CATEGORY 400 STRUCTURES SECTION 413 — MICROPILES
413.01 Description
Design, furnish, install, and test micropiles capable of supporting loads as indicated in the Contract Documents. Furnish all submittals, materials, products, accessories, tools, equipment, services, transportation, labor and supervision, and installation techniques required for installing and testing micropiles as shown on the Plans, specified herein, and as directed by the Engineer. The micropile design capacity, size, and length in the Contract Documents is a minimum requirement for bidding purposes. The actual design capacity, size, and length submitted by the Contractor may be different from that shown but shall be at no additional cost to the Administration. Work also includes survey/layout and record keeping of the micropile installation according to the Contract Documents.
413.02 Materials
All materials shall be new and furnished without defects. Defective materials shall be removed from the jobsite at no additional cost to the Administration. Water 921.01 Concrete Admixtures 902.06 Portland Cement or Blended Hydraulic Cement Section 902 Grout 902.11(c), 915.03 Reinforcement Steel 908.01 Structural Steel Plates and Shapes A 709, Grade 36 or 50
413.02.01 Admixtures for Grout. Conform to the requirements of ASTM C494/AASHTO
M 194. Admixtures that control bleed, improve flowability, reduce water content, and retard set may be used in the grout, subject to the review and acceptance of the Engineer. Admixtures shall be compatible with the grout and mixed in accordance with the manufacturer’s recommendations. Expansive admixtures shall only be added to the grout used for filling sealed encapsulations and anchorage covers. Accelerators and chloride containing admixtures are not permitted.
413.02.02 Centralizers. Fabricate from material nondetrimental to the reinforcing steel and grout.
Wood and aluminum shall not be used. Securely attach to the reinforcement; size to position the reinforcement within 0.5 in. of plan location from center of micropile; size to allow grout tremie pipe insertion to the bottom of the drill hole; and size to allow grout to freely flow up the drill hole and steel casing and between adjacent reinforcing bars. 2025 STANDARD SPECIFICATIONS FOR CONSTRUCTION AND MATERIALS
413.02.03 Steel Casings. Use steel casings with an outside diameter and minimum wall thickness
as shown on the Plans, or as submitted by the Contractor and approved by the Office of Structures. Use steel casings connected by means of threaded joints to provide a flush connection; welding or splicing of the casing is prohibited. The threaded joint connection shall develop the required design strength of the pile as specified in the Contract Documents. Conform to the tensile requirements of A 252 Grade 3, except that the minimum yield strength shall be 50 000 psi.
413.03 Construction
413.03.01 Submittals. Submit the following qualifications, drawings, plans, and information for
accomplishing the work. Make the qualifications submittal listed in 413.03.01(a) below to the Office of Construction’s procurement team. Make all other submittals including any changes to those listed in 413.03.01(a) after award to the Office of Structures through the Engineer. Do not proceed with the work until all submittals are approved by the Administration. The Engineer will accept or reject each submittal within 15 calendar days after receipt of a complete submission. Additional time required due to incomplete or unacceptable submittals will not be the cause for time extension, impact, or delay claims. All costs associated with incomplete or unacceptable submittals shall be at no additional cost to the Administration.
a.Qualification Submittal. After the bid opening but before the contact award, submit an electronic PDF version of the qualification package, as listed below, to the Engineer for review and acceptance. If any changes are needed to this submittal, they must be made in writing at least 60 days before micropile construction. Micropile design is prohibited until the Contractor’s qualification submittal has been received and approved in writing. The qualification package shall include the following:
1.Micropile Installer Qualifications. Submit proof of the Contractor’s, or specialty sub-contractor’s proven record of experience with micropile installation, including at least three projects with similar subsurface conditions, micropile sizes, depths, and minimum volumes of work as contained in the project. Submit a brief description of each project with the owner’s name, address, and current telephone number.
