2−25The material to be excavated is that which is included within the pay lines indicated on the Plans and as hereinafter defined, and which is not otherwise classified in either SECTION 202; EARTHWORK AND EMBANKMENT or SECTION 205; TRENCH EXCAVATION . Structure Excavation and Backfill will be subdivided into the following six classifications:
203.01.1 Structure Excavation; Earth . Structure excavation; earth shall include all excavation
not classified as rock, rock-mechanical, masonry, or unclassified excavation. 203.01.2 Structure Excavation; Rock . Structure excavation; rock shall include the removal of bedrock or boulders and detached bedrock fragments over 1 cubic yard in volume when encountered within the limits of Structure Excava tion. Boulder and rock fragments less than 1 cubic yard volume are considered Structure Excavation; Earth. 203.01.3 Structure Excavation; Rock - Mechanical. This classification of structure excavation - rock shall be employed in areas where blasting is prohibited. Rock excavated under this classification shall be removed by employing hydrau lic splitters, air rams, paving breakers, or any other mechanical methods approved by the Engineer. 203.01.4 Structure Excavation; Masonry . Masonry excavation shall include the removal of all concrete or stone masonry built either with or without mortar (includes incidental structures in excess of 1 cubic yard) wherever they are encount ered within the limits of Structure Excavation, provided that such masonry has not been included under any applicable provision of SECTION 201; SITE PREPARATION , of these Specifications.
203.01.5 Unclassified Structure Excavation . Unclassified structure excavation shall include the
removal and disposal of that composite mixture of various types of materials for which the Engineer determines it is impractical to classify into separate classifications for payment, and which is encountered within the designated pay lines. 203.01.6 Crushed Stone Fill Under Structures . This work shall consist of providing one or more courses of crushed stone fill and filter fabric under structures’ footings on prepared subgrade surfaces in reasonably close conformity with the lines, grades, thickness and typical cross sections indicated on the Plans.
203.02 MATERIALS. Backfill materials as specified in the Contract Documents shall conform to the
applicable requirements of SECTION M.01; BORROW AND AGGREGATES , of these Specifications. All backfill materials shall conform to all applicable specification requirements prior to its final placement on the project. The practice of culling deleterious or out of specification material after placement and/or grading in-place will not be allowed.
203.02.1 Crushed Stone Fill Under Structures . Crushed stone shall conform to the gradation
requirements of Subsection M.01.09, Table I, Column II of these Specifications. Filter fabric shall be one of those materials included on the Department’s Approved Materials List. 203.02.2 Cofferdams . The requirements for structural materials for cofferdams such as tremie concrete, steel sheet piling, and steel bracing will be provided in the Special Provisions of the Contract. 2−26 203.03 CONSTRUCTION METHODS.
203.03.1 Excavation.
a.Notification. The Contractor shall notify the Engineer sufficiently in advance of the beginning of excavation, and immediately when it believes there is a change in classification of structure excavation, in order that cross-sectional elevations and measurements may be taken of the undisturbed ground.
b.Dimensions of Excavation. The excavation for footings shall be of sufficient size to accommodate both the placement of the structure as indicated on the Plans and the placement and compaction of backfill. Excavation shall extend at least 2 feet horizontally beyond the vertical face of footings, and a minimum of 12 inches below the base of footings.
c.Change in Elevation or Dimension of Excavation. The elevation of the bottoms of excavations shall be as indicated on the Plans. However, the Engineer may direct the Contractor to make such changes in the elevation or dimensions of the excavation as may be necessary to secure a satisfactory foundation. Whenever such additional work as described above effects changes in quantities involving items designated in the Contract, the provisions relating to such items as specified under SECTION 104; SCOPE OF WORK , will apply.
d.Approval of Foundation . No formwork or permanent work shall commence until after the Engineer has approved the depth and dimensions of the excavation, the character of the material and the condition of the foundation. Sounding rods shall be driven at such points and to such depths as may be directed by the Engineer. The Contractor shall provide assistance to the Engineer as may be necessary to make an adequate inspection of the foundation material. No extra compensation will be allowed for providing this assistance. All unsheathed excavation shall have sufficient side slopes to prevent earth sliding in on the work.
