Structural System

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