Building structures for architects

Building Structures forBuilding Structures for
ArchitectsArchitects
A compilation by Dr. Jinu Louishidha Kitchley J
AICTE QIP Faculty Development Programme
15-12-2017
Department of Architecture, Thiagarajar College of Engineering – Compiled by Dr. Jinu Louishidha Kitchley

Basic concept of a structure
Structural system
Functions of a structure
Forces on a structure
Structural Materials
Types of Structures
RCC in detail
Innovations in building structure
Hints to guide your student while designing

Basic Concept of a StructureBasic Concept of a Structure

Any form visible to the eyes has a structure behind it…
STRUCTURE AND FORMSTRUCTURE AND FORM

Buildings too…Buildings too…

FUNCTIONS OF A STRUCTUREFUNCTIONS OF A STRUCTURE
The structure imparts strength, stiffness
and stability to the form
STRENGTH IS THE CAPACITY TO RESIST FORCES
STIFFNESS IS THE ABILITY TO RETAIN SHAPE UNDER THE ACTION OF FORCES
STABILITY IS THE MAINTENANCE OF EQUILIBRIUM UNDER THE ACTION OF
EXTERNAL LOADS AND INTERNAL STRESSES

FUNCTIONS (Contd.)FUNCTIONS (Contd.)
OVERALL STABILITY
The structure should not overturn, slide or
twist as a whole
This is usually caused by lateral loads like e.g.,
wind
Wide and rigid foundations or pile foundations
provide overall stability

Structural SystemsStructural Systems
A Structural system is a
stable assembly of elements
designed and constructed to
function as a whole in
supporting andsupporting and
transmitting applied loads
safely to the ground without
exceeding the allowable
stresses in members.
◦ Superstructure
◦ Substructure

Type of
substructure is
chosen by
◦ Relation to
superstructure
SubstructureSubstructure
superstructure
◦ Soil type
◦ Relation to
topography
Department of Architecture, Thiagarajar
College of Engineering – Compiled by Dr.
Jinu Louishidha Kitchley

Shallow Spread Combined

-- If the independent footing of
two columns are connected by a
beam
A spread footing which support
two or more columns
Combined columns are used
based on the three
circumstances. They are
Types of Pad foundationTypes of Pad foundation
If depth of foundation is equal
to or less than its width, it is
called shallow foundations.
Generally it is 3 to 4 m.
which spread the super
improsed load of wall or column
over larger area.
beam
It is used to help distribute
the weight of either heavily
or eccentrically loaded
column footings to adjacent
footings
A strap footing is often used in
conjunction with columns that
are located along a building’s
property or lot line
circumstances. They are
(i) When the columns are very
near to each other so that
their footings overlap.
(ii) When the bearing capacity
of the soil is less, requiring
more area under individual
footing.
(iii) When the end column is
near a property line so that
its footing cannot spread in
that direction.
Shallow foundation Spread foundation
Strap foundation Combined foundation

Raft foundationRaft foundation
It is a large slab supporting a number of columns and walls under
entire structure or a large part of the structure.
Mat foundations are useful in reducing the differential settlements
on non-homogeneous soils or where there is large variation in the
loads on the individual columns.
Department of Architecture, Thiagarajar College of Engineering
– Compiled by Dr. Jinu Louishidha Kitchley

Pile foundations are used
in the following
situations, when there is
a layer of weak soil at
the surface.
This layer cannot support
the weight of the
building, so the loads of
the building have to
bypass this layer and be
These are long and slender members whose length can
be more than 15m.
Piles can be made from concrete, wood or steel
depending on the requirements. These piles are then
driven, drilled or jacked into the ground and connected
to pile caps. Pile foundation are classified based on
material of pile construction, type of soil, and load
transmitting characteristic of piles.
bypass this layer and be
transferred to the layer
of stronger soil or rock
that is below the weak
layer
Department of Architecture, Thiagarajar College of Engineering –
Compiled by Dr. Jinu Louishidha Kitchley

