for Highway Construction Page 395 of 71 5 SECTION 520 – PREDRILLING FOR PILING
520.01 Description.
Drill and backfill holes in soil and rock to allow piles to be driven to the highest pile tip elev ations and minimum bearing capacities specified or as directed.
520.02 Materials.
Provide temporary steel casings of sufficient strength to resist damage and deformation during installation, extraction, and all soil pressures on the casing. Coarse a ggregate for concrete, size No. 1 ......................................................................... 703.02.C. Pea Gravel ............................................................................................................................... 703.09
520.03 Construction Requirements.
Submit a work plan for predrilling at least 4 weeks before pile driving. The work pl an must include descriptions of the following:
1.Equipment.
2.Materials.
3.Sequence of operations, including:
a.Removal or replacement of piles that do not reach the required penetration.
b.Measures to ensure stability during excavation and backfilling (e.g., prevention of caving and bottom heave).
c.Hole cleanout methods.
d.Coarse aggregate placement .
e.Pulling temporary casing. Do not perform this work without approval of the wor k plan. Drill holes into soil or rock to the highest pile tip elevation(s) specified and with a minimum diameter that is at least 4 inches greater than the H -pile diagonal dimension and 6 inches greater than the pipe pile outside dimension. After drilling, fill the hole to the top with coarse aggregate to make it ready for pile driving. Remove the temporary casing in accordance with the approved work plan during coarse aggregate placement , maintaining the coarse aggregate top above the casing bottom. Fill any remaining voids with coarse aggregate after completing pile driving.
520.04 Method of Measurement.
The Engineer will measure acceptably completed work by the foot.
520.05 Basis of Payment .
The Department will pay for accepted work as follows: for Highway Construction Page 396 of 71 5 Pay Item Pay Unit Predrilling for Piling in Soil ...................................................................... FT Predrilling for Piling in Rock .................................................................... FT The Department will not pay for predrilling that extends below the depth specified. C oarse aggregate, pea gravel, and c asing are incidental to this item. for Highway Construction Page 397 of 71 5 SECTION 521 – DYNAMIC PILE TESTING AND CAPWAP ANALYSIS
521.01 Description.
Retain a pre- approved consultant as specified in 521.03.B.5 to perform dynamic pile testing and signal matching analyses using the case pile wave analysis program (CAPWAP) program as specified or as directed. The Engineer will use this information to confirm or modify pile- driving criteria developed by the wave equation analysis for the planned hammer- pile-soil combination.
521.02 Materials.
Provide equipment for dynamic pile testing in accordance with the following: High Strain Dynamic Testing of Piles ........................................................................ ASTM D4945 -12 Provide access to the pile in the leads with a personnel lift or basket that can be raised to the pile top or by other safe methods to attach instrumentation. For access to the test pile on the ground, provide at least 3 feet of clear access to opposite faces of the pile to allow drilling holes for instrumentation. Provide sufficient time for installing in strumentation on the pile in the leads. Short interruptions during driving may be necessary due to instrument malfunction.
521.03 Construction Requirements – Testing.
A.General. Perform dynamic pile testing on each test pile as specified or as directed. If the required bearing capacity is not achieved during initial driving, restrike the test pile as directed. Perform dynamic pile testing during the pile r estrike. Perform a CAPWAP analysis on the pile restrike data, or as directed. A dynamic pile test and CAPWAP analysis will be required for each pile restrike performed.
B.Testing and Reporting. The consultant engineer will operate the pile driving analyzer and monitor pile driving in real time on- site or remotely, from the beginning to the end, or as directed. In addition, the consultant will continuously monitor the test piles for potential damage and for the occurrence of non -axial driving, and inform the Engineer and the Contractor immediately if there is any indication that pile damage has occurred during driving. The consultant will submit preliminary test results to the Engineer and the Contractor within 24 hours of t he dynamic testing completion for each test pile and before leaving the project site. The consultant will include the following information with the preliminary test results:
1.Energy transfer from the pile- driving hammer to the pile (EMX or “Enthru”) and rated transfer efficiency.
2.Peak force (FMX) and stress (CSX) at the pile dynamic analyzer (PDA) sensor location near the pile top.
3.Ultimate pile bearing capacity computed in the field with a suitable case method calculation and preliminary test results using CAPWAP analysis.
4.Graphs showing RMX, BLC, CSI, STK, and FMX by depth of penetration.
Source: Idaho Standard Specifications for Highway Construction, 2023 Edition. Pages 431–432 of 768.