S1

These buildings consist of a frame assembly of steel beams and steel columns. Floor and roof framing consists of cast-in-place concrete slabs or metal deck with concrete fill supported on steel beams, open webjoistsorsteeltrusses. Lateralforcesareresistedbysteelmomentframesthatdeveloptheir stiffness through rigid or semi-rigid beam-column connections. When all connections are moment resisting connections, the entire frame participates in lateral force resistance. When only selected connections are moment resisting connections, resistance is provided along discrete frame lines. Columns are oriented so that each principal direction of the building has columns resisting forces in strongaxisbending. Diaphragmsconsistofconcreteormetaldeckwithconcretefillandarestiff relativetotheframes. Whentheexteriorofthestructureisconcealed,wallsconsistofmetalpanel curtain walls, glazing, brick masonry, or precast concrete panels. When the interior of the structure is finished, frames are concealed by ceilings, partition walls and architectural column furring. Foundations consist of concrete spread footings or deep pile foundations.