2.Micropile Design Engineer Qualifications. Submit the resume of a professional engineer experienced in micropile design and registration in the State of Maryland (hereinafter referred to as the micropile design engineer). The micropile design engineer shall have experience of at least three projects of similar size and scope, one of which needs to be completed within the last five years. Submit the resume with sufficient information for the Engineer to make a determination of the micropile design engineer’s qualifications and experience, to include a listing of micropile projects completed and references.
b.Design criteria. Design the micropiles in accordance with the AASHTO Load and Resistance Factor Design (LRFD) Bridge Design Specifications edition shown on the plans. Steel micropiles are the only acceptable augered or drilled pile types. No other augered or drilled pile type, including helical piles, will be considered. Design the piles to meet the minimum uncased or bond zone lengths shown on the plans and extend 2025 STANDARD SPECIFICATIONS FOR CONSTRUCTION AND MATERIALS below the lowest ground elevation that the structure crosses. Meet or exceed the minimum micropile design capacity, size, and length in the Contract Documents. The number, location, and spacing of micropiles shown on the plans cannot be altered.
c.Working Drawings Submittal. As part of the working drawing submission, include all information required for the construction and quality control of the micropiles; including, but not limited to, the following:
1.Design parameters and applicable codes based on the Contract Documents.
2.General notes for constructing the micropiles including construction sequencing or other special construction requirements.
3.A listing of the summary of quantities for each substructure unit showing pay item estimated quantities.
4.Micropile typical sections; pipe casing and reinforcing bar sizes and details; and connection details to the substructure footing, anchorage, plates, etc.
5.Minimum drillhole diameter, splice types and locations, centralizer and spacer types and locations, grout bond zone and casing plunge lengths, and corrosion protection details.
6.A typical detail of verification test micropiles defining the micropile length, minimum drillhole diameter, micropile casing, steel reinforcement, and load test bonded and unbonded test lengths.
7.Details, dimensions, and schedules for all micropiles, casing, and reinforcing steel, including reinforcing bar bending details.
8.Details for constructing micropiles around drainage facilities (if applicable).
d.Micropile Installation Procedure Submittal. At least 30 calendar days before construction, submit an electronic PDF version of the micropile installation procedure package to the Engineer for review and acceptance. Drilling, installing, and testing of micropiles is prohibited until the Contractor’s construction submittal has been received and approved in writing. The Engineer may suspend the work if the Contractor uses non-approved personnel. If work is suspended, it shall be at no additional cost and no adjustment in Contract time. The micropile installation procedure package shall include the following:
1.Geotechnical Engineer. Employ the services of a qualified geotechnical engineer and geotechnical engineer technician for inspection and testing for installation of micropiles. Ensure that the geotechnical engineer is a Professional Engineer registered in the State of Maryland and that the geotechnical engineer technician works for the same company under the direct supervision of the geotechnical engineer. Ensure that both the geotechnical engineer and geotechnical engineer technician have a demonstrated record of 2025 STANDARD SPECIFICATIONS FOR CONSTRUCTION AND MATERIALS experience with similar micropile installations, and are approved prior to beginning drilling for the micropiles. One or both of these people are hereinafter referred to as the geotechnical engineer in this specification.
2.Detailed systematic description of the proposed micropile construction procedure, including personnel, testing, and equipment to ensure quality control. This systematic procedure shall be shown on the working drawings in sufficient detail to allow the Engineer to monitor the construction and quality of the micropiles.
3.A schedule indicating the proposed start date, duration of micropile installation and micropile installation schedule including a plan sheet with each micropile sequentially labeled.
4.Information on headroom and space requirements for installation equipment that verify proposed equipment can perform at the site.
5.Containment plan describing how surface water, drill flush, and excess waste grout will be controlled and disposed.
6.Certified mill test reports for the reinforcing steel and steel casing which shall include the ultimate strength, yield strength, elongation, and material property composition. For API N-80 pipe casing, coupon test results for the above data may be substituted in lieu of mill certification.
