Manual on Use of Self-Propelled Modular Transporters to Remove and Replace Bridges
Chapter 5. Contracting Issues
The use of SPMTs to move bridges may be incorporated into all types of contracts, from typical design-bid-build to design-build to other innovative types of contracts.
SPMT companies typically work as subcontractors to the prime bridge contractor, providing engineering services and operators with their equipment to ensure bridge moves that are within the required specifications for the job.
5.1. Construction Scheme
For accelerated bridge construction projects, the owner should show one feasible construction scheme to move the bridge in the contract documents, and allow contractor-proposed solutions by plan note as long as the solutions meet the traffic control plan closure windows and other project requirements. To change the construction scheme, the contractor must provide signed-and-sealed analyses and details for approval.
Alternatively, the owner could provide both conventional construction details and details for moving the bridge with SPMTs in the contract documents as an option to be used at the contractor's discretion or as an alternate to be bid against the conventional construction details.
A third alternative would be to provide contract documents that show conventional construction, and by plan note allow the contractor to submit a construction method different from conventional construction. This alternative is likely to result in more conventional construction bids since contractors are geared up for conventional construction projects.
5.2. Staging Area
The bridge owner should work with landowners to ensure that at least one staging area that has a feasible path to the final bridge location is available. If the bridge owner knows it will use specific land for staging, it should acquire the land before the bid. Information on the site should be included in the contract documents, with allowance for contractor options to propose and secure alternate locations if it benefits the contractor's operations. The bridge owner should provide raw geotechnical boring information and address existing utility conflicts as required. Unless specified otherwise in the plans, the contractor is responsible for final negotiations with the landowner for using the staging area during the project.
The ground surface should be relatively level at the staging area where the bridge is constructed and along the transport route between the staging area and the bridge's final location. The contractor must ensure that the staging area and the route of the loaded SPMTs have well-compacted soil. Temporary pavement or steel plates under the load may also be used to ensure adequate ground support. Relying solely on steel plates would require a large number of plates or an efficient process of placing the plates in the path of the loaded SPMTs to maintain a reasonable movement speed.
5.3. SPMT Equipment Payment Strategies
The owner should consider including SPMT equipment and related services as a bid item in the contract documents to recognize the large upfront mobilization costs to get the equipment to the project and set up for use. The owner would need to determine whether to create one or several SPMT bid items (for example, mobilization, move of existing bridge, and move of new bridge).
5.4. Contracting Strategies to Achieve Reduced Timeline
The owner should consider A+B bidding and tie the facility impacts with delay-related user costs in the B component.
The owner should consider bonuses/incentives and penalties/disincentives for early and late completion, respectively, with closure windows clearly defined to achieve accelerated onsite construction timelines. The duration (begin and end date and time of day), day of the week, holidays or exceptions, number of windows allowed, notification requirements, etc., should be included. The owner should set the monetary values high enough to make it worthwhile for the contractors to change their typical operations to achieve the reduced timelines.
The owner should consider lane rental fees for excessive lane closures or late opening of lane closures to encourage the accelerated completion of onsite construction.
The owner should consider allowing value engineering proposals, with the owner and contractor sharing the cost savings.
The owner should consider a prebid conference to ensure that all potential parties understand the project. The SPMT companies should be invited to the conference.