500part1.pdf

DIVISION 550

Bridge Construction

Section 551—Driven Piles

Description

551.01 Work. Furnish and drive piles. In addition, furnish and place reinforcing steel and concrete in concrete-filled steel shell and concrete-filled pipe piles.

Piles are designated as steel H-piles, steel pipe piles, concrete-filled steel shell piles, concrete-filled pipe piles, precast concrete piles, prestressed concrete piles, or timber piles. Pile load tests are designated as static or dynamic.

Materials

551.02 Requirements. Furnish material that conforms to the specifications in the following sections and subsections:

Concrete Piles.....................................................................715.03 Paint Pile Shoes...........................................................................715.08 Reinforcing Steel Sheet Piles..........................................................................715.07 Splices ................................................................................715.09 Steel H-Piles.......................................................................715.06 Steel Pipes..........................................................................715.05 Steel Shells.........................................................................715.04 Structural Concrete Treated Timber Piles...........................................................715.02 Untreated Timber Piles.......................................................715.01

Construction

551.03 Pile-Driving Equipment. Furnish equipment meeting the following requirements:

(a) Pile Hammers. Furnish pile hammers as shown below.

(1) Gravity Hammers. Use gravity hammers to drive timber piles only, and where the ultimate bearing capacity of the timber pile is less than 800 kN. Furnish a hammer with a ram weighing between 900 and 1,600 kg and limit the drop height to 4 m. Ensure that the ram mass is greater than the combined mass of the drive head and pile. Provide hammer guides to ensure concentric impact on the drive head.

(2) Open-End Diesel Hammers. Equip open-end (single-acting) diesel hammers with a device, such as rings on the ram or a scale (jump stick) extending above the ram cylinder, to permit visual determination of hammer stroke. Submit a chart from the hammer manufacturer equating stroke and blows per minute for the hammer to be used. A speed-versus-stroke calibration may be used if approved.

(3) Closed-End Diesel Hammers. Submit a chart, calibrated to actual hammer performance within 90 days of use, equating bounce chamber pressure to either equivalent energy or stroke for the hammer to be used. Equip hammers with a dial gage for measuring pressure in the bounce chamber. Make the gage readable at ground level. Calibrate the dial gage to allow for losses in the gage hose. Verify the accuracy of the calibrated dial gage during driving operations by ensuring that cylinder lift occurs when bounce chamber pressure is consistent with the maximum energy given in the hammer specifications. Do not use closed-end diesel hammers that do not attain cylinder lift at the maximum energy-bounce chamber pressure relationship given in the hammer specification.

(4) Air or Steam Hammers. Furnish plant and equipment for steam and air hammers with sufficient capacity to maintain the volume and pressure specified by the hammer manufacturer. Equip the hammer with accurate pressure gages that are easily accessible. Use a hammer with the mass of the striking parts equal to or greater than one-third the combined mass of the driving head and pile. Ensure that the combined mass is at least 1,250 kg.

When driving test piles, measure inlet pressures for double-acting and differential-acting air or stream hammers with a needle gage at the head of the hammer. If required, also measure inlet pressures during the driving of the production piles. A pressure-versus-speed calibration may be developed for the specific driving conditions at the project as an alternative to periodic measurements with a needle gage.

(5) Nonimpact Hammers. Do not use nonimpact hammers, such as vibratory hammers, unless permitted in writing, SHOWN ON THE DRAWINGS, or provided in the SPECIAL PROJECT SPECIFICATIONS. If permitted, use such equipment for installing production piles only after the pile tip elevation, or embedment length, for safe support of the pile load is established by static or dynamic load testing.

Control the installation of production piles when using vibratory hammers by power consumption, rate of penetration, specified tip elevation, or other acceptable methods that will ensure the required pile load capacity is obtained. On 1 out of every 10 piles driven, strike with an impact hammer of suitable energy to verify that the required pile capacity is obtained.

(b) Approval of Pile-Driving Equipment. Furnish pile-driving equipment of such size that the production piles can be driven with reasonable effort to the required lengths without damage.

Section 551

The Government will evaluate the suitability of the equipment and will accept or reject the driving system within 21 days of receipt of the pile and driving equipment information. Approval of pile-driving equipment will be based on a wave equation analysis under the following conditions:

• When dynamic load testing is required.

• When ultimate pile capacities exceed 2,400 kN.

• When precast or prestressed concrete piles are used.

• When double-acting or differential hammers, air, steam, or diesel are used.

When the wave equation analysis is not used, approval of the pile-driving equipment will be based on minimum hammer energy in table 551-1. Approval of a pile hammer relative to driving stress damage does not relieve the Contractor of responsibility for damaged piles.

Section 551

Table 551-1.—Minimum pile hammer energy.

If the wave equation analysis shows an inability to drive the pile(s) to the required ultimate pile-bearing capacity with an acceptable blow count, or that pile damage will occur, change the proposed driving equipment until the wave equation analysis indicates that piles can be driven as specified. Submit proposed changes to the CO for review.

Approval of the pile-driving system is specific to the equipment submitted. If the proposed equipment is modified or replaced, resubmit the revised data for approval before using. The revised driving system will be accepted or rejected within 21 days of receipt of the revised pile, equipment, and wave equation analysis information (if required). Use only the approved equipment during pile-driving operations.