7.Grouting procedures that include complete descriptions, details, and supporting calculations for the following:
i.Method of placing reinforcing steel, which shall include a catalog cut of a sample centralizer for approval by the Engineer. (ii) Grout mix designs and type of materials to be used in the grout including certified test data and trial batch reports. (iii)Methods and equipment for accurately monitoring and recording the grout depth, grout volume, and grout pressure as the grout is being placed. (iv) Grouting rate calculations when requested by the Engineer. The calculations shall be based on the static head of the grout and losses throughout the placing system including anticipated head of drilling fluid (if applicable) to be displaced.
v.Procedure and equipment for mixing, placing, and monitoring of grout quality. (vi) Theoretical volume of grout for each micropile installation. 2025 STANDARD SPECIFICATIONS FOR CONSTRUCTION AND MATERIALS (vii) Procedure to be followed for cases where the actual amount of grout used exceeds two times the theoretical volume.
8.Load testing plan and calculations, signed and sealed by the micropile design engineer, that include the following:
i.Load test procedures and acceptability criteria for the verification and proof test micropiles, including creep test criteria. Minimum strength acceptance criterion for verification load tests shall be if failure does not occur at 2.0 times the ultimate factored design load test loading. Minimum strength acceptance criterion for proof load tests shall be if failure does not occur at 1.6 times the ultimate factored design load test loading. Failure is defined as loading at which attempts to further increase the test load result in continued micropile movement. The creep test shall hold 1.33 times the ultimate factored design load for at least 1 hour. (ii) Description of the test setup and jack, pressure gauge, and load cell calibration curves. (iii) Method and accuracy of the hydraulic jack for applying the load. Jack ram travel shall be sufficient to allow the test to be done without resetting the equipment. The hydraulic jack calibration report shall be submitted if requested by the Engineer. The calibration tests shall have been performed by an independent testing laboratory and tests shall have been performed within one year of the date submitted. (iv) Type and accuracy of the pressure gauges for measuring load. The pressure gauge shall be graduated in 100 psi increments or less. The jack and pressure gauges shall have a pressure range not exceeding twice the anticipated maximum test pressure. The calibration tests shall have been performed by an independent testing laboratory and tests shall have been performed within one year of the date submitted.
v.Type and accuracy of the apparatus for measuring top of micropile deformation, including placement and support of measuring devices. The top pile movement measurement apparatus shall include three dial gauges equally spaced 120 degrees apart around the pile reading to 0.001 in.; a wire, mirror, and scale system suitably mounted on the pile; and an independent measurement frame as an auxiliary monitoring device. The dial gauges shall have a travel sufficient to allow the test to be done without having to reset the gauges. Support the gauges independently from the jack, pile, and reaction frame. (vi) Type and capacity of the reaction frame. Design the reaction frame to be sufficiently rigid and of adequate dimension so that excessive deformation of the testing equipment does not occur. 2025 STANDARD SPECIFICATIONS FOR CONSTRUCTION AND MATERIALS (vii) Reaction frame piles and configuration.
413.03.02 Pre-construction Meeting. A pre-construction meeting will be scheduled by the
Engineer and held prior to the start of micropile construction. The Engineer, prime Contractor, micropile specialty Contractor, micropile design engineer, geotechnical engineer, excavation Contractor, and geotechnical instrumentation specialist (if applicable) shall attend the meeting. Attendance is mandatory. The pre-construction meeting will be conducted to clarify the construction requirements for the work, to coordinate the construction schedule and activities, and to identify contractual relationships and delineation of responsibilities amongst the prime Contractor and the various subcontractors specifically those pertaining to excavation for micropile structures, anticipated subsurface conditions, micropile installation and testing, micropile structure survey control, and site drainage control.
413.03.03 Utilities. Adhere to the requirements in Section 875 Utility Statement. If not already
stated in a utility statement, the Contractor is responsible for field locating and verifying the location of all utilities shown on the Plans prior to starting the Work. Maintain uninterrupted service for those utilities designated to remain in service throughout the Work. Notify the Engineer of any utility locations different from shown on the Plans that may require micropile relocations or structure design modification.