e.Utilization of Excavated Materials. All suitable excavated material shall be utilized as backfill or in embankments. Surplus excavation or unsuitable materials may be either disposed of in non-critical areas within the project limits or legally disposed of.
f.Blasting. All blasting in connection with rock excavation within project limits shall be completed before the placing of any structure concrete unless an exception is granted by the Engineer in writing.
g.Alternatives & Unsatisfactory Bearing Surfaces. Whenever in the opinion of the Engineer the natural foundation material is inadequate to safely support the structure, the Contractor shall proceed with alternative methods as directed by the Engineer. Where not otherwise listed in the Proposal, such operations shall be considered "Extra Work,” and paid for in accordance with Subsection 104.05 of these Specifications.
h.Water . When water is encountered, provisions shall be made for draining or dewatering within the excavation. The dewatering work s hall be accomplished by means that will prevent 2−27disturbing the bottoms of excavations or adjacent structures. When foundation material is relatively impermeable, such that water accumulations tend to soften the cementing material or puddle the surface, provisions shall be made to drain the excavation by suitable channels outside of, and slightly below, the footing level. These channels shall conduct the water to outfalls or sump pumps. Foundation material unduly disturbed or softened by the use of equipment or by inadequate handling of water shall be removed and replaced with material satisfactory to the Engineer and at the Contractor's expense.
i.Preparation of Bearing Surface . All rock or other hard foundation material shall be freed from all loose material, cleaned and cut to a firm surface, either level, stepped or serrated as directed by the Engineer. All seams shall be properly cleaned out and filled with concrete mortar or grout. All shaping of ledge rock shall be carefully executed to avoid any unnecessary excavation of sound rock. No payment for overbreak will be allowed except as provided under Subsection 203.04; Method of Measurement .
203.03.2 Cofferdams. Cofferdams shall be utilized when the bottoms of excavation are below the
prevailing water surface. Cofferdams, when specified or required in order to dewater such excavations, shall consist of timber, steel sheet pili ng, cylindrical metal shells or other structural components. Earthen embankments and dikes will not be classified as cofferdams.
a.Shop Drawings. For substructure work, the Contractor shall submit drawings showing his proposed method of cofferdam construction and other details left open to his choice or not fully shown on the Plans. Such drawings shall be approved by the Engineer before construction is started, but such approval shall not in any way relieve the Contractor of his responsibility under the Contract, to secure a safe and satisfactory cofferdam. Shop drawings shall be prepared and submitted in accordance with Subsection 105.02; Plans and Shop Drawings, of these Specifications.
b.Construction. Cofferdams for foundation construction shall, in general, be well braced and as watertight as practicable. The interior dimensions of cofferdams shall be such as to give sufficient clearance for the construction of forms and the inspection of their exteriors, and to permit dewatering outside of the forms. Where piles are required, the cofferdam shall be of sufficient size to permit the driving of the piles in the exact positions shown on the Plans without interference from the wales or bracing or requiring excessive rebracing. Cofferdams which are tilted or moved laterally during the process of installation shall be righted, reset or enlarged to provide the necessary clearance. These corrective measur es shall be made at the sole expense of the Contractor. Cofferdams shall be constructed and dewater ed to protect green concrete against damage from water and to prevent damage to the foundation by erosion. No construction materials shall be left in cofferdams in such a way as to extend into the substructure masonry.
c.Tremie Seal. Cofferdams shall be dewatered and the foundations shall be placed in the dry. Well point systems and methods will be approved at suitable locations, if required. However, when conditions are anticipated which would render it impractical to dewater the cofferdam before placing masonry, a tremie seal shall be placed both in accordance with Subsection 808.03.5; Para. f of these Specifications, and to the dimensions shown on the Plans. During the placing of a tremie seal and until the seal has set, the elevation of the water 2−28 inside the cofferdam shall be controlled to prevent any flow through the seal. Pumping to dewater a sealed cofferdam of the gravity type shall not commence until the concrete seal has been in place for at least 3 days for spread footing foundations, and at least 7 days for pile-supported foundations. After dewatering, the balance of the foundations shall be placed in the dry, with such modifications as may be necessary for structural purposes.
