PIN FOUNDATION
SYSTEMS IN PIN FOUNDATION
WALL SYSTEM
These unique foundations are simple to construct by inserting a patented
steel head collar into standard plywood or non-celled forms. A conventional
concrete wall is cast without footing. Once the concrete has set and the forms
are removed, small steel bearing pins are driven through the opening created by
embedded collar head into the bearing soils below the wall. The concrete wall
acts like a beam that spans from one collar head to next and the two bearing
pins at each head collar transfers the load. The bearing pins are driven by
hand held or machine mounted jack hammer generally 1.22- 2.13 metres (4-7 feet)
into the soil. The spacing of the pin pairs along the wall are determined by
analysis of framing loads of the structure, and the length of pins depends on
the strength and driving potential of the side soil.
A buffer material separates the base of the stem walls from the surface
soil. So that any potential frost or expansion is not transferred to the wall.
PLANNING OF PIN FOUNDATION
A pin foundation can be used virtually everywhere, but there are a few
considerations during the planning phase.
SITE
Make sure that the piers are located far enough away from the
obstructions leaving enough space around the pier to drive the pins, also
substructures need to be identified, so piers are set far enough away to allow
full penetration of the pins without interference. Vegetation in the area with
significant roots can be avoided by spinning the piers, so the pins miss large
roots. Diamond piers can accommodate sloping sites, but slopes greater 2:1 make
it difficult to install diamond piers because the downhill pin can’t get much
of a bite into the soil. It is possible to dig the pier into the hill side to
improve the cover on the downhill pin. But the upside of hill needs to cut back
enough to facilitate the installation of the pins.
SOIL
The diamond pier will work in many soil type including clays, silt, sand
and gravel. The properties of different soil types affect the bearing capacity
of diamond pier. The type of soil also affects the length of pin required. It
is important to identify the soil within the typical pin depths. Typically
.6-1.52m(2-5 feet)below the ground surface, but need not involve a testing lab
or expensive coring equipment generally one or two observations is sufficient
for a small project. For high capacity project using DP-100 piers project in
poor soils, a geotechnical evaluation may be required. Most local geotechnical
engineers can make these determinations with a single field visit or be able to
determine the information from regional soil survey or previous soil studies
done on site. For determining load capacity an engineer must require angle of
internal friction.
STRUCTURE
The pier capacity developed in the soil will determine the spacing for
individual diamond piers at post or beam locations. These spacing are
determined from framing layouts, the dead and live loads which are distributed
to the piers. Tall posts need adequate bracing to prevent side sway.
APPLICATION
Diamond Pier can support just about any structure that will connect to a
post or beam bracket. Deck, porches, carports, walkways, ramps, stairs, sheds
etc. Diamond Pier's lightweight components and ease of installation makes it
the first choice for any project. Set the pier, drive the pins, connect the
bracket, and start building. It is that easy. On gentle slopes, series of piers
may be set at different heights to adjust for level. The pin foundation also
uses 40 percent less concrete than conventional foundations.
ADVANTAGES OF PIN FOUNDATION
Pin foundation systems allow the construction of structures with
substantial loads in areas with soft soils or in places where existing
groundcover retention is desired. Construction requires a heavy duty air
compressor and minor labour without any assistance from large machinery.
Specific benefits are:
- · It can be installed in areas with poor soils/drainage.
- · It provides high point-load bearing capacity.
- · It requires minimal disturbance and equipment for installation.
- · It requires minimal material.
- · It can be used in areas of subsurface obstructions or difficult ground.
- · It can be used in case of limited overhead clearance.
- · It can be used in vibration or noise sensitive area.
- · It is used to install elements in close proximity to or through existing footing, columns, walls, or other structures.
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