Advisory Council

A Primary Mission of the Council is to promote effective means of surface preparation in the maintenance industry using water and water/abrasive blasting techniques.

A cost model for bridge painting maintenance was developed to aid specifiers in evaluating the costs associated with currently available painting technologies.

The time required, or the duration of each phase of the work, is estimated using the production rates or speed factors in the Cost Model.

The user can analyze the comparative cost of competing surface preparation and coatings approaches on the same structure, or the user can vary the input parameters describing the structure to measure the sensitivity of each Cost Object on the size and existing condition of the structure.

The results of user selections are viewed with the “Output” spreadsheet.

The Time spreadsheet does not have any changeable input and all cells contain fixed calculations.

It does this by calculating a specific duration for each phase of the work and summing all of the applicable phases based on the user input.

The Cost Variables page also has several fields that are changeable so that the initial conditions (constraints) of a project can be accurately accounted by the Cost Model.

These may include factors such as how long it may take to move containment enclosures and the thickness and density of the existing paint.

These are accounted for by providing places for baseline costs of consumable materials and supplies.

Use this documentation while experimenting with using the Cost Model Spreadsheet.
The Spread Sheet may be found under Miscellaneous Downloads.

A Primary Mission of the Council is to promote effective means of surface preparation in the maintenance industry using water and water/abrasive blasting techniques.

Waterjetting can be used to remove existing coating, rust, surface oil and grease, and water-soluble surface contaminants.1 The water is propelled through a single nozzle or multiple nozzles on a rotating head.

During on-site visits, Corrpro Companies, Inc. observed the Ultrahigh-Pressure Waterjetting process on three different bridge structures, and gathered data from a fourth.

All of the waterjetting equipment was supplied by Commonwealth Waterjetting Group, Jamestown, RI.

Commonwealth also provided training and technical support since this was the first time the contractor performed UHP waterjetting.

The production rate observed for waterjetting in New Hampshire was approximately 142 ft2/man-hr.

Waterjetting produces no dust, which means that less personal protective equipment is necessary to maintain adequate worker health and safety.

The lead levels sampled during waterjetting never reached the permissible exposure limit of 50 g/m3, however, the measurement techniques may not be optimized to sample water mist.3 Weather affects waterjetting different from dry abrasive blasting.

The Joint SSPC/NACE Task Group on Surface Preparation is currently reviewing the criteria and requirements for flash rusting, as “light” flash rusting is not considered to have a detrimental impact on the performance of the coating system.

The current state-of-practice for a spot repair scenario is hand-tool/power-tool cleaning.

However, in order to make a comparison of waterjetting to the current state-of-practice for a spot repair scenario, consideration must be given to the extent of coating deterioration.

On many highway overpasses, bridge painting is an inconvenience to the travelling public as well as a safety hazard.

Therefore, a concept called “Rapid DeploymentSM” has been developed to reduce these inconveniences and hazards.

The main objective of the concept is to mobilize all equipment to the site, blast and paint, and incrementally demobilize all equipment from the site; all in one over-night working shift.

A timeline, which depicts one night’s work and inspection points (one mobilization), is shown in Figure 4 in Appendix A. The contractor began the night’s work by setting up traffic control devices followed by the mobilization of the work platform, an ARK® Overpass Master, towed by a large box truck that housed the paint equipment.

After the final coat was applied, the crew began to remove the containment and touchup any areas that were damaged during the containment removal.

1. To perform the work under time constraints, the contractor must be well equipped, have skilled workers, and have a strong knowledge of what it takes to perform the necessary Rapid DeploymentSM work schedule.

4. Since all coats are applied in one shift and containment is not removed until after the last coat has been applied, there is little chance for surface contamination between coats.

5. Rapid DeploymentSM with one blasting/painting crew (two blasters, one foreman, one helper) is most cost effective on overpasses with paintable area under ~25,000 ft2 when compared to conventional operations.

8. The long term performance of the two coat system with a cure accelerant versus traditional three coat systems without accelerant is as yet unknown.