502.01 502-1 SECTION 502 PILING DESCRIPTION
502.01 This work consists of furnishing and driving foundation piles, other than sheet piling.
MATERIALS
502.02 Rolled Structural Steel Piles . Steel used in rolled structural steel piles shall conform to
the requirements of ASTM A572/A572M or ASTM A992/A992M. Sections of piles shall be of “H” or “W” shape. The flange projection shall not exceed 14 times the minimum thickness of metal in either the flange or the web, and flange widths shall not be less than 80 percent of the depth of the section. The nominal depth in the direction of the web shall not be less than 8 inches. Flanges and web shall have a minimum nominal thickness of 0.375 inches o r greater.
502.03 Steel Pipe Piles . Steel pipe piles shall conform to the requirements of ASTM A252,
Grade 2 or higher. Ends of closed -end pipe piles shall be closed with a flat plate, forged or cast steel conical point, or other end closure design approved by the Engineer. End plates used o n closed -end pipe piles shall be made of ASTM A36/A36M steel or better. End plates shall have a minimum thickness of 0.75 inches. The diameter and thickness of the end plates shall be as shown on the plans. The end plate shall be cut flush with the oute r pile wall. The end of the pipe shall be beveled before welding to the end plate using a partial penetration groove weld.
502.04 Protective Coatings . If there is a required protective coating, the Contractor shall
restore or repair any damage to the coating. CONSTRUCTION REQUIREMENTS
502.05 Pile Driving Equipment . All equipment , including the pile driving hammer , hammer
cushion, helmet, pile cushion, and other appurtenances to be furnished by the Contractor shall be approved in advance by the Engineer before any driving can begin. Pursuant to obtaining this approval, the Contractor shall submit a description of pile driving equipment to the Engineer at least two weeks before pile d riving is to begin. The description shall contain sufficient detail so that the proposed driving system can be evaluated by wave equation analysis. The Contractor shall submit to the Engineer results of a wave equation analysis to show that the piles are drivable. Hammer efficiencies shown in Table 502- 1 shall be used in the wave equation analysis of vertical piles unless better information is available. Hammer efficiencies shall be adjusted for batter driving. 502.05 502-2 Table 502 -1 PILE DRIVING HAMMER EFFICIENCIES Hammer Type Hammer Efficiency (%) Single -acting steam /air 67 Double -acting steam /air 50 Diesel 80 Hydraulic or diesel with built -in energy measurement 90 For steam, air, and diesel hammers, a minimum manufacturer’s rated energy for specific HP Piles sizes shall be used as shown in Table 502 -2. Table 502 -2 MINIMUM MANUFACTURER'S PILE DRIVING HAMMER RATED ENERGY PER PILE SIZE Pile Size Area (Square Inches) Minimum Energy (Foot - Pounds) HP 10x42 12.4 26,000 HP 10x57 16.8 26,000 HP 12x53 15.5 26,000 HP 12x74 21.8 42,000 HP 14x89 26.1 52,000 HP 14x117 34.4 68,000 The rated energy of the hammer shall not be greater than 2,500 foot -pounds per square inch of unit area. Exceptions to these limits are permissible if it is demonstrated by wave equation analysis that the piles can be safely and efficiently installed with hammers having ratings outside of these energy limits. The criteria that the Contractor and the Engineer will use to evaluate the driving equipment shall consist of both the required number of hammer blows per foot at the required nominal resistance and the pile driving stresses over the entire driving process. The required number of hammer blows indicated by the wave equation analysis at the required nominal driving resistance shall be between 30 and 120 blows per foot for the driving equipment to be deemed acceptable. In addition, the piles stresses, which are determined by the wave equation analysis for the entire driving operation, shall not exceed 90 percent of the yield point of the steel pile material. 502.05 502-3 During pile driving operations, the Contractor shall use the approved system. Any change in the driving system shall be considered only after the Contractor has submitted revised pile driving equipment data and wave equation analysis. The Contractor shall be notified of the acceptance or rejection of the driving system changes within two working days of the Engineer’s receipt of the requested change. The time required for submission, review, and approval shall not constitute the basis for a contract time ex tension to the Contractor. Approval of the piling driving equipment shall not relieve the Contractor of responsibility to drive piles, free of damage, to the required nominal resistance and, if specified, the minimum penetration, shown in the contract documents.
a.Pile Hammers . Steam, air , diesel, or hydraulic impact hammers shall be used to drive all types of piles.