Ultimate Pile Capacity

(kN)

Minimum Rated Hammer Energy

(kJ)

≤ 800 14.0

1,330 21.2 1,600 28.1

1,870 36.0 2,140 44.9

2,400 54.4 > 2,400 Wave equation required

(1) Equipment Submittal. Submit two copies of the following pile-driving equip-ment information at least 30 days before driving piles. When dynamic load tests are required, submit a wave equation analysis performed by a pile specialty consultant who meets the requirements specified in Subsection 551.12(a). If dynamic load testing is not required, the Government will perform the wave equation analysis.

(a) General. Project and structure identification, pile driving contractor or subcon-tractor, and auxiliary methods of installation, such as jetting or preboring, and the type and use of the equipment.

(b) Hammer. Manufacturer, model, type, serial number, rated energy ( _____ at _____ length of stroke), and modifications.

(c) Capblock (Hammer Cushion). Material, thickness, area, modulus of elastic-ity (E), and coefficient of restitution (e).

(d) Pile Cap. Helmet mass, bonnet mass, anvil block mass, and drivehead weight.

(e) Pile Cushion. Cushion material, thickness, area, modulus of elasticity (E), and coefficient of restitution (e).

(f) Pile. Pile type, length (in leads), mass per meter, wall thickness, taper, cross-sectional area, design pile capacity, description of splice, and tip treatment description.

(2) Wave Equation. The required number of hammer blows indicated by the wave equation at the ultimate pile capacity shall be between 3 and 15 per 25 mm. In addition, ensure that the pile stresses resulting from the wave equation analysis do not exceed the values at which pile damage is impending. The point of impending damage is defined for steel, concrete, and timber piles as follows:

(a) Steel Piles. Limit the compressive driving stress to 90 percent of the yield stress of the pile material.

(b) Concrete Piles. Limit the tensile (TS) and compressive (CS) driving stresses to:

TS - 3f c

' + EPV

CS - 0.85f c

' – EPV

where f c ' = 28-day design compressive strength of concrete

EPV = effective prestress value (prestressed piles only)

(c) Timber Piles. Limit the compressive driving stress to 3 times the allowable static design stress.

(3) Minimum Hammer Energy. Ensure that the energy of the driving equipment submitted for approval, as rated by the manufacturer, is at least the energy specified in table 551-1 that corresponds to the required ultimate pile capacity.

(c) Driving Appurtenances. Furnish the driving appurtenances shown below.

(1) Hammer Cushion. Equip all impact pile-driving equipment, except gravity hammers, with a suitable thickness of hammer cushion material to prevent damage to the hammer or pile and to ensure uniform driving behavior. Fabricate hammer cushions from durable, manufactured material in accordance with the hammer manufacturer’s recommendations. Do not use wood, wire rope, or asbestos hammer cushions. Place a striker plate, as recommended by the hammer manufacturer, on the hammer cushion to ensure uniform compression of the cushion material. Inspect the hammer cushion in the presence of the CO when beginning pile-driving at each bent or substructure unit or after each 100 hours of pile-driving, whichever is less.

Replace the cushion when its thickness is reduced by more than 50 percent of its original thickness or when it begins to burn.

(2) Pile Drive Head. Provide adequate drive heads for impact hammers, and provide appropriate drive heads, mandrels, or other devices for special piles, in accordance with the manufacturer’s recommendations. Align the drive head axially with the hammer and pile. Fit the drive head around the pile head so that it will prevent transfer of torsional forces during driving while maintaining proper alignment of hammer and pile.

(3) Leads. Support piles in line and position with leads while driving. Construct pile driver leads to allow freedom of movement of the hammer while maintaining axial alignment of the hammer and the pile. Do not use swinging leads unless permitted in writing, SHOWN ON THE DRAWINGS, or provided in the SPECIAL PROJECT SPECIFICATIONS. When swinging leads are permitted, fit swinging leads with a pile gate at the bottom of the leads and, in the case of battered piles, with a horizontal brace between the crane and the leads. Adequately embed the leads in the ground or constrain the pile in a structural frame (template) to maintain proper alignment. Provide leads of sufficient length that do not require a follower and will permit proper alignment of battered piles.

(4) Followers. Followers are not permitted unless approved in writing. When followers are permitted, drive the first pile in each bent or substructure unit and every tenth pile driven thereafter, full length without a follower, to verify that adequate pile embedment is being attained to develop the required ultimate pile capacity. Provide a follower of such material and dimensions that will permit the piles to be driven to the required penetration. Hold and maintain the follower and pile in proper alignment during driving.

(5) Jetting. Do not use jetting unless approved in writing. Provide jetting equipment with sufficient capacity to deliver a consistent pressure equivalent to at least 700 kPa at two 20-mm jet nozzles. Jet so as not to affect the lateral stability of the final in-place pile. Remove jet pipes when the pile tip is at least 1.5 m above the prescribed tip elevation, and drive the pile to the required ultimate pile capacity with an impact hammer. Control, treat, if necessary, and dispose of all jet water in an approved manner.

551.04 Pile Lengths. Unless otherwise specified, furnish piles with sufficient length to obtain the required penetration and bearing capacity and extend into the pile cap or footing as SHOWN ON THE DRAWINGS. In addition, increase the length to provide fresh heading and to provide for the Contractor’s method of operation. When test piles are required, furnish piles in the lengths determined by the test piles, increased to provide for the Contractor’s method of operation.

