Deep Foundations
Pioneering Stability in Construction
A.H. Beck Foundation Company specializes in crafting deep foundation solutions that are not just about depth but are meticulously designed to meet the unique needs and specifications of each project. Our proficiency extends across a multitude of deep foundation techniques, enabling us to propose solutions that are technically advanced and economically beneficial. Whether the requirement is piling, drilling, or any other specialized foundation method, we bring a wealth of experience and precision to every project.
Drilled Shafts
Drilled shaft foundations are a very established deep foundation technology. They are constructed typically by excavating a 3-12 ft in diameter hole and constructing a cast-in-place reinforced concrete foundation within the hole, typically by placing in the steel reinforcement and subsequently pouring in concrete (very commonly using Tremie pipes).
These foundation systems have excellent axial capacity due to a combination of side shearing and end bearing resistance. The size of the foundations also allows for significant resistance to lateral and overturning loads. Drilled commonly reach depths of up to 200 ft and may extend to 300 ft or more.
Tampa International Airport Red Side Expansion
Hensel Phelps Construction Co. contracted A.H. Beck to install the drilled shaft foundations for their Red Side Terminal expansion at Tampa International Airport. A.H. Beck was tasked with installing 145 drilled shafts, varying in diameter, with depths ranging from 15 to 80 feet socketed into Florida Limestone. There were many challenges posed on the project due to congested work areas, dense utility networks, and low overhead restrictions. Beck utilized one of their CAT based drill rigs tailored for low headroom and demanding rock excavation techniques to install the foundations.
US 181 Harbor Bridge Replacement
For the US 181 Harbor Bridge replacement project in Corpus Christi, TX the two main pylons feature 538-foot towers which are currently partially constructed. Each pylon is supported by 21 shafts measuring 10 feet in diameter, drilled to a depth of 230 feet which were installed by A.H. Beck in 2017/2018. A.H. Beck was brought back in 2023 to install additional shafts to supplement the existing pylon foundations. 48-inch diameter shafts along the north and south perimeter of the pylon footings were installed each to a depth of 230 feet. The shafts were installed underneath previously constructed portions of the bridge deck and in coordination with the ongoing construction of the pylon and bridge deck erection.
Augercast Piles
Augercast piles are installed by drilling with a hollow stem, initially plugged, continuously flighted auger to design depth.The plug is then ejected and a high strength sand-cement grout is pumped into the hole as the auger is slowly withdrawn. Dependant on the injection and withdrawal rates, the grout may displace the existing soils optimizing bearing properties.
Limited reinforcing steel can be installed or vibrated down into the fresh grout once completed. The resulting grout column subsequently hardens and forms an augercast pile. Pile diameters of 12 to 18 inches are most common for augercast type piles, with the diameters up to about 36 inches possible. Augercast pile advantages include not requiring casing or slurry for their construction, speed of installation and cost. Augercast piles have the disadvantages of being constructed at smaller diameters and thus lesser capacities, and have limited reinforcement capabilities.
Lynchburg Renewable Energy
In the Lynchburg Renewables project, Dorado Construction Group contracted A.H. Beck for ground improvement to support seven tanks at a renewable fuel plant. A.H. Beck installed 1694 rigid inclusions, 16 inches in diameter, reaching depths between 10 and 30 feet into karst limestone. They also designed a load transfer platform between the inclusions and tank slab. Two high strain dynamic tests were completed prior to production installation to prove the engineering design capacities.
Bushy Park Peaking Modernization
Burns and McDonnell Engineering Company contracted A.H. Beck to complete the deep foundation work for Dominion Energy South Carolina’s new gas turbine. A.H. Beck installed 403 each 50 to 60-foot deep augercast piles through difficult ground conditions within confined work areas of the existing facility. Due to the proximity of the Black and Cooper rivers, weather monitoring and environmentally conscious construction methods were employed throughout the project to ensure a timely and safe delivery.
Low Headroom Shafts and Piles
In many cases, construction sequencing or other existing infrastructure restrictions provide little room and especially airspace for the construction of piles. In these cases, specialized, compact, but powerful equipment may be needed and particular attention is needed on the construction process to ensure the safety of the workers, the stability of the existing infrastructure, and the high quality of construction.
Tampa International Airport Red Side Expansion
Hensel Phelps Construction Co. contracted A.H. Beck to install the drilled shaft foundations for their Red Side Terminal expansion at Tampa International Airport. A.H. Beck was tasked with installing 145 drilled shafts, varying in diameter, with depths ranging from 15 to 80 feet socketed into Florida Limestone. There were many challenges posed on the project due to congested work areas, dense utility networks, and low overhead restrictions. Beck utilized one of their CAT based drill rigs tailored for low headroom and demanding rock excavation techniques to install the foundations.