1.Single or Double Acting Steam and Air Hammers Proximity switches and an electronic readout device shall be provided before driving piling. Hammer performance shall be evaluated by the Contractor at the end of driving each pile by measuring blows per minute and comparing these blows with the manufacturer’s recommendations.
2.Diesel Hammers If open -end (single -acting) diesel hammers are not equipped with a device to measure impact velocity at all times during pile driving operations, the stroke shall be obtained by the Contractor by measuring the speed of operation either manually or with a d evice that takes the measurement automatically. Closed -end double acting diesel hammers shall be equipped with an accurate bounce chamber pressure gauge. The Contractor shall provide the Engineer a calibrated chart equating bounce chamber pressure to either equivalent energy or stroke for the closed - end diesel hammer to be used. A copy of calibration records of actual hammer performance performed within 90 days before the beginning of the work shall be submitted to the Engineer.
3.Hydraulic Hammers Hydraulic hammers shall be equipped with a controlled variable stroke system and a readout device to measure ram energy. The plant and equipment shall be equipped with accurate pressure and velocity gauges and an energy readout device.
4.Vibratory Hammers Vibratory or other pile driving methods may be used only when specified in the Contract or in writing by the Engineer. Except when pile lengths have been evaluated from static load test piles, the nominal driving resistance of piles driven with vibratory hammers shall be verified by additional driving of the first pile driven in each group of 10 piles with an impact hammer of suitable energy to measure the nominal resistance before driving the remaining piles in the group. I n case of variable soils, additional piles shall be verified by an impact hammer as directed by the Engineer. All piles that rely primarily on point bearing capacity shall be re -driven with an impact hammer. 502.06 502-4 (b) Hammer Cushion . All impact pile driving equipment shall be equipped with a suitable hammer cushion to prevent damage to the hammer or piles and to ensure uniform driving behavior. Wood, wire rope, and asbestos cushion material shall not be used. A striker plate recommen ded by the hammer manufacturer shall be used. Any hammer cushion whose thickness is reduced by 10 percent or more of the original thickness shall be replaced at the Contractor’s expense before driving is permitted to continue.
c.Leads. Pile driving leads shall be constructed in a manner that affords the pile hammer freedom of movement while maintaining alignment of the pile hammer and the pile to ensure concentric impact for each blow. Leads may be either fixed or swinging. Swinging leads shall be fitted with a pile gate at the bottom of the leads and shall be long enough to be securely fixed at the ground at all times.
d.Followers. Followers shall be used only when specified on the plans or approved in writing by the Engineer. The follower and pile shall be maintained in proper alignment during driving. The follower shall be of such material and dimensions to permit the piles to be driven to the blow count determined to be necessary.
e.Jetting . Jetting is permitted only if specified in the Contract or approved in writing by the Engineer. The Contractor shall determine the number of jets and the volume and pressure of water at the jet nozzles necessary to freely erode the material adjacent to the pile. The Contractor shall control and dispose of all jet water per subsection 107.2 5. If jetting is specified or approved by the Engineer and is performed according to the specifications or as approved by the Engineer, the Contractor shall not be held responsible for any damage to the site caused by jetting operations. If jetting is used for the Contractor’s convenience, the Contractor shall be responsible for all damages to the site caused by jetting operations. Unless otherwise specified by the Engineer or the Contract, jet pipes shall be removed before or when the pile tip is 5 feet above the minimum or final tip elevation, and the pile shall be driven with an impact hammer, without jetting, to the final tip ele vation or to the required nominal resistance. If the required nominal resistance is not reached at the final tip elevation, the pile may be set up and the required nominal resistance will be determined by re- striking the pile.
