722.1 722.2.3 765 SECTION 722 PRECAST CONCRETE BOX CULVERTS 722.1 722.1 Description 1 722.1 This section contains specifications for the materials, equipment, construc- tion, measurement, and payment for production, transportation, and storage of precast concrete box culverts of the size and dimensions indicated on the Plans, installed in conformity with the Plans, the SCDOT Standard Drawings, the Special Provisions, and these specifications, and true to the line and grades established by the RCE. This section includes specifications for the proper fabrication at the precast plant, finishing, marking, joining, and other incidental items of work. See SCDOT Standard Drawing 722-1 for details and additional installation requirements. 722.2 722.2 Materials 722.2.1 722.2.1 Precast Concrete Sections 1 722.2.1 Ensure that precast concrete box culvert sections conform to the require- ments of either AASHTO M 259 for depths of cover 2 feet and greater or AASHTO M 273 for depths of cover less than 2 feet with the exception of modifications as stated herein. Conform precast concrete box culverts to the requirements of ASTM C 1433 or ASTM C 1577 for manufacturing proce- dures, tolerance, and designs meeting or exceeding ASTM C 1433, Table 2 or ASTM C 1577, Table 1. 2 722.2.1 Manufacture the sections in accordance with the appropriate AASHTO or ASTM designation based on the size (span (W) and rise (H) dimensions), loading (minimum earth dead load and Interstate Live Load to be used in all applications unless otherwise indicated), and earth cover as specified on the Plans and in the Special Provisions. Box sections that exceed the minimum specified requirements may be substituted for the Plan designated box sec- tions at no extra cost to the Department and with prior written approval of the OMR. Ensure that box culvert is obtained from a source listed on the most recent edition of SCDOT Qualified Product List 14. 722.2.2 722.2.2 Site Cast Concrete 1 722.2.2 Except for the aggregate gradation, provide concrete for the precast sec- tions meeting the applicable requirements of Sections 701 and 714. Ensure that concrete for components cast at the site (wingwalls, headwalls, aprons, cut-off walls, etc.) meet the applicable requirements of Section 701 for Class 4000P concrete (minimum). 722.2.3 722.2.3 Reinforcing Steel 1 722.2.3 Provide reinforcing steel conforming to the requirements of ASTM A 706, Grade 60, AASHTO M 259, AASHTO M 32, AASHTO M 55, AASHTO M 221, or AASHTO M 225 as applicable. Ensure that ASTM A 706 steel is obtained from a source listed on the most recent edition of SCDOT Qualified Product
Transcript
722.1 722.2.3
765
SECTION 722 PRECAST CONCRETE BOX CULVERTS
722.1
722.1 Description 1
722.1 This section contains specifications for the materials, equipment, construc-tion, measurement, and payment for production, transportation, and storage of precast concrete box culverts of the size and dimensions indicated on the Plans, installed in conformity with the Plans, the SCDOT Standard Drawings, the Special Provisions, and these specifications, and true to the line and grades established by the RCE. This section includes specifications for the proper fabrication at the precast plant, finishing, marking, joining, and other incidental items of work. See SCDOT Standard Drawing 722-1 for details and additional installation requirements.
722.2
722.2 Materials 722.2.1
722.2.1 Precast Concrete Sections 1
722.2.1 Ensure that precast concrete box culvert sections conform to the require-ments of either AASHTO M 259 for depths of cover 2 feet and greater or AASHTO M 273 for depths of cover less than 2 feet with the exception of modifications as stated herein. Conform precast concrete box culverts to the requirements of ASTM C 1433 or ASTM C 1577 for manufacturing proce-dures, tolerance, and designs meeting or exceeding ASTM C 1433, Table 2 or ASTM C 1577, Table 1.
2 722.2.1 Manufacture the sections in accordance with the appropriate AASHTO or
ASTM designation based on the size (span (W) and rise (H) dimensions), loading (minimum earth dead load and Interstate Live Load to be used in all applications unless otherwise indicated), and earth cover as specified on the Plans and in the Special Provisions. Box sections that exceed the minimum specified requirements may be substituted for the Plan designated box sec-tions at no extra cost to the Department and with prior written approval of the OMR. Ensure that box culvert is obtained from a source listed on the most recent edition of SCDOT Qualified Product List 14.
722.2.2
722.2.2 Site Cast Concrete 1
722.2.2 Except for the aggregate gradation, provide concrete for the precast sec-tions meeting the applicable requirements of Sections 701 and 714. Ensure that concrete for components cast at the site (wingwalls, headwalls, aprons, cut-off walls, etc.) meet the applicable requirements of Section 701 for Class 4000P concrete (minimum).