413.03.04 Site Drainage Control. Control and properly dispose of drill flush and construction
related waste, including excess grout, in accordance with the standard specifications and all applicable local codes and regulations. Provide positive control and discharge of all surface water that will affect construction of the micropile installation. Maintain all pipes or conduits used to control surface water during construction. Repair damage caused by surface water at no additional cost. Upon substantial completion of the Work, remove surface water control pipes or conduits from the site. Alternatively, with the approval of the Engineer, pipes or conduits that are left in place, may be fully grouted and abandoned or left in a way that protects the structure and all adjacent facilities from migration of fines through the pipe or conduit and potential ground loss. Immediately contact the Engineer if unanticipated existing subsurface drainage structures are discovered during excavation or drilling. Suspend work in these areas until remedial measures meeting the Engineer’s approval are implemented.
413.03.05 Micropile Installation. Install micropiles in accordance with approved micropile
working drawings and installation procedures. Use drilling equipment and methods suitable for drilling through the conditions to be encountered, without causing damage to any overlying or adjacent structures or services. The drillhole must be open along its full length to at least the design minimum drillhole diameter prior to placing grout and reinforcement. When appropriate, use a down hole hammer drilling method. Use the grouting procedure for micropile installation in accordance with the approved micropile submittals. Advance the steel casing with the hole. Open hole drilling is prohibited except in the bond zone shown on the plans. The use of drilling fluid containing bentonite is prohibited. 2025 STANDARD SPECIFICATIONS FOR CONSTRUCTION AND MATERIALS 2025 STANDARD SPECIFICATIONS FOR CONSTRUCTION AND MATERIALS Fill out a Micropile Installation Log sheet for each micropile installed. Install micropiles to the minimum depth shown on the Plans, or as directed by the Engineer. The geotechnical engineer shall complete the Pile Drilling portion of the Micropile Installation Log sheet for each production micropile and load test pile. The micropile design engineer, in consultation with the the geotechnical engineer and the Engineer, shall determine if satisfactory material has been encountered. After drilling to the required depth, adjust steel casing (as needed), and flush the hole with water. If necessary, blow clean with compressed air until the hole is clear of all cuttings as evidenced by clean water overtopping the steel casing. If clean water does not overtop the casing within a reasonable amount of time or if satisfactory material is not encountered at the specified elevation or depth, the geotechnical engineer, with the approval of the Engineer, will direct the Contractor to lower the micropile tip by extending the steel casing downward and maintaining the specified bond zone length. The geotechnical engineer shall amend the drill log as appropriate. Final tip elevation will be determined by the micropile design engineer, in consultation with the geotechnical engineer and the Engineer, and will be governed by drilling the required bond zone in satisfactory material as indicated by drilling response (e.g., hammer sound, penetration rate, etc.) similar to the test piles and by the flushing of clean water that overtops the steel casing. The Engineer will determine when the satisfactory material requirements have been met. If, during drilling of the bond zone, unsatisfactory material such as soil, voids, or weathered rock are encountered, the following actions are to be taken. For unsatisfactory material of:
a.Less than 6 in., the bond zone remains unchanged.