551.05 Test Piles. Construct test piles at locations SHOWN ON THE DRAW- INGS. Excavate the ground at the site of each test pile or production pile to the elevation of the bottom of the footing or pile cap before the pile is driven. Furnish test piles that are longer than the estimated length of production piles. Drive test piles with the same equipment as the production piles.

Drive test piles to the required ultimate capacity at the estimated tip elevation. Allow test piles that do not attain the required ultimate capacity at the estimated tip elevation to “set up” for 24 hours before redriving. Warm the hammer before redriving begins by applying at least 20 blows to another pile. If the required ultimate capacity is not attained on redriving, drive a portion or all of the remaining test pile length and repeat the “set up” and redrive procedure as directed. Splice and continue driving until the required ultimate pile capacity is obtained.

Ensure that test piles that are used in the completed structure conform to the requirements for production piles. Remove test piles that are not incorporated into the completed structure to at least 0.5 m below finished grade.

Do not order piling to be used in the completed structure until test pile data have been reviewed and the production pile order lengths are determined. The CO will provide an estimated length list or pile order list within 10 days after completion of all test pile driving.

551.06 Driven-Pile Capacity. Drive piles with approved pile-driving equipment to the specified penetration and to the depth necessary to obtain the required ultimate pile capacity. Splice piles that do not obtain the required ultimate capacity at the ordered length and drive with an impact hammer until the required ultimate pile capacity is achieved.

Use the dynamic formula to determine ultimate pile capacity of the in-place pile, unless the wave equation is required in accordance with Subsection 551.03(b).

(a) Wave Equation. Adequate penetration will be considered to be obtained when the specified wave equation resistance criteria are achieved within 1.5 m of the designated tip elevation as SHOWN ON DRAWINGS. Drive any piles that do not achieve the specified resistance within these limits to a penetration determined by the CO.

(b) Dynamic Formula. Drive the piles to the penetration necessary to obtain the ultimate pile capacity in accordance with the following formula:

where Ru = ultimate pile capacity in kilonewtons E = manufacturer’s rated hammer energy in joules at the ram stroke observed or measured in the field E = W xH x 9.81 W = mass kilograms of striking parts of hammer H = meter height of fall of the ram measured during pile driving in the field log (10N) = logarithm to the base 10 of the quantity 10 multiplied by N

N = number of hammer blows per 25 mm at final penetration

Solving for N:

Factor of Safety (FS) = 3.0

(1) Jetted Piles. Determine the in-place ultimate capacity of jetted piles based on impact hammer blow counts (dynamic formula) after the jet pipes have been removed. After the pile penetration length necessary to produce the required ultimate pile capacity has been determined by impact hammer blow count, install the remaining piles in each group or in each substructure unit to similar depths with similar methods. Confirm that the required ultimate pile capacity has been achieved by using the dynamic formula.

(2) Vibratory Hammers. The ultimate bearing capacity of piles driven with vibratory hammers will be based on impact driving blow count after the vibratory equipment has been removed. When vibratory installation of the piles is approved

Section 551

Ru = E(7 log(10N) - 550 )

N = 10x x = Ru+550

7 E

�1 by the CO and the vibrated piles do not attain the required ultimate pile-bearing capacity at the specified length, splice them as required without compensation, and drive with a specified impact pile hammer until the required ultimate pile-bearing capacity is achieved.

(3) Conditions for Dynamic Formula. The dynamic formula is applicable only if all of the following criteria apply:

(a) The hammer is in good condition and operating in a satisfactory manner.

(b) The hammer ram falls freely.

(c) A follower is not used.

(d) The head of the pile is not broomed or crushed.

(c) “Set Period” & Redriving. If piles do not attain the required bearing capacity when driven to the specified length, allow the piles to stand for a “set period” without driving. The “set period” shall be a minimum of 24 hours unless otherwise approved by the CO. After the “set period,” perform check driving on either 2 piles in each bent or on 1 pile in 10 piles, whichever is more. The CO will designate the piles on which check driving is to be performed. Do not use a cold hammer for redriving. Warm up the hammer before redriving begins by applying at least 20 blows to another pile. Perform redriving by driving the pile to the required bearing with a maximum of 15 blows. If the specified hammer blow count is not attained on redriving, the CO may require driving all of the remaining pile length and repeating the “set period” and redriving procedure. Splice any piles driven to plan grade that do not attain the hammer blow count required, and drive until the required bearing is obtained. If the required bearing capacity is attained for each pile that is redriven, then the remaining piles in that bent will be considered satisfactory when driven to at least the same penetration and resistance as the redriven piles.

551.07 Preboring. Unless otherwise provided in the SPECIAL PROJECT SPECIFICATIONS, prebore holes to natural ground when piles are driven through compacted embankments more than 1.5 m in depth. Use augering, wet rotary drilling, or other approved methods of preboring. Except for piles end bearing on rock or hardpan, stop preboring at least 1.5 m above the pile tip elevation and drive the pile with an impact hammer to a penetration that achieves the required ultimate pile capacity. Preboring may extend to the surface of the rock or hardpan where piles are to be end bearing on rock or hardpan. Seat installed piles into the end bearing strata.

