Assunit1

ADVANCE STRUCTURAL SYSTEMS
UNIT-1
SYLLABUS: Construction and form, Structure and Form Equilibrium under simple
tension or compression, the catenary and the arch, the simply supported beam, the
domical shell.
SUBMITTED BY
CH.LAVANYA 14111AA003
D.SRI LAHARi 14111AA006
K.EKANSH 14111AA015
VINEETHA 14111AA022
O.MANIKANTA 14111AA021
S.ROOPA SREE 14111AA027
K.AKHILA 14111AA037

WHAT IS A STRUCTURE?
 Structure is an arrangement and organization of interrelated
elements in a material object or system, or the object or system so
organized. (WIKIPEDIA)
 A structure is a group of elements somehow united to
support a load with stability. Everything has a structure.
For example: humans have skeleton, bicycles have a
frame, houses have columns, beams and a roof.

WHAT IS ADVANCE
STRUCTURAL SYSTEM?
 Despite using normal structural systems as beams, columns,
slabs…etc.
 Nowadays new advanced structural systems are used with respect to
traditional ones.
 Now nothing is impossible as any form became easier to be
transformed into a real building.
 Forms are more creative as the architects are not stuck to sharp
edges and straight line, curvature and bending takes place in their
design.
LOS MANTIALES BY FELIX CANDELA LOTUS TEMPLE IN INDIA GUGGENHEIM MUSEUM

Construction and Form
 Ludwig Hilberseimer’s “ proposed Construction
and Form” (1924)
 Identity of construction and form is the
indispensable prerequisite of all architecture.
 At first sight, both appear to be opposites.
 But it is precisely in their close conjunction, in
their unity, that architecture consists.
 Construction and form are the material
prerequisites of architectonic formation. They
are in continual interplay.
 Iron , concrete , and reinforced concrete are
the building materials that make possible the
new forms of construction necessary for the
requirements of cities .
 Because of its new types of building
requirement , city architecture was the first to
create the need for new forms of construction
and materials as an inevitable requirement .

STRUCTURE AND FORM
 Structural form is dictated by structural needs, primarily to support
gravity and lateral loads, and usually also the need to provide a
building envelope for shelter against the elements.
 Carefully designed structural form can exhibit the stark beauty of
controlled strength, even to the point of excitement.
 Structure can define the visual impact of a building, as in the case
of large exposed columns which give the appearance of strength
and solidity, or the case of tall slender columns which can create an
elegant loggia effect.
 Structural form is mathematically based, it seeks the greatest
efficiency, economy and elegance that the designer can create.
 It is not random, it is not generated by trial and error, it is not
subject to changes in taste or fashion, it is not symbolic of some
anthropomorphic idea

STRUCTURE AND FORM
 Structure and construction may be
related in a wide variety of ways
ranging between the extremes of
complete domination of the
construction by the structure to
total disregard of structural
requirements in the determination
of both the form of a building and
of its aesthetic treatment.
 The architecture of the Parthenon
is tectonic: structural requirements
dictated the form and, although the
purpose of the building was not to
celebrate structural technology, its
formal logic was celebrated as part
of the visual expression.

STRUCTURE AND FORM EQUILIBRIUM
UNDER SIMPLE TENSION OR
COMPRESSION
What is equilibrium?
• Equilibrium is the term used to designate the
condition where the resultant of a forced system is
zero.
• The sum of the forces in any direction = 0.
• If this is satisfied, the object will have no linear
acceleration
(for instance, it won't accelerate in any direction).
CONDITIONS OF EQUILIBRIUM
• The body may move in any direction .
• The body may rotate about it self with out moving .
• The body may move in any one direction ,and at
the same time it may also rotate about it self .
• The body may be completely at rest.
• IF the body moves in any direction , it means that
there is a resultant force acting on it .
• For example if the body is to be at rest , the
resultant force causing movement must be zero or
all the horizontal forces ΣH and all the vertical

