Not all repairs require the same solution. Different soils and site conditions require different techniques. As a structural specialty contractor, Terratec is able to provide professional project assessment, planning, and services using a variety of current geotechnical technologies and applications.
Micro-piles are another engineered technique to underpin buildings and bridge foundations. In most installations, these piles are quickly and efficiently installed to depths in excess of 100 feet. A typical micro-pile is very cost effective compared to many other traditional methods of underpinning a foundation. Terratec employs state-of-the-art equipment and methods to install many different types of micro-piles, including hollow bar and auger-cast types. Unlike other manufactured products, micro-piles are produced in the field, which requires steady attention to quality and varying site conditions, as well as volumes of experience to meet and overcome obstacles. The use of micro-piles is greatly preferred where larger design loads are required and where unknown site conditions are prevalent.
Stone Columns offer an inexpensive alternative to most pile applications, provided soil conditions and anticipated load applications are suitable. By placing stone in an excavated hole in the ground and consolidating the stone with large tamps, the soil is able to support structures that it could not before augmentation. More recently, stone and sand columns have been utilized as an effective design tool to mitigate and improve seismically challenged sites, in addition to providing less expensive ground improvement for foundation support.
Terratec offers various wall and earth anchoring tieback systems specifically designed for earth retention, providing additional stability on geotechnical and remedial projects. When additional support is required for retaining walls, excavations, abutments, structures, and other support systems, mechanical and grouted anchors offer an effective reinforcement solution. Designed with many different factors in mind, solutions are customized to meet exact project requirements. Terratec follows a strict testing and lock-off procedure design to ensure performance levels above specifications.
Helical Piers, like guy wires for radio, power, and phone towers, use helical shaped screw ties as a tieback into earth slopes or vertical excavations. The helical piers are rotated into the soil in a clockwise direction until the design torque is achieved. There is a direct correlation of torque to pull-out capacity in each installed pier. In essence, each pier is load tested as it is installed.
Blade Rotation Tiebacks consist of a flat blade connected to a high strength wire rope or steel rod which is normally air driven into the soil. Once the design depth is reached, the wire rope or steel rod is hydraulically pulled and load tested for design capacity. It is then mechanically connected to a flat plate. Blade rotation tiebacks can be an inexpensive solution to an earth anchor problem; however, they do not have the higher capacities of the other tieback systems.
Soil Anchors/Nails are constructed by drilling and injecting grout into the soil in order to develop the soil friction required to resist pull out forces. These anchors/nails are constructed using many different techniques, and are only dissimilar to micro-piles in that they are installed along the horizontal axis and are primarily designed for the development of soil friction, with no end bearing design element included.
Concrete “Dead Men” is another method of installing a tieback system which has been used for many years. This particular technology normally involves the construction of a large reinforced concrete “dead man” with wire rope attached and covered by lifts of compacted soil. The construction can be repeated for as many lifts necessary to complete, for example, a retaining wall.
Pressure injection grouting is a known and proven method of construction to stabilize and improve soil bearing capacities and to control or cut off water flow through soils. Terratec utilizes both chemicals and cements, and combinations of both, to solve different soils and water-related problems. Terratec’s experience of over 30 years with injected grouts has made it possible for the company to be very successful on grouting programs.
Chemical Grouts number in the hundreds—each type has a different molecular makeup used for different applications, and each type has different means and methods of application. Experience with the characteristics and placement of these grouts is essential to the success of the project.
Cementitious Grouts have a limited range of applications, but are much less expensive than chemical grouts. This is especially true on high-volume projects which normally have the criteria that cements can fulfill. As with chemical grouts, experience with pumping and grout-take volumes plays a big part in the actual placement of the grout, and in the case of cements, this is a significant factor.
And of course, combining chemicals with cements gives the designer the opportunity to take advantage of the characteristics of the chemicals and the cost effectiveness of the cements on high-volume projects.