Prebore holes smaller than the diameter or diagonal of the pile cross section while allowing penetration of the pile to the specified depth. If subsurface obstructions such as boulders or rock layers are encountered, the hole diameter may be increased to the least dimension adequate for pile installation. After driving is completed, fill any void space remaining around the pile with sand or other approved material.

Do not use a punch or a spud in lieu of preboring.

Do not impair the carrying capacity of existing piles or the safety of adjacent structures. If preboring disturbs the load carrying capacities of previously installed piles or structures, restore the required ultimate capacity of piles and structures by approved methods.

551.08 Jetting. Jetting will be permitted only when SHOWN ON THE DRAW- INGS or approved in writing by the CO. When jetting is not required, but approved at the Contractor’s request, 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 without affecting the lateral stability of the final in-place pile. Control, treat if necessary, and dispose of all jet water in a satisfactory manner. Drive all jetted piles with an approved impact hammer.

551.09 Preparation & Driving. Perform the work specified in Section 206 prior to driving piles. Make the heads of all piles plane and perpendicular to the longitudinal axis of the pile. Coordinate pile driving so as not to damage other parts of the completed work.

Drive piles to within 50 mm of plan location at cutoff elevation for bent caps, and within 150 mm of plan location for piles capped below finished ground. Ensure that the pile is no closer than 100 mm to any cap face and no closer than 225 mm to the face of any footing. Drive piles so that the axial alignment is within 20 mm/m of the required alignment. The CO may stop driving to check the pile alignment. Check the alignment of piles that cannot be internally inspected after installation before the last

1.5 m are driven. Do not pull laterally on piles or splice to correct misalignment. Do not splice a properly aligned section on a misaligned pile.

Unless otherwise SHOWN ON THE DRAWINGS, drive piles at least 5 m below the footing or cap. If the required minimum penetration cannot be obtained, provide a larger hammer, prebore or jet holes, or use other methods approved by the CO and in accordance with Subsection 551.03.

If the specified location and/or alignment tolerances are exceeded, the effect of the pile misalignment on the substructure design will be investigated. If the CO determines that corrective measures are necessary, implement suitable measures to correct the problem without compensation.

Place individual piles in pile groups, either starting from the center of the group and proceeding outward in both directions, or starting at the outside row and proceeding progressively across the group.

In an approved manner, correct all piles that are driven improperly, driven out of proper location, misaligned, or driven below the designated cutoff elevation. Replace piles damaged during handling or driving. Obtain approval for the proposed method(s) of correcting or repairing deficiencies.

Ensure that the method used in driving piles does not produce crushing and spalling of the concrete; injurious splitting, splintering, and brooming of the wood; or deformation of the steel.

(a) Timber Piles. Use piling that meets the minimum diameter requirements SHOWN ON THE DRAWINGS. Do not use piles with checks wider than 15 mm.

Drive treated timber piles within 6 months after treatment. Handle and care for pressure-treated piles in accordance with American Wood Preservers Association (AWPA) standard M 4 and applicable portions of Subsection 557.04.

Install pile shoes as SHOWN ON THE DRAWINGS. Carefully shape the pile tip to secure an even, uniform bearing for the pile shoe. Fasten the shoe securely to the pile. Treat all holes, cuts, or daps in treated piles with two brush applications of creosote-coal tar solution or other preservative, as provided in the SPECIAL

PROJECT SPECIFICATIONS.

Regulate the drop of the hammer to avoid damage to the pile if driving with a gravity hammer is permitted.

Select piles for any one bent to avoid undue bending or distortion of the sway bracing. Exercise care in the distribution of piles of various sizes to obtain uniform strength and rigidity in the bents of any given structure.

(b) Steel Piles. Furnish full length unspliced piles for lengths up to 18 m. If splices are required in the first pile driven and it is anticipated that subsequent piles will also require splices, place the splices in the lower one-third of the pile. Splice lengths less than 3 m are not permitted, and only two splices per pile are allowed, unless otherwise approved by the CO.

Load, transport, unload, store, and handle steel piles so that the metal is kept clean and free from damage. Do not use piles that exceed the camber and sweep permitted by allowable mill tolerance. Steel piles damaged during installation are considered unsatisfactory unless load tests prove that the bearing capacity is 100 percent of the required ultimate capacity. Load tests performed will be at no cost to the Government.

(c) Precast & Prestressed Concrete Piles. Support concrete piles during lifting or moving at the points SHOWN ON THE DRAWINGS or approved shop drawings. If points are not shown, provide support at the quarter points. Provide slings or other equipment when raising or transporting concrete piles to avoid bending the pile or breaking edges.

Protect the heads of concrete piles with a pile cushion at least 100 mm thick. Cut the pile cushion to match the cross section of the pile top. Replace the pile cushion if it is either compressed more than one-half its original thickness or begins to burn.

Provide a new pile cushion for each pile.

A concrete pile is defective if any defect is observed that will affect the strength or long-term performance of the pile.

(d) Concrete-Filled Pipe or Steel Shell Piles. Furnish and handle the steel shells or pipes in accordance with Subsection 551.09(b). Cutting shoes for shells or pipes may be inside or outside the shell. Use high-carbon structural steel with a machined ledge for shell bearing or cast steel with a ledge designed for attachment with a simple weld.

