508Driven Piles

508.01.01 General. This work consists of furnishing and driving piles.

508.01.02 Submittals . Submit the following information for review and approval at least 30 days prior to driving

piles:

508.01.03 Pre -activity Meeting. Before commencement of pile driving, t he Engineer will designate a time and

place satisfactory to the Contractor for a pre -activity meeting. The pre -activity meeting shall be held not more than 2 weeks in advance of scheduled pile driving. The meeting shall be attended by the Contractor’s supe rintendent and the pile driving subcontractor’s superintendent. Do not commence pile driving until all issues raised at the pre-activity meeting have been satisfactorily addressed .

508.01.04 Dynamic Testing Consultant. Secure the services of an independen t dynamic testing consultant to

perform wave equation modeling, high -strain dynamic testing and signal matching analyses, and to develop pile driving criteria. 508 DRIVEN PILES 298 MATERIALS

508.02.01 General. Material shall conform to the following Sections and Subsections:

Portland Cement Concrete ................................ ................................ ................................ ................................ ..................... Section 501 Reinforcing Steel ................................ ................................ ................................ ................................ ................................ .... Section 505 Steel Piles ................................ ................................ ................................ ................................ ............................... Subsection 712.03.07 Steel for Pipe Piles ................................ ................................ ................................ ................................ .................. Subsection 712.03.08 Piles shall be of the type and cross section shown on the plans. Furnish and attach pile shoe as shown on the plans. Concrete for steel pipe piles shall be Class D with the following exceptions: Minimum Compressive Strength ................................ ................................ ................................ ................................ . 28 MPa (4,000 psi) Grading Limits of Combined Aggregate s ................................ ................................ ................................ ........................... 13 mm (1/2 in.) Slump ................................ ................................ ................................ ................................ ............................... 150 to 200 mm (6 to 8 in.) CONSTRUCTI ON

508.03.01 Furnished Pile Length. Furnish piles in accordance with the contract documents and as required to

develop the specified nominal pile capacit ies and satisfy minimum pile tip elevations . The lengths given in the contract documents will be based on the undamaged lengths which remain after cutoff in the completed structure. Furnish additional pile length , without added compensation, to provide for fresh heading and for such additional length as may be necessary to suit the method of operation or to facilitate high-strain dynamic test ing.

508.03.02 Equipment. Furnish p ile driving equipment that is in good operating condition and conform s to the

requirements herein . Equipment will be subject t o review and approval. Use an open -end diesel or hydraulic impact hammer . Size the hammer to drive piles to the ir required nominal pile capacit ies and to the minimum tip elevation s shown on the plans without overstressing the piles. Furnish a device for monitoring the stroke of open -end diesel hammers during driving of each pile. The device shall detect each hammer blow, determine the interval of time between blows and automatically calculate and display the hammer stroke real time. Equip hydraulic hammer s with a ram energy measuring system which displays hammer energy real time. Notification of acceptance or rejection of the hammer will be made within 30 days of receipt of the pile and driving equipment data form and wave equation analysis. Approval of the hammer will be based on the following criteria determined from preconstruction wave equation analys es:

508.03.0 3 Preparation for Driving. Do not drive piles until all equipment has been reviewed and approved and

the pile d riving area has been prepared as specified h erein. Complete pile cap excavation , where applicable. Construct embankment to an elevation of at least 0.5 m (1.5 ft) above the bottom elevation of the pile cap. When an abutment area is to be surcharged, place the surcharge and wait the required period of time. Where applicable, p rebore to the depths shown on plans according t o Subsection 508.03.0 4. Remove the striker plate and hammer cushion from the helmet for inspection. Hammer cushion will be inspected when beginning pile driving at each structure or after each 100 hours of pile driving, whichever is less. Replace the hamm er cushion when it becomes compressed in excess of 25% of its original thickness, is cracked , or begins disintegrating.

508.03.0 4 Driving Piles . Drive piles with the approved pile driving equipment to the required nominal pile

