5-234 SECTIO N 528 – TEMPORAR Y BRIDGE 528.0 1 DESCRIPTION . This work shall consist of the design, construction, maintenance, and removal of a temporary bridge, its substructures, and approaches. 528.0 2 MATERIALS . The Contractor may use any material or combination of materials that will conform to the requiremen ts of this subsection and meet the approval of the Engineer. The Engineer reserves the right to reject materials and details that are structurally unsafe for the use proposed. Unless s pecifically permitted in the Contract or upon written authorization of the Construction Engineer, the use of pipes will not be allowed for temporary bridges. Unless otherwise authorized on the approved drawings, all main load carrying members shall be continuous between supports. Splices will only be approved for the following conditions:
a.Fully -Bolted Connections . Fully bolted connections, with high -strength bolts, shall be designed for their location in accordance with the AASHTO LRFD Bridge Design Specifications .
b.Fully -Welded Connection s. Fully welded connections shall be designed, welded, inspected, and tested in a ccordance with the requirements of AASHTO LRFD Bridge Design Specifications and AWS requirements. Any welded connection performed in the absence of and without the approval of the Agency’s welding inspector will not be approved. Any welding done for work u nder this section shall be detailed on the working drawings and performed in conformance with Section 506 . 528.0 3 WORKING DRAWINGS . Working draw ings shall be prepared by the Contractor for the proposed work under this item in accordance with the requirements of Subsection 105.06 .
a.Calculations . The Contractor shall provide calculations for the horizontal and vertical alignments and all structu ral components of the temporary bridge. When a temporary bridge is expected to be open to traffic for longer than 24 months, the calculations shall include a load rating for the design vehicle as well as the other Vermont Standard Load Rating Trucks define d in the VTrans Structures Design Manual .
b.Drawings . Drawings for bridge approaches shall include plans, profiles, typical sections, and specific cross -sections for the temporary roadway and channel, when applicable, with complete details and identification of materials to be used. Drawings for the tempo rary bridge structure shall include plan, elevation, and section views of the structure and shall include size and spacing of all members or components for the following: 5-235 (1) Abutments
2.Piers
3.Main supporting members or stringers
4.Floor system
5.Diaphragms and lateral bracing
6.Bridge railing and approach railing, including the connection details between the two
7.Curbs
8.Bearings
9.Other applicable informa tion 528.0 4 DESIG N REQUIREMENTS AND CONSTRUCTIO N DETAILS .
a.Channel . The Contractor shall provide for the waterway and clearances shown on the Plans. When temporary bridge requirements are not shown on the Plans, the opening area shall be at least equal to 40% of the waterway provided for the 1% annual exceedance probability (AEP) for the new structure, with a minimum clear height equal to a 10% AEP headwater. This waterway shall be adequate for safely conve ying 43% AEP flow at a headwater no greater than what would be created by the existing structure at 10% AEP. Questions regarding hydraulic information not furnished shall be addressed to the Engineer. Fill placed in or adjacent to the stream shall be clea n granular or rock material meeting the requirements of Subsection 703.04 or Subsection 703.05 and protected with sufficient stone to prevent erosion to a 10% AEP headwater elevation (based on the new structure). Any fill placed in the stream to protect th e temporary bridge and approaches shall be removed to the satisfaction of the Engineer upon completion of the project.
b.Roadway . The geometric design of the temporary bridge and approaches, except as otherwise shown on the Plans or as noted herein, shall be designed in accordance with A Policy on Geometric Design of Highways and Streets . The roadway width shall be increased on cur ved portions of the approaches to account for the off tracking characteristics of a WB -62 vehicle in accordance with A Policy on Geometric Design of Highways and Streets . 5-236 Approach embankments shall be constructed of acceptable fill material, compacted to adequately support design loading requirements. A minimum of 15 inches of approved gravel or other acceptable surfacing material shall be provided for the full width of the typical section. When the Plans designate paved approaches, the approaches shall be paved with a minimum 2 inch wearing course of Type IIIS or Type IVS bituminous concrete pavement with an Ndesign value of 65 gyrations and an asphalt binder grade of 58S -28. Bituminous concrete pavement shall conform to the requirements of Section 716 . The temporary pavement shall extend for the full length and width of the approaches and both the approaches and the bridge shall have temporary pavement markings applied in accordance with Section 646 . Turnouts with adequate space for two -way traffic shal l be provided at each end of a one lane structure or coordinated with traffic signalization, if used.
c.Bridge .
1.Loading . Unless otherwise specified, all temporary bridge structures shall be designed for an HS -20 or HL -93 live load, and for all other applicable forces, in accordance with the AASHTO Standard Specifications for Highway Bridges or the AASHTO LRFD Bridge Design Specifications . Sidewalks and pedestrian structures shall be designed for a minimum live load of 60 pounds per square foot.
2.Clearances . A one lane temporary brid ge shall have a minimum clear width between the faces of railing s of 14 -1/2 feet. A two lane temporary bridge shall have a minimum clear width between the faces of railing s of 24 feet. Sidewalks and pedestrian bridges shall have a minimum clear width of 4 feet between the faces of railing s or the edge of curb and face of railing. A minimum vertical clearance of 14 feet shall be provided for vehicular traffic and 8 feet for pedestrian traffic.
