Ballast Deck Components
- Sub-panels
The width of sub-panels may vary from 2" to 24". A typical sub-panel is 24" wide and is comprised of 3 timbers surfaced four sides to 5 ¾" x 8".
- The timbers are dowel laminated with ¾" spiral steel dowel pins hydraulically inserted in a prebored undersized hole.
- Ballast Retainers
- Surfaced from 6" x 8" stock and dowel laminated to a finished dimension of 5 ¾" x 15 ½".
- The length is determined by the length of deck panel.
- The ballast retainer is prebored typically on 24" centers for ¾" machine bolts.
- Deck Panels
- Consist of sub-panels and ballast retainers that are bolted together with ¾" machine bolts.
- Panel length is determined by specified drawings or requirements. Panels are being manufactured in lengths of 12’ or less.
- Walkways
- Walk blocks are supplied with deck panels as required. They are pre-attached with ¾" machine bolts and countersunk to allow field application of walkway planking.
- Handling
- To prevent wracking panels they must be lifted at four points during unloading and placement on the bridge.
- The drain holes ate typically used as lift points.
Shipment
- For rail shipments chain flats have proven the most economical and with proper blocking and restraints very secure.
- Truck shipments limit panel lenghts to 10’ or less.
- Treatment
- All deck components are framed prior to treatment. Treatment is accordance with A.W.P.A. specifications.
Advantages of Paneled Ballast Deck Bridges
- Structural Advantages
- All framing and boring is performed prior to treatment providing maximum treatment in decay prone areas.
- Material is fabricated in a controlled environment to design specifications with stringent quality control.
- In plant fabrication allows maximum flexibility in design while maintaining engineering oversight.
- The sub-panel design reduces hardware and eliminates "Binder Planks."
- Economic Advantages
- Train delays are reduced by 30% to 60%.
- The labor force on the job is reduced up to 30%.
- Installation time cut by up to 60%.
- Safety Advantages
- The system reduces open deck time and the risk of falls.
- Eliminates physical manual labor and the risk of injuries.
- Encourages environmentally safe construction practices.