capacity and minimum tip elevation shown on the plans. Reduce the fuel setting of open -ended diesel hammer s and the stroke setting of hydraulic hammers as necessary to avoid overstressing piles. During driving , maintain proper axial alignment of the hammer with the pile. Unless otherwise specifie d or approved, the order of installing individual piles in groups shall be by starting from the center of the group and proce eding progressively outward in all directions or starting at an outside row and proceeding progressively across the group. Drive each pile to the pile tip elevation shown on the p lans unless refusal occurs at a higher elevation. Refusal is defined as a driving resistance that exceeds 10 blows per inch at highest stro ke that will not overstress the pile. If the pile refuses prematurely, verify that the hammer is operating properly. Each pile shall penetrate below the minimum p ile tip elevation shown on the p lans. When approved, preboring may be used to obtain minimum p ile tip elevation. Spudding or jetting will not be permitted. Where required, p rebore holes at pile locations to the depths shown on the plans. Prebored holes shall generally be of a size smaller than the diameter or diagonal of the pile cross section that is sufficient to allow penetration of the pile to the specified depth. If subsurface obstructions, such as boulders , caliche, or rock layers are encountered, the hole diameter may be increased to the least dimension which is adequate for pile installa tion. Fill any void space around the pile with aggregate conforming to Subsection 706.03.03 . Backfill after insertion of the pile to the bottom of the hole and after positioning and aligning the pile. Top off the prebored hole with backfill as the pile is being driven and the backfill settles. Drive piles such that the pile heads at cutoff elevation are within 50 mm (2 in.) of plan locations for bent caps supported by piles, and within 150 mm (6 in.) of plan locations for all piles capped below final grade. Install piles so that the axial a lignment of the pile top is within 2% of the specified alignment . At shallow pile penetration , while pile alignment can be corrected , frequently stop driving to check and correct pile alignment. Within 3 days of co mpleting pile driving at respective pile group, provide as -built pile locations and alignments for all piles within a group if any piles within the group exceed location or alignment tolerances. 508 DRIVEN PILES 300 The Department will determine if each pile has adequate capac ity based on the results of the high -strain dynamic testing, signal matching analysis, and refined wave equation modeling based on the results of the signal matching analysis. In general, piles driven to refusal and exhibiting no loss of driving resistance upon restrike will be assumed to have sufficient axial capacity. If the Department determines the pile capacity is insufficient at the estimated pile tip elevation shown on the plans, drive the piles deeper as directed. Splice another section onto the pile as needed. Splice as specified in Subsection 508.03.05. Take accurate level readings referenced to a fixed datum to monitor pile heave resulting from pile driving. For each pile , take a reading immediately after each pile is driven and another reading after all piles within a 5 m (16 ft) radius are driven. Document all level readings and compute pile top elevations. Redrive all piles that have heaved more than 6 mm (1/4 in.) to their original position . Submit documentation of pile heave monitor ing results, including elevation of pile tops at end of driving of each pile, elevation of pile tops after all piles within 16 feet radius are drive n, and final elevation of redriven piles.

508.03.0 5 Splicing. Each pile may be built up from shorter length s spliced together. Joined lengths shall be

identical in cross secti on and aligned so that the axis of the pile is straight. Splicing a properly aligned section on a misaligned section will not be permitted. Weld the entire cross section of each connection in conformance with Subsection 506.03.16. If lengths are added to lengths of pile previously installed, weld it while the splice is at least 1 m (3 ft) above the ground to permit visual observation of the welded connection during driving.

508.03.06 High -Strain Dynamic Testing. Perform high -strain dynamic testing on piles shown or noted as test

piles on the plans, or as directed. Collect test data at end of driving (EOD) and beginning of restrike (BOR) for each test pile. Restrike test piles no sooner than 24 hours after EOD. Provide extra pile length so that 1.2 m (4 ft) of pile length remains between the pile head and the ground surface when the estimated tip elevation is reached for the placement of the testing instrumentation. If additional driving is required, splice the pile and reattach the sensors to the next pile segment prior to continuing driving. Perform dynamic monitoring in accordance with ASTM D4945 . Warm up the hammer before restriking test piles by applying at least 20 blows to another pile. The maximum amount of penetration required during restrike shall be 75 mm (3 in), or the maximum number of hammer blows required shall be 50, whichever occurs first. The restrike may be terminated after 20 blows if pile movement is less than 6 mm (0.25 in.) during the restrike and the hammer energy output is satisfactory. Perform signal matching analysis of at least one EOD hammer blow and at least one BOR hammer blow for each test pile. Determine based on the results of signal matching analyses the total bearing capacity at EOD and BOR for each test pile. Also determine based on the results of the signal matching analyses, the amount of end bearing, distribution of shaft resistance, and dynamic pro perties at EOD and BOR for each test pile. Hammer blows analyzed should be representative and suitable for analysis. Software used for signal matching shall have a published data base of at least 50 cases with correlations to static load tests. Based on t he results of the signal matching analyses, refine the wave equation model and develop appropriate driving criteria. Within 24 hours of each high -strain dynamic test, the Dynamic Testing Consultant shall prepare and submit an individual test report summar izing the high -strain dynamic test results and results of corresponding signal matching analysis. The individual test reports shall include the calculated driving stresses, transferred energy, and estimated pile capacity at the time of testing. Variation f rom previous trends of high -strain dynamic test results shall also be noted. Include a discussion of hammer and driving system performance, driving stress levels, and pile integrity.