Grillage
foundation is a
special type of
isolated footing
and it is
provided for
heavily loaded
steel stanchions
GRILLAGE FoundationGRILLAGE Foundation
steel stanchions
-The depth of
foundation is 1
to 1.5m

Structural SystemsStructural Systems
A Structural system is a
stable assembly of
elements designed and
constructed to function
as a whole in supporting
and transmitting applied
loads safely to theloads safely to the
ground without
exceeding the allowable
stresses in members.
◦ Superstructure
◦ Substructure

Shell – Consisting of
the roof, exterior
walls, windows,
provides shelter and
protection.
Structure: A
Super StructureSuper Structure
Structure: A
structural system
required to support
the shell- columns,
beams, walls etc.,

Structural materialsStructural materials
Type : Masonry – Brick , Stone etc
Physical Property :
◦ Moderate compressive strength, minimal
tensile strength and relatively high density.
◦ The very low tensile strength restricts the use of
masonry to elements in which the principal
internal force is compressive, i.e. columns, walls
and compressive form-active types such as arches,
vaults and domes.
Where significant bending moment occurs in Gothic church -Where significant bending moment occurs in
masonry elements, for example as a
consequence of side thrusts on walls from
rafters or vaulted roof structures or from out-
of plane wind pressure on external walls, -
‘improved’ cross-section is used -Traditional
versions of this are buttressed walls.
Gothic church -
Chartres Cathedral,
France, twelfth and thirteent
centuries.

Type : TIMBER
Physical Property :
It possesses both tensile and compressive strength
and, in the structural role is therefore suitable for
elements which carry axial compression, axial
tension and bending-type loads.
Many different designs of timber connector are currently
available but, despite their development, the difficulty of
making satisfactory structural connections with
mechanical fasteners is a factor which limits the
load carrying capacity of timber elements, especially
tensile elements.
Limitations:
Limitations:
In all cases spans are relatively small, typically 5 m
for floor structures of closely spaced joists of
rectangular cross-section, and 20 m for roof
structures with triangulated elements. All timber
structures rarely have more than two or three
storeys..
Laminated timber : The laminating process also
allows the construction of elements which are
tapered or have curved profiles.
The all-timber house in
which all of the structural
elements in the walls,
floors and roof are of
timber.

Type : Steel
Physical Property :
It has high strength and equal strength in tension and
compression and is therefore suitable for the full range of
structural elements and will resist axial tension, axial
compression and bending type load with almost equal
facility.
Steel components are not excessively heavy in relation
to their load carrying capacity, so long as structural
forms are used which ensure that the material is used
efficiently.
Renault Sales Headquarters,
Swindon, UK, 1983; Foster
Associates, architects; Ove Arup &
Partners, structural
efficiently.
Therefore, where bending loads are carried it is essential
that ‘improved’ crosssections and longitudinal profiles are
adopted.
It allows the production of structures of a light, slender
appearance and a feeling of neatness and high precision.
It is also capable of producing very long span structures,
and structures of great height.
Partners, structural
engineers. Joints in steelwork can
be detailed to look very neat and to
convey a feeling of great precision
Hot rolled
steel sections
Cold formed
steel sections
Department of Architecture,
Thiagarajar College of Engineering –
Compiled by Dr. Jinu Louishidha
Kitchley

Type : Reinforced Concrete
Physical Property :
Concrete may be regarded as a kind of artificial masonry
because it has similar properties to stone and brick (high
density, moderate compressive strength, minimal
tensile strength).
Reinforced concrete possesses tensile as well as compressive
strength and is therefore suitable for all types of structural
element including those which carry bending-type loads
Although concrete can be moulded into complicated shapes,
Although concrete can be moulded into complicated shapes,
relatively simple shapes are normally favoured for reasons of
economy in construction
The mouldability of concrete also makes possible the use of
complex shapes and the inherent properties of the material are
such that practically any shape is possible. Reinforced concrete
has therefore been used for a very wide range of structural
geometries.
Exhibition Hall of the CNIT, Paris,
France; Nicolas Esquillan, architect.
Form-active shells for which reinforced
concrete is ideally suited
Department of Architecture, Thiagarajar College of Engineering – Compiled
by Dr. Jinu Louishidha Kitchley

Types of structuresTypes of structures
◦ Mass structure
◦ Vaulted structure◦ Vaulted structure
◦ Arches
◦ Trusses
◦ Frame structure
◦ Ribbed structures
Thiagarajar College of
Engineering – Compiled by Dr.

