handrail assembly and steel stairs. handrail terminology u guardrail –top most rail on balcony...

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 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

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,