502.06 Driving Piles . Piles shall not be driven until required excavation or fill placement is
complete, unless authorized by the Engineer. After driving is complete, all loose and displaced material shall be removed from around the piling before pouring any concrete. Piles shall be driven within a variation of 1/4 inch or less per foot from the vertical or from the batter shown on the plans. The tendency of steel piles to twist or rotate shall be prevented and corrected. Foundation piles shall be within 6 inches of the position shown on the plans after driving. No pile shall be closer than 4 inches from an edge of the pile cap. Pulling or pushing laterally on installed piles to correct misalignment or splicing a properly aligned section on a misaligned section will not be allowed. The at cutoff elevation shall be within 2 inches of plan elevation for bent caps supported by piles. Piles driven at integral end bents shall be installed so that the axial alignment of the top 10 feet of the pile is within two percent of the specified alignment. 502.07 502-5 The order of placing individual piles within a pile group shall begin from the center of the group and proceed outward in both directions unless an alternate installation sequence is approved by the Engineer in writing. For a bent with a single row of piles, pile driving shall begin at one end of the bent and proceed toward the opposite end. If the location or alignment tolerances are exceeded, the extent of overloading shall be investigated. If the Engineer determines that corrective measures are necessary, such corrective measures shall be designed and constructed by the Contractor. Proposed corrective measures will be subject to approval by the Engineer.
502.07 Predrilling to Facilitate Pile Driving . Drilled holes shall be 2 inches smaller than the
diameter or diagonal of the pile cross -section. If subsurface obstructions, such as boulders or rock layers, are encountered, the hole diameter may be increased to the least dimension that is adequate for pile installation. Except for end bearing piles, drilling shall be stopped at least 5 feet above the pile tip elevation shown on the plans. The pile shall then be driven with an impact hammer to the specified penetration resistance. Where p iles are to be end bearing on rock or very dense cobbles and gravels (hardpan), drilling may be carried to the surface of the rock or the hardpan. The piles shall then be driven with an impact hammer to ensure proper seating. Any void space remaining around the pile after completio n of driving shall be filled with sand, pea gravel, concrete, or other materials as specified in the Contract. If the diameter of the drilled hole is exceeded due to sloughing, drifting, over -drilling, or other causes, additional material required to fill this added void area will be at the Contractor’s expense. The Engineer will determine if shooting holes with explosives or redesign is necessary when piles cannot be driven or holes drilled. When test piles are shown on the plans they shall be used to determine if drilling or jetting holes to facilitate pile driving is required. If the test pile or piles do not reach the minimum tip elevation shown on the plans and do not develop the required nominal resistance as specified in subsection 502.09, holes shall be drilled or jetted to facilitate pile driving.
502.08 Filling and Capping Piles . Steel pipe piles will be inspected after all adjacent piles
within a 5 -foot radius have been driven. Before concrete is placed in the pipe pile, it shall be inspected by an acceptable method to confirm the full pile length and dry bottom condition. If accumulations of water in the pipe piles are present, the water shall be removed before the concrete is placed. The concrete for concrete- filled pipe piles shall be Class BZ and shall conform to the requirements of section 601. Concrete shall be placed in each pipe pile in a continuous operation. No concrete shall be placed until all driving within a radius of 15 feet of the pipe pile has been completed, or all driving within a 15 -foot radius shall be discontinued until the concr ete in the last pipe pile cast has set for at least two days.
502.09 Determination of Nominal Driving Resistance . The Engineer will use one of the
following methods as specified to determine the nominal driving resistance of a driven pile.