d.Removal of Cofferdams . Unless otherwise provided, cofferdams including all sheeting and bracing, shall be removed by the Contractor as directed by the Engineer. The removal operation shall be effected in such manner to not disturb or otherwise damage the work. The Contractor shall not remove cofferdams without prior notification and approval of the Engineer. If the cofferdam is to remain in place, it shall be vented or ported below low water level when dewatering is no longer necessary. 203.03.3 Dewatering. Dewatering from the interior of any foundation enclosure shall be carried out in such manner as to preclude the possibility of movement of water through any fresh concrete. No pumping will be permitted during the placing of concrete or for a period of at least 24 hours thereafter, unless it be done from a suitable sump separated from the concrete work by a mortar-tight form, bulkhead, or other effective means. 203.03.4 Embankments Under Structure Foundations. Embankments under stub abutments, walls, culverts, footings, and other foundations where stability requirements are essential shall be constructed of gravel borrow conforming to Subsection M.01.09, Table I, Column I, except that the material shall not contain particles greater than 6 inches maximum dimension. Embankments shall be constructed such that side slopes are sufficiently stable, and such that the widths of embankments shall extend hor izontally 2 feet beyond the vertical faces of footings. The gravel borrow shall be placed in layers not exceeding 12 inches in depth before compaction and shall be compacted to 95 percent of maximum density as determined by AASHTO T180. Embankments under pile supported foundations shall be compacted to 90 percent of maximum density as determined by AASHTO T180. 203.03.5 Backfilling.
a.Protection of Structures During Backfilling. No fill material shall be placed against any structure until permission to place fill has been granted by the Engineer and in no case until the masonry has obtained the 28-day compressive strength or unless otherwise specified in the Special Provisions. In all cases proper precautions shall be taken to assure that the method of backfilling does not cause movement of or undue strain on any part of the structure. Fill material shall be deposited and compacted behind abutments, walls and miscellaneous structures as hereinbefore specified. Special precautions shall be taken when placing fill around slender foundations, rigid frame legs, piers or over and around arches and box culverts, to deposit the material on both sides of such structures to approximately the same elevation at the same time. 2−29Backfill materials shall be carefully placed to avoid damage to masonry and waterproofing treatments. If backfilling or other operations do in fact damage masonry or waterproofing, the Contractor shall remove the backfill and replace or repair the damaged work or waterproofing at the direction of the Engineer. All such repairs, replac ement of materials, and la bor shall be provided at no additional cost to the State.
b.Pervious Fill Adjacent to Structures. The material placed adjacent to, or in contact with arches, culverts, retaining walls, wingwalls, secondary structures, and other areas indicated on the Plans shall be pervious fill. Pervious fill shall be placed in layers not over 12 inches in depth before compaction and shall be compacted to 95 percent of maximum density as determined by AASHTO T180. In those locations not accessible for normal placing and rolling and for minor operations, pervious fill shall be placed in lifts not to exceed 8 inches and compact ed by means of mechanical tampers, or suitable vibratory equipment. For minor operations, hand tamping with heavy iron tampers may be used.
c.Common Backfill. All spaces excavated and not occupied by permanent works, pervious fill, or gravel borrow, shall be backfilled with suitable material, such material to be compacted in 1-foot lifts up to the surface of the surrounding ground. Suitable material shall be free of vegetative matter, organic or compressible soils, and shall meet the requirements for Common Borrow except that the material shall not contain particles larger than 6 inches. The Engineer may approve excavated soil for re-use as suitable material. The surface shall then be neatly graded. Backfill shall be compacted to 95 percent of maximum density as determined by AASHTO T180. No separate payment will be made for this work. 203.03.6 Crushed Stone Fill Under Structures . The crushed stone shall be placed and compacted on a prepared surface to the required thickness indicated on the Plans. A filter fabric must be placed between the crushed stone and surrounding soils. The surface of the crushed stone must be placed in such a manner that a reasonably uniform texture is provided. The surface will have a tolerance of ½-inch, plus or minus, to the grade indicated on the Plans and/or as directed by the Engineer. 203.04 METHOD OF MEASUREMENT.
