203.01 138 SECTION 203 – EXCAVATION AND UNDERCUTTING
203.01 Description ................................ ................................ ................... 138
203.02 Classification ................................ ................................ ................ 138
203.03 Reserved ................................ ................................ ....................... 141
203.04 General ................................ ................................ ......................... 141
203.05 Undercutting ................................ ................................ ................. 145
203.06 Stripping, Stockpiling, and Placing Topsoil ................................ . 146
203.07 Disposing of Excess or Unsuitable Material ................................ 147
203.08 Shaping and Dressing ................................ ................................ ... 147
203.09 Method of Measurement ................................ .............................. 147
203.10 Basis of Payment ................................ ................................ .......... 151
DESCRIPTION
203.01 Description
This work consists of excavating and grading the roadway (including the removal of slides), borrow pits, waterways, and ditches (including structure inlet and outlet ditches, channels, waterways, and similar features , even if they extend beyond the highway limits); excavating for intersections, approaches, and benches under the side -hill embankments; excavating unsuitable material from roadbed and beneath embankment areas; excavating selected material found in the roadway that is required for specific use in the construction; the construction and removal of detours authorized by the Engineer or otherwise shown on the Plans ; trimming and shaping of all slopes; and disposing of all excavated material. The work also includes all embankment construction as specified in 205, shoulder and ditch construction as specified in 208, and if the Contract includes construction of pavement or other surfacing, Subgrade Construction and Preparation as specified in 207.
203.02 Classification
The Department will classify excavation as follows: 203.02 139 A. Road and Drainage Excavation (Unclassified) The Department will consider all excavation performed under this item, including Portland cement concrete located above subgrade elevation, other than Borrow Excavation, Channel Excavation, and Undercutting, as unclassified excavation regardless of the natu re of the material excavated.
B.Borrow Excavation Borrow Excavation consists of material required for the construction of embankments or other portions of the work. The Contractor may use excavated materials, other than B orrow Excavation (Unclassified), on the Project as specified in 104.09 provided it meets the specifications of the designated borrow material. However, if the flattening of certain cut slopes on projects graded unde r previous contracts is desirable and approved in writing by the Engineer, the Contractor may use this material for borrow if the material is satisfactory and in accordance with plans approved by the Engineer, and if the requirements of 203.04.E regarding borrow areas are met. Do not obtain borrow material from wetland areas, unless otherwise shown on the Plans and approved by applicable environmental permits. The Department will classify borrow as:
1.Borrow Excavation (Solid Rock) , which consists of removing and placing non -degradable rock that cannot be economically excavated by the proper use of a power shovel or without the use of explosives.
2.Borrow Excavation (Unclassified) , which consists of removing and placing al l approved material included under the classification of Borrow Excavation (Solid Rock) and all other approved material.
3.Borrow Excavation (Graded Solid Rock) , which consists of removing and placing sound, non -degradable rock having the following character istics:
a.Maximum particle size of 3 feet in any direction . 203.02 140 b. Particle size distribution in which at least 50 % of the rock is uniformly distributed between 1 foot and 3 feet in diameter, and no more than 10 % is less than 2 inches in diameter.
c.Roughly equi-dimensional in shape.
d.No thin, slabby material. Process the material until it meets the required gradation and quality requirements of 903.25. Obtain the Engineer’s approval before using the material.
4.Borrow Excavation (Select Material) , which is used for special construction purposes and meets the requirements set forth in the Contract or shown on the Plans. Borrow m aterial other than solid rock , graded solid rock, or select materials shall be AASHTO M 145, classification A -6 or better if reasonably available. If classification A -6 is not reasonably available, the borrow shall be no worse than the predominant soil type in the roadway excavation based on AASHTO classification. Do not use material obtained from an approved borrow source off the right-of-way to produce processed aggregate as described in 903. Borrow Excavation (Graded Solid Rock) may be obtained from an approved borrow source. Do not use material excavated from an offsite borrow source in base or other paving courses above the elevation of the subgrade. Unless otherwise designated in the Contract, arrange for obtaining borrow material according to the manual Procedures for Providing Offsite Waste and Borrow on TDOT Construction Projects .
