5-114 the Special Detour is no longer n eeded and is closed to traffic ; the final 20 percent of the lump sum price will be paid when the Special Detour is removed and the area encompassing the Special Detour is acceptably restored. Traffic control devices, tempor ary erosion control, pavement, a nd dust control will be paid for in accordance with the applicable Contract items. Payment will be made under: P a y I t e m P a y U n i t
510.10 Special Detour, ___ foot Roadway L u m p S u m
Width Vehicular and Pedestrian Traffic N o t S e p a r a t e d 510.11 Special Detour, Pedestrian Traffic Only L u m p S u m
510.12 Special Detour, ___ foot Roadway L u m p S u m
Width Vehicular and Pedestrian Traffic S e p a r a t e d SECTION 511- COFFERDAMS
511.01 Description This work shall consist of the complete des ign, construction,
maintenance and removal of cofferdams and other related work, i ncluding dewatering and inspection, required to allow for the excavation of foundation units, to permit and protect the construction of bridge or other structural units and to protect adjacent Roadways, embankments or other structural units, in accordance with the C ontract.
511.02 Materials As specified in the cofferdam Working Drawing s.
511.03 Cofferdam Construction
A.Working Drawings. The Contractor shall submit Working Draw ings, showing the materials to be used and the proposed method of construction of cofferdams to the Department. Construction shall not start on cofferdams until s uch Working Drawings have been submitted. Any review of or comment on, or any lack of review of or comment on, these Working Drawings by the Department shall not result in an y liability upon the Department and it shall not relieve the Contractor of the respo nsibility for the satisfactory functioning of the cofferdam.
B.Construction. Construct cofferdams in conformance with the submitted Working Drawings. Cofferdams shall, in general, be carried below the e levation of the bottom of footings to adequate depths to ensure stability and adequate he ights to seal off water. Cofferdams shall be braced to withstand pressure without buckli ng, secured in place to prevent tipping or movement and be as watertight as necessary f or the safe and proper construction of the substructure Work inside them. With the ex ception of construction of a 5-115 concrete foundation seal placed under water, the interior dimen sions of cofferdams shall provide sufficient clearance for the construction and inspectio n of forms and to permit pumping outside of forms. The Cont ractor shall be responsible for the righting and resetting of cofferdams that have tilted or moved laterally, as required for construction. During the placing and curing of seal concrete, maintain the wa ter level inside the cofferdam at the same level as the water outside the cofferdam, to prevent flow through the concrete. No timber or bracing shall be used in cofferdams in such a way as to remain in the substructure Work. Cofferdams shall be constructed to protect fresh concrete again st damage from the sudden rising of the water body, to prevent damage by erosion a nd to prevent damage to adjacent Roadways, embankments or other structural units. Unless otherwise noted, cofferdams, including all sheeting and bracing involved, shall be removed after the completi on of the substructure work in a m anner that prevents disturbance or injury to the finished Work. Cofferdams shall be constructed, dewatered and removed in accor dance with the requirements of Section 656 - Temporary Soil Erosion and Water Pollution Control and related Special Provisions.
C.Inspection of Seal Cofferdams. Seal cofferdam excavations shal l initially be inspected and approved by the Contractor. For each seal cofferdam excavation, the Contractor shall submit a written procedure to the Resident for sediment/overburden removal and excavation ins pection. For cofferdams where seal concrete is to be placed on bedrock, the inspection procedure shall describe the Contractor’s final cleaning and inspection process for attainin g cleanliness of each cofferdam excavation. For cofferdams where seal concrete is no t excavated to bedrock, the procedure shall describe the Contractor’s final cleaning and in spection process for attaining the bottom of seal elevation shown on the Plans. The Contractor shall notify the Resident at least 48 hours prio r to when each seal cofferdam excavation will be ready for final inspection by the Department. The Contractor shall allow adequate time for each occurrence of cofferdam exca vation inspection by the Department. The Contractor sha ll provide and maintain access a nd equipment, such as steel probes, for the Resident and/or the Department’s Dive Team to i ndependently inspect each cofferdam excavation. No seal concrete placement shall begin until the Department has approved the cofferdam excavation. 5-116
511.04 Pumping Pumping from the interior of any cofferdam shal l be done in such a
manner as to prevent any current of water that would carry away or segregate the concrete. Pumping to dewater a sealed cofferdam shall not commence until the seal concrete has set sufficiently to withstand the hydrostatic pressure and meet s the following minimum curing time, after the completion of the installation of the se al concrete:
1.When the temperature of the water body outside the cofferdam is greater than 40 degrees Fahrenheit, a minimum of 5 days.
