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– 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 Stairs

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

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 10”

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

Section of a Concrete “U” Shape Stairs

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 weldingWelding 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 Baluster Detail 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,