722.2.3
722.2.3 Reinforcing Steel 1
722.2.3 Provide reinforcing steel conforming to the requirements of ASTM A 706, Grade 60, AASHTO M 259, AASHTO M 32, AASHTO M 55, AASHTO M 221, or AASHTO M 225 as applicable. Ensure that ASTM A 706 steel is obtained from a source listed on the most recent edition of SCDOT Qualified Product
722.2.4 Use a joint seal material that is a preformed flexible joint sealant conform-ing to the requirements of AASHTO M 198 and is manufactured by a supplier listed on the most recent edition of SCDOT Qualified Product List 13.
722.2.5
722.2.5 Liquid Membrane-Forming Compounds 1
722.2.5 Use liquid curing compounds conforming to the requirements of Subsection 702.2.2.11.
722.3
722.3 Equipment 1
1722.3 Ensure that the equipment necessary for the proper construction of the work is on site, in acceptable working condition, and approved by the RCE as to both type and condition before the start of work under this section. Provide sufficient equipment to enable prosecution of the work in accordance with the project schedule and completion of the work in the specified time.
722.4
722.4 Construction 722.4.1
722.4.1 Fabrication 722.4.1.1
722.4.1.1 General 1
722.4.1. The precast concrete box sections may be precast by either the dry cast (machine) or wet cast method. Use steel forms for both, and ensure that forms are mortar-tight and of sufficient strength to prevent bulging and the misalignment of adjacent boxes when placed in the field. Ensure that the forms permit removal without damage to the concrete.
2 722.4.1.1 Do not allow offsets at form joints to exceed ⅛ inch. Make certain forms
are clean and have a light coating of a bond-breaking material applied before concrete placement.
3 722.4.1.1 Provide a maximum of four lifting holes, 2 inches in diameter or 2 inches
square or lifting lugs, as required, in each section to properly complete fabri-cation and installation. Form the holes in-place, cut them into the fresh con-crete, or core them into the hardened concrete.
4 722.4.1.1 Provide precast sections with a minimum length of 4 feet. Use positive
methods acceptable to the OMR to support reinforcing steel and prevent dis-placement during the casting operation. Weld reinforcing steel only as shown on the Plans.
5 722.4.1.1 Cast precast boxes by a process that provides for uniform placement of the
concrete in the forms and compaction by mechanical devices that ensures dense, well-compacted concrete. Mix concrete in a central batch plant or other approved batching facilities.
6 722.4.1.1 Construct all formed openings between the precast sections and adjacent
structures (including pipes, inlet structures, manholes, connecting culverts, etc.) to accommodate a soil tight seal. Provide additional reinforcement
722.4.1.1 722.4.1.3
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around all formed openings as shown in the SCDOT Standard Drawings for culvert openings or as directed by the RCE.
7 722.4.1.1 Install 3-inch diameter weep holes at intervals of approximately 8.0 feet at
an elevation of about 1.0 foot above the normal water surface in accordance with Subsection 702.4.19.2.
722.4.1.2
722.4.1.2 Finishing and Marking 1
722.4.1.2 Finish and mark precast sections in accordance with the applicable re-quirements of AASHTO M 259, AASHTO M 273, ASTM C 1433, or ASTM C 1577 with the addition of the SCDOT project number.
722.4.1.3
722.4.1.3 Fabrication Tolerances 1
722.4.1.3 Make certain that the precast sections do not exceed the geometric toler-ances allowed in the applicable sections of AASHTO M 259, AASHTO M 273, ASTM C 1433, or ASTM C 1577.
2 722.4.1.3 Cast the slab thickness and the tongue and groove joint configuration to
provide a continuous line of box sections with interior offsets at the joints less than 1% of the dimensions of the rise and span. Fabricate end sections with exposed end flat in lieu of tongue or groove joint. Fabricate end sections with holes for resin anchors or inserts for mechanical anchors to connect headwall, wingwalls, and apron unless these connections are specifically omitted by directions in the Plans.
3 722.4.1.3 To ensure the proper fit of contiguous sections, check the squareness tol-
erance of the boxes by measuring the distance between opposite interior cor-ners at the ends of the sections. Make certain the diagonal measurements do not vary by more than ½ inch.