C.Channel Excavation (Unclassified) This item consists of removing and disposing of all material excavated in widening, deepening, and straightening exi sting channels or constructing new ones, which have a bottom width of more than 14 feet as shown on the Plans. Perform similar excavation activities for channels with a bottom width of 14 feet or less, as shown on the Plans, under the Road and Drainage Ex cavation (Unclassified) item. The 203.03 141 Department will measure Channel Excavation (Unclass ified) within the limits of box bridges or box culverts according to
204.12 A.2.b . Construct channel excavation that includes an existing
stream or a proposed stream relocation in accordance with the applicable environmental permits.
D.Undercutting This item consists of removing and disposing of unsatisfactory materials below grade in cut sections and from areas upon which embankments are to be placed, and may also include excavating material below the foundation elevation for pipe, box culverts, and box bridges as provided for in 204.12. Undercutting does not include the stripping, stockpiling, and placing of topsoil, a s specified in 203.06, nor does it include step - benching in the preparation of embankment areas on hillsides, as provided for under 205.03.
203.03 Reserved
CONSTRUCTION REQUIREMENTS
203.04 General
Perform the required Clearing and Grubbing, Removal of Structures and Obstructions, and placement of Erosion Control Devices as specified in 201, 202, and 209, respectively, before starting excavation, grading, and embankment operations. Address both natural and created steep slope areas as required in the TN Construction General Permit. M aintain and stabilize steep slopes according to the TN Construction General Permit and all applicable environmental permits. Remove excavation materials so that the slopes may be neatly trimmed to the lines given. The Engineer may change the slopes shown on the original cross- sections, depress raised medians or islands, raise depressed medians or islands, or daylight cuts to increase or decrease the quantity of Road and Drainage Excavation (Unclassified) if the material can be excavated without blasting an d these changes are set in the slope stakes before excavation of the affected slopes, medians, or islands begins. 203.04 142 Use all suitable materials removed from the excavation areas to construct embankments, intersecting road approaches, and in such other place s as directed by the Engineer . Construct embankment as specified in 205. Remove all loose rock on cut slopes immediately. Do not waste, deposit or dispose of excavated material outside the construction lines without the En gineer’s approval. Ensure that all excavation material wasted, deposited, or disposed of outside the construction lines is in accordance with the manual Procedures for Providing Offsite Waste and Borrow on TDOT Construction Projects . Temporarily discont inue excavating operations upon encountering remains of prehistoric archeological sites or artifacts of historical or archaeological significance. The Engineer will contact archaeological authorities to determine the disposition thereof. Scarify, obliterate, and apply topsoil and seed to all existing roads within the right-of-way, and not in the graded area, which are to be abandoned. Obliteration of old roadways shall include all grading operations necessary to incorporate the old roadway into the new roadway and surroundings to provide a natural terrain appearance from the new roadway.
A.Additional Material If more material is required to complete the embankments after all cuts have been brought to grade and all Road and Drainage Excavation (Unclassified) has been removed from within the balance, obtain additional materials from within the right -of-way by flattening, widening, or daylighting cut slopes, or by depressing raised medians or islands at locations designated and as directed by the Engineer, provided:
1.The cost of this material is more economical than borrow excavation.
2.The material is available within the adjusted balance where the shortage exists , or the material may be hauled outside the limits of adjusted balance if the cost of t he material is more economical than borrow after considering the additional cost of overhaul.
3.The material can be excavated without blasting. 203.04 143 4. There is a minimum of 20 feet between the top of the existing slope and the top of the new slope and a minimum of 5 feet between the top of the new slope and right -of-way line or Control Access fence. The 20-foot minimum will not apply when the existing slope is 4:1 or flatter or to overlapping or near overlapping slopes in medians or between parallel roads or ramps. The Engineer may reduce the 20 - foot minimum at the Contractor’s written request.
5.The material has not been designated as potentially acid producing material.
B.Rock Cuts Construct roadbed through rock cuts to the grading line shown on the Plans, with an allowable working tolerance of plus 1 inch to minus 3 inches. Bring portions of the roadway that are less than 3 inches below grade up to grade with spalls or other suitable granular material that is available from the excavation within the balance. If such excavation is not available, the Engineer may direct the Contractor to use approved base material for capping. If the roadbed is excavated in excess of 3 inches below the grading line shown on the Plans, provide and place, at no additional cost to the Department, sufficient amounts of spalls or base material to bring the roadbed to a line 3 inches below the grading line. Where the Plans require placement of sod on rock cuts, remove the rock to 1 foot below the grading line and bac kfill to grade with earthen material before placing the sod. Where boulder formations occur, scarify the roadbed in the excavation area and remove all boulders to a depth of 12 inches below grade. Backfill and compact resulting cavities with suitable ma terial.