203.04.1 Structure Excavation. Structure excavation of the various classifications will be
measured by the number of cubic yards of the respective materials actually removed in accordance with the Plans and/or as directed by the Engineer. The volume will be computed by taking the difference in elevation between the existing ground su rface or the bottom of roadway excavation or channel excavation, whichever is lower, and the surface of the completed structure excavation at plan grade or approved revised plan grade all between the designated horizontal pay lines. Structure excavation in roadway cuts, or em bankment areas where the removal of muck is indicated on the Plans shall include only that portion below the bottom of the muck. Structure excavation in roadway cuts shall include only that portion below the subgrade, shoulder foundations, and cut slope lines, or as specifically indicated on the Plans. 2−30 When bedrock, boulders, or masonry are encountered, the Contractor shall notify the Engineer and shall expose the same to such an ext ent that in the Enginee r's opinion the necessary measurements can be taken for structure excavation. If the Contractor shall fail to give such notice or notices, or removes any material prior to the taking of measurements, the Engineer shall presume that measurements taken at the time the Engineer first sees the material in question will give the true quantity of excavation.
a.Pay Lines. Horizontal payment limits will be measured between plumb lines and 2 feet outside of the neat lines of the original foundations only as shown on the Plans. However, should the size of the footing be increased more than 2 feet in any direction, the area of the footing that extends beyond the original payment lines, as established hereinbefore, will be used for determining the additional amount of excavation. No allowance for rock overbreak will be made beyond the above limits or more than 6 inches below bottom of footing, unless indicated otherwise on the Plans. 203.04.2 Pervious Fill, Gravel Borrow, and Common Borrow. "Pervious Fill,” "Gravel Borrow,” and "Common Borrow" will be measured by the num ber of cubic yards actually placed in accordance with the Plans and/or as directed by the Engineer. 203.04.3 Crushed Stone Fill Under Structures . “Crushed Stone Fill Under Structures” will be measured by the number of cubic yards actually placed in accordance with the Plans and/or as directed by the Engineer. 203.04.4 Cofferdams . Cofferdams do not require a measurement for payment.
203.04.5 Tremie Seals. When underwater concrete is specified, the horizontal and vertical
payment limits will be those specif ied for the tremie seal as indicated on the Plans. When underwa- ter concrete is not specified, but is required, the horizontal payment limits will be extended to the actual inside face of the cofferdam, and the ve rtical payment limits will be established by the Engineer. 203.05 BASIS OF PAYMENT.
