structural system
Post on 18-Jan-2015
774 Views
Preview:
DESCRIPTION
TRANSCRIPT
Structural System
What’s structure
•Structure is the performance of pattern. !
•The structure could be for everything life, system of being.
•Social, economical, musical, biological, and chemical.
•Relationship between the matter and the space.
Architectural Structure
Architectural Structure
•Architectural structure: a structure is a body or assemblage of bodies in space to form a
system capable of supporting loads.
•It’s a system or sub-system, means holding the components of a certain system and transfer
the load through the members of a structure to provide stability and durability.
•Most systems share Common Characteristics, including:
.1Systems have structure.
.2Systems have behavior, which involves inputs, processing and outputs of material, energy, information, or data;
.3Systems have interconnectivity: the various parts of a system have functional as well as structural relationships to each other.
.4Systems may have some functions or groups of functions
Loads on structure
• Static forces:
- Dead load.
- Live load.
- Settlement load.
- Ground pressure.
- Water pressure.
- Thermal stresses.
• Dynamic forces:
- Wind load.
- Earthquake load.
The action of External Forces on a structure
.1A compression / compressive force will cause a member of structure to be squashed.
2 .A tension / tensile force cause a member of structure to be stretched.
3 .A torsion / torsional force cause a member to be twisted.
4 .A shear force cause a member to slide/tilt to a side.
5.A Bending force is a complex force state associated with the bowing of a member such as beam. it causes fiber on one face of the member to elongate and hence be in tension
and fibers on the opposite face to compress
SYNTHESIS OF ARCHITECTURAL AND STRUCTURAL FORM
•In these cases structure defines architectural form and often functions, at least partially, as
the building envelope.
Shell Structure
> Definition. > History vs. Nowadays. > Materials. > Application.
> Definition.
-They are light weight constructions using shell elements.
- Shell structures achieve the most pure synthesis of architectural and structural forms. Also known as ‘surface structures’, shells resist and transfer loads within their minimal thicknesses. They rely upon their three-dimensional curved geometry and correct
orientation and place-ment of supports for their adequate structural performance .
-Advantage:-Allowing wide areas to be spanned without the use of internal
supports, giving an open, unobstructed interior.
-Span thickness ratio of 400-500• Ex: 8cm Thickness.....30-38m Span
No bending moment in shell structures.
Shell structures are suited to carrying distributed loads not concentrated loads.
Loads applied to shell surfaces are carried to the ground by the tensile, shear, compressive forces
> Materials.
•Shell structures can be made of such materials as;Reinforced thin-shell concrete,Glass SteelGlass & SteelPlastic
Tent and membrane Structure
> Definition. > History vs. Nowadays. > Materials. > Types . > Application.
-A Membrane is a thin, flexible surface that carries loads primarily through the development of tension forces.
-Holding a stress tension force.
-Provide strong lighting features.
-Desert architecture identity, inspired from ten design and geometry.
((Net structures are conceptually similar; expect that their surfaces are made from cable net meshes)).
>Definition
•There are several ways of stabilizing a membrane or net surface:
.1An inner rigid supporting framework.
.2Prestressing the surface by:
a. external force )Tents(
b. internal pressurization )Pneumatic
structure.)
•The traditional tents structure.
> History vs. Nowadays.
•Hajj Terminal, Jeddah, Saudi Arabia, Skidmore, Owings and Merrill
Jeddah Sports Hall, Jeddah, Saudi Arabia, Frei Otto
-Net structure.
.Icables structure:
•Cables can be of mild steel, high strength steel
)drawn carbon steel(, stainless steel,
polyester.
•Structural cables are
made of a series of small strands twisted or bound together to form a much
larger cable
>Types
2 .Tents
-A membrane structure pre-stressed by externally
applied forces so that it is held completely taut under
all anticipated load conditions.
-The purpose of a tent structure is to provide a means of
shelter that is lightweight, portable, and quick to
install.