When practicable, drive all pile shells or pipes for a substructure unit prior to placing concrete in any of the shells or pipes. Do not drive pile shells or pipes within 5 m of any concrete-filled pile shell or pipe until the concrete has cured for at least 7 days, or 3 days if using high-early-strength concrete. Do not drive any pile shell or pipe after it is filled with concrete.

Remove and replace shells that are determined to be unacceptable for use due to breaks, bends, or kinks.

551.10 Splices. Submit details for pile field splices for approval. Align and connect pile sections so the axis of the spliced pile is straight.

(a) Steel Piles. Submit a welder certification for each welder. Use welders certified for structural welding.

Make surfaces to be welded smooth, uniform, and free from loose scale, slag, grease, or other material that prevents proper welding. Steel may be oxygen cut. Carbon-arc gouging, chipping, or grinding may be used for joint preparation.

Weld in accordance with AASHTO/American Welding Society (AWS) D 1.5, Bridge Welding Code. Weld the entire pile cross section using prequalified AWS groove weld butt joints. Weld so there is no visual evidence of cracks, lack of fusion, undercutting, excessive piping, porosity, or inadequate size. Manufactured splices may be used in place of full penetration groove butt welds.

(b) Concrete Pile Splices. Submit drawings of proposed splices for approval. Use dowels or other acceptable mechanical means to splice precast concrete or precast prestressed concrete piles. Ensure that the splice develops strengths in compres-sion, tension, and bending equal to or exceeding the strength of the pile being spliced.

(c) Concrete Pile Extensions. Construct precast concrete piles and prestressed piles as shown below.

(1) Precast Concrete Piles. Extend precast concrete piles by removing the concrete at the end of the pile and leaving 40 diameters of reinforcement steel exposed. Re-move the concrete to produce a face perpendicular to the axis of the pile. Securely fasten reinforcement of the same size as that used in the pile to the projecting rein-forcing steel. Form the extension to prevent leakage along the pile.

Immediately before placing concrete, wet the top of the pile thoroughly and cover with a thin coating of neat cement, retempered mortar, or other approved bonding material. Place concrete of the same mix design and quality as that used in the pile.

Keep forms in place for not less than 7 days after the concrete has been placed. Cure and finish in accordance with Section 552.

(2) Prestressed Piles. Extend prestressed precast piles in accordance with Subsec-tion 551.10(c)(1). Include reinforcement bars in the pile head for splicing to the extension bars. Do not drive extended prestressed precast piles.

(d) Timber Piles. Do not splice timber piles.

551.11 Heaved Piles. Check for pile heave during the driving operation. Take level readings immediately after each pile is driven and again after piles within a radius of 5 m are driven. Redrive all piles that heave more than 5 mm. Redrive to the specified resistance or penetration. Continue readings until the CO determines that such checking is no longer required.

551.12 Pile Load Tests. Pile load tests are not required unless SHOWN ON THE

DRAWINGS.

(a) Dynamic Load Test. Use a qualified pile specialty consultant with at least 3 years experience in dynamic load testing and analysis, to perform the dynamic load test, the Case Pile Wave Analysis Program (CAPWAP), and the wave equation analysis including the initial wave analysis specified in Subsection 551.03(b)(1).

Submit a resume of the specialty consultant for approval by the CO.

Furnish a shelter to protect the dynamic test equipment from the elements. Locate the shelter within 15 m of the test location. Provide a shelter with a minimum floor size of 6 m2 and minimum ceiling height of 2 m. Maintain the inside temperature between 10 °C and 35 °C.

Furnish equipment and perform dynamic load tests in accordance with ASTM D 4945 under the supervision of the CO.

Place the piles designated as dynamic load test piles in a horizontal position and not in contact with other piles. Drill holes for mounting instruments near the head of the pile. Mount the instruments and take wave speed measurements. Place the desig-nated pile in the leads. Provide at least a 1.2 x 1.2-m rigid platform, with a 1.1-m safety rail, that can be raised to the top of the pile.

Provide a suitable electrical power supply for the test equipment. If field generators are used as the power source, provide functioning meters for monitoring power voltage and frequency.

Drive the pile to the depth at which the dynamic test equipment indicates that the required ultimate pile capacity is achieved. If necessary to maintain stresses in the pile below the values shown in Subsection 551.03(b)(2), reduce the driving energy transmitted to the pile by using additional cushions or reducing the energy output of the hammer. If nonaxial driving is indicated, immediately realign the driving system.

At least 24 hours after the initial driving, redrive each dynamic load test pile with instrumentation attached. Warm the hammer before redriving by applying at least 20 blows to another pile. Redrive the dynamic load test pile for a maximum pene-tration of 150 mm or a maximum of 50 blows, whichever occurs first. Practical driving refusal is defined as 15 blows per 25 mm for steel piles, 8 blows per 25 mm for concrete piles, and 5 blows per 25 mm for timber piles.

Verify the assumptions used in the initial wave equation analysis submitted in accordance with Subsection 551.03(b) using CAPWAP. Analyze one blow from the original driving and one blow from the redriving for each pile tested.

Perform additional wave equation analyses with adjustments based on the CAPWAP results. Provide a graph showing blow count versus ultimate capacity. For open-end diesel hammers, provide a blow count versus stroke graph for the ultimate capacity.

