Custom Search
|
|
|
||
 Advantageously, the repetitive truss system allows large hangar bay doors on both ends of the
hangar bay, adding flexibility to positioning of aircraft and avoids concentrating large loads on
few critical elements. The system also has built in redundancy which can be a beneficial factor
in seismic and anti-terrorism/force protection design. Disadvantageously, the lateral load
resisting system in the direction parallel to the doors is complicated by the lack of walls in that
direction.
Hybrid Systems
The possibility exists to combine structural systems in multiple ways. The designer is cautioned
to carefully consider the ramifications of combining systems as the negative influences of a
hybrid is often greater any one system independently.
Materials
Weathering steel
Weathering steel, if considered, should not be used where exposed to recurrent wetting by salt
water or airborne abrasives. Weathering steel should not be used at or below grade. Careful
detailing should be maintained throughout the design to ensure that weathering steel does not
trap and hold water. Pockets which hold water will not form the required oxide coating which
gives the steel its enhanced corrosion protection. In areas where weathering steel is acceptable,
proper detailing and use of materials should be a requirement to prevent staining of adjacent
building components.
Hollow Structural Sections
Hollow Structural Sections (HSS)are an attractive design choice for their weak axis stability or
bi-axial properties. There may also be additional benefits derived from efficiency in 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 which are not
pre-approved and/or more extensive weld testing than normally found on hot rolled steel
construction.
Architecturally Exposed Structural Steel
Architecturally Exposed Structural Steel (AESS) may be an attractive choice for architectural
reasons, such as maximizing the useable floor space or minimizing facia and cladding. Exposed
27
|
 
|
|
|
||
