UFC 4-211-01N
25 October 2004
steel use and minimization of exposed steel surfaces. The bi-axial strength
characteristics provide for enhanced erectibility and greater resistance to
progressive collapse resulting from localized damage. However, HSS
connections are more challenging to design and often more difficult to fabricate.
The design engineer should consider and clearly represent in the contract
drawings the difficulty of the HSS connections. Additionally, a greater reliance on
shop connections is the norm in HSS practice. The designer is encouraged to
consider the complications of transporting large, built-up elements to the site.
HSS connections may involve the use of welds that are not pre-approved and/or
more extensive weld testing than normally found on hot rolled steel construction.
4-4
STRENGTH AND SERVICEABILITY REQUIREMENTS. Design
the overall structural system for wind uplift conditions peculiar to the site.
Provide a bridge crane in the OH space of each maintenance hangar module
supporting helicopters, propeller driven aircraft, or the C-9, V-22, or AV-8 aircraft.
In the future, H-53 will normally be housed in a type II hangar. If NAVAIR
headquarters makes special exception for housing an H-53 in a special modified
type I hangar, the minimum hook clearance must be 8.2 meters (27 feet). Do not
use bridge cranes in maintenance hangars supporting other types of aircraft
except in specialized instances approved by NAVFACENGCOM or when
specifically required by the Facility Requirement Document (FRD.)
Requirements for the bridge crane, motor, and controls are given in par. 3-23. In
all cases, design the hangar roof support structure to accommodate the loading
from overhead bridge crane described in par. 3-23.1.
4-4.1
Gravity Loads. Gravity loads on the main structural frame should
be determined using UFC 1-200-01, supplemented by actual physical data of
known equipment and materials where appropriate. In determining design load
combinations for structures in which the dead load of one portion of the building
serves as stability enhancing function for another portion of the building (i.e.
cantilevered construction), the following cases should be considered in addition
to the basic load cases
4-4.1.1
load is factored with a coefficient exceeding unity, that portion of the dead load
serving to resist overturning should be factored with a 0.9 coefficient.
4-4.2
Wind Loads. Design wind with importance factor of 1. Refer to
UFC 1-200-01 to quantify and distribute wind loads to the building.
Wind load on main building wind force resisting system should be
determined based on the following two conditions:
Hangar doors fully open for winds up to 96 km/h (60 mph); design
as a "partially enclosed structure."
Hangar doors closed for winds above 96 km/h (60 mph) up to the
42
Previous Page
