00510.04 419 Section 00510 - Structure Excavation and Backfill
Description
00510.00Scope - This Work consists of excavating, backfilling and disposing of materials in
connection with the construction of Bridges, grade separation Structures, rigid frame Structures, and other major Structures. Other major Structures under this Section are retaining walls, reinforced concrete box culverts, headwalls, structural plate Structures, and pipe culverts, sewers, siphons and irrigation pipes greater than 72 inches in diameter.
This Work does not include any earthwork covered under any sections of Parts 00300 or 00400, or any earthwork that may be specifically included and provided for as I ncidental Work for particular items or parts of the W ork. The construction, measurement, and payment of embankment at bridge ends and engineered fills will be according to Section 00330.
00510.01Lines, Grades, and Cross Sections - Perform the Work to the lines, grades and Cross
Sections shown or as established.
00510.02Definitions :
Shoring - A temporary earth retention and support system that is installed prior to or during excavation using top-down construction techniques.
00510.03Cofferdam Working Drawings , Calculations, and Design Submittals - Submit stamped
cofferdam Working Drawings and design calculations according to 00150.35 except as modified by this Subsection. Design cofferdams according to the ODOT Bridge Design Manual .
Submit a Cofferdam Design Summary and complete a Cofferdam Design Checklist prepared by the cofferdam design engineer, to accompany the Working Drawings and calculations. Include the following in the summary:
• A list of cofferdam members with their capacities and design stresses • Design loading assumptions for each member • Design specifications • Subsurface materials and conditions used in design Complete the checklist included in the Special Provisions.
Submit five sets (nine sets if Railroad approval is required) of the Working Drawings , and three copies (five copies if Railroad approval is required) of the calculations, summary, and checklist.
00510.04Shoring Working Drawings , Calculations, and Design Submittals - Submit Shoring
stamped Working Drawings and design calculations according to 00150.35 except as modified by this Subsection. Design Shoring according to Section 15.3.26 and other applicable sections of the most current version of the ODOT Geotechnical Design Manual (GDM) at the time of Advertisement . Submit a Shoring Design Summary and complete a Shoring Design Checklist prepared by the shoring design engineer, to accompany the Working Drawings and calculations. Include the following in the summary:
00510.04 420 • A list of Shoring members with their capacities and design stresses • Design loading assumptions for each member • Design specifications • Subsurface materials and conditions used in design
Complete the checklist included in the Special Provisions.
Submit five sets (nine sets if Railroad approval is required) of the Working Drawings , and three copies (five copies if Railroad approval is required) of the design calculations, summary, and checklist.
Shoring systems provided in Section 15.3.26 of the ODOT GDM.
published in Section 15.2.4.2 of the ODOT GDM are considered atypical Shoring systems. If proposing an atypical Shoring system, submit stamped Working Drawings according to 00150.35. The review and response time allowed for the Agency to return the Working Drawings will be 120 Calendar Days. The submittal of calculations and other data must satisfy the requirements of the Specifications and include sufficient detail and explanation of the design for the Agency to process and comment on the Working Drawings. If the Engineer requests additional information or explanation related to the review of the atypicalS horing system the Engineer may restart the 120-Calendar Day review period.
Include the following additional information in the atypical Shoring system submittal:
If applicable, a list of projects that used the atypical Shoring system. Include reference contacts. A list of supervisory personnel who will be on -site during construction of the atypical Shoring system and documentation of their experience and qualifications to perform the Work .
Design Shoring according to the most current versions at the time of Advertisement of one or more of the following design standards:
ODOT Geotechnical Design Manual (GDM) AASHTO Standard and Guide Design Specifications U.S. Department of Transportation Federal Highway Administration (FHWA) design manuals
Geotechnical and st ructural analysis and design for the Shoring shall include but not be limited to the items listed in the Shoring Design Checklist. Submit a completed Shoring Design Checklist and a written Shoring Design Summary, prepared by the shoring design engineer, t o accompany the Working Drawings and calculations. Include the following in the Design Summary:
Identification of the design manuals and specific methodologies used for the analysis and design. Identification of the methods of analysis and all computer programs used. Soil and material properties used in the Shoring design. Include any additional boring logs and laboratory test data performed. Design loading assumptions and loading diagrams for each Shoring (including all construction staging loads). Design performance requirements, including design life, allowable settlement, and alignment tolerance. 00510.41 421 Construction requirements (specifications), including Materials, Equipment, and labor necessary for construction of the atypical Shoring system. Quality cont rol plan, including required performance and verification tests. Performance requirements (actual threshold limits of tolerable differential foundation settlement and/or lateral movement). Indicate how the performance requirements will be monitored during construction. If applicable, temporary Shoring removal plan. All other applicable information for design, detail, sequencing, and construction of the Shoring.
