Utility contractors face some of the most challenging job site conditions and restrictions. Baltazar Contractors Inc., Ludlow, Mass., is used to taking on tough utility projects. The multi-facetted contractor is experienced in deep utility installations, including large diameter pipe, manhole structures, and more.
A recent project in Newington, Conn., put the Baltazar team to the test. With significant work restrictions in place, Baltazar was contracted to install two 36-inch casings under highly traveled Route 175 (Cedar Street) to house new water and sewer mains. However, work schedules and lane closure restrictions placed on the project by the Connecticut Department of Transportation (DOT) meant that Baltazar would need to employ a pipe installation method that would limit disruption and work efficiently in tight conditions. Pneumatic pipe ramming was ultimately selected.
Baltazar project manager Kyle Murphy said, “The pipe ramming method worked ideally for this application because we could keep a narrow pit. Route 175 is a four-lane, heavily traveled roadway. Originally, the design called for pipe jacking, but the DOT and town did not desire the road to be closed for any period of time, nor would it permit a large pipe jacking pit. The roadway needed to be completely open at the end of every day.”
Pipe ramming specialist Ric Micelotta with trenchless equipment manufacturer TT Technologies, Aurora, Ill., helped in specifying the ramming equipment for the project. Micelotta said, “This project was challenging to say the least. It really demonstrated the high skill set of the Baltazar crews not only from a ramming perspective but an overall project management and execution standpoint. They were very efficient in every aspect of the process from ramming the 36-inch casings to managing the project mandates.”
The project included installing a new water transmission main in order to improve water pressure for area residents. Demand on the area’s sanitary sewer system was also being addressed through the project. The area had been suffering from backups for quite some time and the new, larger sewer main would help alleviate the issues through a much-needed increase in sewer capacity. For the ramming portion, Baltazar Contractors used an 18-inch-diameter Grundoram Goliath to install the steel casings under Route 175.
High Quality Contractor
Baltazar Contractors Inc. is a family-owned and operated construction firm established over twenty years ago. The company prides itself in providing the highest quality work when completing all types of construction projects in an accurate, professional, and timely manner. The company employs over 100 people, seasonally. Baltazar Contractors Inc. is an approved contractor with the Massachusetts Department of Transportation (DOT), as well as the Connecticut DOT and Department of Administrative Services. While specializing in utility work, the company has expanded over the years into road construction and site development.
In addition to conventional construction techniques, Baltazar also incorporates a variety of trenchless pipe installation and rehabilitation methods including slip lining, spiral lining, pipe bursting, and pipe ramming.
Murphy said, “Open cut, that’s our primary, but we understand that in this business, trenchless technology has to go hand in hand, and as a general contractor, we have to look at what works best for our customers and give them the best product whether it is open cut or trenchless. You choose whatever method makes the most sense for the project.”
Safety Is Priority
According to Murphy, safety is priority at Baltazar. “Every winter we do an all-company meeting where we bring everyone together and one of the main focuses is safety. In addition to morning tailgate meetings and toolbox talks, all throughout the off season there are safety training seminars, meetings, etc.,” added Murphy.“ In the spring, we do a start-up meeting with the foreman and superintendents, and in the fall we do a dinner with the management team to go over significant issues relating to safety. We review areas where we can improve, what’s working, and what’s not working. Feedback from the crews in the field plays a big role in this and it’s a critical component. We have a safety incentive program as well for those crews going above and beyond. Safety is taken very seriously here.”
The pipe ramming portion of the project was a smaller part of a larger project that included the installation of a total of 3,800 feet of 20-inch ductile iron water transmission main and 2,400 feet of 18-inch PVC sanitary sewer. For the section that ran under Route 175, Baltazar crews had to contend with some very specific and limiting project constraints.
Murphy said, “We could only work on the road from 8:00 a.m. until 3:00 p.m., so we had to accomplish everything we needed to accomplish that day in a 7-hour shift. But that’s not the least of it. We couldn’t just cover our ramming pits with a standard road plate as that was not allowed. We were required to put a road plate down, then gravel and pave over our trench so that at the end of the day traffic would be driving over asphalt. At one o’clock in the afternoon we’d send a truck to get some mix and had to have it back an hour later so that we could pave and be off the road by three o’clock. Then, every morning we ripped out the asphalt, opened up the pit, rammed pipe and then closed it up and paved over it.”
Pipe Ramming Efficiency
Prior to the project, bore samples were conducted revealing glacial till soils that were conducive to pipe ramming. The project required two ramming pits, each 50 feet in length, one right next to the other. However, Baltazar crews only opened one pit and performed one ram at a time to limit the amount of disruption. The first 36-inch-diameter casing would house the 20-inch ductile iron water transmission main. Next to it, another 36-inch casing would facilitate the 18-inch PVC upgraded sewer line. Each casing traveled under two 54-foot-by-30-inch twin corrugated metal culverts.
Micelotta said, “The crews completed one ram before starting the next. This way they only needed to open one pit at a time, which, given the constraints of the job, allowed things to be manageable. They excavated out a 50-foot pit and used dense graded crushed stone and steel plates to create the ramming platform. To ensure a solid excavation, they poured flowable fill all around the trench box and cut the wood facing on the box to help launch the steel casing.”
Murphy added, “On the other side, where you’d typically have a receiving pit, we did not have a pit because we were about 300 feet away from the intersection where we would make the pipe connections. We used a 30-foot-long H-beam on the ground, positioned on line and grade, that we used as a track for ramming the pipe. We had our surveyors make sure that it was staying on line so that on the other side, when it came time to open up the intersection, we would be able to find the casing and make the pipe connections.”
Once the traffic was routed and the pit established, crews set up for ramming. Crew size for the ramming portion included seven crew members and two welders. Standard ramming gear made the connection between the Goliath and the 36-inch pipe.
Micelotta explained, “For a standard ramming connection, a soil removal cone made the connection between the 36-inch-diameter segmented ram cones and the 18-inch-diameter tool. Because of the limited amount of space in the ramming pit itself, crews rammed 10-foot sections of casing. Casings took anywhere between 20 minutes and an hour to ram into place. Once completed, the next 10-foot casing segment was placed in the pit and welded in place, ready for ramming.”
Even with the limited work schedule and project constraints, the Baltazar crew was able to install both casings within two weeks. For spoil clean out, Baltazar crews used a small skid steer unit that was modified with an auger on the front.
Murphy said, “The unit is able to clean out about 30 feet in one direction. We lowered it down into the ramming pit and augured one way, then used an air spade and shovels to clean out the rest of what we could. Then, when we opened up the intersection and found the other end of the casing, we used the modified skid steer again and cleaned out the rest from that side. From there we installed spacers inside each casing and installed the new pipe one section at a time, restrained joint PVC for the sewer main and restrained joint ductile iron for the water transmission main. Then we grouted the casings after the pipes were installed.”
Micelotta said, “This has to be one of the more challenging ramming projects in terms of site requirements that I have seen in some time. The Baltazar crews were excellent. They made this project a success. Hats off to them!” UP
The Author: Jim Schill is a technical writer based in Mankato, Minn.