Rev. 5-08-97

 ALTERNATES TO STRUCTURAL PLATE STRUCTURES 
717-R-152

         The Standard Specifications are revised as follows:

 SECTION 717, LINE 123, DELETE AND INSERT AS FOLLOWS:
        717.06 Blank Alternate Structural Plate Structures. The Contractor will be permitted to furnish and place an alternate type structural plate structure to such structure specified. The alternate structure shall be in accordance with the following requirements.

  1. Plans and specifications shall be submitted for review and approved prior to commencing work.

  2. The structure shall be designed for the more critical of AASHTO HS20-44 live load or alternate military loading of two axles spaced 1220 mm (4 ft) apart with each axle weighing 10 900 kg (24,000 lb). The alternate military loading shall be applied to structures under primary, secondary, or local routes if the design year truck traffic volume exceeds 600 vehicles per day, or structures under interstate routes.

  3. The design shall be in accordance with the applicable minimum design requirements of the AASHTO Standard Specifications for Highway Bridges, Division I, Article 12.6 Long Span Structural Plate Structures. Either continuous longitudinal structural stiffeners or properly designed reinforcing ribs will be permitted. The design shall also include revisions to foundations if required. Applicable drawings and design calculations, signed and sealed by a registered professional engineer, shall be submitted.

  4. The structure shall have the same geometrical shape as the originally specified structure.

  5. The extent of the backfill envelope shall equal or exceed the horizontal and vertical limits of the originally specified structure. Backfill material shall be B borrow for structure backfill of nominal size of 25 mm (1 in.) or greater and in accordance with 211.02, compacted in accordance with 203.23. If the Contractor considers some of this backfill material to be unacceptable, such material shall be excluded when the specifications and plans are submitted for approval. Exposed backfill material shall be encased with geotextiles and riprap, both in accordance with 616.

  6. A list shall be submitted listing 30 similar structures of the same span or larger which have been installed within the continental United States.

  7. An itemization shall be submitted showing the contract requirements which are to be changed if the structure is accepted.

  8. A qualified field inspector, provided by the manufacturer, shall be present during erection and backfilling of the structure.

 

SECTION 717, BEGIN LINE 215, DELETE AND INSERT AS FOLLOW:
        The costs of excavation, concrete field paved inverts, disposal of surplus materials, reinforcing steel, straps, and hook bolts used in anchors, substitution of an alternate structural plate structure, and necessary incidentals
shall be included in the costs of the pay items.

        The costs of metal bearings and other hardware needed to attach the structural plate arch to its substructure shall be included in the cost of the arch.

         The cost of paved invert shall be included in the cost of pipe or pipe arch, structural plate, concrete paved invert.