a.Wave Equation Analysis. The Engineer will use a wave equation analysis to determine the driving criterion necessary to reach the required nominal driving resistance of the pile. Soil and pile properties to be used in this analysis shall be as shown in the Contract or as determined by the Engineer. The Contractor shall supply the Engineer the necessary information on the proposed driving equipment to perform the wave equation analysis. 502.09 502-6 (b) Dynamic Testing. The length of the pile used in the dynamic test shall be a minimum of 10 feet greater than the estimated length of production piles in order to provide for variation in soil conditions. Dynamic monitoring shall be performed to obtain the nominal driving re sistance, pile driving stresses, pile integrity, pile driving system performance, and final driving criteria. Dynamic monitoring shall be conducted by Pile Driving Analyzer (PDA) per ASTM D4945. PDA shall be performed on the first pile driven to the plan requirements. A minimum of one production pile per bent (abutment or pier foundation) shall be monitored as a test pile. Dynamic monitoring shall be conducted by the Contractor's Engineer. The Contractor’s Engineer conducting the PDA shall be a licensed Professional Engineer who has achieved one of the following certification levels: intermediate, advanced, master, or expert through the Dynamic Measurement and Analyses Proficiency Test conducted by Pile Dynamics, Inc., and the Pile Driving Contractors Association. A Contractor’s Engineer with a lower certification level than intermediate can provide dynamic monitoring as long as this individual is under the direct supervision of an Engineer with intermediate certification level or higher. The Contractor shall notify the Project Engineer at least seven calendar days before the scheduled date of driving piles to be monitored by PDA. The Contractor shall confirm the driving date three calendar days before the scheduled driving date. The Contractor shall indicate where foundation production pile driving is to begin. The Contractor’s Engineer conducting the PDA will provide final driving criteria for the indicated foundation. Each pile to be tested shall be instrumented with force and acceleration transducers. The transducers shall be installed before striking the pile. The pile driving may need to be temporarily interrupted for the transducers to be adjusted or replaced, or for the monitoring results to be assessed. The Contractor shall drive the test pile to the minimum tip elevation and to the penetration depth that the dynamic test equipment indicates that the nominal driving resistance shown on the plans has been achieved. The Contractor may reduce the driving energy transmitted to the pile by using additional cushions or reducing the energy output of the hammer in order to maintain stresses below the value shown in subsection 502.05. If non -axial driving is indicated by the dynamic test equipment measurements, the Contractor shall immediately realign the hammer system. If restriking is specified in the Contract documents, the Contractor shall wait at least one hour before the restriking of the test pile. The hammer shall be warmed up before restriking begins by applying at least 20 blows to another pile or other fixed object. The maximum amount of penetration required during restrike shall be 3 inches, or the total number of hammer blows shall be 20, whichever occurs first. If the pile does not achieve the required nominal driving resistance during restrike, the Contractor’s Engineer conducting the PDA shall specify additional pile penetration and testing. If the required nominal driving resistance has been reached in natural ground and piles have not been driven to the estimated tip elevation, but have been driven below minimum tip elevation, the Contractor’s Engineer conducting the PDA may direct the driving to be continued for 40 additional blows. 502.10 502-7 Once the dynamic monitoring is complete, the Contractor’s Engineer conducting the PDA shall run Case Pile Wave Analysis Program (CAPWAP ) analyses and shall provide the final driving criteria the same day of the test to the Engineer. Production piles driven before receipt of the final driving criteria shall be done at the Contractor’s risk. Final driving criteria for additional structures shall be provided within two business days of the test or when multiple test piles are dynamically tested the same day. A detailed report electronically sealed by the Contractor’s Engineer conducting the PDA shall include the pile driving criteria with the PDA and CAPWAP results and shall be submitted to the Engineer for acceptance within two business days after the dynamic monitoring. If changes are made to the pile driving system (hammer, fuel setting, piling, cushioning, etc.) after the dynamic monitoring has been completed and driving criteria established, new driving criteria shall be determined using the PDA. New criteria shall be determined at the Contractor’s expense. If the Engineer requests additional piles to be monitored, pile monitoring will be paid for per subsection 502.16.
