Half turn stair

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Half turn stair

• These stairs are common in residential and public
  building.
• These are having direction reversed or changed by
  180 degree.
• These are of two types dog legged stair
  open newel stair.

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Dog legged stair

• Newel post are provided at the beginning and end
  of each flight.
• There is no space between two flights.
• A half spaced landing is provided generally to
  affect the change in direction.

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These components are reinforced with steel that
give stability to the structure. Staircase is
one such important component in a RCC structure.
Dog Legged Stair In this article, we will discuss
different types of staircases and study the RCC
design of a dog-legged staircase Stairs Stairs
consist of steps arranged in a series for purpose
of giving access to different floors of a
building. Since a stair is often the only means
of communication between the various floors of a
building, the location of the stair requires good
and careful consideration. In a residential
house, the staircase may be provided near the
main entrance. In a public building, the stairs
must be from the main entrance itself and located
centrally, to provide quick accessibility to the
principal apartments.
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Open newel stair

• Space of width 0.15m to 1m is left between two
  parallel flights.

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Bifurcated stair

• Used in public building at or near the entrance
  hall.
• Wider flight from the bottom bifurcate into two
  narrower flight one towards right and other
  towards right at the landing.

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Continuous stair

• It do not have intermediate newel post or
  landing.
• These stairs may be of circular, helical or
  spiral in shape.
• These are emergency stairs.

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Material for stair construction

• These may be constructed of timber, steel, stone,
  RCC and bricks.
• RCC commonly used for residensial or public
  building.
• RCC stairs are of two types
  Stair with slab spanning longitudinally
  Stair with slab spanning horizontally

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Stair with slab spanning longitudinallythe slab
is supported at bottom and top of the flight and
remain unsupported on sides.
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Stair with slab spanning horizontally

• The slab is supported by wall on one side and
  stringer beam on other side.
• Thickness of slab vary between 8 to 12cm.

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NOW WE ARE GOING TO SEE 10 CRAZY STAIRS FROM
AROUND THE WORLD
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ADMIN
Stairs and staircases have been a engineering
marvel since the start of the multi story
architectural designs. But now in this modern era
engineers have taken designing to its utmost
limit, here are some of the most amazing
staircases from around the world. Top 10 crazy
stairs.
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TRAVERSINERTOBEL SWITZERLAND BRIDGE-STAIRIn
traversinertobel Switzerland you will find an
amazing Bridge-stair on a side valley of Via
Mala, it is one of its kind amazing staircases
from around the world, designed by Engineer
jurgConzett and his associate Rolf Bachofner. The
main engineering problem they faced was the
problem of connecting two different elevations
over the gorge by creating a staircase. The
staircase replaces a rope bridge for hikers that
was wiped out by a rock slide. This suspended
footbridge spans a distance of 56 metres, with a
difference in height of 22 metres between the two
ends.
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Vertigo Staircase at the Queen Victoria
Building Australia The Grand Staircase"
of Sydney's Grand Queen Victoria Building
Australia is affectionately known as the QVB,
was designed and completed 1898 by George McRae,
replacing the original Sydney markets on the
site. Built as a monument to the long reigning
monarch, construction took place in dire times,
as Sydney was in a severe recession. The
elaborate Romanesque architecture was specially
planned for the grand building so the Government
could employ many out-of-work craftsmen
stonemasons, plasterers, and stained window
artists in a worthwhile project.
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Long champ Store
stairs at New York