b.Greater than 6 in. but less than 1 ft, extend the bond zone length 1 ft. (c) Greater than 1 ft, recount from the bottom of the unsatisfactory material to conform to either (a) or (b). Continually test the bottom of the steel casing for running material and take all measures necessary to prevent disturbance of the subsoil or loss of ground. Observe the conditions near the micropile construction site daily for signs of subsidence or ground heave. Immediately notify the Engineer if signs of movement are observed. Immediately suspend or modify drilling or grouting operations if ground heave or subsidence is observed, if the micropile structure is adversely affected, or if adjacent structures are damaged from the drilling or grouting. If the Engineer determines that the movements require corrective action, take corrective action necessary to stop the movement or perform repairs. When the Engineer determines that the adverse conditions are due to the Contractor’s methods or operations, or failure to follow the specified/approved construction sequence, the corrective actions shall be at no additional cost. Reinforcement may be placed either prior to grouting or placed into the grout-filled drillhole before temporary casing (if used) is withdrawn. The geotechnical engineer shall provide certification with their Professional Engineer stamp that the micropiles were properly drilled to a satisfactory depth in bearing materials. Reinforcement surface shall be free of deleterious substances such as soil, mud, grease, or oil that might contaminate the grout or coat the reinforcement and impair bond. Pile cages and reinforcement groups, if used, shall be sufficiently robust to withstand the installation and grouting process and the withdrawal of the drill casings without damage or disturbance. Check pile top elevations and adjust all installed micropiles to the planned elevations. Place a minimum of two centralizers on the central reinforcement, with the upper most centralizer located a maximum of 4 ft from the top of the central reinforcement. Maintain a maximum spacing of 15 ft between all additional centralizers. Centralizers shall permit the free flow of grout without misalignment of the reinforcement. The central reinforcement steel with centralizers shall be lowered into the stabilized drill hole to the desired depth without difficulty. Do not drive partially inserted reinforcing bars into the hole. Secure lengths of casing and reinforcing bars to be spliced in proper alignment and in a manner to avoid eccentricity or angle between the axes of the two lengths to be spliced. Threaded pipe casing joints shall be located at least two casing outside diameters from a splice in any reinforcing bar. When multiple bars are used, bar splices shall be staggered at least 12 inches. Provide means and methods of measuring the grout quality through field and laboratory sample testing, quantity, and pumping pressure (if applicable) during the grouting operations. Complete the Pile Grouting portion of the Micropile Installation Log sheet, to show quantities, test data, and grout pressures (if applicable) for inspection by the Engineer. Grout the micropiles on the same day that the load transfer bond length drilling is completed. Produce a colloidally mixed grout, free of lumps and undispersed cement. Grout shall be mixed for a minimum of two minutes and then kept in a continuous slow agitation until the grout is pumped to the micropile. Place grout that is manufactured off-site and delivered in a freshly mixed and unhardened state in conformance with M 157 and 915.03.05. Equip the grout pump with a pressure gauge to monitor grout pressures. The pressure gauge shall be capable of measuring pressures of twice the actual grout pressures used. Size the grouting equipment to enable the grout to be pumped in one continuous operation. Place primary grout by pumping the grout through a tremie pipe exiting at the bottom of the borehole. Ensure that the grout is not diluted or contaminated during placement. The grout shall progressively displace water and other fluid debris out of the hole. Embed the tremie pipe in the grout column at all times a minimum of 10 ft. and remove upon the completion of grouting. Use the tremie method to place grout along the full depth of the micropile. If more than two times the theoretical volume of grout is used, see measurement and payment for the payment of excess grout. Complete the Micropile Installation Log sheet. The geotechnical engineer shall sign and seal the Micropile Installation Log sheet with their Professional Engineer stamp, and submit it to the Engineer, upon completion of each micropile installation. 2025 STANDARD SPECIFICATIONS FOR CONSTRUCTION AND MATERIALS Grout within the micropiles shall be allowed to attain the required design strength prior to load testing and application of superstructure loads. Grout strength shall be determined as specified in 413.03.06.
413.03.06 Field Quality Control. Make grout cubes as specified in 902.11(c) in the presence of
the Engineer and deliver them to the Office of Material Technology to test the compressive strength at the following frequencies:
a.One set of four specimens for each work shift.
b.Test one specimen after 7 days. (c) Test two specimens after 28 days.
d.Retain one specimen in reserve in case later testing is required. If testing passes all criteria in 902.11(c) after 7 days, do not test the remaining cubes. 413.03.07 Tolerances. Micropile construction tolerances are as follows:
a.Center line of piling shall not be more than 3 in. from specified Plan location. (b) Variation from the vertical or from the batter shall be within 2 percent of total length Plan alignment.
c.Top elevation of pile shall be plus 1 in. or minus 2 in. maximum from specified Plan vertical elevation.
d.Center line of reinforcing steel shall not be more than 0.5 in. from specified location. (e) Joint connections shall not permit eccentricities or kink angles. When micropiles are installed with dimensions outside of the specified tolerances, with grout not conforming to the specified strength, or with any other nonconforming condition, the Engineer will make a determination regarding the proper corrective measures to be taken. Corrective measures may include the removal and replacement of defective micropiles, the installation of additional micropiles at nearby locations, modification of the foundation over the micropyles, additional testing and engineering including the evaluation and redesign or other measures the Engineer deems appropriate, at no additional cost.