STRUCTURE AND FORM EQUILIBRIUM
UNDER SIMPLE TENSION OR
COMPRESSION
 Figure2a shows vertical member in direct tension .
Under this load the members spanning between
two end points lengthens elastically
 It stays straight under tensile force or becomes
straight if it was slack.
 Its load capacity is determined by p= Af ,
where f is tension strength of material, where a is area .
 The compression member of fig 2b in contrast has
two ways of getting shorter elastically along its axis
and by bending side ways
 The later action can lead to bulking
 The capacity of thin member to support loads is
determined by their bulking capacity which is in
simplest form , is determined by Euler's formula
P = π2 EI/L

Catenary
 The catenary curve has a U-like shape,
superficially similar in appearance to a parabolic
arch, but it is not a parabola.
 The word catenary is derived from the Latin word
catena which means CHAIN. The catenary is the
curve thats an idealized hanging chain or cable
assumes under its own weight when supported
only its ends .
 The curve has u shaped , superficially similar in
appearance to a parabola, but it is not a parabola
it is scaled ,rotated, graph of the hyperbolic cosine
.
 Catenary curve equation is y= cosh (x)
 It is often used in the construction of kilns,
bridges,etc .

Catenary
 A catenary arch is a type of arch that keeps its
members in compression.
 In compression they are extremely strong. In
tension they are relatively weak. The purpose
of the arch is to spread the load on the brick in
such a way that the brick is always in
compression.
 But the same arch expanded become very
useful as a dome or a vault.
 Vaults built in this way can be very slim and
use a minimum of material for maximum
strength.
 Deriving the Catenary
Curve Equation. A catenary curve describes
the shape the displacement cable takes when
subjected to a uniform force such as
gravity. This curve the shape of a perfectly
flexible chain suspended by its ends and acted
on by gravity.

Arch
 An arch is a curved structure
that spans an elevated space
and may or may not support the
weight above it.
 Arches may be synonymous
with vaults, but a vault may be
distinguished as a continuous
arch forming a roof. Arches
appeared as early as the 2nd
millennium BC in
Mesopotamian brick
architecture, and their
systematic use started with the
ancient Romans, who were the
first to apply the technique to a
wide range of structures.
1. Keystone 2. Voussoir 3. Extrados 4.
Impost 5. Intrados 6. Rise 7. Clear span
8. Abutment

Forces in arch
 Compression Arch bridges are
always under compression. The
force of compression is pushed
outward along the curve of the
arch toward the abutments
 Tension in an arch is negligible.
The natural curve of the arch and
its ability to dissipate the force
outward greatly reduces the
effects of tension on the underside
of the arch. The greater the
degree of curvature (the larger the
semicircle of the arch), however,
the greater the effects of tension
on the underside.

Pros and cons
• Arches provide a structure which
eliminates tensile stresses in
spanning an open space.
• Arches take advantage of the
strength under compression of
several construction materials:
stone, cast iron and concrete (all
can strongly resist compression but
are very weak in tension).
• An arch can achieve significant
width, due to the compressive
forces that hold it together in
balance.
• Arches can be built with materials
of frictionless surfaces
• An arch needs to be restrained in
the base either with heavy sides
and friction or angled cuts, because
in this point the arch forces push
outwards, this also happens in
other varieties of this structure such
as in Arch dams.
• Need skilled laabour
advantages disadvantages

APPLICATIONS &
ADVANTAGES
 Roman architecture are immediately
recognized by the circular arch motif.
Romans were pioneers in the use of
arches for bridges, buildings, and
aqueducts. This bridge, the Ponte
Fabricio in Rome, spans between the
bank of the River Tiber and Tiber
Island. Built in 64 B.C. (Rome, Italy.)
 The gothic high rise arch & the
buttresses required to absorb its
thrust are typical of one of the
greatest achievements in
architectural design.
 Roman circular arches spanned about
100’ & medieval stone bridges up to
180’.

arch
 The NEW RIVER GORGE
BRIDGE in west Virginia, the
longest steel arch spans
1700’ (1986).
 The largest single arch span
in reinforced concrete built to
date is the 1280feet span
KRK BRIDGE , Yugoslavia.
 Combinations of trussed
arches with cantilevered half
arches connected by trusses
were built to span as much
as 1800feet in THE QUEBEC
BRIDGE in 1917.