C.Presplitting and Blasting Presplit all rock cuts at the outside limits of the cut areas. Presplitting shall consist of forming a plane of split rock, for the entire depth of the cut or to a predetermined bench level, prior to any primary blasting . To accomplish presplitting, drill holes of appropriate size to the desired depth along the outside limits of the cut area, load such holes with appropriate charges of explosives, stem with minus 3/8 -inch clean stone 203.04 144 chips to the collar of each hole, and simultaneously detonate the charges. The initial horizontal spacing of holes and vertical spacing of charges and blasting cord for simultaneous detonation shall be as recommended by a reliable powder company. Adjust h orizontal hole spacing and vertical spacing of charges as necessary to obtain a relatively smooth shear plane. Do not use sand, gravel, clay, or dirt for stemming. In drilling holes for presplitting, ensure that the drills are plumbed for vertical slopes or set on the required slope when other than vertical slopes are specified, and that all holes are drilled in the same plane. Presplitting will not be re quired on slopes flatter than 1: 1. Presplit rock cuts under bridge sites as specified in this Subsec tion, but comply with the hole spacing specified in 204.08.A. After presplitting is done, drill primary blast holes at least 3 feet from the presplit face. Provide blasting records to the Engineer upon request. Do not perform blasting within 300 feet of any structure or concrete until at least 72 hours after concrete placement. Replace and/or repair all damage associated with blasting operations at no cost to the Department.
D.Unsuitable Soil The Engineer will designate as unsuitable those soils that cannot be properly compacted in embankments. Dispose of all unsuitable soil as directed and at no additional cost to the Department. If the location of unsuitable soil is shown on the Plans, remove an d replace as shown.
E.Borrow Areas Notify the Engineer before opening any borrow area to allow adequate time for the Engineer to take cross -section elevations and measurements of the ground surface after being stripped, and to test the borr ow material before use. Obtain approval for the borrow area according to the Procedures for Providing Offsite Waste and Borrow on TDOT Construction Projects . Allow at least 30 days for testing borrow materials or other material from roadside pits proposed for construction purposes. Borrow materials shall not contain acid producing materials. Representative samples of the proposed borrow material shall be independently tested for pH (EPA600/2 -78-054 or ASTM D4239). 203.05 145 Material with a p H less than 5 is considered acid producing and will not be accepted. Unless otherwise allowed, do not place borrow material until after the roadway excavation material has been placed in the embankments. If the Contractor places more borrow than is requi red and thereby causes a waste of excavation, the Department will deduct the amount of such waste from the measured borrow volume. Do not excavate beyond the dimensions and elevations established. The Contractor may remove highway fencing to obtain borrow materials. Replace the fencing removed with new fence at no cost to the Department, and assume responsibility for confining livestock, as necessary. Excavate borrow pits to be self -draining where possible and practicable, and of a shape that can be easil y cross-sectioned. After completing excavation operations, provide the area with a neat appearance. Cover all self -draining borrow areas with topsoil and stabilize. Provide and place topsoil and seeding (with mulch) as specified in 203.06 and 801, respectively. For borrow pits 1 acre or larger in size that are not self -draining, refer to Sections 53 -801 through 53 -809 of the TCA. Full information regarding the requirements to be complied with an d the necessary permits that the property owner must secure for the construction of a pond, lake, borrow pits, etc., 1 acre or larger that is not constructed to drain, will be supplied upon application to the TDEC.
203.05 Undercutting
The Department will designate areas to be undercut on the Plans if appropriate information is available. However, the Engineer may increase, decrease, or shift such designated areas as conditions require during construction. Backfill undercut areas with suitable material from within the grading balance, or in the first 1,000 feet of the adjacent balances if obtainable. If road and drainage excavation is not available, use borrow excavation as backfill. 203.06 146 Conduct operations so that the Engineer can take the necessary cross - sectional measurements. Compact backfill materials as specified in 205. If disposing of undercutting material off the right -of-way, adhere to the manual Procedures for Providing Offsite Waste and Borrow on TD OT Construction Project s, and obtain advance approval for the disposal site from the Engineer, Environmental Coordinator, and the Environmental Division.