Materials
00510.10Selected General Backfill - Furnish Soil selected from Roadbed, ditch, trench, or structure
excavations meeting the requirements of 00330.13.
00510.11Selected Granular Backfill - Furnish Granular Material selected from Roadbed, ditch,
trench or structure excavations meeting the requirements of 00330.14.
00510.12Granular Wall Backfill - Furnish granular wall backfill meeting the requirements
of 02630.11.
00510.13Granular Structure Backfill - Furni sh granular structure backfill meeting the requirements
of 02630.10 and the following:
not exceed 15 percent by weight. Test according to AASHTO T 11.
exceed 6. Test according to AASHTO T 90.
00510.15Quality Control - Provide quality control according to Section 00165
Labor
00510.30Quality Control Personnel - Provide technicians having CEBT and CDT technical
certifications.
Construction
00510.40Clearing, Grubbing, and Removal Work - In the absence of Pay Items under
such Work as I ncidental Work for which no separate payment will be made.
Clearing, grubbing, and removal limits shall be at least 10 feet outside of the entire Structure , including the ends of the Structure but within the Right -of-Way .
00510.41Structure Excavation - Structure excavation includes:
• Removal of all material necessary for the construction of foundations and Substructures as shown or specified. • Placement of all backfill except granular wall backfill and granular structure backfill. • Disposal of excavated material not required or suitable for backfill according to 00330.41(a)(5). 00510.42 422 • Correction, according to recognized practice, of conditions detrimental to the Work , including removal of excess water.
Shore, brace, or use cofferdams to protect excavations unless open excavation would not be detrimental to adjacent Structures, Roadways, or waterways. Where the Plans show concrete in footings placed against undisturbed material, make excavation for footings as nearly as possible to the limits shown. Fill the space between the footing and remaining undisturbed material to the top of the footing with footing concrete or granular structure backf ill material , as directed. Compact the granular structure backfill to 97 percent of maximum density, according to 00330.43.
Concrete placed against steel sheet piles in cofferdams or cribs will be considered placed against undisturbed material, whether or not the steel sheets are later removed.
Where practicable, excavate Rock materials using pavement breakers, rippers, backhoes, other excavation Equipment or non -explosive means that preclude breakage of Rock materials below and outside of the structure excavation limits. If blasting is required, perform such Work in a manner that avoids disturbing Rock outside the structure excavation limits. Use controlled blasting techniques for all structure excavation requiring blasting according to Section 00335. Backfill and repair as directed, at no additional cost to the Agency, any excavation, shattered Rock , void, fault, or unstable condition caused by the Contractor outside the limits of structure excavation. Backfill and repair of voids, faults or unstable condition not caused by the Contractor or covered elsewhere in the Specifications will be paid for according to 00195.20.
Consider the elevations of the bottoms of footings or foundations shown as approximate only. The Engineer may order, in writing, changes in elevations of footings necessary to secure a satisfactory foundation.
Backfill, seal, or otherwise repair excavations beyond the limits shown or as directed by the Engineer with Materials acceptable to the Engineer at no additional cost to the Agency.
00510.42Structure Excavation and Backfill Below Elevations Shown - Excavate soft, unstable
or Unsuitable Material below footings or bases of Structures, including bedding, if any, to elevations as directed.
Perform one of the following as directed:
• Increase the length of columns or walls until the bottom of the footing is at the new established elevation. • Increase the thickness of footings until the bottom of the footing is at the new established elevation. • Backfill the subexcavated area to the plan elevation according to 00510.46(a).
00510.43Preservation of Channel - Do not excavate outside of caissons, cribs, cofferdams, sheet
piling or sheeting, or disturb the natural streambed unless specified or allowed. Where such excavation is allowed, comply with Section 00405. Do not sidecast any excavated material into the stream.
When allowed, the necessary excavation for placement of riprap outside the perimeter of the footing may be made without the use of cofferdams or cribs, and disposed of according to 00330.41(a)(4).
00510.45 423 00510.44 Cofferdams and Shoring - Construct cofferdams and Shoring as follows:
when determined by the Contractor to be necessary for performing the W ork:
Prepare and submit Working Drawings , calculations, summary and checklist for cofferdams or crib designs accordi ng to 00510.03. Provide interior dimensions for cofferdams and cribs to give sufficient clearance for the inspection of forms. When weighted cribs are used to partially overcome the hydrostatic pressure acting against the bottom of the foundation seal, provide an appropriate special anchor system such as dowels or keys to transfer the entire weight of the crib into the foundation seal. Do not leave cofferdam or crib timber or bracing extending into the Substructure concrete. Place and cure seal con crete according to 00540.48(e). Vent or port, at low water level, any cofferdam that is to remain in place. Unless otherwise directed, remove cofferdams or cribs, including all sheeting and bracing, after the completion of the Substructure . Do not disturb or damage the finished concrete.
