UNDERSTRUCTURE
The understructure of the bleacher shall consist of a series of welded aluminum angle frames
spaced at intervals of no more than 6'-0" and joined by means of aluminum sway braces, alloy
6061-T6, mill finish. Each frame shall consist of vertical members, adequate diagonal braces,
and horizontal members welded to form an 8" rise and a 24" back to back spacing between seat
rows. Front walkway elevated 32’’ above grade, 54’’ clear width. Design of the bleacher shall
conform in all respect to the IBC 2009 Edition for bleachers and grandstands. All welded
connections shall be by certified aluminum welders and all mating parts shall be welded on all
sides to assure adequate strength.
DESIGN
The bleacher shall be designed to support, in addition to its own weight, a uniformly distributed
live load of not less than 100 pounds per square foot of gross horizontal projection of the
bleacher. All seat and foot plank members shall be designed to support not less than 120
pounds per lineal foot. The bleacher shall be designed to resist, with or without live load, a
horizontal wind load appropriate for local conditions. It shall also be designed to resist, in
addition to the live load, sway forces applied to the seats in a direction parallel to the length of
the seat planks 24 pounds per lineal foot; and, in a direction perpendicular, stresses in
aluminum members and connections shall not exceed those specified for Building Type
Structures by the Aluminum Association.
SEATS AND DECKING
Seats shall be 2"x 10" nominal extruded (1.75"x9.5"actual) aluminum, alloy 6063-T6, wall
thickness .078" (+/- .006" industry tolerance) with a raised fluted surface to provide a non-skid
surface. Seats shall be anodized clear (204R1), conforming to the Aluminum Association
Architectural Standard AA-C22A31. Seat planks shall have one internal support leg, and shall
be designed to rest on a seat support with a minimum bearing surface of 8-1/2" to provide
adequate resistance to torsion stress. Footboards shall consist of two 2"x10" nominal extruded
(1.75"x9.5" actual) aluminum, alloy 6063-T6, wall thickness .078"(+/- .006" industry tolerance)
with a raised fluted surface to provide a non-skid surface. Footboards shall have a mill finish.
End caps provided for footboards shall match in both color and finish, shall be full length single
piece, and shall attach by means of aluminum rivets on the underside of the plank.