203.06 Stripping, Stockpiling, and Placing Topsoil
The Engineer will designate areas for stripping and stockpiling existing topsoil between slope stake points in both cut and fill areas. Strip the quantity of material necessary to cover all areas to be seeded with 2 to 3 inches of topsoil. If the quant ity of topsoil available in such areas is insufficient, obtain additional topsoil from an approved borrow area according to the manual Procedures for Providing Offsite Waste and Borrow on TDOT Construction Projects. The Engineer will designate areas to b e deleted from stripping operations because of rock or other unsuitable material. Before performing stripping operations, notify the Engineer. Stockpile the stripped topsoil in the areas designated by the Engineer. Neatly dress each stockpile, when completed, to facilitate measurement. Immediately before the Contractor prepares an area for seeding, the Engineer will take cross -section measurements of the topsoil stockpiles. Until the construction sequence for seeding has been established and is read y to proceed, the Engineer will not cross -section stockpiles, and the Contractor shall not spread topsoil. Place a 2 to 3 -inch layer of topsoil on all areas requiring seeding or sod, except for cut slopes steeper than 2:1. On cut slopes steeper than 2:1 that require seeding or sod, spread topsoil to a depth of 1 to 2 inches, as directed by the Engineer. Cover rock slopes and other rock areas that require seeding with 9 inches of suitable material and 2 to 3 inches of topsoil. After placing the stockpil ed topsoil, neatly dress the former stockpile areas and allow the Engineer to take final cross -sections. 203.07 147 203.07 Disposing of Excess or Unsuitable Material Use excess ex cavation material to raise, widen, or flatten the slopes of embankments; to fade embankments into cuts; or to place in such other locations and for such purposes as the Engineer may direct. The Engineer will provide specific instructions regarding the disp osal of surplus material. Place and compact excess or unsuitable material within the right-of-way limits as specified in 205.04. Foundation preparation for and drainage through these waste areas shall be equivalent to that prov ided for the adjacent roadway embankment. If no suitable place can be found to dispose of excess or unsuitable material within the right -of-way, the Engineer may direct the Contractor to provide a suitable offsite disposal area at no additional cost to the Department in accordance with the manual Procedures for Providing Offsite Waste and Borrow on TDOT Construction Projects . Ensure the offsite disposal grading plan is properly designed (including but not limited to slope stability and fill placement reco mmendations) regulated, and implemented.
203.08 Shaping and Dressing
Trim and shape the slopes of all excavated areas, ditches, waterways, channels, borrow pits, and embankments to be in reasonably close conformity with the cross -sections shown on the Plans or as directed by the Engineer. Scale all loose fragments, projecti ng points, and debris from rock cuts, and leave in a neat, safe, and workmanlike condition. Dispose of excess material created by trimming slopes, resloping, and shaping as specified in 203.07. Perform Final Dressing as specified in 206. COMPENSATION
203.09 Method of Measurement
Where excavation of different classifications overlap, the following order of measurement and computation for payment applies: 203.09 148 1. Road and Drainage Excavation (Unclassified) or Channel Excavation (Unclassified) shall supersede Structure Excavation and Foundation Preparation. Road and Drainage Excavation (Unclassified) shall supersede Channel Excavation (Unclassified).
2.Excavation, the cost of which is included in lump sum items or the unit price bid for other items of construction, shall supersede all other classifications. Excavation of embankment will not be measured for payment unless the Engineer approved the excavation in writing. Where it is impracticable to measure m aterial by the cross -section method due to the erratic location of isolated deposits, the Department may use methods involving three -dimensional measurements. The Department will measure w ater used in the work by the M. G. (1,000 gallons) using calibrated t anks or distributors, or accurate water meters.
A.Road and Drainage Excavation
1.The Department will measure Road and Drainage Excavation by the number of cubic yards of material, acceptably excavated, measured in its original position by cross -sectioning t he area excavated. The Engineer may determine cross -sections from conventional manual surveys, aerial surveys, Digital Terrain Modeling, or a combination of these methods.