Do not begin cofferdam or crib construction Work until all submittals have been approved. Upon completion of the cofferdam construction, and immediately after dewatering, the cofferdam design engineer of record, accompanied by the Engineer, shall field inspect the cofferdam. Do not continue construction until the cofferdam design engineer furnishes the Engineer a written statement that the cofferdam conforms to the design and will serve the intended purpose.
applicable sections of Part 00500 "Bridges" and as specified or determined by the Contractor to be necessary for performing the Work . Do not begin Shoring construction Work until all submittals have been approved.
Upon completion of the Shoring construction, the shoring design engineer of record, accompanied by the Engineer, shall field inspect the Shoring. Do not continue construction until the shoring design engineer furnishes the Engineer a written statement that the Shoring conforms to the design and will serve the intended purpose.
according to 00520.43(g). Do not begin weldi ng until all of the following have been approved by the Engineer:
Welding Procedure Specification (WPS) Procedure Qualification Records (PQR) Welder Qualification Test Records (WQTR) Material Test Report (MTR) AWS Certified Welding Inspector (CWI) 00510. 45 Pumping - No pumping of water from the interior of any foundation enclosure will be allowed during the placing of concrete or for a period of at least 24 hours thereafter unless an effective means of eliminating moving water through fresh concrete is employed. Water may then be pumped, if approved.
Do not pump to dewater a sealed cofferdam until the seal concrete meets the requirements of 00540.48(e). 00510.46 424
00510.46Preparation of Foundations - Do not place concrete on prepared foundations without
prior approval. Construct foundations as follows:
the area to serve as a foundation unless otherwise shown or directed. Use selected granular backfill or granular structure backfill as directed. Place in 6 inch layers and compact to not less than 95 percent of maximum density according to 00330.43.
excavations . Place concrete against undisturbed Soil when shown. Concrete may be used as backfill, subject to 00540.45(a). If Soil is disturbed, compact all disturbed Material to 95 percent of maximum density according to 00330.43.
is disturbed, compact all disturbed M aterial to 95 percent of maximum density according to 00330.43.
• Clean all Rock surfaces and remove loose material • Clean seams and fractures according to 00510.41, and seal with grout • Level, step or roughen the Rock surface as shown or as directed
Construct formwork, if allowed or required, and place concrete as soon as practica ble following the removal of material, to the specified elevation.
00510.47Embankment Construction at Bridge Ends - Construct embankments at bridge ends
according to 00330.42(c)(7) and, when shown, engineered fills according to 00330.42(c)(8) .
00510.48Backfill :
Do not place backfill that will cause unbalanced loading on the concrete until the concrete has been in place 7 Calendar Days and test cylinders show the concrete strength to be 100 percent of design strength according to 00540.17(c).
Do not place backfill against any other concrete until the concrete has been in plac e 3 Calendar Days, and test cylinders show the concrete strength to be 40 percent of design strength according to 00540.17(c). Place backfill and riprap in a manner that will not damage the concrete footings, drain pipes, and other permanent Work . Do not jet or puddle the backfill unless approved in writing. Prevent large lateral or wedging compaction forces from occurring directly against the concrete ; for sloped excavations, step the slope or use other approved means to prevent the wedge action. Dispose of excess materials according to 00330.41(a)(4).
minimum, to the pay limits shown. Backfill abutments, wingwalls, retaining walls, and approach slabs with specified backfill to the pay limits shown, and as follows:
00510.80 425 (1) Placement at Abutments - Do not place backfill at Bridge abutments until Superstructure elements are set, pinned and tensioned. Place backfill required at the front face of retaining walls and wingwalls before backfilling behind the wall unless shown otherwise. For single span Bridges with abutments, keep the backfill hei ghts within 2 feet of each other.
abutments, wingwalls, and retaining walls, provide walk behind vibratory roller compactor with a single smooth drum, vibratory plate compactor, or rammer/tamper plate compactor; each with a gross static weight of not more than 1,000 pounds and a total compaction static plus dynamic force of not more than 5,000 pounds. Compact backfill to 95 percent of maximum density using the required number of Passes determined according to the test pad method, and not less than three compaction Passes.
necessary to achieve the specified density by constructing a test pad that is at least 5 feet wide, 15 feet long, and 3 feet in final depth. Construct test pad fill in layers no more than 8 inches thick using the same Equipment and methods that will be used to compact the wall backfill. Perform at least one density test according to AASHTO T 310 on each test pad layer. Construct and test a new test pad when changes in Material occur or different Equipment is used during the construction of the wall backfill.
abutments, wingwalls, and retaining walls, provide vibratory roller compactor with a single smooth drum, vibratory plate compactor, or rammer/tamper pl ate compactor. Compact backfill to 95 percent of maximum density. Unless otherwise specified, test in- place field density according to AASHTO T 310. Provide sampling, testing, and quality control according to Section 00165.
according to 00510.46(a).