A mass structure can be made by
piling up or forming similar
materials into a particular shape or
design.
Mountains and coral reefs are
natural mass structures. Snow
sculptures, dams, and brick walls
are manufactured mass
structures.
The structure is held firmly in place
by its own weight.
Mass StructuresMass Structures
by its own weight.
If small parts are worn away or
broken, this usually makes very
little difference.
Department of Architecture, Thiagarajar College of Engineering – Compiled
by Dr. Jinu Louishidha Kitchley

An arch is a curved structure that spans an elevated
space and may or may not support the weight above
it.
An arch is a pure compression form. It can span a
large area by resolving forces into compressive
stresses and, in turn eliminating tensile stresses.
This is sometimes referred to as arch action. As the
forces in the arch are carried to the ground, the arch
will push outward at the base, called thrust.
As the rise, or height of the arch decreases, the
outward thrust increases] A masonry arch
ARCH structuresARCH structures
outward thrust increases]
In order to maintain arch action and prevent the arch
from collapsing, the thrust needs to be restrained,
either with internal ties or external bracing, such
as abutments
A masonry arch
1. Keystone 2. Voussoir 3. Extra
dos 4. Impost 5. Intrados
6. Rise 7. Clear span
8. Abutment
An arch is held in place by the weight of all of its
members, making construction problematic.
One answer is to build a frame (historically, of wood)
which exactly follows the form of the underside of the
arch. This is known as a centre or centring.
Department of Architecture, Thiagarajar College of
Engineering – Compiled by Dr. Jinu Louishidha Kitchley

Arch structures such as
bridges, aqueducts, and gates are
common throughout history

Arches may be synonymous with vaults, but a
vault may be distinguished as a continuous
arch forming a roof.
The parts of a vault exert lateral thrust that
requires a counter resistance.
When vaults are built underground, the
ground gives all the resistance required.
However, when the vault is built above ground,
various replacements are employed to supply the
needed resistance.
VAULT STRUCTURESVAULT STRUCTURES
An example is the thicker walls used in the
case of barrel or continuous vaults.
Buttresses are used to supply resistance when
intersecting vaults are employed.

A dome is an arch
revolved around
its vertical axis.
A dome can rest upon
a rotunda or drum, and
can be supported
by columns or piers that
transition to the dome
through squinches or pe
ndentives.
Dome STRUCTURESDome STRUCTURES
ndentives.
A lantern may cover
an oculus and may itself
have another dome.
An example of quadrangular to
circle transition – The mosque
of Isfahan international
conference center

Department of Architecture, Thiagarajar College of Engineering – Compiled by
Dr. Jinu Louishidha Kitchley

A truss is a structure that
"consists of an assemblage
of individual linear
elements arranged in a
triangle or combination of
triangles to form a rigid
framework that cannot be
deformed by the application
of external members without
TRUSSESTRUSSES
of external members without
deformation of one or more
of its members.

TRUSSESTRUSSES

Steel Truss - Heavy Trusses span 30 feet to
300 feet
Wood Truss - Heavy Trusses span 30 feet to
200 feet
Department of Architecture, Thiagarajar College
of Engineering – Compiled by Dr. Jinu Louishidha
Kitchley

FRAMED STRUCTURESFRAMED STRUCTURES

Rectangular Framed StructuresRectangular Framed Structures
A framed structure is a
network of beams and
columns joined up to form
the skeleton framework of
the building.
The structural frame carries
the total load of the building
and transfers it to the
the total load of the building
and transfers it to the
foundation.
Cladding is fixed over the
framework, or infill panels are
placed between its members,
to totally enclose the space
within the building.

