridge system, is designed to increase bridge clearance and minimize approach work, thanks to the low profile of the SpaanSpan® through-girder design.
Key Features of SpaanSpan®
SpaanSpan® bridges are fabricated by Fort Miller Precast in conjunction with design services provided by Janssen & Spaans Engineering, Inc. of Indianapolis, Indiana. As a construction option, SpaanSpan® offers several key benefits.
- High-performance concrete: Precast concrete has revolutionized the construction industry by providing an easy way to ensure quality and consistency in the construction of bridge parts. SpaanSpan® is a made from high-performance precast concrete with strengths in excess of 10,000 pounds per square inch (psi).
- Post-tensioned structures: SpaanSpan® bridges are post-tensioned, which adds support to the bridge’s precast concrete deck panels and allows for an efficient streamlined construction process.
- Minimal structural depth: When using SpaanSpan®, the depth of the structure is limited to the thickness of the deck panels, allowing for a simple way to increase the clearance of a bridge without adding to the size of its approach.
Construction Process
One of the most valuable aspects of using precast concrete bridge design is the quick and efficient construction process that it allows. For the Route 159 bridge, the crew followed six simple steps for installation: (1) erect the edge girders, (2) drop in the deck panels, (3) cast the edge and end closure pours, (4) install post-tension and grout edge girders and deck panels, (5) install the barrier, and finally (6) overlay the deck panels. Let’s take a closer look at some of the aspects of the construction process.
Precast, Pre-tensioned Deck Slab Units
Precast, pre-tensioned deck slab units were placed between and supported by the longitudinal edge girders. This also included the installation of temporary bracing and support falsework.
Longitudinal Edge Girders
The longitudinal edge girders were spliced over the active tracks to provide a completed span of 130 feet. Spliced girders were used to facilitate shipping and jobsite erection.
Spliced Girders
Post-tensioned edge girders were shipped to the job site on special hauling equipment. Girder-mounted hangers supported those slabs until closure pours and post-tensioning were complete.
SpaanSpan® Benefits and Advantages for Other Bridge Projects
With the Route 159 bridge project, the NYSDOT was able to construct a 130-foot span with a structural depth of approximately 21 inches through the use of SpaanSpan®. As we look to the future of innovative precast bridge design, SpaanSpan® offers a pragmatic advancement in bridge construction that emphasizes efficiency and durability in modern infrastructure projects.
