423 Page 294423 TEMPORARY WORKS
423.1DESCRIPTION
This work consists of the design, construction, and subsequent removal of all temporary works including, but not limited to; falsework, formwork, cofferdams, work berms and platforms, temporary traffic and stream diversions, and temporary retaining structures.
423.2MATERIALS (Not Specified)
423.3CONSTRUCTION REQUIREMENTS
A.Design of Temporary Works: The design of falsework, formwork, temporary retaining structures, and other related temporary works is the responsibility of the Contractor. The design will conform to the latest edition of the AASHTO "Guide Design Specification for Bridge Temporary Works." All temporary works in waters of the US are required to be covered in the Corp of Engineers 404 Permit. At the time of the preconstruction meeting, the Contractor will submit documentation for all temporary works for the purpose of complying with the 404 Permit requirements. The documentation will include at a minimum: 1.A written description of the proposed temporary works including types of materials to be used, how the temporary works will be installed, removed, and what portion, if any, will remain in place after construction; 2.Details showing approximate size and location of the temporary works. Details will include at a minimum, a plan view and a cross-section view of the temporary works. Details will provide sufficient dimensions such that the approximate size of the temporary works and location of the temporary works from a known point is shown; and, 3.Estimated quantities of all temporary fill material below the ordinary high water elevation. If the temporary fill is to be placed in a wetland, the estimated quantity will be the amount of temporary fill below the ordinary high water elevation and the amount of wetland loss (in acres). If during the course of construction there is a need for additional temporary works, the documentation will be submitted to the Engineer at that time. The Engineer will submit the documentation to the Corp of Engineers for approval. Construction of temporary works below the ordinary high water mark or in wetlands may not begin until Corps of Engineers approval is attained by the Engineer. B.Structure Falsework: 1.Substructure Falsework: Plans and design calculations for substructure falsework will be prepared by a Professional Engineer registered in the State of South Dakota. Falsework will be constructed in accordance with the falsework plans. 423 Page 2952.Superstructure Falsework: Plans and design calculations for superstructure falsework will be prepared by a Professional Engineer registered in the State of South Dakota. The Contractor will submit detailed and dimensioned falsework plans with full design calculations to the Department for the Department’s opportunity for review. Any review by the Department of the falsework plans and design calculations is limited to general conformance with the contract plans and specifications only. Falsework plans will include a plan and elevation view and any details necessary for the Department's general review. The falsework plan will include a minimum 2 foot walkway on both sides outside the edge of the concrete pour. For concrete slab bridges, the total dead load deflection will not exceed 1/4 inch. The Contractor will send an email with the falsework plans and design calculations attached as two separate PDFs to the Project Engineer and Office of Bridge Design. Upon request, the Project Engineer will provide the Contractor the appropriate email addresses. Within 28 calendar days of receiving the falsework plans and design calculations, the Office of Bridge Design will respond to the Contractor in one of the following ways: 1) No Exceptions Noted; 2) Returned for Revision; or 3) Not Required for Review. If the Department’s response states “Returned for Revision”, the Contractor must make the revisions and resubmit the falsework plans and design calculations for review as specified above. The Contractor will not begin falsework construction until the Department has confirmed, in writing, a completed review with a response of “No Exceptions Noted” or “Not Required for Review”. The review of the falsework plans and design calculations by the Department will not relieve the Contractor of any responsibility for safely and adequately designing and constructing falsework. Falsework will be constructed in accordance with the final falsework plans. Before placing any loads on the falsework, the Contractor will provide the Engineer written certification from the Contractor’s Professional Engineer stating the falsework has been assembled in conformance with the final falsework plans. If field changes are made during falsework construction, new falsework plans prepared by a Professional Engineer registered in the State of South Dakota will be submitted to the Project Engineer and Office of Bridge Design for review. Falsework construction affected by the change will not continue until the Department confirms, in writing, a completed review of the change with a response of “No Exceptions Noted” or “Not Required for Review” and the Contractor has submitted a revised written certification. C.Cofferdams, Cribs, and Shoring for Substructures: Plans and design calculations for substructure cofferdams, cribs, and shoring will be prepared by a Professional Engineer registered in the State of South Dakota. The Contractor will submit detailed and dimensioned cofferdam, crib, and shoring plans with full design calculations to the Department for the Department’s opportunity for review. Any review by the Department of the cofferdam, crib, and shoring plans and design calculations is limited to general conformance with the contract plans and specifications only. Cofferdam, crib, and shoring