413.03.08 Pile Load Tests. Perform verification and proof testing of the micropiles in tension at
the locations specified or designated by the Engineer. The Quick Load Test procedure with creep test and the apparatus for measuring load and movement, both specified in ASTM D3689, shall be used for the verification and proof tests in tension, except as modified herein. Submit load test results to the Engineer. The report shall be reduced and presented in an appropriate tabular and graphical form, signed and sealed by the micropile design engineer, and shall also include time, load, and displacement data. Obtain the Engineer’s approval of the load 2025 STANDARD SPECIFICATIONS FOR CONSTRUCTION AND MATERIALS test results before installing the remaining production micropiles. The Engineer will notify the Contractor of acceptance, or if modification to the micropile design is required, within 3 working days from receipt of the load test report. If a micropile fails to meet the applicable acceptance criteria, submit to the Engineer a written plan of remedial action for approval modifying the design, the construction procedure, or both to correct the problem and prevent its reoccurrence. Any modification that necessitates changes to the structure shall require the Engineer’s prior review and acceptance. Any modifications of design or construction procedures, or cost of additional verification test micropiles and verification and/or proof load testing, or replacement micropiles, shall be at no additional cost to the Administration.
a.Verification Load Tests. Verification load tests shall be performed on one non- production test micropile per substructure unit, installed near each substructure unit but outside of the footing using method specified in ASTM D3689 (Tension Testing). If there is no location shown on the plan for this test, the Engineer shall find a suitable location that is between 10 ft and 20 ft away from the footprint of each substructure unit. The verification test micropile shall be loaded to the verification test load specified in the Plans. Do not load the verification test micropile to more than 80 percent of its structural capacity. The verification test micropile’s structural capacity shall be designed by the micropile design engineer and shall not be less than the structural capacity of the micropiles shown in the Plans. Any required increase in strength of the verification test micropile elements above the strength required for the production micropile elements shall be provided for in the Contractor’s bid price. The verification test shall be performed prior to installation of the proof load test micropiles. The drilling and grouting method, casing length and outside diameter, reinforcing bar lengths, and depth of embedment for the verification test micropiles shall be identical to those specified for the production piles at the given locations. The verification test micropile structural steel sections shall be sized to safely resist the maximum load test. Verification load tests shall be performed to verify that the Contractor installed micropiles will meet the required compression load capacities and load test acceptance criteria and to verify that the length of the micropile bond zone is adequate. The micropile verification load test results must verify the micropile design and the Contractor’s installation methods. At the completion of verification testing, verification test micropiles shall be removed down to the elevation specified by the Engineer.
b.Proof Load Tests. Perform proof load tests using method specified in ASTM D3689 (Tension Testing) on the production test micropiles installed at each substructure unit during each stage of construction, as specified on the Plans, prior to the installation of any other production micropiles in that unit during that stage. The installation of the proof loaded test micropiles shall be identical to the production micropiles, except that the center bar can be increased in size to handle the additional tensile force from the proof load test. 2025 STANDARD SPECIFICATIONS FOR CONSTRUCTION AND MATERIALS
c.Testing Equipment and Data Recording. Provide testing equipment, including dial gauges, dial gauge support, jack and pressure gauges, and reaction frame in accordance with approved micropile installation submittal. The jack, bearing plates, and stressing anchorage shall be aligned so that unloading and repositioning of the equipment will not be required during the test. Apply and measure the test load with a hydraulic jack and pressure gauge. Monitor the creep test load hold during verification tests with both the pressure gauge and the electronic load cell. Use the load cell to accurately maintain a constant load hold during the creep test load hold increment of the verification test. Visually align the gauges of the top of micropile movement system to be parallel with the axis of the micropile. The required load test data shall be recorded by the geotechnical engineer.
413.03.09 Site Clean Up. Clean and remove from the project site all surplus and discarded
materials and equipment and remove all debris and objectionable materials of any kind from areas used or disturbed by the construction operation.
