Handrail Assembly and Steel Stairs

Handrail Terminology u Guardrail –top most rail on balcony –higher than handrail u Vertical Rail –members between balusters –ensure safety u Handrail –member that parallels angle of stairs –ensure safety u 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 ” (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 top of guardrail: –baluster 5 feet apart –5 (x) 20 = 100 lbs u Baluster 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 10C15.3 –new callout C10 x 15.3 u 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 10”

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  Concrete poure d in place  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/ 1” =1’-0” u Section/Elevation view of stairs u Changes: –Reverse direction of section 7-7 –vertical more

Drawing Example Handrail Assembly 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,