>Types
3 .Pneumatic structure
-A class of membranes that obtain its stability through internal
pressurization.
• -There are two primary classes of pneumatic structure:
.1Air supported structures
-Less degree of pressurization to achieve stability
-Greater span
2 .Air inflated structures
-Higher degree of pressurization to achieve stability
-Less span
>Types
Truss Structure
> Definition. > History vs. Nowadays. > Materials. > Types . > Application.
•Trusses are composed of straight members connected
at their ends by hinged connections to form a stable
configuration .
•Because of their light weight and high strength, are among the most commonly used to
span long lengths in the place of solid
•Trusses provide complete flexibility in
exterior cladding .
>Difinition
•Timber trusses started by Romans 500 B.C
> History vs. Nowadays.
Andrea Palladio illustration for
triangulated truss
•Main uses: Roof Structures & Bridges.
• Modern use new formation and materials for members
result in a new structure shapes.
Steel structural members.
> History vs. Nowadays.
Trusses
comprising one or more (tetrahedonal, cubical, octahedronal ) ..,, units constructed with straight
members whose ends are connected at joints.
Span: 123 feet (37.5 meters).
> Materials
Steel is most commonly used.
Span: 123 feet (37.5 meters).Precast Trusses -Span:12m-20m-
Wood Trusses -Span:10m-17m-
1. Planar Truss
Two Main Types
2.Space Frame TrussThe simplest form of a truss is one single triangle.
A planar truss lies in a single plane.
An optimum depth of the truss will maximize the efficiency.
It is a three-dimensional framework
A tetrahedron shape is the simplest space truss,
Large planar structures may be composed from tetrahedrons with common edges
•Warren truss used in pombidue building.
> Types
1.Pratt Truss
The design uses vertical members for compression and horizontal members to respond to tension.
2.Bowstring Truss
Used for arched truss bridges,
4.Town's Lattice Truss
Members arranged diagonally with short spaces in between them.
5.Vierendeel TrussThe members are not triangulated but form rectangular openings,
3.King Post Truss
Consists of two angled supports leaning into a common vertical support.
> Application
The Hong Kong Bank of China Tower has an externally visible truss structure.
A space truss carrying a floor in The Woodlands Mall.
Arches
> Definition. > History vs. Nowadays. > Materials. > Types . > Application.
> Difinition
• A structure, forming the curved, pointed, or flat upper edge of an open space and supporting the
weight above it, as in a bridge or doorway.
The main advantage of an arch is that it can be supported without any tension .
Suitable for long term use )longer than say 500 years )e.g. cathedrals( arches are probably essential.
In stone arches, the last stone to be placed at the top is called the keystone
KEYSTONE
It provides a structure which eliminates tensile stresses in spanning a great amount of open space.
All the forces are resolved into compressive stresses.
By using the arch configuration, significant spans can be achieved. This is because all the compressive forces hold it
together in a state of equilibrium
Cylindrical shells and vaults
•Barrel vault.•Groin vault.•Rib vault (intersecting between two barrel
vaults).
> Materials
Common structural materials are:•Iron:
Wrought ironCast iron
SteelStainless steel
•ConcreteReinforced concretePrestressed concrete
•Aluminium•Composite materials•Alloy•Masonry•Timber
Quadror Structure
> Definition. > Application.
> Definition
It is a space truss geometry system inspired by versatility and structural integrity of interlocking members.
Concept:The simple geometry of four identical L-shaped pieces,
results in a trestle structure allowing for a very flexible and versatile design.
> Application
These building blocks allow for rapid assembly
1.Road Barriers 2.Structural Frames
3.Interior Partitions
4.Interior Columns
Types of structure
•Post and beam structure.
Span: 7-8 meters.
Types of structure
•Shear wall
Span: 7-8 meters.
Cantilever Beam
A special type of beam that is supported only at one end
The top fibers of the cantilever are in tension; the bottom fibers are in compression
Column
A vertical structural element that carries an axial force in compression.
COLUMN
top related