2.The Department will measure excavation required to bench side -hill slopes of e mbankment construction as follows:
a.Excavation in solid rock will be paid for as Road and Drainage Excavation (Unclassified) whether the excavation material is bladed and dozed or picked up and hauled.
b.For excavation in other than solid rock:
1.The Department will measure excavated material that is picked up and hauled as Road and Drainage Excavation (Unclassified). 203.09 149 (2) The Department will not directly measure excavation material moved by blading or dozing and will consider such work as incidenta l to other items.
3.When the Plans specify or the Engineer directs that rock embankment material be obtained from the roadway excavation, all costs of constructing the rock embankment material, including, but not limited to, excavating, reserving, hauling and placing, will be measured and paid for under the item for Road and Drainage Excavation (Unclassified) and no additional compensation will be made for this work.
4.Authorized excavation of rock, shale, or unsuitable material below grade consists of th at excavation necessary to provide the designed thickness of backfill. If the plane of the designated bottom of excavation falls within a layer or stratum of rock, the below -grade excavation to the bottom of the layer, not exceeding 3 inches below grade, will be considered as authorized and will be measured for payment. If the Engineer directs the Contractor to use approved base material to bring portions of the roadway that are less than 3 inches below grade up to grade, the Department will measure and pay for the furnishing and placing of such base material in tons under the applicable item in 303.15. If base material is not a bid item in the Contract, the Contractor shall provide the material under the provisions of 104.02.D. If the roadway is excavated in excess of 3 inches below the grading line shown on Plans, the Contractor shall furnish and place, at no cost to the Department, sufficient amount of spalls or approved base course material, or other suitable approved granular material, to bring the roadway to a line 3 inches below the grading line.
B.Road and Drainage Excavation (Additional Material)
1.If the Engineer adjusts the slopes shown on the original cross - sections, depresses raised medians or islands, or flattens, widens, or daylights cuts, the Department will measure the additional material thus obtained in cubic yards under Road and Drainage Excavation (Additional Material).
2.If additional material is paid for under the item for Road and Drainage Excavation (Additional Material) and additional clearing and grubbing is required, the Department will measure and pay for 203.09 150 the additional clearing and grubbing by the acre, provided the item for Adjusted Clearing and Grubbing is in the Contract, or as negotiated. No additional payment will be made for extra handling of stockpiled topsoil made necessary by the use of the item for Road and Drainage Excavation (Additional Material).
C.Borrow Excavation The Department will measure and pay for Borrow Excavation by the cubic yard or ton in accordance with 109.
D.Presplitting If the Contract contains an item for Presplitting, the Department will measure presplitting of rock cuts by the number of square yards of rock face determined by multiplying the difference in elevation in yards between the bottom and top of face at each station and intermediate stations (where break sections are needed to accurately show the work) by the length of face in yards taken from cros s-sections. If the Contract does not have an item for Presplitting, the required presplitting shall be included in the price bid for Road and Drainage Excavation or Channel Excavation (Unclassified).
E.Undercutting
1.The Department will measure unsuitable materials e xcavated and removed to obtain proper compaction in cut sections, in foundations for fill sections, and for pipe and box culverts in accordance with
204.12 The removal and disposal of this unsuitable material will
be classified as Undercutting, unless otherwise specified.
2.The Department will not measure suitable material temporarily removed and replaced to facilitate compaction of the material for the full depth shown on the Plans.
3.The Department will measure Undercutting by the cubic yard based on cross-sectional measurement or the most feasible method.
F.Topsoil
1.Except for topsoil obtained from a source outside the right -of-way, the Department will measure and pay for stripping and stockpiling 203.10 151 of topsoil as Road and Drainage Exca vation (Unclassified ) by the cubic yards of material in its original position.
2.The Department will measure the Placing and Spreading of stockpiled topsoil on slopes and elsewhere within the right -of-way by the cubic yards of material in the stockpile as de termined using the cross-section method.
3.Furnishing and Spreading Topsoil obtained from an approved borrow source located outside the right -of-way will be measured by the cubic yards of material removed as determined by cross - sectioning the area before and after removal.