Miami SR 836 Bridge
Working with Archer Western – De Moya Joint Venture, A.H. Beck installed drilled shaft foundations for Miami’s SR 836 Signature Bridge, a project for Miami-Dade Expressway Authority and FDOT. The shafts were located underneath and between the existing bridge spans in the Miami river and had to be accessed via trestle. Using the CAT based Beck 250 drill rig, they placed 48-inch diameter 90-foot deep shafts between the existing bridge structure adjacent to the existing bridge foundations. To protect the existing structures, full-length temporary casing was advanced with an oscillator through the sand and limestone layers.
Displacement piles
Displacement piles are a specialized deep foundation technique, constructed by advancing a distinct displacement tool with a high-torque drilling platform into the ground. Especially effective in soils from loose to medium density, this method enhances shaft friction, allowing for the installation of shorter or more robust piles compared to conventional augered ones. Notably producing minimal spoils, it’s ideal for areas with contaminated soils or urban locales where spoil removal is costly.
Driven Piles
Piles are used to transfer surface loads to a competent soil or rock at depth when the surface layer is not adequate or is not economically feasible to use.This load transfer may be by vertical distribution of the load along the pile shaft (skin friction) or a direct application of load to a lower stratum through the pile point (end-bearing). Piles can also serve to carry lateral, uplift and overturning loads. Driven piles are typically delivered to construction sites prefabricated and consist of either reinforced, pre- or post-tensioned concrete, timber, open- or closed-ended steel pipe or H-beams. Diesel hammers are the most common driving mechanism used to drive piles although other driving methods are seldom used. A primary drawback to driving piles is the large noise and vibration associated with this form of deep foundation construction.
Driven piles are typically of small diameter and are often grouped into clusters or rows. The pile groups are then tied together using pile caps or grade beams that carry the column and wall loads. An indicator pile program can be conducted at the onset of construction using a pile driving analyzer, to help correlate driving energies and capacities, and optimize design.
Helical pile
The shafts are advanced to bearing depth by twisting them into the soil while monitoring torque to estimate the pile capacity.
The helical pile system is a deep foundation system that consists of helical bearing plates around a central shaft. They are advanced to bearing depth by being screwed in the soil with minimal disturbance. By monitoring the torque necessary to install them, the pile capacity can also be estimated. Once installed the loads from the superstructure are transferred from the pile to the soil through the helical bearing plates.
Post Grouted Drilled Shafts
Post grouted drilled shafts are essentially drilled shafts that have an increased end bearing capacity compared to conventionally constructed drilled shafts. This is achieved by pressure grouting beneath the shaft tip. A major advantage of the post grouted drilled shafts is that they typically mobilize their tip capacity at lower displacements.
Micro Piles
Micro Piles are small diameter piles that can be installed in a variety of soils from non-cohesive, poorly-graded granular soils, to cohesive plastic clays. Also known as mini piles, pin piles, needle piles or root piles, micro piles can offer a viable alternative to conventional piling techniques, particularly in restricted access or low headroom situations.
A micro pile foundation system may be advantageous in areas where large boulders are sporadic in the subsurface, as the small diameter micro piles may be able to be installed around such boulders. Micro piles are installed using water flush rotary drilling or rotary percussion drilling techniques. Measuring between 6 and 12 inches in diameter, micro piles consistently achieve capacities of 20 to 100 tons, with special installations up to 200 tons. Micro pile drilling methods generate minimal disturbance or vibration to adjacent structures, making micro piles an excellent underpinning alternative.
Rock Anchors
Post-tensioned rock and concrete anchors consist of high tensile strength bars or strands installed in drilled holes which are subsequently tensioned.The anchors provide lateral and vertical load capacity for the installed structures to resist movement. The anchor bottom is bonded to rock or concrete by a cement grout, resin, or can be fixed by a mechanical anchor. The upper portion, or free length, is initially left ungrouted for prestressing; then subsequently grouted to lock in the tension and provide additional corrosion resistance. Rock anchors are used as a cost effective solution to tie down and tie back dams, towers, bridges and other critical structures, for seismic retrofitting, to anchor raft foundations below the groundwater table, and to secure caisson bottoms. Anchors have the design advantage of being able to provide support at hundreds of feet in depth with relatively limited access and disturbance. Corrosion resistant anchors are also available should the project be located in a harshly corrosive environment.