2.When the temperature of the water body outside the cofferdam is less than 40 degrees Fahrenheit, a minimum of 7 days. Procedures for the removal of all water and materials from coff erdams shall be described in the Soil Erosion and Water Pollution Control Plan as require d in Section 656 Temporary Soil Erosion and Water Pollution Control and related Special Pr ovisions.
511.05 Method of Measurement Cofferdams will be measured as on e lump sum unit, as
indicated on the Plans or called for in the Contract.
511.06 Basis of Payment The accepted quantity of cofferdam wil l be paid for at the
Contract lump sum price for the respective cofferdam items, whi ch price shall be full compensation for design, construction, maintenance, inspection and removal. When required, the elevation of the bottom of the footing of an y substructure unit may be lowered, without change in the price to be paid for cofferda ms. However, if the average elevation of more than 25 percent of the area of the excavation is more than three feet below the elevation shown on the Plans, and if requested by the Contr actor, then the additional costs incurred that are included in the cofferdam Pay Item will be paid for in accordance with Section 109.7, Equitable Adjustments to Compensation and T ime. The Contractor shall immediately notify the Department when these additional c osts commence. Failure of the Contractor to provide this notification will result in undo cumented additional work that will be non-reimbursable. The Department will evaluate this ad ditional work to determine an appropriate time extension, if warranted. All costs for sedimentation control practices, including, but n ot limited to, constructing, maintaining, and removing sedimentation control structures, and pumping or transporting water and other materials for sedimentation control will not be paid for directly, but will be considered incidental to the cofferdam Pay Item(s). All costs for related temporary soil erosion and water pollutio n controls, including inspection and maintenance, will not be paid for directly, but will be considered incidental to the cofferdam Pay Item(s). All costs associated with preparation of Working Drawings, desi gn calculations, written procedure for sediment/overburden removal and excavation inspec tion, and the inspection of the seal cofferdam excavation shall be considered incidental to the cofferdam Pay Item(s). 5-117 There shall be no additional payment for repeated inspection by the Department of the same cofferdam excavation. All costs for cofferdams and related temporary soil erosion and water pollution controls, including inspection and maintenance, will be considered incide ntal to related Pay Items, when a specific Pay Item for cofferdams is not included in the Contract. Seal concrete will be evaluated under Section 502. Payment will be made under: P a y I t e m P a y U n i t
511.07 Cofferdam L u m p S u m
SECTION 512 - FRENCH DRAINS
512.01 Description This work shall consist of furnishing, plac ing and compacting stone
and gravel and furnishing and placing erosion control geotextil e for French drains in accordance with these specifications and in reasonably close co nformity with the lines and grades shown in the Contract.
512.02 Materials. Materials shall meet the requirements of the following Sections of
Division 700 — , Materials.
Aggregate for Subbase 703.06(b) G r a v e l B o r r o w 703.20 Stone for French Drains 703.24 Erosion Control Geotextile 722.03 (Class 1) Gravel for French drains shall meet the requirements of either Aggregate for Subbase, Type D, or Gravel Borrow, at the Contractor's option.
512.03 Drains Stone shall be placed behind and against the str uctures with the bottom
of the stone at the elevation of the flow line of the weeper dr ains. The stone shall form a box section, 2 feet wide and 2 feet high, for the entire length of the structure. Erosion control geotextile shall be installed to separate the stone box section from the surrounding gravel. Installation of the erosion control geotextile shall b e in accordance with Section 620, Geotextiles. Gravel shall be placed to form a box section around the stone, to the limits of 2 feet above the stone, 2 feet behind the stone and 2 feet b elow the stone, but not to be placed below the top of the footing.
Source: Maine Standard Specifications for Road and Bridge Construction, 2020 Edition. Pages 406–409 of 817.