Hand forming more than 200 feet of culvert will probably lose a contractor money. For long- or multiple-barrel culverts, leasing form frame travelers and accessories is a more profitable choice. A box culvert traveler is a retractable, rolling three-sided form. Wall and roof form panels are tied into a steel frame to create the three-sided traveler form. The steel frame consists of interchangeable headers and legs that are selected to match the width and height of the culvert opening. A slip plate in the roof form and a sliding header assembly permit horizontal movement that allows the vertical forms to be retracted from the concrete walls. Manually operated hydraulic jacks lower the three-sided form onto wheels that allow it to be rolled into a new position.
Three major activities are involved in constructing the forms for a box culvert. First, the base slab is formed. The base slab is the foundation for the box culvert that assists the traveler. Next, the inside barrel and outside walls are formed. The outside walls are usually gang-formed with vertical stiffbacks and horizontal stringers. Removable tapered form ties connect the outside wall to the inside traveler. Finally, the roof slab must be shored in order to achieve 1-day cycle times. The bottom shore plate underneath the roof is also the slip plate for the roof forming system. This plate not only provides for horizontal frame movement of the traveler but also connects the roof support ties.