• Use either selected general backfill, selected granular backfill, riprap or other M aterials as shown or directed. • Deposit backfill around piers and columns on all sides to approximately the same elevation at the same time. • Place backfill up to the original ground surface, the upper limits of pay excavation, or as shown or directed.
Materials conforming to 00510.12 or 00510.13 unless otherwise specified. Place and compact as shown and according to 00405.46. Place backfill up to the surrounding ground surface, to the top of trench, or the upper backfill pay limits shown or as dir ected.
Measurement
00510.80Measurement - The quantities of Work performed under this Section will be measured
according to the following:
00510.80 426 (a) Shoring, Cribbing and Cofferdams - No measurement of quantities will be made for S horing, cribbing, and cof ferdams.
structure excavation will be listed in the Special Provisions.
original position (position before excavating).
Quantities will be limited to the limits shown, or if not shown, will be limited to the following:
footings or bases, including bedding, if any.
or established.
side slopes of the excavations.
outside the Neat Lines of the footings or bases of all Structures, except for structural plate Structures and pipe culverts over 72 inches in diameter, which will be as shown. When the Engineer approves or directs, structure excavations less than the specified horizontal limits, the measured limits will be the actual excavation made.
shown will be measured according to the following:
structure excavation below the elevations shown, measurement to extend the excavations will be made as follows:
• 0 to 3 Feet Below Elevations - For excavation 0 to 3 feet below elevations shown, measurement will be determined according to 00190.10(h) and based on a theoretical unit price of the lump sum structure excavation item.
• More than 3 Feet Below Elevations - For excavation more than 3 feet below elevations shown, measurement will be determined according to 00195.20.
structure excavation below the elevations shown, measurement to extend the excavations will be made on the volume basis.
Quantity limits will be from the bottom limit described in 00510.80(b)(2)(a) to the new lower limits of the ex cavation for the footing or base of the Structure , including bedding, if any, established by the Engineer. The horizontal limits will be vertical extensions of the quantity limits established according to 00510.80(b)(2)(c) . 00510.90 427
measured according to the following:
granular wall backfill or granular structure backfill will be listed in the Special Provisions.
measured on the volume basis in the final position. The quantities will be limited to the quantities placed according to the Plans and Specifications or as directed. When backfilling excavated areas, the quantities will be limited to the pay limits of the excavation for the part of excavated areas backfi lled with the specified granular backfill Material.
Payment
00510.90Payment - The accepted quantities of Work performed under this Section will be paid for
as follows:
Contract lump sum amount for the item "Shoring, Cribbing , and Cofferdams".
No separate or additional payment will be made for maintaining and removing all materials.
No separate or additional payment will be made for clearing and grubbing, preparing foundations, pumping, or cleaning up.
If the Engineer orders excavations that extend below the elevation shown, the Contractor will be compensated to extend Shoring, cribbing, and cofferdams as follows:
Footing Elevation Changes Compensation
0 to 3 feet below .................................................................. No extra payment More than 3 feet below ..................................................................... 00195.20
When the Contract Schedule of Items does not indicate payment for Shoring, cribbing and cofferdams, no separate or additional payment will be made. Payment will be included in payment made for the appropriate items under which this Work is required.
Payment will be payment in full for designing, furnishing Materials, constructing, inspecting, and for providing all Equipment , labor and Incidentals necessary to complete the Work as specified.
or the Contract unit price, per c ubic yard, for the item "Structure Excavation".
Except for granular wall backfill, no separate or additional payment will be made for backfilling and compacting to the elevation specified.
shown will be paid for as follows:
and made according to 00190.10(h). For excavation more than 3 feet below elevations shown, payment will be determined and made according to 00195.20.
00510.90 428 (2) Volume - For excavation 0 to 3 feet below elevations shown, payment will be made at the Contract unit price, per cubic yard, for the item "Structure Excavation".
For excavation more t han 3 feet below elevations shown, payment will be made at the Contract unit price, per cubic yard, for the item "Structure Excavation Below Elevations Shown". If the Contract Schedule of Items does not indicate payment for this Work , payment will be determined according to 00195.20.
Contract unit price, per unit of measurement, for the following items:
Pay Item Unit of Measurement
Payment will be payment in full for furnishing and placing all Materials, and for furnishing all Equipment , labor, and Incidentals necessary to complete the Work as specified.
No separate or additional payment will be made for:
removing material forced up between foundation piles during driving or of material used in backfilling around piles, should subsidence occur during driving bedding excavations made beyond the limits shown or beyond the limits directed, or below the elevations established for the bottoms of the footings , bases, cofferdams, or walls including bedding water removed from excavations and water used in compaction or other items of Work