4 722.4.1.3 Deviations from the above tolerance are acceptable if the sections can be
fitted at the plant and it is determined that an acceptable joint can be made. A joint is considered acceptable if the sections can be fitted together on a flat surface in the position in which they will be installed and the joint opening at any point does not exceed ¾ inch.
5 722.4.1.3 Match-mark sections pre-fitted at the precast plant.
6 722.4.1.3 Repair small damaged or honeycombed areas that are purely cosmetic.
Excessive damage, honeycomb, or cracking is subject to structural review. Make repairs to the satisfaction of the OMR. Ensure that such repairs are sound, properly finished, and cured in accordance with Subsection 722.4.1.5. When fine cracks or hair-checks on the surface indicate poor cur-ing practices, discontinue further production of precast boxes until corrections are made and proper curing is provided.
7 722.4.1.3 Store precast boxes on level blocking in a manner acceptable to the OMR.
Do not place load upon sections until design strength is reached and curing completed. Ship boxes when the design strength has been met and the boxes have been inspected and stamped by the Department’s inspector.
722.4.1.4 722.4.3
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722.4.1.4
722.4.1.4 Samples and Tests 1
722.4.1.4 Provide concrete compressive strength test cylinders in accordance with the requirements of AASHTO M 259, AASHTO M 273, ASTM C 1433, or ASTM C 1577, except that when a wet cast method is used, provide a mini-mum of 4 test cylinders for each day’s production of each size and design of box. Strength tests for each production lot are based on the average strength of 2 cylinders that are tested any time after the curing period. When design strength is attained on the initial test, further tests on that lot are not required.
2 722.4.1.4 Should the initial test fail to meet the design strength, perform a subsequent
test at 28 days unless additional cylinders were made for intermediate breaks. Check low cylinder strengths by compression strength of cores. Obtain cores for testing and repair the core holes at no cost to the Department.
722.4.1.5
722.4.1.5 Curing 1
722.4.1.5 Cure precast concrete box culverts made in a precast plant in accordance with the requirements of AASHTO M 259, AASHTO M 273, ASTM C 1433, or ASTM C 1577.
2 722.4.1.5 Protect the boxes from freezing during the curing period.
3 722.4.1.5 Cure test cylinders at the same time and in the same manner as the boxes.
4 722.4.1.5 Cure concrete placed at the job site during construction in accordance with
Subsection 702.4.4.2. 722.4.2
722.4.2 Bedding 1
722.4.2 Ensure that excavation for foundations of precast concrete box culverts conform to the requirements of Section 204 and the details shown on the Plans. Exercise special care in leveling the foundation area to ensure uniform support throughout the entire width and length of the structure. Make certain bedding material is minimum fine aggregate, and no larger than coarse ag-gregate (No. 57 stone) in conformance with the requirements in Section 701. Erect shoring, bracing, or other devices necessary to achieve safe working conditions without additional compensation. Ensure that culvert bedding is protected from scour during the installation of culvert sections.
2 722.4.2 When a firm foundation is not encountered at the required grade, remove
all such unstable material and backfill the resulting excavation with suitable material (no larger than Aggregate No. 57) in accordance with Section 203, the Plans, or the contract documents. For culverts on shallow rock, cast-in-place construction is recommended. If placing precast culvert sections on rock is required, provide a minimum of 3 inches of bedding material between the rock surface and the bottom of the bottom slab.
722.4.3
722.4.3 Laying Sections 1
722.4.3 Place sections beginning at the outlet end of the conduit with the groove end being laid upgrade (and the flat end toward the outlet) unless otherwise approved by the RCE. Install successive tongue ends into each adjoining
722.4.4 722.4.6
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groove. Provide positive means to pull or push each section firmly into the previously placed section so that the joints are tightly meshed. Install final section with flat end toward inlet. Repair and fill lift holes with mortar or con-crete and cure as directed after the sections have been installed. Install French Drain in accordance with the requirements of Subsection 702.4.19.2. Completely wrap French drain with geotextile for drainage filtration to prevent migration of site soils into aggregate.
722.4.4
722.4.4 Joints 1
722.4.4 Make joints between the precast box sections using preformed flexible joint sealant in accordance with AASHTO M 198. Do not use mortar. Install joint sealant in conformance with the details on SCDOT Standard Drawing 722-1, and in accordance with the manufacturer’s recommendation and as specified herein.