Provide the driving stresses, transferred energy, and pile capacity as a function of depth for each dynamic load test.

Based on the results of the dynamic load testing, CAPWAP analyses, and wave equation analyses, the production driving criteria may be approved by the CO, who will provide the order list and the required cutoff elevations, or additional pile penetration and testing may be specified. This information will be provided within 10 days after receipt of all required test data for the test piles driven.

(b) Static Load Tests. Perform static load tests in accordance with ASTM D 1143 using the quick load test method, except as modified herein. Submit drawings of the proposed loading apparatus for approval by the CO, in accordance with the following:

(1) Have a licensed professional engineer prepare the drawings.

(2) Furnish a loading system capable of applying 150 percent of the ultimate pile capacity or 9,000 kN, whichever is less.

(3) Construct the apparatus to allow increments of load to be placed gradually without causing vibration to the test pile.

When tension (anchor) piles are required, drive tension piles at the location of permanent piles when feasible. Do not use timber or tapered piles installed in permanent locations as tension piles. Take the test to plunging failure or the capacity of the loading system.

The safe axial pile load is defined as 50 percent of the failure load. The failure pile load is defined as follows:

• For piles 600 mm or less in diameter or diagonal width:

• For piles greater than 600 mm in diameter or diagonal width:

where S f = settlement at failure in millimeters

D = pile diameter or diagonal width in millimeters S = elastic deformation of pile in millimeters

Determine top elevation of the test pile immediately after driving and again just before load testing to check for heave. Wait a minimum of 3 days between the driving of any anchor or the load test piles and the commencement of the load test.

Prior to testing, redrive or jack to the original elevation any pile that heaves more than 6 mm.

After completion of static testing, remove or cut off any test or anchor piling not a part of the finished structure at least 500 mm below either the bottom of the footing or the finished ground elevation.

Sf = S+

D

S f = S + 3.8+ 0 .008 D( )

Based on the results of the static load testing, the production driving equipment may be approved by the CO, who will provide the order list and the required cutoff elevations, or additional tests may be specified. This information will be provided within 10 days after receipt of all required test data for the test piles driven.

551.13 Pile Cutoffs. Cut off the tops of all production piles and pile casings at the required elevation. Cut off the piles clean and straight parallel to the bottom face of the structural member in which they are embedded.

Ensure full bearing between timber caps and piles by making accurate, square cuts.

Remove all unused pile cutoff lengths and dispose of them in accordance with applicable State and local laws and regulations. Dispose of treated timber pile cut-offs in accordance with the requirements of Subsection 202.04(a) for disposal of treated material.

(a) Steel Piles. Do not paint steel to be embedded in concrete. Before painting the exposed steel pile, thoroughly clean the metal surface of any substance that will inhibit paint adhesion. Paint in accordance with Section 563. Paint portions of completed trestle or other exposed piling to a point not less than 1 m below finished groundline or to the waterline, as SHOWN ON THE DRAWINGS or as provided in the SPECIAL PROJECT SPECIFICATIONS.

(b) Wood Piles. When possible, cut the top of the pile on a bevel. Treat the heads of all treated timber piles that are not embedded in concrete using one of the following methods:

(1) Where possible, reduce the moisture content of the wood to no more than 25 percent and allow no free moisture on the surface. Brush on one application of creosote-coal tar solution as required in AWPA standards, or preservatives as provided in the SPECIAL PROJECT SPECIFICATIONS.

(2) Build up a protective cap by applying alternate layers of loosely woven fabric and hot asphalt or tar similar to membrane waterproofing, using three layers of asphalt or tar and two layers of fabric. Use fabric at least 150 mm wider in each direction than the diameter of the pile. Turn the fabric down over the pile and secure the edges by binding with two turns of 3-mm-diameter galvanized wire. Apply a final layer of asphalt or tar to cover the wire. Neatly trim the fabric below the wires.

(3) Cover the sawed surface with three applications of a hot mixture of 60 percent creosote and 40 percent roofing pitch, or thoroughly brush coat with three applications of hot creosote and cover with hot roofing pitch.

551.14 Unsatisfactory Piles. Correct unsatisfactory piles using an approved method. Methods of correcting unsatisfactory piles may include one or more of the following:

(a) Using the pile at a reduced capacity.

(b) Installing additional piles.

(c) Repairing damaged piles.

(d) Replacing damaged piles.

(e) Splicing on additional length(s) and driving, when necessary.

(f) Building up pile(s).

551.15 Placing Concrete in Steel Shell or Pipe Piles. After driving, clean the inside of shells and pipes by removing all loose material. Keep the shell or pipe substantially watertight. Provide suitable equipment for inspecting the entire inside surface of the driven shell or pipe just before placing concrete.

(a) Reinforcing Steel. When reinforcing steel is required, make the spacing between adjacent cage elements at least 5 times the maximum size of aggregate in the concrete.

Securely tie concrete spacers or other approved spacers at fifth points around the perimeter of the reinforcing steel cage. Install spacers at intervals not to exceed 3 m measured along the length of the cage.

Place the reinforcement cage into the driven shell or pipe when the concrete reaches the lower limits of the reinforcement. Support the reinforcement so it remains within 50 mm of the required vertical location. Support the cage from the top until the concrete reaches the top of the pile.