It took
six months and 1.14
inches of ho rolled steel to
build
the stairs at Long-
champ store, these stairs
weight
55 tons and is has
a ribbon like form which
give wave
look. They divide
and converge to form a
topography of
walkways,
landings and steps.
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Umschrei bung KPMG
Building Munich
(Germany)
This amazing
staircase are
actually functional and not just
a design. Designed by Olafur
Eliasson this staircase is
called
Umschreibung (Rewriting), and
was completed in 2004. It's in
the courtyard of the
global
accounting firm KPMG in
Munich.
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World's Longest Mosaic Stair the San Francisco's
Tiled Steps (USA)This could be the world's
longest mosaic staircase (163 steps, 82' high)
the 16th Avenue Tiled Steps, are , was conceived
and fabricated by Irish ceramicist Aileen Barr
and San Francisco mosaic artist Colette Crutcher.
It took about 2 and half years of hard work by a
group of neighbors who raised funds and lobbied
city government to make the project, unveiled in
August 2005, a reality. Over 2000 handmade tiles
and 75,000 fragments of tile, mirror and stained
glass went into the finished piece, located at
16th Ave. and Moraga, in San Francisco.
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The Lello Bookshop Staircase at
Portugal
The amazing grand staircase at Lello Bookshop in
Portugal is one its kind. The steps of this
staircase are like two channels pouring and
swirling to a single point. The side view gives
you a closer idea of the immense curves and giddy
sinking feeling to each step.  
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Tulip Staircase design from Queen's House
England This beautiful architecture of Tulip
Stairs can be seen at the Queen's House it is
the first geometric self-supporting spiral stairs
in Britain. Although called the 'Tulip Stairs,'
it is thought that the stylized flowers in the
wrought-iron balustrade are actually
fleurs-de-lis, as this was the emblem of the
Bourbon family of which Queen Henrietta Maria
(wife of Charles I) was a member. The Tulip
Stairs are also the location of the Rev R. W.
Hardy's famous 'ghost' photograph taken on 19
June 1966, which when developed revealed what
appear to be two or three shrouded figures on
the staircase.
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Loreto Chapel Staircase at New Mexico
USThe Loreto Chapel is a chapel in Santa Fe, New
Mexico, is a spiral staircase that is an artistic
work of carpentry and engineering. The
construction and builder of the staircase are
considered a miracle by the Sisters of Loreto and
many who visit it, because it had no central
support (a support was added later). The
resulting staircase is an impressive work of
carpentry. It ascends twenty feet, making two
complete revolutions up to the choir loft without
the use of nails or apparent centre support. It
has been surmised that the central spiral of the
staircase is narrow enough to serve as a central
beam. Nonetheless there was no attachment unto
any wall or pole in the original stairway.
Instead of metal nail,the staircase was
constructed using dowels or wooden pegs. The wood
for the staircase cannot be found anywhere in the
region. The stairs had 33 steps, the age of Jesus
when he died. The mystery had never been
satisfactorily solved as to who the carpenter was
or where he got his lumber, since there were no
reports of anyone seeing lumber delivered or even
seeing the man come and go whilethe construction
was being done. Since he left before the Mother
Superior could pay him, the Sisters of Loretto
offered a reward for the identity of the man, but
it was never claimed.
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The Spiral Staircase at the Vatican Museum
(Italy) The Vatican Museums spiral staircase is
one of the most Photographed staircases in the
world, and certainly one of the most beautiful.
Designed by Giuseppe Momo in 1932, the broad
steps are somewhere between a ramp and a
staircase. The stairs are actually two separate
helixes, one leading up and the other leading
down, that twist together in a double
helixformation. Little did the Vatican Museum
know in 1932 that this formation would come to
represent life itself, with the discovery of the
double helical DNA strand.
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Spiral Stair
(Australia)


This amazing staircase

is located at Garvan

Institute in Sydney,

Australia. 6.5 revs and

five stories from top to

bottom white paint and

lights. The six storey

staircase is the show-

piece of the Garvan

Institute of Medical

Research in Australia. Its shape


reminds me of a DNA helix,

and its clean
white colour, glass

sides and chrome railings
the

facilitys medical function. The

six
levels of the structure are also

featured in
the fantastic dome-

covered atrium.
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Basics about Stair Slabs

• Types There are two types of stair flights,
  classified on the direction of span
• 1. Transverse The steps may be supported on both
  sides, or may be cantilevered from an adjacent
  wall, for example.
• 2. Longitudinal The stair flight spans onto
  landings or beams at either end of the stair
  flight.
• Design of Transverse Stairs Design of these
  sections are based on the average effective depth
  of the section. These flights may cantilever from
  a wall or span from a wall to a stringer beam,
  for example.
• Design of Longitudinal Stairs The design of
  these stairs is more complicated. The additional
  factors to consider are

