SYSTEMS IN PIN FOUNDATION
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.
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.
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.
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.
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 dutyair 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.