Framed Structure Load Bearing Structure
01. In framed structure, load
transfer path is from slab/floor
to beam, beam to column and
column to footing.
01. In load bearing structure,
load transfer path is from
slab/floor to walls and walls to
footing.
02. Multi storey buildings can
be constructed.
02. Limited storey buildings
can only be constructed.
03. Framed structure is more
resistant to Earthquake.
03. Load bearing structure is
less resistant to Earthquake.resistant to Earthquake. less resistant to Earthquake.
04. Mostly used form of construction
NOWADAYS.
05. Rarely used a form of construction
nowadays.
05. Excavation for this type of construction is
less.
06. Excavation for this type of construction is
more.
06. It is less labour intensive. 07. It is more labour intensive.
07. The speed of construction is more. 08. The speed of construction is less.

09. It is less material intensive. 09. It is more material intensive.
10. Cost of repair of the framed structure is
more.
10. Cost of repair of load bearing structure is
less.
11. Life is reduced if not done with proper
technique.
11. Life is not affected with the technique of
work.
12. Only skilled worker are needed for its
construction.
12. Skilled as well as non skilled worker can
construct.
13. The thickness of wall can be
maintained uniform throughout.
13. The thickness of wall cannot be maintained
uniform throughout.
14. It is flexible in design as you can shift
the location of walls.
14. It is not flexible in design as you can’t
remove/shift walls.
15. Room dimension can be changed. 15. Room dimensions cannot be changed
as walls have to be above walls.
16. Cantilever elements can be easily
included in the system.
16. The inclusion of Cantilever element is a
difficult task.
17. The thickness of wall remains same with an
increase in height.
17. The thickness of wall increases with
increase in height.increase in height. increase in height.
18. No Limitation of the span. 18. Limitation of the span.
19. In framed structure, large span areas
possible.
19. In load bearing structure, large span areas
not possible.
20. There is not much increase in cost with an
increase in depth of foundation.
20. Foundation cost of Load Bearing is more
than Framed Structure if the depth of
foundation increases beyond 1.5m.
23. The frame can be RCC frame, Steel
frame, Wood frame etc.
23. Load Bearing walls can be of Brick, Stone,
concrete block etc.
24. Large openings in walls are possible. 24. Limitations for openings in walls.

Ribbed structuresRibbed structures
Ribs usually cantilever
from their foundations or
are propped near the
bases.
If they are inclined or
curved in elevation they
may be propped by othermay be propped by other
ribs
They generally enclose
single volumes rather
than multi storey spaces
– to avoid compromising
the arch language of ribs
with additional interior
load bearing structures.

RCC Structures in DetailRCC Structures in Detail

REINFORCED CONCRETEREINFORCED CONCRETE
Alternative to steel frame
Columns support beams on which are
laid slab flooring sections
Columns, beams and slabs integrally
cast to form a monolithic structure

Structural VolumeStructural Volume
STRUCTURAL UNIT A
structural unit is a discrete
assembly of structural
members capable of forming
the boundaries of a single
spatial volume.
Two columns supporting a beam or girderTwo columns supporting a beam or girder
creates an open framework that both
separates and unites adjacent spaces. Non
bearing wall might be erected for visual
privacy / shelter.
A bearing wall provides support as well as
divides into distinct spaces. Opening on it
weakens its structural integrity.
Columns support concentrated loads.
As the number of columns increases
and the column spacing decreases,
the supporting plane becomes more
solid.

Spanning options : In looking at
the fundamental ways of spanning
the space between two support
planes, we must consider both the
way applied forces are distributed to
the supporting planes as well as the
form of spanning system.
One way spanning system: One
way systems transfer applied
forces to a pair of more or lessforces to a pair of more or less
parallel supporting planes. This
configuration leaves two sides
open, giving it a strong
directional quality.
Two way spanning systems: Two
way spanning systems transfer
applied forces in two directions,
requiring two sets of supporting
planes or columns.

One way slabOne way slab
If the slab is poured
monolithically with the
walls then rigidity is
developed at the
supports. Therefore some
negative moment occurs
at the support and steel isat the support and steel is
required.