508.03.0 7 Pile Acceptance. Piles will not be accepted until all piles wi thin a group are driven. Each pile shall be

in its proper location and alignment, penetrate to minimum tip elevation, have the required nominal capacity, and be free of defects or damage. Upon completion of driving all piles within a group, determine and document the location and alignment of each pile within the group. If the location and/or alignment tolerances specified in Subsection 508.03.0 4 are exceeded, the Department will evaluate the acceptance of the pile. Submit documentation of the location and alignment of each pile within the group for the evaluation. The Department will determine if piles are mispositioned, misaligned, damaged, or defective. DRIVEN PILES 508 301 Do not force mispositoned or misaligned piles back into proper position/alignment. Maintain a minimu m of 100 mm (4 in.) clearance between piles and any edge of the pile cap. Increase the size of the pile cap to meet this edge distance requirement as directed at own expense . If the Department determines that corrective measures are necessary, submit a plan for remedial action for review. Furnish all work necessary, including engineering analysis and redesign, to mitigate mispositioned, misaligned, defective , or damaged piles. Modifications to piles caused by remedial action will require calculations and working drawings stamped by a Registered Professional Engineer licensed to practice in the State of Nevada. Do not commence repair operations until remedial correction procedure s or designs have been approved.

508.03.0 8 Pile Cut Off. Do not cut off piles until given approval . Cut off piles such that the pile heads at cutoff

elevation are within 25 mm (1 in.) of plan elevation. Dispose of cut off lengths of piling that are not incorporated into other piles according to Subsection 107.14.

508.03 09 Steel Pipe Piles. Steel pipe piles consist of steel pipe driven to the required nominal pile capacity

and subsequently filled with reinforcement and concrete. Reinforcing steel at the top of each pile shall conform to the details shown on the plans and the requirements of Section 505. Do not place reinforcing steel and concrete in steel pipes until after heaved pi pes have been redriven to their original position and all the steel pipe s in the group have been inspected and accepted. Each steel pipe will be inspected for damage, presence of water, soil, rock or debris. Provide suitable light for inspection of the p ipes. If the bottom of the p ipe cannot be seen or damage is suspected, pro vide a down -hole video camera for closer inspection. Remove water, soil, rock, and debris before placing reinforcing steel and concrete in each p ipe. Place reinforcing steel as shown before placing concrete. Place concrete in the steel pipe continuously a nd so that it is dense and homogeneous. Vibrate the upper portion of the pile to a depth of 4.5 m (15 ft). METHOD OF MEASUREMENT

508.04.01 Measurement. Piles will be measured by the linear meter (linear foot), from the tip of the completed

pile to the plane of pile cutoff. Driving piles will be measured by the each for each completed pile. High-strain d ynamic tests will be measured by the each . Splic es will be measured by the each, limited to the number required to splice the pile if it becomes necessary to drive beyond estimated pile tip elevati on shown on plans. Length of extensions will be determined. Splices necessary to build up piles to the estim ated length shown on the plans will not be paid for . BASIS OF PAYMENT

508.05.01 Payment. The accepted quantities, measured as provided above, will be paid for at the contract

price per unit of measurement for the pay items listed below that are shown in the proposal. Payment will be full compensation for the work prescribed in this section. Test piles that become a part of the completed structure will be paid for at the contract prices for the type of piling used. Payment will be made under: Pay Item Pay Unit Furnish Steel Piles (type) ................................ ................................ ................................ ................................ . Linear Meter (Linear Foot) Furnish Steel Pipe Piles ( size) ................................ ................................ ................................ .......................... Linear Meter (Linear Foot) Drive (type) Piles ................................ ................................ ................................ ................................ ................................ ............... Each High-Strain Dynamic Test ................................ ................................ ................................ ................................ ................................ . Each Splices ................................ ................................ ................................ ................................ ................................ .............................. Each 303 SECTION 509 DRILLED SHAFT FOUNDATIONS DESCRIPTION

509.01.01 General. This work consists of constructing drilled shaft foundations.

509.01.02 Qualifications of Drilled Shaft Contractors. No later than 30 days prior to constructing drilled

shafts, submit in writing, qualifications to perform the drilled shaft construction as specified and provide a list of 3 projects successfully completed within the previous five years using drilled shaft construction. The list of projects shall contain names and current phone numbers of owner’s representatives who can verify participation on those projects. On-site supervisors shall have a minimum of 3 years experience in supervising construction of dril led shafts of both diameter and length, and similar geotechnical conditions, to those shown on the plans. Drill rig operators shall have a minimum of 1 year drilling experience in construction of drilled shafts of both diameter and length, and similar geotechnical conditions, to those shown on the plans.

509.01.03 Submittals. Submit an installation plan for review a minimum of 15 days prior to constructing drilled

shafts. This plan shall provide information on the following:

509.01.04 Pre -Activity Meeting. A pre-activity meeting will be scheduled prior to commencement of drilled

shaft construction. As a minimum, the Contractor, the drilling sub -contractor, and the Engineer shall attend the meeting.