Structural
Steel Deck thicknesses are being soft converted
The primary lesson learned is design dimensions must be
(ex, 38 mm).
rounded dimensions. Bar spacing, wall and slab
thickness, and similar dimensions, shall be even mm
Structural Steel shall be specified in SI only, such as 250
(100, 250, 400 mm) not conversions. (ex, 305 mm)
MPa. Shapes shall be specified according to the
millimeter sizes and dimensions in ASTM A6M.
Calculations End results of structural calculations, and
all summary data shall be SI. Calculations shall be SI to
Welds are shown in even mm sizes. (ex, 5, 6 mm)
the fullest degree feasible.
Wind Pressures are given in Pa.
Cambers State in even mm. (ex, 20, 22 mm)
Wind Speeds are most frequently given in m/s.
Floor Load capacity is specified in kPa.
Significant hinderance to use of kPa has been allowing
dual dimensions. No feel for kPa is acquired unless kPa
only are used.
Our typical office rating is 5 kPa: with 4 kPa and
1 kPa components. Drawings and calculations should
reflect these numbers only.
In existing facilities, it is preferred to convert values to
exact kPa and round to next lowest 0.1 kPa, unless
strong reasons exist not to use this method.
Ex 1, A load capability exactly converts to
9.58 kPa. Round to 9.5 kPa. This is rounded, easy to
remember, less than 1 % error.
Ex 2, at Richmond VA Federal Building renovation:
"Existing Structure Allowable Live Load Per Original
1959 Building Plans Are As Follows:
Lobbies, Stairs, and Corridors 4.8 kPa
Toilets
2.9 kPa
All Other Areas
3.8 kPa"
Situations needing mass loading might use the following
rounded, slightly conservative, rule:
kPa x 100 = kg/m2 (5 kPa x 100 = 500 kg/m2)
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