Slab jacking is a pressure grouting technique used to lift and stabilize sunken slabs of concrete. Chemical and cement grouts are typically injected beneath the slab through small diameter holes drilled through the concrete. There are also several patented systems on the market utilizing hydraulically driven piers that can offer not only lifting and leveling benefits, but also added load carrying capability in areas of poor soil support. These repairs can be time-saving and less intrusive than replacing concrete inside a structures or on highway pavements. Terratec is able to provide professional project assessment, planning, and services using slab jacking with pressure grout, hydraulically driven piers, or a combination of both techniques.
Cement Slab Jacking is dependent on the pressure of the pump to “lift” the slab back into place. After the lift is achieved, the grout injection hole is quickly plugged. The cement grout is normally allowed a minimum of 24 hours to gain sufficient strength to hold the slab in place before vehicular traffic or other heavy loading is allowed.
Chemical Slab Jacking utilizes an expansive chemical grout. Although chemical slab jacking can be expensive, it normally allows heavy loading very quickly.
Hydraulically Installed Steel Piers are mechanically attached to the slab after lift is achieved. This method of slab jacking can be less expensive than chemical jacking but takes more time for installation. This is an excellent application when the addition of equipment is a part of the design. Once lifted, there typically is some cement grouting beneath the slab to regain soil bearing characteristics.
Over the years Terratec has designed and installed various dewatering systems as part of our work in soils stabilization. Ground water migration through porous soils can have a devastating effect on structures and general construction excavations. Terratec can provide investigation, design, and installation of dewatering systems for temporary and permanent solutions to ground water problems. Systems that we routinely design and install include horizontal systems (underdrains and French drains) and vertical systems (well points and sumps).
In addition to soil and foundation stabilization and strengthening, Terratec has offered our clients complete foundation support systems to include the construction of the foundations themselves. Normally these projects consist of difficult foundation designs which are dependent on deep foundation support.
Concrete restoration of walls, floors, columns, and beams has been a big part of Terratec’s growth for the past 30 years. Concrete can crack, separate, and produce spalls (popping off in large pieces), and in general deteriorate and loose valuable design strength. The products that have been introduced into the market offer technologies which make repair and restoration stronger than the original design. Means and methods can be as simple as applying a modified polymer concrete to cosmetically repair and protect walls, columns, and beams, and injecting epoxy to “weld” cracks back together and protect rebar from moisture intrusion. Whatever the problem, Terratec has the experience and installation knowledge to bring concrete back to its original intended design.
Along with concrete restoration of concrete foundations, walls, beams, and columns, Terratec has developed experience and knowledge in reinforced concrete pipe (RCP) repair. Not only can RCP be restored to its original strengths (and water cut off), but also the surrounding soils and bedding can be strengthened to provide longer service life for the pipe. This work is performed both inside and outside the pipe. Practically all of the chemical and cement grouts, epoxy injection materials, and coatings can come into play in an RCP restoration. This work normally requires close coordination with the owner, engineers, and OSHA. Terratec can also design and install any necessary shoring, if required for the project.
Many times in deep excavations, especially in cities, the use of sheet piling is prohibitive. On many occasions Terratec has been contracted to construct reinforced gunite wall shoring systems in combination with earth tiebacks. These walls are typically constructed in concert with the general construction excavations. Terratec can provide geotechnical review and analysis, design, coordination with the general contractor, and installation.
Because on the nature of our business, Terratec has the equipment and driller certifications to provide drilling services such as well design and installation, well closure, and drilling small and large diameter holes in soils and rock. A large part of Terratec’s stabilization and repair business utilizes drilling services which are performed in-house to offer our client single-source turnkey responsibility.
There is an innovative technique which has been developed to economically improve soil bearing over large areas. This technique appears unsophisticated; however, it has been substantiated with volumes of geotechnical data and successful projects. Simply put, Deep Dynamic Compaction, as some would say “ground pounding”, consists of dropping (free fall) a large weight from various heights by utilizing a proper crane. There is a direct relationship of the weight, height from which the weight is dropped, and the soil conditions one would like to improve. Terratec has completed numerous projects requiring different levels of ground improvement. We can provide the geotechnical investigation, design, and performance to improve the usability of your site at an economical cost.