Deflection form of one way slabDeflection form of one way slab

>2l
l
Distribution Rods
One way slab reinforcementOne way slab reinforcement
>2l
Main
Reinforcement

Joist slabs are cast integrally
with a series of closely spaced
joists which in turn are
supported by parallel set of
beams. ( Designed as a series
of T beams)
More suitable for longer spans
Joist slabsJoist slabs
More suitable for longer spans
and heavier loads than
oneway slab
Spans 15ft to 35 ft (4.7 to
10.7 m)

A SQUARE unrestrained, simply supported
slab, continuously supported on all four
sides – The load is shared by all four sides.
Two way slabTwo way slab

Two way slab reinforcementTwo way slab reinforcement

Main short span
Main long span
Deflected form of two
way slab.

Or Flat plate

Ribbed
Construction
produces a
relatively light
concrete system
for spans of 24’ to
40’ ( 7.3 to
12.2m); longer
spans up to 60’
(18m) are possible
with post
tensioningDepartment of Architecture, Thiagarajar College of Engineering – Compiled by Dr. Jinu Louishidha Kitchley

One way slabs (1.8M TO 5.5M) till 20’
Joist slabs (4.7 to 10.7 m) 15ft to 35 ft
Two way slabs with beams (4.6M TO
9.1M) – till 30’
Flat plates (3.6 to 9.1m) 12ft to 30 ft
Flat slabs (6 TO 12M)
Waffle slabs (7.3 to 12.2m)
SlabsSlabs
Waffle slabs (7.3 to 12.2m)
Precast concrete slabs (3.6 to 11.6m)

The structural grid is defined principally by column positions and
the main beams spanning between them. This defines on plan two sets of grid lines
which are normally perpendicular. The establishment of this structural grid is a very
important design decision and the following points should be considered:
◦ a column should normally be positioned at every intersection of two
grid lines
◦ a main beam should normally be positioned along every grid line
◦ ideally grid lines should be orthogonal (the two sets of parallel lines forming
a rectangular grid, and the spacing between grid lines should be regular (for
The choice of structural grid defines column positionsThe choice of structural grid defines column positions
and is a very important design decision.and is a very important design decision.
a rectangular grid, and the spacing between grid lines should be regular (for
circular buildings radial and circumferential grids are often used)
◦ in practice the shape of the building and/or site may require some variation from
this, and irregular spacings or skewed grid lines cannot be avoided.
However, these can generally be concentrated in small areas, allowing the main
part of the building to be set out in accordance with a regular orthogonal grid.

The proportions of the
structural bays influence and
may dictate the material and
structural systems.
A bay is a spatial division, usually
one of a series, marked off by the
principal Vertical supports of a
structure.
Structural baysStructural bays
Bay dimensions: The
dimensions of the structural bays
obviously impact the direction
and length of the horizontal
spans.
Direction of spans: The
direction of horizontal spans
affects the nature of spatial
composition.

Scale:
The scale of a structural grid is related
to:
•The type of human activity to be
accommodated.
•The efficient span range for a particular
spanning system and
•The nature of foundation soil.
Thiagarajar College of Engineering
– Compiled by Dr. Jinu Louishidha
Kitchley
Structural Grain: Is determined
by the direction, size and
arrangement of spanning
elements.
Those activities requiring large clear spans
will often dictate the structural approach.
Smaller scale activities will have many
structural options.

These
examples
show
various
types and
scales of
structural
patterns and
the pattern
Spatial FitSpatial Fit
the pattern
and scale of
human
activity each
might be
able to
accommodat
e

Regular Grids
◦ Square or nearly square grids
◦ Rectangular grids
◦ Tartan grids
◦ Radial grids
Irregular Grids
◦ Modifying grids
By addition / subtraction
Types of Grids+Types of Grids+
By addition / subtraction
By scale and proportion
Geometry
◦ Corner grids
◦ Transition grids

Square, Rectangular and Tartan grids
are all regularly recurring elements
regulated by orthogonal space
relationships.
They grow in a predictable manner.
Radial grids also have recurring
relationships defined by their
Regular gridsRegular grids
relationships defined by their
circular geometry.
A regular grid improves construction
efficiency.