Simply supported beam
 Beam A structural member
which is long when compared
with its lateral dimensions,
subjected to transverse forces
so applied as to induce
bending of the member in an
axial plane, is called a beam.
 A simply supported beam is a
type of beam that has pinned
support at one end and roller
support at the other end.
Depending on the load applied,
it undergoes shearing and
bending. It is the one of the
simplest structural elements in
existence.

simply supported beam
 A simply supported beam is a
type of beam that has pinned
support at one end and roller
support at the other end
 Depending on the load
applied, it undergoes
shearing and bending .
 It is one of the simplest
structural element in
existence.

Through history
 Archaeological wonders such as the
ones shown below can be considered to
be Simply Supported beams:

TYPES OF LOADINGS:-A beam may be subjected
to either or in combination of the following types of
loads:-
1.Concentrated Or Point Load:-It is a type
of load which acts at the centre of the beam
2.Uniformly Distributed Load:-It is a type of
load which is distributed uniformly over the
entire length of the beam.
3. Uniformly Varying Load:-These are the
loads varying uniformly from zero to a
particular value and spread over a certain
length of the beam.Such load is also called
triangular load.

Bridges as example
 Bridges are good example of simply supported
structure. The bridge deck is supported over
bearings which generates a simply supported
condition.
 The most basic type of bridge
 Typically consists of a beam simply supported on
each side by a support and can be made
continuous later
 Typically inexpensive to build
Forces:
 When something pushes down on the beam, the
beam bends. Its top edge is pushed together, and
its bottom edge is pulled apart.

 In simply supported
beams the bending
moment diagram is simply
parabolic and nature of
moment is same
throughout the span i.e. in
between 2 consecutive
piers.
 whereas for continuously
supported beam with UDL
the nature of moment
changes at support and
hence the reinforcement
placement will be very
complicated and
congested
L = span length of bending member, M = maximum bending moment, P = total concentrated load,
R = reaction load at bearing point, V = shear force, W = total uniform load,∆ = deflection or
deformation, x = horizontal distance from reaction to point on beam

DOMICAL SHELL
 Dome shells have emerged due to
new concept in building design.
 These structures have the potential
for significant markets in commercial
and many other small residential
and industrial applications .
 The structures utilize superior
material technology .
 one of the principle objective of this
invention is to provide the framing
configuration for a domical structure
so as to allow flat sheathing material
to be used on the curved surface of
the dome.

DOMICAL SHELL
 flat sheathing materials to construct
the curved roof of a
domicalstructure with the underlying
dome frame and the shape of the
roof panels designed to permit
originally flat sheathingmaterial to
be curved in different directions.
Thus, a single flat sheet of
sheathing material may contain
several differentcurved surfaces,
improving the appearance and the
shell effect of the roof and
increasing the strength and
economicefficiency of the domical
structure.

Internal forces
 A masonry dome produces thrusts
down and outward. They are thought
of in terms of two kinds of forces at
right angles from one another.
Meridional forces (like the meridians,
or lines of longitude, on a globe) are
compressive only, and increase
towards the base, while hoop forces
(like the lines of latitude on a globe)
are in compression at the top and
tension at the base, with the transition
in a hemispherical dome occurring at
an angle of 51.8 degrees from the
top.The thrusts generated by a dome
are directly proportional to the weight
of its materials. Grounded
hemispherical domes generate
significant horizontal thrusts at their
haunches.

Advantages
 Very strong shape, gets strong
as the dome size increases
 Perfect load distribution
 No need for structural supports
 Great aerodynamic performance
 Domes are extremely durable
and strong.
 They are fire proof.
 They are wind resistant.

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