Precise Alignment Was Critical to Installation of Bascule Bridge Over Loxahatchee River
Category: Bridges & Moveable Structures
Method(s) Used: On-Site Machining
Location: Jupiter, Florida
During a short 45-day outage in the spring of 2022, IPM provided precision alignment services for contractors to successfully place the new FEC Railroad Bridge bascule span over the Loxahatchee River. The IPM services included not only ensuring the proper placement of the span itself, but also alignment of the trunnion towers and all operating machinery.
Precision Metrology and Custom Designed Tools Assist in Bridge Installation
The project required first locating the centerline of rotation of the span in space by measuring the distance from the abutment, centerline of tracks, elevation, and level alignment. This process was critical to ensure proper operation of the span and ensuring clearance to adjacent fixed spans. Once the XYZ coordinates were determined, IPM ensured proper alignment of the open gearing, floating shafts, and primary machinery. Ultimately the plan called for the trunnion towers, counterweight girders, and all machinery to be installed prior to the final step which involved lifting the span into place with two large cranes, and transferring the span to IPM designed and manufactured manipulators. These devices were used to mate the span to the counterweight girders and allow 750 structural bolts to be simply dropped into the holes at the splice and tensioned.
IPM worked with contractors for a two-year period prior to the start of the outage to define the means and methods to accomplish the installation in accordance with the project specifications. This work included multiple trips to the job site in Jupiter, FL, as well as trips to the fabricator facility in Alabama. During these trips, IPM utilized a laser tracker and other precision measurement instruments to collect data from the existing job site, and from the new span as it was assembled in the fabrication shop. This data was merged and used during the final outage to ensure proper placement of the bridge.
IPM Custom Designed Drilling Templates
During this period, IPM also designed several core drilling templates that were used to ensure proper placement of anchor bolts, which would secure the trunnion towers and machinery components to the pier. These templates were precisely aligned using the laser tracker and verified by secondary means to ensure the precision of this first critical step. The proper placement of these anchors ensured that all machinery (and the bridge overall) was in precision alignment to the specification requirements. One such requirement was that the thrust gaps at the trunnion bearings were to be held within ±0.020” – this was to be accomplished prior to the span being installed without the ability to adjust after the installation.
Fulfilling a Tight Schedule on an Operating Bridge… In Only 45 Days
Once all machinery was in place and rough aligned, the span was lifted into place and transferred to the IPM manipulators. These manipulators supported most of the 120,000 lb. weight of the span and allowed crews to precisely move the span to bring the 750 bolt holes into alignment without disturbing the previously set thrust gaps. Once the bolts were installed and tensioned, machinery was adjusted into final alignment and operational testing of the bridge was performed. Throughout the project, components were manufactured and modified as needed utilizing the IPM Portable Machine Shop. The original bridge span was removed on April 10, 2022 and the new span became operational on May 25, 2022 – a 45-day window during which dozens of trains and boats were allowed to pass with minimal restrictions.
Visit our Bridges & Moveable Structures page to learn more about In-Place Machining Company’s services for infrastructure, or feel free to Contact Us at any time at 414.562.2000.