(b) Concrete. Construct concrete in accordance with Section 552. Place concrete in one continuous operation from the bottom to the top of the pile. Before the initial concrete set, consolidate the top 3 m of the concrete pile using approved vibratory equipment.

Measurement

551.16 Method. Use the method of measurement that is DESIGNATED IN THE

SCHEDULE OF ITEMS.

Measure piles by the meter or by the each. When measurement is by the meter, measure the length of pile from the cutoff elevation rounded to the tip.

Measure pile load tests by the each or by the lump sum.

Measure preboring by the meter.

Measure splices by the each for those made as required to drive piling in excess of the estimated plan tip elevation.

Measure test piles and pile shoes by the each.

Payment

551.17 Basis. The accepted quantities will be paid for at the contract unit price for each PAY ITEM DESIGNATED IN THE SCHEDULE OF ITEMS.

Payment will be made under:

Pay Item Pay Unit

551(01) __________ piles, furnished.............................................Meter

551(02) __________ piles, driven.................................................Meter

551(03) __________ piles, furnished.............................................Each

551(04) __________ piles, driven.................................................Each

551(05) __________ pile load test................................................ Each

551(06) __________ pile load test.............................................Lump Sum

551(07) Preboring..........................................................................Meter

551(08) Splices ..............................................................................Each

551(09) Test piles..........................................................................Each

551(10) Pile shoes......................................................................... Each

Section 552—Structural Concrete

Description

552.01 Work. Furnish, place, finish, and cure concrete in bridges, culverts, and other structures.

Structural concrete class is designated as shown in table 552-1.

Table 552-1.—Composition of concrete.

a. Maximum slump is 200 mm if approved mix design includes a high-range water reducer.

b. See Subsection 552.03 for maximum air content.

Materials

552.02 Requirements. Furnish material that conforms to specifications in the following subsections:

Air-Entraining Admixtures.................................................711.02 Boiled Linseed Oil..............................................................725.14 Chemical Admixtures.........................................................711.03 Coarse Aggregate................................................................703.02 Color Coating.....................................................................725.23 Curing Material..................................................................711.01 Elastomeric Bearing Pads...................................................717.10 Elastomeric Compression Joint Seals..................................717.16 Epoxy Resin Adhesives......................................................725.21 Fine Aggregate....................................................................703.01 Fly Ash ...............................................................................725.04 High-Strength Nonshrink Grout..........................................701.02 Latex Modifier....................................................................711.04 Low-Strength Grout............................................................701.03 Mortar ................................................................................ 701.04 Portland Cement................................................................ 701.01

Class of

Concrete

Minimum Cement Content (kg x m3 )

Maximum W/C Ratio

Slumpa

(mm)

Minimum Air Contentb

Coarse Aggregate

AASHTO M 43

A 360 0.49 50–100 – No. 57

A(AE) 360 0.44 25–100 5.0 No. 57

C 390 0.49 50–100 – No. 7

C(AE) 390 0.44 25–75 6.0 No. 7

P 390 0.44 0–100 – No. 67

Seal 390 0.54 100–200 – No. 57

Section 552

Sealants, Fillers, Seals, & Sleeves..................................... 712.01 Water .................................................................................. 725.01

Construction

552.03 Composition (Concrete Mix Design). Design and produce concrete mixtures that conform to table 552-1 for the class of concrete specified and the minimum strength requirements as SHOWN ON THE DRAWINGS or in Subsec-tion 552.04. Determine design strength values in accordance with ACI 214. Ensure that structural concrete also conforms to the following ACI specifications:

• ACI 211.1 for normal and heavyweight concrete.

• ACI 211.2 for lightweight concrete.

• ACI 211.3 for no-slump concrete.

Submit written concrete mix designs for approval at least 30 days before production.

Include the following in each mix design submittal:

(a) Project identification.

(b) Name and address of Contractor and concrete producer.

(c) Mix design designation.

(d) Class of concrete and intended use.

(e) Material proportions.

(f) Name and location of material sources for aggregate, cement, admixtures, and water.

(g) Type of cement and type of cement replacement, if used. Fly ash, ground iron blast-furniture slag, or silica fume may partially replace cement as follows in any mix design except for prestressed concrete:

(1) Fly ash.

(a) Class F. Not more than 20 percent of the minimum weight of Portland cement in table 552-1 may be replaced with class F fly ash at the rate of 1.5 parts fly ash per 1 part cement.

(b) Class C. Not more than 25 percent of the minimum mass of Portland cement in table 552-1 may be replaced with class C fly ash at the rate of 1 part fly ash per 1 part cement.

(2) Ground iron blast-furnace slag. Not more than 50 percent of the minimum mass of Portland cement in table 552-1 may be replaced with ground iron blast-furnace slag at the rate of 1 part slag per 1 part cement.

(3) Silica fume (microsilica). Not more than 10 percent of the minimum mass of Portland cement in table 552-1 may be replaced with silica fume at the rate of 1 part silica fume per 1 part cement.

The water/cement ratio for modified concrete is the ratio of the mass of water to the combined masses of Portland cement and cement substitute.

(h) Cement content in kilograms per cubic meter of concrete.

(i) The saturated surface dry batch weight of the coarse and fine aggregate in kilograms per cubic meter of concrete.

(j) Water content (including free moisture in the aggregate plus water in the drum, exclusive of absorbed moisture in the aggregate) in kilograms per cubic meter of concrete.

