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Handrail Assembly and Steel Stairs. Handrail Terminology. Guardrail top most rail on balcony higher than handrail. Vertical Rail members between balusters ensure safety. Handrail member that parallels angle of stairs ensure safety. Horizontal Rail lower rail parallel to handrail
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Handrail Terminology • Guardrail • top most rail on balcony • higher than handrail • Vertical Rail • members between balusters • ensure safety • Handrail • member that parallels angle of stairs • ensure safety • Horizontal Rail • lower rail parallel to handrail • ensure safety • Baluster • member that holds up handrail and vertical & horizontal railing
Handrail Terminology • Newel (newel post) • Large terminating post at the bottom or top of stairs or landing • Half newel is next to the wall on the right
Handrail Terminology • Gooseneck • transition from handrail to guardrail due to height difference
Handrails • Definition: a member that parallels the angle of the stairs allowing a person to grasp by hand to aid using the stairs • Serves 2 purposes • aid in ascending/descending stair • safety • Height restriction set by code • usually 34 - 38” (measured from edge of nosing)
Guardrail • Located at balconies, lookouts, and decks • Any platform more than 30” above grade • Top most rail of balcony railing • Provides safety • Height restrictions set by code • Not less than 42”(measured from floor )
Guardrail Forces • Horizontal thrust normally 20 lbs/linear foot @ top of guardrail: • baluster 5 feet apart • 5 (x) 20 = 100 lbs • Baluster attachment @ floor: • 100 lbs (x) 3’ height = 300 lbs • Holding power of bolts - quantity and size determined by architect/engineer
Vertical Rail • Spacing restricted set by code • present code 4” maximum gap between vertical member, (9” in book is old code) • applies to all open railings if stairs are 30” or more off floor
Steel Stair Details • Reasons for steel stairs • building code requirements for specific buildings • commercial buildings (occupancy count considered) • exterior design of steel weather better than wood • fire protection • structural strength and stability • aesthetics and design compatibility • steel gives more flexibility in design • design rules are same as for other stair designs
Materials in Steel Stairs • Steel stringers • Handrails • Treads • Metal clips and attachment • Welding plates
10” Steel Stringers • Usually selected from steel channels • old callout 10[ 15.3 or 10C15.3 • new callout C10 x 15.3 • New callout explanation • 10 = nominal height of channel • C = type of steel section, in this case an American Standard channel • 15.3 = weight per foot of steel section
Steel Stringer Designs • A. Compound cut (two cuts) & plates welded to enclose channel • B. Completed design of A • C. Single cut of channel • D. Another channel cut as leg of stringer • E. & F. Completed design of leg & stringer welded together
Example of Steel Channels Stringerswith Pre-fabricated Stair Units
Steel Handrail, Guardrails, & Treads • A thru D--Handrail/guardrails designs • E & F--Baluster attachment designs • G & H--Tread designs
Treads Materials and Construction Methods • Pre-cast/reinforced concrete • Reinforced concrete/metal pan
Treads Materials and Construction Methods • Concrete poured in place • Steel
Metal Clips/Brackets • Metal angles • steel angles welded to inter side of stringer • Metal brackets • triangle or other shapes welded to top of stringer Metal angle Metal bracket
Metal Tread Bracket • Metal bracket welded to stringer to accommodate treads
Welding Plates • Used to enclose end of stringer (channel) • aesthetic • attachment of stringer to structure • Embedded in underneath side of pre-cast treads • purpose of attaching tread to structure by welding Welding plates
Handrail Assembly Details • Elevation/Section to include • material/size • handrail • vertical rails • bottom rails • height of handrail • spacing of vertical rails • detail callouts
Drawing Example Section/ Elevation @ 1” =1’-0” • Section/Elevation view of stairs • Changes: • Reverse direction of section 7-7 • vertical rails @4”OC more
Drawing ExampleHandrail Assembly Detail @ 6” =1’-0” • Section of wood handrail • callout of catalog to match cross-section or sufficient dimensions to mill • connection method as shown • profile wood handrail more
Drawing Example BalusterDetail Section 6” =1’-0” • Baluster • weld symbol should be weld all around • size of screws: 2-1/4” X 1 1/2” flathead screw • locate center of screws 5/16” from edge,