arcpress stairs - 2nd edition - section 8 - concrete stairs 9 of 15

7/29/2019 ARCPRESS Stairs - 2nd Edition - Section 8 - Concrete Stairs 9 of 15

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Stairs

Second edition

Alan and Sylvia Blanc



Concrete stairs

8.1 Early forms

-1'lie earliest forms of concrete stai1-sxc '

I<oiiian where concrete was placed o\w

Ixick vaulting to support ramps or steps

such as in the construction of tlie

Colosseum (Figure8.1a).The introduction

o f

filler joist flooring in theeiglitcenthcen-tulg., with wrought-iron beams infilled ly

lit-ick arches,wasadapted t ostaircasescxi-

tile\,eredoff masonry walls (Figure8.1h).

Thee d y use of concrete in the twenti-

eth century \V;IS found in composite forms

of lxiilcling. I n the case of stairs,steel joists

often foi-med tlie stringers to reinforced

roncrete infilling (Figure 8.1c). Nenri,

OIIC of the fincst concrete engineers,

clesigiied 21 minimum doul,le-spii;il staii.

for the F I O ~ ~ I I W Sports Stadium (Figure8.1 l ) . Ilis :i\;ant-garde npprox-I1 t o rein-

forcwiientdesign is not without proljlems,

1osh of co~'ero the exposed main 1,e;iins

Ii;t\.ingled to extensive repairs.



Concrete stairs 137

8.2 Developed forms ofreinforced concrete stairs



138 Stairs

v -

L,' 7

L-

Thicker slabto preserve soffit

ross span for

Landing Wellbeam

L _ _ _ _ _ _ J

Key plan (showing landing beam or slab)

Cantilever stepsI

Cantileverslab

Extendedbeam

Key plan

Key section



Concrete stairs 139

'L ' shaped tread andriser planks

P re-cast edgeframe including -strings. notchedto receive risers

Pre-cast landing-slabs

Ceramic tile fixed at work

Pre-cast stringw



140 Stairs

Connectedto frame or

wall-bearing Cantilever end/to carry balustrade/

P re-cast tread and

Connectionto frame or to wall bearing

Twin pre-cast beams

Bracing by steelhandrailassembly

Saddle joint over'v\pine beams with

bolting in both directions

1.



Concrete stairs 141

-Bracket

- -I 1 ..-

Height to

follow basic

plate set screwed to back

Guardina

Upstand wallfollows basicgeometry of stairs

Solid balustradeReinforced concrete upstand wall(in fair faced finish)

8.3 Pre-cast spiral stairs



142 Stairs

qround floor

-7

. ~4

-330-rc stair

U L J , larta

SECTION A-A xa k I 10

RBmm concrete wII

with 13mmp1aterJ F Abothsides -_-

25 mmdamms bolurters

[ e m m axe / 127r279mmpocket4-I t

L i p J

ELEVATION OF TREAD C scale I 10

191mm deep pocket/

PLAN scale 153

PLAN OF TREAD C Fale I 10SECTION E-E xale I 10

41mm dam Columbpine hondrail

Rabrnrny J

.~

plaster f t

127

4

nut and washer--,



Concrete stairs 143

F&

shc

A Y

Moulded coved//skirting tiles .+ \,; Riser tiles

and



144 Stairs

Mortice for balustrade

Well stri

(terrazzo finish)

terrazzo strings '(reinlorcement top and bottom)

Pre~casterrazzoplanks

in-situ terrazzo

reintorcement\

\C stairspre-castOR in-situ Fa'r

lor paint

8.4Detailing

ofwell endsand balustrades



Concrete stairs 145

1400

i

4

Lower flight

Galvanizedsteel angle frame to landing (infill of pre-cast slates)

r landing if needed

Stay atmid height

J p

P re-cast ringsand treads withteel rod

ba lytrade steel tubular/ columnL

Standardsto eachtread

30



146 Stairs

Metal Mustracks to concrete stairs k)l-lom- the principles laid clown in C1i;ipter 7,

the differences arising if reinforced coti-

crete fender spine \v:ills :ire in \ .o l \~~l .

The achwmges of the latter rest m,itli

less metalwork to install :incl maintain.

Figure 8.Sg demonstrates Aalto's cletailing

at the I?iimio Sanitoriuin ; I S ;I superh

esample. The photograph c\xs taken in

1968mlien the original finishes n ~ etill

intact. Another Lwsion of the concept

could be made by using pre-cast terrazzo

to the strings t o recei\,e the railings, \\sit11

the flights also pre-c;ist with terrazzo tilr

finislies (Figure8.Sh).



Concrete stairs 147

P lan detail forminimum scheme

Handrail and

1over top and bottom

Vertical step

handrail to R H

Preferred line at soffit (XX)

Better solutionwith staggeredrelation to riserand neat soffits line i l l)



148 Stairs

Note reinforcementto NIBS tied to mainbars

Radius work

Alternative Birds mouthbeam profile bearing joint

for lower

flight Identic; unitsfor dog-leg flights

Curved rakingline for handrailand string

(9 \ -7 --,

Width equal

to tread

{{I :/P

Swept curveto handrailand lining

Half tread moved



Concrete stairs 149

Core rail

Balustrade zoneplaced externalto concrete stairs

Continuous4 411.*.

*Y

steel tubular I 1mullions

Circular

handrail run 1 l wwithin stairspace I l l 1 I I

I Infilling

wellinimalf 1OOil25 ~ - ~m(between ha1

Ideal if

gmension

RC fender beam

Handrailing -and bracketsplaced externalto fender

plan (tread

diameter)givesperfectsweepto wreathing

60 to

70 clear oftender

idrail)



150 Stairs

Note set screwsTubular rail on underside

Hardwood mop stick

10 x 40 steel core rail

25 rnrn tubular railswith internal sleevedTapered 12.5 X 60

steel standards

10 x 60 x 120base plate (welded)

handle varyingguarding level ofhandrail

Tile bed and screed

Texture paint finish

l . ' / <y / / l ~ [ J.517 f i ~ l l t l < J l .l l / ) l F l ~ ~l . Y / ( ~ l ' t Y I : ~ o

usually

arcpress stairs - 2nd edition - section 8 - concrete stairs 9 of 15

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