203.05.1 Structure Excavation. The accepted quantities of "Structure Excavation; Earth,”
"Structure Excavation; Rock,” "Structure Excavation; Rock Mechanical,” "Structure Excavation; Masonry" and "Unclassified Structure Excavation" will be paid for at their respective contract unit prices per cubic yard as listed in the Proposal. The prices so-stated constitute full and complete compensation for all labor, materials, and equipment, including dewatering, removal within the prescribed limits, backfilling and disposal of surplus material, and all incidentals required to finish the work, complete and accepted by the Engineer. 203.05.2 Pervious Fill, Gravel Borrow and Common Borrow. The accepted quantities of "Pervious Fill,” "Gravel Borrow,” and "Common Borrow" will be paid for at their respective contract unit prices per cubic yard as listed in the Proposal. The prices so-stated constitute full and complete compensation for all labor, materials, and equipment, including stockpiling, hauling, placing, compaction, and all incidentals required to finish the work, complete and accepted by the Engineer. 203.05.3 Crushed Stone Fill Under Structures . The accepted quantity of “Crushed Stone Fill 2−31Under Structures” will be paid for at the contract unit price per cubic yard as listed in the Proposal. The price so-stated constitutes full and complete compensation for all labor, materials, and equipment, including stockpiling, hauling, placing and compaction, preparation of the subgrade, filter fabric and all incidentals required to finish the work, complete and accepted by the Engineer. 203.05.4 Cofferdams. "Cofferdams" will be paid for at their respective contract lump sum prices as listed in the Proposal. The prices so-stated constitute full and complete compensation for all labor, materials, and equipment, and all incidentals required to finish the work, complete and accepted by the Engineer. 203.05.5 Tremie Seals. The accepted quantity of concrete "Tremie Seals" will be paid for at the contract unit price per cubic yard as listed in the Proposal. The price so-stated constitutes full and compete compensation for all labor, materials, and equipment, and all incidental s required to finish the work, complete and accepted by the Engineer. SECTION 204 TRIMMING AND FINE GRADING
204.01 DESCRIPTION. This work consists of the trimming and fine grading of all shoulders,
ditches, side slopes, sidewalks, and subgrade whether in excavation or embankment. In the case of the subgrade surface, the work also includes the compaction of the surface upon which the pavement structure shall be placed. All such work shall be to the dimensions and details indicated on the Plans or as directed by the Engineer, all in accordance with these Specifications. 204.02 MATERIALS. Not applicable.
204.03 CONSTRUCTION METHODS. The areas to be graded shall be cleared of unsatisfactory
material and shall then be compacted as directed within the areas of the proposed pavement structure. A tolerance of a maximum of 1 inch, plus or minus, shall be allowed, provided that this plus or minus deviation from grade shall not continue for more than 100 feet in any direction. Any depressions which may occur during compaction shall then be filled with additional suitable material. The surface shall then be regraded and compacted true to the lines and grades, as required. The subgrade upon which the pavement structur e and sidewalk are pl aced shall be graded and compacted to 95 percent of maximum density in accordance with Subsection 202.03.3 of these Specifications. This operation shall be performed prior to pavement structure construction. All slopes shall be graded and finished to conform with the lines and gr ades as indicated on the Plans. Areas to be loamed shall be trimmed and graded to the lines and grades as indicated on the 2−32 Plans or as directed.
204.04 METHOD OF MEASUREMENT. "Trimming and Fine Grading" will be measured by the
number of square yards actually graded in accordance with the Plans and/or as directed by the Engineer. 204.04.1 Area to be Measured. In general, the areas of trimming and fine grading to be measured will be the products of the appropriate "lengths" and "widths" as defined below:
a.Length - All Roadway Sections. The length shall be the length of the Contract measured along the roadway centerline.
b.Widths. The width shall be the sum of the lengths of the line segments (both straight and curved) which are designated as the "TRIMMING AND FINE GRADING LINE" for representative roadway sections as illustrated on the following page. 204.04.2 Resurfacing/Reconstruction Projects. On resurfacing or reconstruction type projects, lesser limits may be applicable. In such cases m easurement limits will be as shown on the Plans or determined by the Engineer. 204.05 BASIS OF PAYMENT. The accepted quantity of "Trimming and Fine Grading" will be paid for at the contract unit price per square yard as listed on the Proposal. The price so-stated constitutes full and complete compensation for a ll labor, materials and equi pment and all incidentals required to finish the work, complete and accepted by the Engineer. SECTION 205 TRENCH EXCAVATION
205.01 DESCRIPTION . This work consists of the excavation, dewatering, and backfill, or disposal,
of all materials required for the construction of box culverts, pipe culverts, storm drains, drainage structures, utilities, utility structures and ditches in reasonably close conformity with the dimension and details indicated on the Plans or as directed by the Engineer, all in accordance with these Specifications. Trench excavation also includes the provision of temporary or permanent trench protection as indicated on the Plans and as specified herein. Trench excavation will be subdivided into the following four classifications:
205.01.1 Trench Excavation; Earth. Trench excavation; earth shall consist of all trench
excavation not otherwise classified.
Source: Rhode Island Standard Specifications (Bluebook), 2024 Edition. Pages 135–142 of 826.