Transcript Handrail Assembly and Steel Stairs

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 10”
– 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 Stringers
with 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 Example
Handrail 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,