Square or nearly
square bays.
Square bays always have
to be spanned with two
way systems.
A linear arrangement of
square bays allows one
way spanning

In architectural design, grids are
powerful organizing devices.
However regular grids are only
generalized patterns that can be
modified and made specific in
response to circumstance of program
Irregular grids.Irregular grids.
response to circumstance of program
site and materials.
The objective is to develop a grid
that integrates form, space and
structure into a cohesive whole.

Transitional patternsTransitional patterns

Where floor voids are required, for example
for stair wells or atria, the following
guidelines for the location of each void,
listed in order of preference, should be
followed:
Locate entirely within a structural bay to
avoid cutting across the line of a main
beam
Accommodating floor voidsAccommodating floor voids
beam
For very large voids, omit complete bays,
including main beams if necessary

Floor voidsFloor voids

In structural engineering, a shear wall is a structural system
composed of braced panels (also known as shear panels) to
counter the effects of lateral load acting on a structure. Shear
walls are like vertically-oriented wide beams that carry
earthquake loads downwards to the foundation.
Wind and seismic loads are the most
common loads that shear walls are
designed to carry.
These walls generally start at foundation level and
are continuous throughout the building height.
Their thickness can be as low as 150mm, or as
high as 400mm in high rise buildings.
Department of Architecture, Thiagarajar College of Engineering – Compiled by Dr. Jinu Louishidha
Kitchley

Cantilever construction allows for
overhanging structures without external
bracing
CantileversCantilevers
The span to depth ratio for a cantilever slab
should not exceed 7.
L/d <=7
Also maximum size of cantilever provided should
be 10m i.e ;length of the cantilever should not
be more than 10 meters.
ref: IS 456:2000, art 23.2.1.

The "Skypark" on top of the building
includes a 213 foot (63 meter) cantilever,
at 200 meters height.

◦ Shell structures
◦ Fabric structures / Membrane structures
◦ Suspension structure
Innovative structuresInnovative structuresDepartment of Architecture, Thiagarajar

SHELL STRUCTURESSHELL STRUCTURES Department of Architecture,

Shell structure, a thin, curved plate
structure shaped to transmit applied
forces by compressive, tensile, and shear
stresses that act in the plane of the
surface.
It attains strength and rigidity with
relatively thin and curved form
They are usually constructed
of concrete reinforced with steel mesh

TWA TERMINAL –
EERO SAARINEN

Fabric or membrane structuresFabric or membrane structures

Barton Malow Silverdome. A very large span is
achieved here with a cable-reinforced air-supported
membrane, which is a tensile form-active structure.

Suspended Structures are those with
horizontal planes i.e. floors are
supported by cables (hangers) hung
from the parabolic sag of large,
high-strength steel cables. The
strength of a suspended structure is
derived from the parabolic form of
the sagging high strength cable.
To make this structure more efficient,
the parabolic form is so designed that
its shape closely follows the exact
form of the moment diagrams.
Suspended structuresSuspended structures
form of the moment diagrams.
The sagging cable is more stable
under symmetrical loading conditions
as the cable may deform as it
attempts to adjust to an eccentric
loading. As the cable adjusts to this
load its shifts the rest of the
structure.

A cable stayed structure does not have
this parabolic curve

Department of
Architecture, Thiagarajar
College of Engineering –
Compiled by Dr. Jinu
Louishidha Kitchley

InnovationsInnovations

There are three fundamental ways in
which the structural system can relate to
the form of an architectural design –
1. Exposing the structure
2. Concealing the structure
3. Celebrating the structure.
Architectural StructuresArchitectural Structures

Other special conditionsOther special conditions

The development of a new language of
structures - Wolfgang Schueller
https://www.slideshare.net/WolfgangSchu
eller/the-development-of-a-new-
language-of-structures
RefRef

Structures – Daniel L.Schodek
Building Structures Illustrated – Francis
D.K.Ching
Structure and Architecture – Angus J.
MacDonald
THANK YOUTHANK YOU

Building structures for architects

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