3.Erection . As part of the working drawings submittal, the Contractor shall, depending upon the type of structure being erected, include the information required under Section 506 or Section 510 pertaining to erection or installation. Submittal of the computations indicating the magnitude of the stresses in the segments is not required. For modular prefabricated panel bridge systems, the Contractor shall have a representative from the manufacturer of the bridge system present during the erection of the bridge components. 5-237 (d) Railing . Approach railing and temporary barrier rail shall conform to Subsection 621.07 . Details for either rail system or combination thereof shall conform to applicable AASHTO requirements. Rail sections shall be continuous from the approaches across the structure. Approach railing shall be provided for a minimum of 25 feet off the ends of any structure and shall b e provided for all approach fill slopes steeper than 1:3 (V:H). The ends of all rail or barrier systems shall be terminated in accordance with the requirements of the MUTCD , the Roadside Design Guide , and applicable Agency standards and specifications. Bridge railing and pedestrian railing shall be designed in accordance with the AASHTO LRFD Bridge Design Specifications . Bridge railing shall be designed for Test Level 2 criteria unless a higher test level is specified on the Plans. When temporary barrier rail is specified or used as a movable rail system, an adequate connection shall be provided when concrete median barrier is used in combination with standard steel beam rail.
e.Walkways and Approaches . Temporary bridges with walkways, temporary pedestrian bridges, walkways, and approaches to walkways shall be designed and constructed to provide width, grade, surface, etc. in conformance with the requirements set forth in the Americans with Disabilities Act standards for sidewalks. 528.0 5 MAINTENANC E AND LIABILITY . The Contractor shall maintain each temporary bridge and its approaches in conformance with Contract requirements and to the satisfaction of the Engineer. The Contractor shall assume all liability for the installation, maintenance, and removal of the tempo rary bridge and its approaches. Unless otherwise specified, all rights -of-way on private property required for the performance of this work shall be provided by the Contractor. Costs for replacing the loss of any part of the temporary bridge or its approac hes shall be included in the unit price for the temporary bridge item except as provided in Subsection 107.1 7. 528.0 6 METHO D OF MEASUREMENT . The quantity of One Lane Temporary Bridge, Two Lane Temporary Bridge, or Temporary Pedestrian Bridge to be measured for payment will be on a lump sum basis for each type specified in the complete and accepted work. 528.0 7 BASIS OF PAYMENT . The accepted quantity of One Lane Temporary Bridge, Two Lane Tempo rary Bridge, or Temporary Pedestrian Bridge will be paid for at the Contract lump sum price for each type specified. Payment will be full compensation for designing, detailing, constructing, maintaining, and removing the bridge and its approaches, includin g placing and removing pavement and pavement markings when paved approaches are required. 5-238 Partial payments for these items may be made as follows:
a.The first payment of 10% of the Contract lump sum price may be made when working drawings have been submitted and approved in accordance with the requirements of Subsection 105.06 .
b.The second payment of 65% of the Contract lump sum price may be made w hen the temporary bridge, its substructures, and approaches have been fully constructed and accepted by the Engineer.
c.The third payment of 15% of the Contract lump sum price may be made when the temporary bridge and its approaches have been removed.
d.The final payment of 10% of the Contract lump sum price may be made when the site has been cleaned up and vegetation has been established to the satisfaction of the Engineer. Unless otherwise specified as a separate Contract item , the costs of all approach and bridge railing associated with the temporary bridge will be considered incidental to the applicable temporary bridge pay item. Payment will be made under: Pay Item Pay Unit
528.10 00 One Lane Temporary Bridge ................................ ................................ ....Lump Sum
528.11 00 Two Lane Temporary Bridge ................................ ................................ ....Lump Sum
528.12 00 Temporary Pedestrian Bridge ................................ ................................ ...Lump Sum
5-239 SECTIO N 529 – REMOVA L OF STRUCTURE S AND BRIDG E PAVEMENT 529.0 1 DESCRIPTION . This work shall consist of the removal, wholly or in part, and the satisfactory disposal of all structures, including accessories and appurtenances, bridge pavem ents, and the backfilling of holes when required. 529.0 2 GENERAL REQUIREMENTS . Unless otherwise specified, all materials resulting from the removal of structures and removal of bridge pavements shall become the property of the Contract or, wh o shall properly dispose of them. 529.0 3 REMOVA L OF BRIDG E PAVEMENTS . The removal of pavement on bridges shall include the removal of bituminous concrete material, and, when a new wate rproofing membrane is included in the Contract or as directed by the Engineer, the removal of sealants or membranes. When not otherwise specified, sealants or membranes shall remain in place. If removal is by milling, work shall be done in accordance with the requirements of Section 210 . Removal methods shall be subject to the approval of the Engineer and shall be such as to prevent any damage to the remaining surface. Any necessary deck repair will be paid for as shown on the Plans, except damage caused by Contractor’s negligence shall be repaired at the Contractor’s expense. 529.0 4 REMOVA L OF STRUCTURES . The Contractor shall dismantle the structure and shall remove the dismantled members or materials. Removal of structures spanning bodies of water will be conducted so as to avoid dropping materials into the water. The entire site of the old structure shall be restored to a condition satisfactory to the Engineer. The existing concrete or masonry shall be removed by drilling, chipping, or other methods approved by the Engineer. All cut surfaces, unless otherwise specified, shall be on a reasonably vertical or horizontal plane with sharp straight corners. Existing re inforcing steel to be retained shall be carefully preserved and cleaned for use in the new construction. Existing reinforcing steel damaged beyond reuse as determined by the Engineer shall be replaced by splicing a bar of equal diameter to the damaged bar in a manner approved by the Engineer at no additional compensation to the Contractor. Holes for expansion bolts or dowels shall be drilled in the retained concrete at the locations shown on the Plan s. When the material from the structure is to be retained by the Agency or others, or is to be reused in the construction, it shall be carefully dismantled by the Contractor and all adhering concrete removed. Materials to be retained or reused shall be stored at the location specified in the Contract or as direct ed by the Engineer.
Source: Vermont Standard Specifications for Construction, 2024 Edition. Pages 648–652 of 1,380.