CEMP-E
TI 809-02
1 September 1999
steel. Column bases should be terminated on concrete curbs or piers above grade, and tops
of curbs or piers will be pitched to drain.
(4) Where extremely corrosive conditions exist, consideration should be given to
providing cathodic protection in addition to protective coatings for steel members exposed to
salt water moisture environments.
(5) Structural members embedded in concrete and exterior railing, handrails, fences,
guardrails, and anchor bolts will be galvanized or constructed of stainless steel.
(6) Dissimilar metals, (e.g., aluminum and steel, stainless steel and carbon steel, zinc
coated steel and uncoated steel) should be isolated by appropriate means to avoid the
creation of galvanic cells which can occur when dissimilar metals come in contact.
12-3. STEEL STRUCTURES EXPOSED TO EXTREME CLIMATIC CONDITIONS.
a. Arctic and Antarctic Zones. For carbon steel, the transition from ductile to brittle
behavior occurs within temperatures to be expected in Arctic and Antarctic zones. Ductility is
important for structures in high seismic areas. Toughness, a characteristic also affected by
cold temperatures, is important for structures which could be subjected to cyclic or impact
loadings. Information in ASTM A 709, "Structural Steel for Bridges", although related to bridge
structures, does contain information on fatigue and toughness useful in the design of
buildings. Structures in cold climates, which could be subjected to cyclic or impact loads,
should considered the following measures to mitigate potential fatigue and fracture problems.
(1) Provide ample fillets to avoid stress risers.
(2) Use bolted joints whenever possible. If welded joints are used, take precautions
to eliminate gas and impurities in welds. Proper preheating and post cooling are essential.
(3) Use low-carbon steels and nickel-alloy steel that have good toughness
characteristics at low temperatures.
b. Tropical Zones. The effect high ambient temperatures have on steel properties, with
respect to buildings constructed in tropic zones, is minimal.
12-4. STEEL STRUCTURES SUBJECTED TO ELEVATED TEMPERATURES.
a. Hot-rolled Carbon Steel. Up to 65 degrees C (150 degrees F), strength of steel will
be assumed to be same as the strength at normal temperature. Above 65 degrees C (150
degrees F), the yield strength decreases with increasing temperature.
b. High-strength and Heat-treated Steels. The effect of elevated temperatures on high
strength and heat-treated steels should be thoroughly investigated. For example, quenched
and tempered materials will undergo radical changes in their mechanical properties as well as
toughness when subjected to temperatures above 260 degrees C (500 degrees F).
12-2
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