Handrail Assembly and Steel Stairs Handrail Terminology u

Handrail Assembly and Steel Stairs

Handrail Terminology u Guardrail – top most rail on balcony – higher than handrail u u u 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 u Baluster – member that holds up handrail and vertical & horizontal railing

Handrail Terminology u Newel (newel post) – Large terminating post at the bottom or top of stairs or landing u Half newel is next to the wall on the right

Handrail Terminology u Gooseneck – transition from handrail to guardrail due to height difference

Handrails u Definition: a member that parallels the angle of the stairs allowing a person to grasp by hand to aid using the stairs u Serves 2 purposes – aid in ascending/descending stair – safety u Height restriction set by code – usually 34 - 38” (measured from edge of nosing)

Guardrail u Located at balconies, lookouts, and decks u Any platform more than 30” above grade u Top most rail of balcony railing u Provides safety u Height restrictions set by code – Not less than 42”(measured from floor )

Guardrail Forces u Horizontal thrust normally 20 lbs/linear foot @ top of guardrail: – baluster 5 feet apart – 5 (x) 20 = 100 lbs u Baluster attachment @ floor: – 100 lbs (x) 3’ height = 300 lbs u Holding power of bolts quantity and size determined by architect/engineer

Vertical Rail u 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 Stairs

Steel Stair Details u 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 u Steel stringers u Handrails u Treads u Metal clips and attachment u Welding plates

Steel Stringers u Usually selected from steel channels – old callout 10[ 15. 3 or 10 C 15. 3 – new callout C 10 x 15. 3 u New callout explanation – 10 = nominal height of channel – C = type of steel section, in this case an American Standard channel 10” – 15. 3 = weight per foot of steel section

Steel Stringer Designs u A. Compound cut (two cuts) & plates welded to enclose channel u B. Completed design of A u C. Single cut of channel u D. Another channel cut as leg of stringer u E. & F. Completed design of leg & stringer welded together

Example of Steel Channels Stringers with Pre-fabricated Stair Units

Steel Handrail, Guardrails, & Treads u. A thru D-Handrail/guardrails designs u E & F--Baluster attachment designs u G & H--Tread designs

Treads Materials and Construction Methods u Pre-cast/reinforced concrete u Reinforced concrete/metal pan

Treads Materials and Construction Methods 4 Concrete poured in place 4 Steel

Section of a Concrete “U” Shape Stairs

Metal Clips/Brackets u Metal angles – steel angles welded to inter side of stringer u Metal brackets – triangle or other shapes welded to top of stringer Metal angle Metal bracket

Metal Tread Bracket u Metal bracket welded to stringer to accommodate treads

Welding Plates u Used to enclose end of stringer (channel) – aesthetic – attachment of stringer to structure u Embedded in underneath side of pre-cast treads – purpose of attaching tread to structure by welding Welding plates

Handrail Assembly Details u 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” u Section/Elevation view of stairs u Changes: – Reverse direction of section 7 -7 – vertical rails @4”OC more

Drawing Example Handrail Assembly Detail @ 6” =1’-0” u 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 Baluster Detail Section 6” =1’-0” u 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,