c.Static Load Test. If a static load test is used to determine the pile axial resistance, the test shall not be performed less than five days after the test pile was driven unless approved by the Engineer or otherwise specified in the Contract . The static load test shall follow the procedures specified in ASTM D1143/D1143M, and the loading procedure shall follow the Quick Load Test Method, unless detailed longer -term load -settlement data are needed, in which case the standard loading procedure shall be used. Testing equipment and measuring systems shall conform to ASTM D1143/D1143M. The Contractor shall submit detailed documents for the proposed loading apparatus, prepared by a Licensed Professional Engineer, to the Engineer for review. The submittal shall include calibrations for the hydraulic jack, load cell, and pressure gauge conducted within 30 days before mobilization to the jo b site. Tension (anchor) piles that will later be used as permanent piles in the work shall be of the same type and size as the production piles and shall be driven at the same time as the test pile in the location of permanent piles , where feasible. While performing the static load test, the Contractor shall provide safety equipment and employ adequate safety procedures. Adequate support for the static load test plates, jack, and ancillary devices shall be provided to prevent them from falling in the event of a release of load due to hydraulic failure, test pile failure, or other cause. The method of defining failure of the static load test shall be as defined in the Contract . Based on the static load and dynamic test results, the Contractor’s Engineer conducting the PDA will provide the final driving criteria for production pile acceptance. When specified, tension static load tests shall be conducted per ASTM D3689. When specified, lateral load tests shall be conducted per ASTM D3966.
502.10 Nominal Driving Resistance of Production Piles Production piles shall be driven to the
depth necessary to obtain the required nominal driving resistance as determined by subsection
502.09 If a minimum pile tip elevation is shown on the plans, in addition to obtaining the
required nominal driving resistance, production piles shall also be driven to the minimum pile tip elevation. 502-8 When the nominal driving resistance is determined per subsection 502.09(a) or subsection 502.09(b) for acceptance, the Engineer will record the blow count per inch or foot of pile movement and the associated hammer stroke for the last two consecutive feet of driving, and the final pile tip elevation as per t he pile driving criteria established through the wave equation analysis or dynamic test. Practical refusal will be defined as 10 blows per inch of penetration for a maximum of three consecutive inches of pile penetration and with the hammer operated at its maximum fuel or energy setting, or at a reduced fuel or energy setting recommended by th e Engineer based on pile installation stress control and less than 1/4 inch rebound per blow. The Contractor shall stop driving as soon as the Engineer determines that the pile has reached practical refusal. Absolute refusal is defined as 20 blows for 1 inch or less of pile penetration. Driving shall terminate immediately if this criterion is achieved. In the case of hard rock, an absolute refusal criterion of 5 blows per 1/4 inch or 10 blows per 1/2 inch should be adopted to reduce the risk of pile toe or driving equipment damage. The nominal driving resistance of jetted piles shall be based on impact driving penetration resistance after the jet pipes have been removed. Jetted piles not attaining the nominal driving resistance at the ordered length shall be spliced and driven with an impact hammer until the nominal driving resistance is achieved per the driving criteria in subsection 502.09.
502.11 Piling Length . The lengths of piles shown on the plans and in the Schedule of Pay
Items are estimated lengths and are for bidding purposes only. Piles may be ordered in plan lengths or standard production lengths. The Contractor shall provide the actual length of piles n ecessary to obtain the nominal driving resistance and penetration depth required as determined from results obtained from driving representative test piles or other pertinent data. There will be expected variations in final tip elevations due to differe nces in nominal pile driving resistance. The final tip elevation of each pile shall be determined during the driving operation. A minimum pile penetration of 10 feet below the bottom of the footing elevation in natural ground is required for all piles. This requirement may be waived by the Engineer if the subsurface material at the pile tip location is bedrock or other acceptable b earing material provided that the bearing elevation is below scour depth. If minimum tip elevations are specified, the Contractor shall drive piles to a penetration depth that satisfies this requirement in addition to the nominal driving resistance. If the pile cannot be driven to the minimum tip elevation, the Engineer will det ermine if pre- drilling is required. Water jets may be used in conjunction with the hammer to obtain the specified penetration only with approval by the Engineer. The last 5 feet of penetration shall be obtained by driving without the use of water jets. Test blows to determine average penetra tion shall be applied after the jets have been removed. The use of water jets shall not modify any of the requirements of this specification.
