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1808.4.1.3 Compressive Load Test Procedures
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Compressive load tests shall be conducted in accordance with ASTM D 1143 standard procedures and the following conditions:
- Dial extensometer gages shall provide readings to the nearest 0.001 inch (0.025 mm). Electrical transducers may be used to make settlement observations, provided that backup measurements are made utilizing dial extensometers as described herein at sufficient times to validate the transducer readings.
- If the allowable axial compressive load is less than or equal to the Basic Maximum Allowable Pile Load in Table 1808.4.1.3, the total test load shall remain in place for a minimum of 12 hours, and shall be held until the average rate of settlement as measured over a 12-hour period does not exceed 0.001 inches (0.025 mm) per hour. The total load shall be removed in decrements not exceeding 25 percent of the total load at 1 hour intervals or longer. For cases where the allowable pile load is greater than the values prescribed in Table 1808.4.1.3, refer to Section 1808.4.1.5.
- In addition to observations required by ASTM D 1143, settlement observations shall be performed 24 hours after the entire test load has been removed.
Exception: A static load test for drilled piles using an embedding load transfer mechanism shall be considered acceptable, provided that the test is performed in general accordance with ASTM D 1143 — Quick Load Test Method. The pile shall be suitably instrumented to evaluate the load transfer through soil or rock at multiple locations along the shaft.
- Any temporary supporting capacity that the soil might provide to the pile during a load test, but which would be dissipated with time, shall be eliminated by casing off or by other suitable means, such as increasing the total test load to account for such temporary capacity.
|TYPE OF PILE||MAXIMUM ALLOWABLE PILE LOAD (TONS)|
|Caisson Piles||No upper limit|
|Open-end pipe (or tube) piles bearing on rock of Class 1a, 1b, or 1c||18-in O.D. and greater||250|
|14-in to 18-in O.D.||200|
|12-in to 14-in O.D.||150|
|10-in to 12-in O.D.||100|
|8-in to 10-in O.D.||60|
|Closed-end pipe (or tube) piles, H-piles, cast-in-place concrete, enlarged base piles, and precast concrete piles bearing on rock of Class 1a, 1b, or 1c||150|
|Piles (other than timber or helical piles) bearing on soft rock of Class 1d||80|
|Piles (other than timber or helical piles) that receive their principal support other than by direct bearing on rock of Class 1a through 1d||75|
|Timber piles bearing on rock of Class 1a through 1d||25|
|Timber piles bearing in suitable soils|| 40 tons maximum permissible |
with load test, 30 tons maximum
without load test.
|Helical piles||30 tons maximum permissible|
For SI: 1 ton = 907.18 kg.