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On January 15, 2009, Shaw Brothers Construction, Inc. was awarded the City of Portland contract to construct Phase II of the Fall Brook Watershed Improvements Project, located in the North End of Portland. This project is part of a multi-year, three phase infrastructure improvement project located within the Fall Brook Watershed. This phase of the project was designed to close the open storm drain system running along Maine Avenue and the Mona Bernard Neighborhood as well as separating the combined storm and sanitary sewer flows along the corridor. With this project complete the continuous street and house flooding that plagued this neighborhood would be eliminated and the City of Portland would be one step closer to meeting their goal of storm water and sanitary sewer separation.
 Of the various challenges that Shaw Brothers Construction had to overcome, the biggest challenge was the removal of 6,000cy of ledge within a highly residential area that also contained a 200 bed nursing home (St. Joseph’s Manor). Compounding the ledge removal issue was a 72 inch sewer main, carrying almost all of Portland’s North End’s sewerage, located in the middle of the narrow right of way between 2 box culverts that needed to be installed. The project team decided early on that the only way to remove the ledge safely on such a restricted site was through the use of hydraulic hammers. Utilizing hydraulic hammers was the least efficient ledge removal process but allowed the greatest flexibility. This would allow us to protect the resident’s homes from damage and allow for continued and uninterrupted operation of St. Joseph’s Manor whose only vehicle access ran through the middle of the project. We were also able to start the project immediately by eliminating time consuming pre blast inspections. It was not unusual to see 4 excavators all working with hydraulic hammers during this phase of the project.
Another challenge encountered by the project team was how to handle and place the (475) eight by five foot box sections, all weighing approximately 24,000 lbs, while maintaining access to the site for other construction activities. Most contractors would have handled these heavy loads with a crane but because Shaw Brothers owned a 650 Hitachi excavator (132,000 lbs) we were not only able to offload these sections but transport them down the pipe trench and set them with efficiency. Without such a large excavator we would have had to construct a haul road for adequate truck access and would have had multiple time consuming crane setups in order to place the culvert sections. Utilizing the Hitachi 650 excavator was a real time saver.
The 72” sewer main located between boxes B and C within the construction right of way presented yet another challenge for the team.The top of the 72” pipe was approximately 2 feet below the invert of the new box culverts and centered between box B and box C.We were very concerned about crushing or damaging the sewer main as we excavated for and placed the box sections.To further complicate the issue we ran into heavy blue marine clay, which needed to be over excavated by 2 feet and replaced with stone.The only way it was possible to set these boxes and cross over the 72” main without damaging it was to use crane mats to disperse the weight of the excavator and the boxes.Even with the crane mats in place, the project team took additional time to make sure the 72” pipe remained in service.With these measures in place it was still a very time consuming process.
The Shaw Brothers team that accepted this challenge was Jon and Dan Shaw, Project Managers Bruce Brown and Bob Brady, Superintendents Jeff Fay and Justin Loveitt and their crews.Critical vendors included American Concrete Industries who supplied all the box culvert sections and Hydro International who supplied the Downstream Defender.American Concrete was outstanding as they started form preparation and set up work ahead of shop drawing approvals at their own risk.This allowed for an immediate start and they were able to make 10 castings per day and 5 on Saturdays to keep up with Shaw Brothers’ demands.They utilized both of their plants, Auburn and Veazie, which allowed tractor and trailers to head north with reinforcing cages and head south with finished products.Hydro International provided the Downstream Defender which is an advanced hydrodynamic separator that uses vortex motion of the water flow path to remove suspended solids and floatable pollutants such as oil and trash, in a much smaller footprint than would otherwise be required by conventional means.The production and installation went flawlessly thanks to Hydro Internationals perseverance and attention to detail.
A project of this magnitude could not have been successfully completed without the support and cooperation of everyone involved.A very special thanks goes out to Nathaniel Smith and his crew at the City of Portland for their urgency in getting a contract signed and allowing us to start work in January.Their continued support during the course of the project was much appreciated.We would also like to thank Sebago Technics for their design work, along with Unitil and the Portland Water District for their efforts in working with us to relocate existing utilities.All of these entities came together and worked as a team to get the project completed safely efficiently and ahead of schedule.
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Site Work