502.12 Extensions and Splices. When the American Welding Society (AWS) D1.1 Structural
Welding Code is cited in this section, it shall be the current edition. Full length piles shall be used where practicable. The number of splices shall be kept to a minimum. Commercially available splices may be used if approved by the Engineer. 502.13 502-9 All welded splices shall be partial joint penetration (PJP) unless designated otherwise on the plans. All welded splices shall be made by using a prequalified joint designation per AWS D1.1. The CJP design shall include beam copes (weld access holes) through the web of the pile at the junctures with the flanges. Copes shall be made per AWS D1.1, section 5.17. If backing is used it shall be per AWS D1.1. Removal of the backing after welding is not required. Personnel performing welding inspection shall be a certified welding inspector (CWI) per AWS D1.1, Chapter 6. All welded pile splices shall be made per a written Welding Procedure Specification (WPS) that shall be reviewed and approved by the Contractor’s CWI, before welding any piling splices on the project. The WPS shall list all essential variables of the process per AWS D1.1. The WPS shall be available for review by the Engineer. All welded splices shall be made with low hydrogen electrodes. The Contractor shall adhere to the low hydrogen practice for electrodes per AWS D1.1. All cuts at splices shall be made normal to the longitudinal axis of the pile. The cut -off portion may be driven to start the next pile, or it may be welded to previously driven piles to provide the necessary extension length. All welders shall be currently qualified per AWS D1.1. Welder qualifications shall be approved by the Contractor’s CWI before the start of welding. The welder shall be requalified if any essential variables listed in AWS D1.1 are not met. The Contractor shall provide an AWS Certified Welding Inspector (CWI) on the project site for quality control. The CWI shall inspect all production stages of the welded splice, including assembly of the splice joint, during welding, and after welding to en sure that workmanship and materials meet the requirements of the Contract. The CWI shall submit a record of all weld inspection documentation to the Engineer. The Contractor’s inspector performing UT testing of CJP splices shall be qualified per the current edition of the American Society for Nondestructive Testing Practice N o. SNT-TC-1A. Individuals who perform nondestructive testing shall be qualified for NDT Level II. The first two CJP welded splices shall be ultrasonically tested (UT) for acceptance per Table 6.3 of AWS D1.1. If both of the UT tested CJP splices are determined to be acceptable, no further UT testing of CJP splices will be required. If either of the first two UT tested CJP splices are not acceptable, UT testing of CJP splices shall cont inue until two consecutive tests are acceptable.
502.13 Defective Piling . Piles damaged in driving by reasons of internal defects or improper
driving shall be corrected by one of the following approved methods:
1.The pile shall be withdrawn and replaced by a new, and if necessary, longer pile.
2.A second pile shall be driven adjacent to the defective pile. Piles driven below the specified butt elevation shall be corrected by one of the following approved methods:
1.The pile is spliced or built up as otherwise provided.
2.A sufficient portion of the footing is extended down to properly embed the pile. 502.14 502-10 A pile driven out of its proper location per subsection 502.06 shall be corrected by one of the following methods:
1.One or more replacement piles are driven next to the out -of-position piles.
2.The footing is extended laterally to incorporate the out- of-location pile.
3.Additional reinforcement is added. All such remedial materials and work shall be approved by the Engineer and furnished and performed at the Contractor’s expense. All piles pushed up by the driving of adjacent piles shall be driven down again.