413.04 Measurement and Payment
The payment will be full compensation for all design, material, labor, equipment, tools, and incidentals necessary to complete the work.
413.04.01 Micropiles. Micropiles (production and proof load test) will be measured and paid for
at the Contract unit price per linear foot for the pertinent Micropile item. The measured length of all piling will be taken from the bottom of the bond zone to the final cutoff, measured along the axis, unless otherwise specified in the Contract Documents. The payment will be full compensation for design, setup, drilling, steel casings, steel plates, reinforcement steel, centralizers, geotechnical engineering services, and grouting up to two times the theoretical volume. No additional compensation will be made for if the Contractor’s design exceeds the design standard from what is shown in the original contract documents.
413.04.02 Excess Grout. Grout ordered and accepted by the Engineer that is greater than two
times the theoretical volume will be measured and paid for at the Contract unit price per cubic yard for the Excess Grout item per each individual micropile installation. This is a contingent item just to establish a unit cost for the excess grout and GP-4.04 will not apply to this item.
413.04.03 Proof Load Tests. Proof load tests satisfactorily performed and completed will be
measured and paid for at the Contract unit price per each for the pertinent Micropile Proof Load Test item. Payment will also include full compensation for furnishing, removal, and disposal of the load frame, reaction piles, instrumentation and all items required to complete the testing work with the exception of the micropile itself. In the event that the properly conducted load test fails to achieve the designed capacity, the additional tests will be completed at no additional cost to Administration. 2025 STANDARD SPECIFICATIONS FOR CONSTRUCTION AND MATERIALS
413.04.04 Verification Load Tests. Verification load tests satisfactorily performed and
successfully achieving the verification test load will be measured and paid for at the Contract unit price per each for the Micropile Verification Load Test Item. Payment will also include full compensation for furnishing, removal and disposal of the load frame, reaction piles, installation and removal of micropile, instrumentation and all items required to successfully complete the testing work. In the event that the properly conducted verification load test fails to achieve the verification test capacity, the micropile shall be abandoned and the contractor shall not be paid for the micropile or testing. 2025 STANDARD SPECIFICATIONS FOR CONSTRUCTION AND MATERIALS 418 — PROTECTIVE JACKETS FOR PILES CATEGORY 400 STRUCTURES SECTION 418 — PROTECTIVE JACKETS FOR PILES
418.01 Description
Install protective jacket for piles.
418.02 Materials
Fine Aggregate 901.01 Portland Cement 902.03, Type II Concrete Admixture 902.06 Water 921.01 Welded Wire Fabric 908.08 Fiberglass Protective Pile Jackets 921.10 and 418.02.01 Anchor/Standoff Devices A185 Stainless Steel Screws A193, Type 303
418.02.01 Jackets. Fabricate jackets for new piles in one solid piece with no longitudinal joint.
Closure joints on jackets for existing piles need not be self-locking provided the joint can be field formed with fiberglass and is approved. Ensure that the field formed closure joint meets the tensile strength of the jacket. All jackets shall be at least 3/16 in. thick. Ensure that the surfaces of the fiberglass are free of bond inhibiting agents. For steel and concrete piles, provide noncorrosive standoffs on the inside face of jackets to maintain the jackets in the required position.
418.02.02 Closure Joint Warranty. When closure joints are used for existing piles, furnish the
Administration a written 5 year warranty against installation defects, and ensure that the manufacturer submits a similar warranty against manufacturing defects. Submit both prior to starting the installations.
418.02.03 Grout. Submit the proposed grout mix design and method of installation for approval.
Steel and Concrete Piles. Use grout consisting of at least 845 lb./yd 3 of cement, 6 ± 1 percent of air entrainment by volume, and proportioned with fine aggregate and water to provide a pumpable mixture. The minimum 28 day compressive strength shall be 3500 psi. 2025 STANDARD SPECIFICATIONS FOR CONSTRUCTION AND MATERIALS
Source: Maryland Standard Specifications for Construction and Materials, 2025 Edition. Pages 414–425 of 1,113.