203.10 Basis of Payment
The Department will pay for accepted quantities at the contract prices as follows: Item Pay Unit Road and Drainage Excavation (Unclassified) Cubic Yard Road and Drainage Excavation (Additional Material) Cubic Yard Channel Excavation (Unclassified) Cubic Yard Borrow Excavation ( _____ ) Cubic Yard or Ton Presplitting of Rock Excavation Square Yard Undercutting Cubic Yard Placing and Spreading Topsoil Cubic Yard Furnishing and Spreading Topsoil Cubic Yard Water M.G. Such payment is full compensation for providing all materials, including hauling excavation and borrow, and provi ding all equipment, labor, and incidentals to complete the work as specified. The Department will pay for Road and Drainage Excavation (A dditional Material) at a rate per cubic yard equal to 1.5 times the contract unit price for Road and Drainage Excavation (Unclassified). The Department will pay for excavation required to correct slides , regardless of its location r elative to the theoretical slope line, or excavation required to prevent potential slides including blasting, and the dressing, reshaping or flattening of the affected slopes as direc ted by the Engineer, under the i tem for Road and Drainage Excavation (Add itional Material). If it becomes 203.10 152 necessary to flatten a slope to correct a slide or prevent a potential slide after the cut has been started but not completed, payment under Road and Drainage Excavation (Additional Material) will be limited to material re moved between the original staked slope line and the newly established slope line above the elevation to which the cut has been made. The Department will pay for all other material at the contract unit price of Road and Drainage Excavation (Unclassified). Seeding, sod and other items required to repair the slide area will be paid for at the contract unit price bid for the respective items. The Department will pay for Undercutting at the contract unit price per cubic yard. If unsuitable material not descr ibed in the Plans is encountered and no contract unit price has been established for Undercutting, the Department will pay for this work at a rate per cubic yard equal to 1.5 times the contract unit price for Road and Drainage Excavation (Unclassified) due to the nature of the unforeseen, slower production work. However, if the unsuitable material is known and described in the Plans and has been accounted for in grading quantities (either Undercut ting or Road and Drainage), it will be paid at the contract bid price. If the Plans require placement of sod on rock cuts, the Department will pay for rock removal, earthen backfill, and sod placement under Road and Drainage Excavation (Unclassified) and Sodding (New Sod). The Department will pay for furnishing and placing topsoil and seeding waste areas inside the right -of-way at the contract unit prices for the respective items. The Department will not directly pay for furnishing and placing topsoil and seeding waste and borrow areas located outside the right-of-way. The Department will pay for the removal of concrete pavement, base, parking strip, and sidewalk, curb and gutter, and similar features under the classifications specified in 202.06 and 203.02.A. The Department will pay for roadway obliteration as Road and Drainage Excavation (Unclassified). The Department will pay for the application of topsoil and seed to obliterated roadways under the items for Topsoil and Seeding. 204.01 153 SECTION 204 – STRUCTURE EXCAVATION FOUNDATION PREPARATION, AND BACKFILL
204.01 Description ................................ ................................ ................... 153
204.02 Classification ................................ ................................ ............... 153
204.03 Foundation Fill Material ................................ .............................. 155
204.04 Bedding Material ................................ ................................ ......... 155
204.05 Reserved ................................ ................................ ....................... 155
204.06 Backfill Material ................................ ................................ .......... 155
204.07 Reserved ................................ ................................ ....................... 158
204.08 Excavation ................................ ................................ ................... 158
204.09 Protection of Excavation ................................ .............................. 160
204.10 Foundation Preparation ................................ ................................ 161
204.11 Backfilling ................................ ................................ ................... 163
204.12 Method of Measurement ................................ .............................. 165
204.13 Basis of Payment ................................ ................................ .......... 169
DESCRIPTION
204.01 Description
This work consists of excavation, foundation preparation, and backfill for the installation or construction of bridges, culverts, underdrains, and other structures not otherwise provided for in the Specifications. This work also includes constructing and subsequently removing all bracing, shoring, cribbing, and cofferdams, all pumping and bailing, backfilling, and disposing of excess or unsuitable material.
204.02 Classification
The Department will classify and pay for Structure Excavation and Foundation Preparation under the following designations:
Source: Tennessee Standard Specifications for Road and Bridge Construction, 2021 Edition. Pages 147–161 of 1,072.