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Basics about Stair Slabs
1. Geometry Given the rise, going and the number
of steps, the span and overall height rise can be
determined Span (No. Steps 1) going Height
No. Steps rise Slope Length v(Span2
Height2) When the flight is built monolithically
into members spanning at right angles to its
span, the effective span is given by la
0.5(lb1 lb2) where la clear horizontal
distance between supporting members lb1 Breadth
of supporting member at end 1 but 1.8 m lb2
Breadth of supporting member at end 2 but 1.8
m
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Basics about Stair Slabs
Loading The dead load is based on the slope
length of the stair flight. The average thickness
of the stair slab is used to calculate the dead
load h 0.5 rise going / v(rise2 going2)
waist finishes Finishes are included as they
are generally assumed to have a density equal to
that of concrete. The live load is based on the
plan area of the stairs and is to be taken as the
same to the floor which the stairs give access,
but (60 psf) 3 kN/m2 and (100psf) 5
kN/m2. If two stair flights, at right angles,
share a landing, the landing loads may be assumed
to be divided equally between the spans. As part
of the landing may be considered as part of the
stair flight, the loading on the landing must be
taken into account in the shear check. Design
Flights with significant end restraint, such as
those that are continuous with their supporting
slabs or beams may be designed for mid-span
design moment of wl2/10 and hogging moment at the
supports of the same value. Where there is not
sufficient end restraint the stair slab is to be
designed for wl2/8. The maximum shear should be
ascertained from a simply-supported model of
the stair slab. When the stair flight (on plan)
occupies at least 60 of the effective span, the
permissible span/d ratio may be increased by
15.
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Detailing The reinforcement arrangement in stair
flights follows a standard pattern. Deviation
from this is not recommended unless a specific
need arises. Longitudinal steel is the main
reinforcement and in the transverse direction the
minimum percentage of steel is provided as
distribution steel to help prevent
cracking. Strength requirements are not always
critical for stair slabs. It is
therefore essential that the other limit states
are checked a. Deflection b. Cracking c. Min As
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• The usual form of stairs can be classified into
  two types ( 1) Those spanning horizontally in
  the transverse direction, and (2) Those spanning
  longitudinally.

• Stairs of this type may be supported on both
  sides or they may be cantilevered from a
  supporting walls
• -Figure shows a stair supported on one side by a
  wall and on the other side stringer beam. Each
  step is usually designed as having a breadth b
  and an effective depth of d D/2 as shown in the
  figure
• -Distribution steel in the longitudinal direction
  is placed above the main reinforcement.
• -Details of a cantilevered stair are shown in
  figure The effective depth of the member is taken
  as the mean effective depth of the section and
  the main reinforcement must be placed in the top
  of the stairs and anchored into the support.
• A light mesh of reinforcement is placed in the
  bottom face to resist shrinkage cracking.

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Stair Slab Spanning Longitudinally

• The stair slab may span into landings which span
  at right angles to the stairs as in Figure a or
  it may span between supporting beams as in figure
  b

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Design of Stair slab

• The dead load is calculated along the slope
  length of the stairs but the live load I, based
  on the plan area. Loads common to two spans which
  intersect at right angles and surround an open
  well may be assumed to be divided equally between
  the spans. The effetive spa n (I) is measured
  horizontally between the centres of the supports
  and the thlckness of the waist (h) is taken as
  the slab thickness.
• Span-effective depth ratios may be increased by
  fifteen per cent provided that the stair flight t
  occupies at least 60 per cent of the span.
• Stair slabs which are continuous and constructed
  monolithically with their
• supporting slabs or beams can be designed for a
  bending moment of say F1/ 10.where F is the total
  ultimate load. But in many instances the stairs
  are precast or constructed after the main
  structure, pockets with dowels being left in the
  supporting beams to receive the stairs , and with
  no appreciable end restraint the design may be
  done by Fl/8

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Design Example
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