Field Inspection. Bosch 11335K - 35 lb. Demolition Breaker Hammer

FIELD INSPECTION

A Diamond Pier foundation code inspection may take place at any time during or after installation and may be combined with the structural framing inspection as each jurisdiction warrants. The top ends of all pins should be accessible for measuring pin lengths.

Pin Length

Diamond pier foundations are designed to be inspected from above grade after they have been installed.

An inspection plug must be installed at the lower (driven) end of the pin to keep soils from moving up inside it and to allow a tape measure to be slid down from the top of the installed pin to verify its length

(see “Inspection Plugs” on page 16).

NOTE: The Diamond Pier system is a shallow bearing technology and does not require “refusal” or

“friction” resistance, or the professional installation monitoring or special inspection typically associated with conventional vertical or battered piling.

NOTE: If framing members will be too close to the top of the pier to allow the tape measure to be inserted, then the inspection should be done before the framing is in place. Also, if inspection plugs have been unintentionally forgotten, then the pins can be twisted or jacked out with a pipe wrench to verify

their length (see “Removing Pins” on page 12). They can then be redriven into the same soil cavity. If a plug has been removed to facilitate driving in an obstructed condition (see "Encountering Obstructions," page 12), be sure to note or mark the location of this pin for the inspector. Pins are to be their full

specified length without joints or coupling (length tolerance is ±1/2”).

Pin Specifications

Bearing pins provided with the piers are schedule 40 galvanized pipe, Grade A electric resistance welded, with no threads. This also can be verified from above grade; with the rubber cap removed, the weld can be verified on the inside wall of the pin, and the wall thickness can be checked. If the wall thickness is thinner than specified, the pins have been substituted with a lower schedule pipe or conduit and must be replaced with the properly specified pipe—1” nominal schedule 40 pipe has a wall thickness of 0.133” (just over 1/8”), 1-1/4” nominal schedule 40 pipe has a wall thickness of 0.140”. The wall thickness tolerance is ±12%.

Pier Integrity

If the Installation Instructions are properly followed, the piers should be level, and they should not have structural cracks as a result of improper handling or pin driving. (Surface spalls or chips may occur during driving or handling, but these are not structural, and will not affect the pier.) A structural crack is a fissure running internally into the pier. It is perpendicular to the outer face of the pier and heads inward to the pier core. This can weaken the pier strength and/or allow water to penetrate and cause freeze/thaw problems in the concrete. If a pier is more than 5 degrees out of level, the symmetry of the pin pairs may be compromised, and the pier should be removed and correctly reinstalled. If a pier has a structural crack, it should NOT be patched. It must be removed and replaced.

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Installation Manual 15

Allowable Capacity

The piers should not be overloaded. The total load on any specific pier is based on the individual tributary loads of the structure, supported by the corresponding post or beam connected to the pier. This weight is a combination of the live load (snow, people, furnishings) and the dead load (weight of structure itself). Therefore the total tributary load can be expressed in pounds per square foot (psf) as the

area X total load (live load plus dead load). This value should not exceed the published capacity of the

Diamond Pier model and corresponding pin length intended for use.

Inspection Plugs

Hard plastic plugs are inserted in the bottom of each bearing pin prior to installation to keep soil from moving up inside the pins as they are driven into the ground. This allows inspectors to slide a tape measure down a pin from above to verify its length. You may also check with your building official or local inspector for other acceptable methods for verifying pin length.

Align the slot in the plug with the interior weld bead and insert (see Figure 8). The allowable tolerance in

pin wall thickness means that some plugs will fit high in the end of the pin, and some will fit down almost to the plug shoulder. In either case, tap the point of the plug with a hammer to seat it firmly enough in the end of the pin so that it will not drop out as you slide it through the driving holes in the pier. Don’t worry that tapping the end of the plug with the hammer will blunt the point; it is not intended as a piercing or

cutting tip, and this will happen anyway as the plug is driven into the soil. (See see "Encountering

Obstructions," page 12, for plug use where buried obstructions may be encountered.)

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Figure 8. Inspection Plugs

Diamond Pier

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Installation Manual