Supporting the Northeast since 1966
Our construction services include multiple areas of expertise to tackle a wide variety of drilling needs.
A good foundation is necessary for the success of any project. Hub has the experience you need to get the job done right the first time.
Drilled shafts are high capacity foundation elements used for large bridges, high-rise buildings, and other extreme loading conditions. A hole is drilled typically using a temporary or permanent steel casing and an auger or digging bucket, as well as other tools for specific situations. A caisson can be developed in the same manner by driving or oscillating and then digging out the shaft using a spherical grab and chisel. Diameters of these shafts range from 18 inches to upwards of 12 feet. These shafts develop their load-bearing capacity by end bearing and/or friction—end bearing and friction in sound rock, with additional friction load developed in clay, and, or till. Hub has an extensive line of deep foundation drilling equipment and the ability to adapt and overcome the industries greatest challenges.
Drilled micropiles (DMPs) range from 4 to 12 inches in diameter. They are used where other deep foundation elements are not feasible due to access, headroom, or inability to support heavy equipment, or for loads that do not require the capacity of a drilled shaft. DMPs are the most versatile of the deep foundation elements. Projects can be performed in existing structures, basements, and alleys. They can be used for high and low capacities, for large or small overall foundations, on unrestricted or the most highly confined sites. The management of spoils with berms, remote settling tanks, and diverters is coordinated with the site contractor and owner for efficiency, and the ability to minimize the mess typically expected with microdrilling jobs has become a part of the system, especially when working in occupied indoor spaces. Hub performs pile load tests meeting both job specific and local requirements. Our fleet of four colloidal grout mixers, operated by trained personnel, yield typical grout strengths of 6,500 to 7,500 psi. Many employees have attended a 40-hour grout school at the Colorado School of Mines. Hub has innovated new designs, installation methods, and logistics practices to meet demanding schedules and overcome the challenges of the modern jobsite.
Drilled in place H-beams or drilled micropiles (DMPs) are used in conjunction with lagging, walers and tie-backs for support of excavation and earth retaining systems. Drilled in placed H-beams accommodate drilling through obstructions, dense till, and bedrock while obtaining the necessary embedment required for these applications where driving or vibrating a beam is not possible. H-beams can be placed to high tolerances due to the ability to adjust the location before placing the concrete in the hole. Flowable fill is typically used to fill the excavation from top of concrete to grade after the H-beam and concrete are placed. This fill provides safety to ground crews and allows for efficient excavation and lagging. H-beams can be installed using a vibratory hammer provided the soil conditions and neighborhood are conducive to such a method. The use of DMPs for SOE can be very effective for limited access, low overhead, and efficient and timely installs. In many cases, multiple techniques are used for a single site due to diverse soil and rock conditions.
Tiebacks follow the same concept as rock anchors but can be terminated in soils as well. Tiebacks are also post-tensioned, and Hub tests and locks off the ties installed. Installations can be with solid or hollow steel bar, or with stranded anchor systems. Hub has performed several challenging tieback jobs and has developed specialty equipment unique to the industry to overcome some of the most demanding access issues met in these projects.
Secant piles are a series of drilled shafts in a sequence where one shaft is drilled in between and through part of two adjacent shafts. This creates a waterproof barrier or cutoff wall. Tangent piles are a series of drilled shafts placed one right next to another. Secant drilling can be used to remove contaminated soils from a precise area and depth. They can also be used as a SOE wall or a foundation wall in lieu of a slurry wall.
Soil nails and shotcrete are ways of stabilizing walls. Soil nails, reinforcing steel or tendons, are drilled and grouted or hammered into the slope to reinforce it. Shotcrete facing is then installed pneumatically by a high pressure hose over the wall to keep the soils in place. The high pressures and velocity of the shotcrete pump allows the concrete to be compacted onto the surface and make a strong, stable surface on contact. The area is then finished and smoothed.
Rock Anchors are small diameter holes drilled into rock with a tendon or other steel bar placed inside with a high-strength grout. Anchors can be used where significant uplift or overturning must be overcome and in extremely hard rock or other conditions where drilling a deep large diameter hole would not be cost effective. Rock anchors are post-tensioned units and Hub performs post tensioning and testing. Hub has installed rock anchors for Wynn Casino, monopole foundations, granite block abutment rehabilitations, observation towers, utility towers and other projects where direct transfer to bedrock in a safe and predictable manner were required.
Helical piles are a foundation system where loads are transferred to the soil through bearing plates that are welded to a central steel shaft. Depending on the soil conditions, helical piles can be a cost effective way to install a deep foundation. Hub has installed helical piles for bike paths, buildings, at train stations, and at Logan Airport.
slurry walls, otherwise known as diaphragm walls, are foundation elements that are created by a series of rectangular panels that interlock. Each panel can go to depths of over 100' and are stabilized by a thick bentonite slurry, which is pumped back to a desanding system and reused, and then concreted with a rebar cage. The resulting foundation can be used as either a cutoff wall or a structural wall. Load Bearing Elements (LBE's) are a single panel of the cutter and are used in lieu of a drilled shaft on projects where the cutter is already on site. In both cases the softer soils are removed by a bucket or grab and the cutter is then used to remove the till and/or rock, depending on the depths needed.
Hub Foundation Co., Inc.
139 Billerica Rd.
Chelmsford, MA 01824