2 722.4.4 Clean and dry all surfaces of the joint to remove all debris and contami-
nants. Lubricate joint surfaces with a lubricant that does not cause damage to or deteriorate joint sealant material. Use continuous sealant of the minimum size to produce a soil-tight joint in the annular space of the joint. The joint sealant size may be varied by the RCE to provide enough sealant material to properly fill the annular space or to prevent waste of the sealant material. When the culvert is in place, ensure that the joint sealant is visible on the in-side or the outside of the joint. Give special attention placing the joint sealant on the tongue to prevent excess seal from squeezing out of the culvert joints. If excess seal is observed squeezing out on the inside and outside, check the placement of the joint sealant or reduce the joint sealant size if required to prevent waste of seal material.
3 722.4.4 Ensure that the culvert trench is free of standing water and mud when a
section is placed. Press culvert sections together to form a durable soil tight and structurally sound joint. Install the joint sealant material without stretching it.
722.4.5
722.4.5 Backfilling 1
722.4.5 Conform backfilling materials and construction methods to the requirements on the Plans and Subsection 205.4.2.
2 722.4.5 When multiple barrel structures are specified, place the barrels a minimum
of 3.5 inches apart. Place the material between culvert barrels in accordance with the Plans and the SCDOT Standard Drawings. When not specified in the Plans, use flowable fill or continuous concrete for gap material. Provide a minimum 6-inch cast-in-place concrete plug along the length of the barrels at the exposed ends of the barrel to prevent erosion of the gap material.
722.4.6
722.4.6 Connections 1
722.4.6 Make connections with other structures including headwalls, wingwalls, aprons, inlets, structures, or manholes in accordance with the Plans.
using cast-in-place reinforced concrete consisting of Class 4000 (minimum) Portland cement concrete conforming to the applicable requirements of Sections 701 and 702 unless directed by the RCE. Use reinforcing steel conforming to the requirements of ASTM A 706, Grade 60 and applicable re-quirements of Section 703.
3 722.4.6 Place a minimum of ½ inch grout layer between culvert top slab and bottom
of drainage structure. Do not install risers directly on top slab of culvert unless directed by the RCE.
4 722.4.6 Ensure that all inlet structures and pipe openings are soil tight. Consult the
Design Engineer and the box culvert manufacturer before field cutting any opening in the culvert.
5 722.4.6 Install resin anchors in accordance with the Plans and SCDOT Standard
Drawings for Road Construction. 722.5
722.5 Measurement 1
722.5 The quantity of the precast concrete box culvert is the length of the box culvert and is measured by the linear foot (LF) in-place, complete, and ac-cepted. The length is obtained by measuring the centerline length of each barrel between the end treatments.
2 722.5 Structure excavation is measured in accordance with Subsection 204.5
and includes unstable material removed as specified in Subsection 203.4. 3
722.5 The quantity of cast-in-place Class 4000 concrete used in wingwalls, cut-off walls, parapet walls, and aprons is measured for payment by the cubic yard (CY) of Concrete for Structure Class 4000 (Culvert) in accordance with Subsection 701.5.
4 722.5 Reinforcing steel used in the cast-in-place portion of the culvert is meas-
ured for payment by the pound (LB) of Reinforcing Steel for Structures (Road-way) in accordance with Subsection 703.5. Reinforcing steel in the precast portion of the culvert, including resin anchors, is not measured for payment, but is included in the contract unit bid price of the precast culvert.
722.6
722.6 Payment 1
722.6 Payment for the accepted quantities of PC Box Culverts (of the size, type, and fill height specified), measured in accordance with Subsection 722.5, is determined using the contract unit price for the applicable pay item. Payment is full compensation for constructing precast concrete box culverts as speci-fied or directed and includes bedding; fabricating, transporting, and laying cul-vert sections; furnishing and installing joint material; connections to headwalls and other drainage structures; French drains and weepholes; backfilling; and all other materials, labor, equipment, tools, supplies, transportation, and inci-dentals necessary to fulfill the requirements of the pay item in accordance with the Plans, the Specifications, and other terms of the Contract.
722.6 722.6
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2 722.6 Structure excavation is paid for as Structure Excavation for Culverts in ac-
cordance with Subsection 204.6. 3
722.6 The quantity of cast-in-place Class 4000 concrete is paid for in accordance with Subsection 701.6.
4 722.6 The quantity of reinforcing steel other than that in precast box sections is
paid for as Reinforcing Steel for Structures in accordance with Subsection 703.6.
5 722.6 Payment includes all direct and indirect costs and expenses necessary to
complete the work. 6
722.6 Pay items under this section include the following: 722.6
Item No. Pay Item Unit
722XXXX (size) P C Box Culvert (type) Fill Height < (fill height)'' LF