plans will include any details necessary for the Department's general review. The Contractor will send an email with the cofferdam, crib, and shoring plans and design calculations attached as two separate PDFs to the Project Engineer and Office of Bridge Design. Upon request, the Project Engineer will provide the Contractor the appropriate email addresses. Within 28 calendar days of receiving the cofferdam, crib, and shoring plans with design calculations, the Office of Bridge Design will respond to the Contractor in one of the following ways: 1) No Exceptions Noted; 2) Returned for Revision; or 3) Not Required for Review. If the Department’s response states “Returned for Revision”, the Contractor must make the revisions and resubmit the cofferdam, crib, and shoring plans and design calculations for review as specified above. The Contractor 423 Page 296will not begin cofferdam, crib, or shoring construction until the Department has confirmed, in writing, a completed review with a response of “No Exceptions Noted” or “Not Required for Review”. The review of the cofferdam, crib, and shoring plans and design calculations by the Department will not relieve the Contractor of any responsibility for safely and adequately designing and constructing cofferdams, cribs, and shoring. Cofferdams, cribs, and shoring for foundation construction will be carried to adequate depths and heights, be safely designed and constructed, and be made watertight as necessary for the proper performance of the work. When the bottom of the excavation is of sandy or porous material, which will not permit the footing to be poured in the dry, the excavation will be sealed in accordance with Section 423.3 D. The interior dimensions of cofferdams and cribs will give sufficient clearance for the construction of forms, inspection, and to permit pumping outside of the forms. Cofferdams or cribs which are tilted or moved laterally during the process of sinking will be righted, reset, or enlarged to provide the necessary clearance at the expense of the Contractor. Cofferdams, cribs, and shoring will be constructed to protect fresh concrete against damage from sudden rising of the stream and to prevent damage to the foundation by erosion. Timber or bracing that extends into the substructure concrete will not be left in the cofferdams or cribs. After completion of the substructure, cofferdams, cribs, and shoring including all sheeting and bracing will be removed without disturbing or otherwise damaging the finished concrete. D.Foundation Seals : A foundation seal will not be used unless specified on the plans or approved by the Engineer. If the necessity for a foundation seal is due to inadequate or improper cofferdam construction, the Engineer may order the removal or reconstruction of the cofferdam or permit the placing of a foundation seal at the expense of the Contractor. When a foundation seal is specified on the plans, the construction of the foundation seal will be in accordance with these specifications unless otherwise specified on the plans. When no foundation seal is specified in the plans, the Contractor is responsible to design the foundation seal in accordance with the AASHTO "Guide Design Specifications for Bridge Temporary Works". Foundation seal plans and design calculations will be prepared by a Professional Engineer registered in the State of South Dakota. The Contractor will submit detailed and dimensioned foundation seal plans with full design calculations to the Department for the Department’s opportunity for review. Any review by the Department of the foundation seal plans and design calculations is limited to general conformance with the contract plans and specifications only. Foundation seal plans will include any details necessary for the Department’s general review. The Contractor will send an email with the foundation seal plans and design calculations attached as two separate PDFs to the Project Engineer and Office of Bridge Design. Upon request, the Project Engineer will provide the Contractor the appropriate email addresses. Within 28 calendar days of receiving the foundation seal plans and design calculations, the Office of Bridge Design will respond to the Contractor in one of the following ways: 1) No Exceptions Noted; 2) Returned for Revision; or 3) Not Required for Review. If the Department’s response states, “Returned for Revision”, the Contractor must make the revisions and resubmit the foundation seal plans and design calculations for review as specified above. The Contractor will not begin foundation seal construction until the Department has confirmed, in writing, a completed review with a response of “No Exceptions Noted” or “Not Required for Review”. The review of the 423 Page 297foundation seal plans and design calculations by the Department will not relieve the Contractor of any responsibility for safely and adequately designing and constructing foundation seals. Foundation seal concrete will be placed in accordance with Section 465.3 K and will be placed up to the elevation of the bottom of the footing elevation, unless otherwise approved by the Engineer. The pumping of water from the interior of any foundation enclosure will be done without moving water through any freshly placed concrete. Pumping will not be permitted during concrete placement or for at least 24 hours thereafter unless it can be done from a suitable sump which separates fresh concrete from the water. Dewatering of the foundation enclosure may proceed when the foundation seal concrete has attained sufficient strength to withstand the hydrostatic pressure. After dewatering, all laitance and other unsound material on the top of the foundation seal will be removed by scraping, chipping, or other approved methods prior to placing the