Micropiles
and other deep foundation solutions are employed to transfer the load
of a structure to a stronger subsoil layer. Before installing deep
foundations, geotechnical engineers need to study the site location and
soil sensitivity, and determine the budget and amount of time allotted
for the project. Once the requirements are established, it's time to
weigh and choose from the different solutions.
Micropiles
Made
of steel with diameters from 60 to 200 mm, micropiles can be installed
on almost any subsurface condition and on sites with restricted access.
They're often used for underpinning. Hollow bar micropiles are a variant
that are suited to collapsible soils.
Caissons
Also
called drilled shafts, drilled piers, or bored piles, caissons can
easily carry heavy loads because they allow larger diameter piles. They
also enable construction in dense or hard strata. A variation,
mini-caissons, can be employed in dense urban locations.
Helical Piles
Also
known as screw piles, helical piles and anchors have been used in
construction for over 200 years. The piles consist of central shaft with
helix-shaped flights or plates and a bracket that can be attached to a
structure. The system can be used for new construction or retrofit
applications. Their installation doesn't generate spoils, doesn't
require a curing period before load testing, and can be done even in bad
weather.
Continuous Flight Augur Piles
CFA
piles or augercast piles are often used for sensitive sites because
it's quick, requires no casing, and creates minimal disturbance. A
hollow auger is drilled to the required depth and a cement grout mix is
immediately pumped down to create the pile.
When
two or more options are both feasible, choosing the most suitable
method can be difficult, unless tempered with considerable practical
experience. An established geotechnical services firm can install the
deep foundation on time and on budget, and possesses the tools and
experience needed to select and apply the most appropriate solution.
To learn more about deep foundation, visit www.moretrench.com.