(k) Target water/cement ratio.

(l) Dosage of admixtures. Entrained air may be obtained either by the use of an air-entraining Portland cement, or by the use of an air-entraining admixture. Do not use set-accelerating admixtures with class P (prestressed) concrete. Do not mix chemical admixtures from different manufacturers.

(m) Sieve analysis of fine and coarse aggregate.

(n) Absorption of fine and coarse aggregate.

(o) Bulk specific gravity (dry and saturated surface dry) of fine and coarse aggregate.

(p) Dry rodded unit mass of coarse aggregate in kilograms per cubic meter.

(q) Fineness modulus (FM) of fine aggregate.

(r) Deleterious substances (coarse and fine aggregate); clay lumps and friable particles; material finer than the 75-µm sieve; coal and lignite (AASHTO M 80 7.1.6); chert (coarse aggregate only); and organic impurities (fine aggregate only).

(s) Evaluation of potential aggregate reactivity.

(t) Percentage of wear (L.A.R.) for coarse aggregate only.

(u) Sand equivalent (fine aggregate only).

(v) Material certifications for cement, admixtures, and aggregate.

(w) TV’s for concrete slump with and without high-range water reducers.

(x) TV’s for concrete air content. Include the proposed range of air content for concrete to be incorporated into the work. Describe the methods by which air content will be monitored and controlled. Provide acceptable documentation that the slump and compressive strength of the concrete are within specified limits throughout the full range of proposed air content. In the absence of such acceptable documentation, ensure that the maximum air content is 10 percent.

(y) Concrete unit mass.

(z) Compressive strengths of 7- and 28-day concrete. Pending 28-day strength results, a mix design may be approved on the basis that the 7-day com-pressive strength results equal or exceed 85 percent of the minimum strength requirements, when no accelerators or early strength cements are used.

(aa) Material samples, if requested.

Use a testing laboratory that is fully equipped and capable of performing the required tests and services. Base the mix design on representative samples of aggregates, cement, water, and admixtures to be used on the project. Take aggregate samples in accordance with AASHTO T 2 and reduce to testing size in accordance with AASHTO T 248. Submit a separate proposed mix design for each class of concrete to the CO for review.

Current mix designs for other projects may be acceptable, provided that all items required herein are covered by certified submittals. Ensure that mix design and aggregate quality tests from other projects have been run within 12 months of the date of submittal, and that the aggregate source is the same.

Begin production only after the mix design is approved.

Furnish a new mix design for approval if there is a change in a source of material, or when the FM of the fine aggregate changes by more than 0.20.

Use type II cement for all classes of concrete, but use type III cement when concrete work is permitted by the CO in air temperatures below 2 °C. Type III cement may be used in class A and seal concrete with the approval of the CO. Type III cement may be used in class P concrete when documented in the approved mix design.

552.04 Concrete Compressive Strength. Use the minimum 28-day compressive strength for the given classes of concrete shown in table 552-2, unless otherwise

SHOWN ON THE DRAWINGS.

Table 552-2.—Specified minimum concrete strength (MPa).

Make two standard test specimens for a strength test. Take enough specimens to make at least one 7-day strength test and one 28-day strength test (a minimum total of four specimens) for each structural element. Use the average of the strengths of the two specimens for test result, but discard any specimen that shows definite evidence, other than low strength, of improper sampling, molding, handling, curing, or testing, and consider the strength of the remaining cylinder to be the test result.

Extend the standard 28-day curing period for compressive strength tests for fly-ash-modified concrete by 1 day (rounded to the nearest whole day) for each 1.5 percent of Portland cement replaced with fly ash at the selected rate. (Example: If the maximum of 20 percent cement is replaced, the curing period for cylinders is 41 days.)

552.05 Storage & Handling of Material. Store and handle all material in a manner that prevents segregation, contamination, or other harmful effects. Do not use cement and fly ash containing evidence of moisture contamination. Store and handle aggregate in a manner that ensures a uniform moisture content at the time of batching.

Obtain the CO’s approval before using cement that has been stored on the site for more than 60 days. Provide separate storage of cement that is of different blends, types, or from different mills.

552.06 Measuring Material. Batch the concrete in accordance with the approved mix design and the following tolerances:

Cement................................................................................ ± 1% Water ................................................................................... ± 1% Aggregate............................................................................ ± 2% Additive............................................................................... ± 3%

Submit to the CO, for approval, a written procedure for adding the specified amount of admixture. Provide separate scales for the admixtures that are to be proportioned by mass and accurate measures for those to be proportioned by volume.

A calibrated volumetric system may be used if the specified tolerances are maintained.

Concrete Class

At Time of Transfer of

Prestress Force 7-Day 28-Day

A & A(AE)

C & C(AE)

P

P (AE)

Seal

31.5

31.5

15.9

18.2

13.8

24.2

27.7

34.5

20.7

552.07 Batching Plant, Mixers, & Agitators. Use a batching plant, mixer, and agitator conforming to AASHTO M 157. Use continuous volumetric mixing equipment that conforms to AASHTO M 241.

552.08 Mixing. Mix the concrete in a central-mix plant or in truck mixers. Operate all equipment within manufacturer’s recommended capacity. Produce concrete of uniform consistency.

(a)…