502.14 Pile Tips. If difficult driving conditions are encountered, the Engineer may direct
the Contractor to furnish and attach pile tips even though tips are not required on the plans. METHOD OF MEASUREMENT
502.15 Piling will be measured by the linear foot in place. Measurement shall be from the
tip to the cut -off elevation. Where piling is driven to within 1 foot of the elevation of cut -off, butt ends will be included in the length measured for piling actually driven. Measurement of splices will be limited to two per steel pile. Partial Joint Penetration (PJP) welded splices for piles, when specified on the plans, will be measured as additional length of pile. The additional length for each PJP splice will be measured as follows: steel “H” piles, 3 linear feet; steel pipe piles, 3 linear feet. CJP welded spl ices, when specified in the plans, will be the actual number completed and accepted per splice. Pile tips and end plates for steel pipe piles will be measured by the actual number installed. Drilled holes to facilitate pile driving will be measured by linear foot. BASIS OF PAYMENT
502.16 The accepted quantities will be paid for at the contract unit price per unit of
measurement for each of the pay items listed below that appear in the bid schedule. Payment will be made under: Pay Item Pay Unit Steel Piling (size) Linear Foot Steel Pipe Piling (size) Linear Foot Drilling Hole to Facilitate Pile Driving Linear Foot End Plate Each Pile Tip Each Dynamic Pile Test Each Static Pile Load Test Each Complete Joint Penetration (CJP) Splice Each 502.16 502-11 All costs for providing Certified Welding Inspector (CWI) services for Partial Joint Penetration (PJP) welded splices shall be included in the additional measured length of pile per subsection 502.12. Complete Joint Penetration (CJP) splices shall be paid for at the contract unit price for each completed and accepted CJP Splice. All costs for completing the CJP welded splices including, but not limited to, Ultrasonic Testing, Certified Welding Inspecto r (CWI) services, and required documentation shall be included in the price per each for Complete Joint Penetration (CJP) Splice. Steel cut -offs 10 feet or less in length will be paid for at the contract unit price minus 20 percent. These cut -offs shall become the property of the Contractor. Steel cut -offs greater than the above specified lengths will not be paid for. Authorized jetting, blasting, or other work necessary to obtain the specified penetration of piles will be paid for per subsection 109.04. Concrete used to fill steel pipe will not be measured and paid for separately but shall be included in the work . 502.16 502-12 PAGE INTENTIONALLY LEFT BLANK 503.01 503-1 SECTION 503 DRILLED SHAFTS DESCRIPTION
503.01 This work consists of furnishing all materials, labor, tools, equipment, services and
incidentals necessary to construct the drilled shafts (also referred to as drilled caissons, drilled piers, cast -in-place -drilled -holes, or cast -in-situ piles) per the Contract Documents and this Specification. SUBMITTALS AND MEETINGS
503.02 Submittals. At least 30 days before the start of drilled shaft construction, the
Contractor shall submit to the Engineer an electronic file of a project reference list verifying the successful completion by the Contractor of at least three separate foundation projects within the last five y ears with drilled shafts of similar size (diameter and depth) and construction difficulty to those shown on the Plans in similar subsurface geotechnical conditions. A brief description of each project and the project ow ner's contact name and current phone number shall be included for each project listed. Work shall not begin until all required submittals have been received by the Engineer.
a.Experience and Personnel. The personnel assigned to the project shall have the following minimum experience:
1.On-site supervisors shall have a minimum of two years of experience in supervising construction of drilled shaft foundations of similar size (diameter and depth) and installation method to those shown on the Plans and similar geotechnical conditions to those described in the geotechnical report. The work experience shall be direct supervisory responsibility for the on -site drilled shaft construction operations. Project management level positions indirectly supervising on -site drilled shaft construction operations are not acceptable for this experience requirement.
2.Drill rig operators shall have a minimum of one year of experience in construction of drilled shaft foundations. The Engineer may request a list identifying on -site supervisors and drill rig operators assigned to the project for review. The list shall contain a detailed summary of each individual's experience in drilled shaft excavation operations. The Contractor sh all inform the Engineer in writing of changes to field personnel.
b.Drilled Shaft Installation Plan . At least 30 days before the start of drilled shaft construction the Contractor shall submit an electronic file of a Drilled Shaft Installation Plan narrative. In preparing the narrative, the Contractor shall reference the available subsurface geotechnical data provided in the Co ntract and any geotechnical reports prepared for this project. This narrative shall provide at a minimum the following information:
1.Description of overall construction operation sequence and the sequence of drilled shaft construction when in groups or lines.
2.A list, description, and capacities of proposed equipment including but not limited to cranes, drills, augers, bailing buckets, final cleaning equipment and drilling unit. As appropriate, the narrative shall describe why the equipment was selected and suit ability to the anticipated site and subsurface conditions.
Source: Colorado Standard Specifications for Road and Bridge Construction, 2023 Edition. Pages 411–422 of 943.