SECTION 409—STEEL GRID FLOORS
409.01 Description
This work shall consist of constructing a steel grid floor as shown on the Plans or elsewhere in the Contract in accordance with these Specifications or as directed by the Engineer.
409.02 Materials
Materials shall conform to Section 227. 409.02
409.03 Procedures
The floor shall conform to the design requirements for steel grid floors in the AASHTO LRFD Bridge Design Specifications.
a.Arrangement of Sections: Where main elements are normal to the centerline of the roadway, units shall generally be of such length as to extend over the full width of any roadway up to 40 feet. In every case, units shall extend over at least three panels. Where joints are required, ends of main floor units shall be welded at joints over their full cross-sectional area or otherwise connected to provide full continuity in conformance with the manufacturer’ s recommendations. Where main elements are parallel with the centerline of the roadway, sections shall extend over at least three panels and ends of abutting units shall be welded over their full cross-sectional area or otherwise connected to provide full continuity in accordance with the Department’ s approved design.
b.Provision for Camber: Steel units so rigid that they will not readily follow the camber required shall be cambered in the shop. The stringers shall be canted or provided with shop-welded beveled bearing bars to provide a bearing surface normal to the crown of the roadway. If beveled bars are used, they shall be placed along the centerline of the stringer flange, in which case the design span length shall be governed by the width of the bearing bar instead of the width of the stringer flange. Longitudinal stringers shall be cambered at the mill or provided with bearing strips so that the com- pleted floor after dead-load deflection shall conform to the longitudinal camber shown on the plans.
c.Field Assembly: The Contractor shall assemble areas of considerable size before the floor is welded to its supports. Main elements shall be made continuous, and sections shall be connected together along their edges by the welding of bars. The Engineer must approve connections before acceptance.
d.Connection to Supports: The floor shall be connected to its steel supports by welding. The Contractor shall load the floor to make a tight joint with full bearing or clamp the floor down before any welding is performed. The Contractor will not be allowed to clamp the floor in any manner to compensate for distorted, warped, or improperly welded units in order to secure a connection. The locations, lengths, and sizes of the welds shall be as approved by the Engineer, but in no case less than the manufacturer’ s standards.
e.Welding: Welding shall conform to Section 407.
f.Damaged Galvanized Coatings: Damaged coatings shall be repaired in accordance with Section 233.
g.Concrete Filler: Floors with open bottom flanges shall be provided with bottom forms of metal or wood to retain the concrete filler. If the Contractor uses metal form strips, they shall fit tightly to bottom flanges of floor units and be placed in short lengths extending approximately 1 inch beyond the edge of each support. The form shall be such as will result in the adequate bearing of the slab on the support. Concrete shall be placed and cured in accordance with Section 404 and thoroughly consolidated by vibrating the steel grid floor. The Engineer will approve the vibrating device and manner in which it is operated. 409.03
Steel Grid Floors in other states
Get an email when 409 changes
Virginia revises spec sections through supplementals and new editions. We check this one every week and email you the day it changes. Free, no account.
Source: Road and Bridge Specifications, 2020 Edition. Pages 555–556 of 1,065. View official source ↗