footing. E.Formwork: 1.Wood Forms: Forms will be designed, built, and maintained to sustain the pressure and weight of the concrete and construction loads. The design of the forms will take into account the effect of vibration of the concrete as it is placed. Forms and form lumber will be clean and in good condition. Lumber that is split, warped, bulged, marred, or that has other defects will not be used. Forms for concrete surfaces will be constructed to produce mortar tight joints with smooth even concrete surfaces. Forms will be filleted at all sharp corners and will be given a bevel or draft in all projections, such as girders and copings. Plywood will be orientated in the strong direction and continuous over three or more supports unless the design shows an alternate orientation is adequate for strength and deflection. The required strength and smoothness may be obtained by lined forms or metal forms. Metal ties and anchorages within the forms will be constructed to permit placement without injury to the concrete. Ties used in the presence of epoxy coated reinforcement will be epoxy coated or made of other corrosion resistant material. If ordinary or epoxy coated wire ties are permitted, all wires will be cut back at least 1/4 inch from the face of the concrete after the forms are removed. Fittings for metal ties will be designed so on removal the resulting cavities will be the smallest practical size. Forms will be set and maintained true to the line designated. When forms appear to be unsatisfactory, either before or during the placing of concrete, the work will be stopped until the defects have been corrected. Forms will be surface treated with an approved form oil or saturated with water immediately before placing the concrete. For members with exposed faces, the forms will be surface treated with an approved form oil to prevent the adherence of concrete. Material which will adhere to or discolor the concrete will not be used. 2.Metal Forms: The requirements for wood forms in regard to design, mortar tightness, filleted corners, beveled projections, bracing, alignment, reuse, and oiling will apply to 423 Page 298metal forms. The metal used for forms will be of such thickness that the forms will remain true to shape. Bolt and rivet heads will be countersunk. Clamps, pins, and other connecting devices will hold the forms rigidly together and allow removal without injury to the concrete. Metal forms, which do not present a smooth surface or line up properly, will not be used. Special care will be exercised to keep metal forms free from rust, grease, and other foreign matter, which will discolor and contaminate the concrete. F.Removal of Temporary Works: Unless otherwise specified on the plans or approved by the Engineer, all temporary works, except foundation seals, will be removed. The removal of temporary works will be done in such a manner that no damage occurs to the structure. The removal of falsework and formwork will be in accordance with Section 460.3 O. and Section 460.3 P.
423.4METHOD OF MEASUREMENT
No field measurement will be made for any temporary works unless otherwise specified in the plans.
423.5BASIS OF PAYMENT
No payment will be made for temporary works. All costs involved in designing, constructing, and removing temporary works will be incidental to the other contract items. 430 Page 299430 BRIDGE END BACKFILL
430.1DESCRIPTION
This work consists of backfilling bridge abutments and sills.
430.2MATERIALS
A.Porous Backfill: The porous backfill material will conform to the requirements of Section 800 with the following modifications: The material will consist of natural sand. Crushed material is not acceptable. The percentage of material passing a #200 sieve will not exceed 2.0%. B.Granular Bridge End Backfill: The granular bridge end backfill material will conform to Section 882. C.Reinforcement Fabric (MSE): The reinforcement fabric will conform to Section 831 (Reinforcement Fabric MSE). D.Drainage Fabric: The drainage fabric will conform to Section 831 (Drainage Fabric-Type B). E.Polyethylene Sheeting: The polyethylene sheeting will be a minimum thickness of 6 mils and will be sufficiently durable so the polyethylene sheeting will not puncture or tear when installed as intended. F.Drainage Tubing: The drainage tubing will be corrugated polyethylene drainage tubing conforming to Section 990. G.Black Steel Pipe: The black steel pipe will conform to ASTM A53. H.Vertical Composite Drain: The vertical composite drain will be a geocomposite sheet drain material consisting of a drainage core with a subsurface drainage geotextile attached to or encapsulating the core. Include all necessary fittings and material to splice one sheet, panel, or roll to the next. The drainage core will be of a material using long chain synthetic polymers composed of at least 85% by mass of polypropylene, polyester, polyamide, polyvinyl chloride, polyolefin, or polystyrene. The core will be fabricated in sheets, panels, or rolls of adequate strength to resist installation stresses and long-term loading conditions. The core will be built up in thickness by means of columns, cones, nubs, cusps, meshes, stiff filaments, or other approved configurations. The geocomposite sheet drain will have a minimum compressive strength of 40 psi when tested in accordance with ASTM D1621 Procedure A. Splices, fittings, and connections will be of sufficient strength to maintain the integrity of the system during construction handling and under permanent loading without impeding flow or damage to the core. The geocomposite drain material will be covered with an opaque, ultraviolet resistant waterproof covering during storage. The maximum allowable exposure to ultraviolet radiation prior to installation is 10 calendar days.