alias STRUCTURE

UNDERSTANDING the

LOAD CARRYING SYSTEM

of BUILDINGS

SYSTEM

•Method of approach to understanding

•Collection of interrelated elements

•Various aspects of elements and relationships

•Problems related to the whole system

STRUCTURE

•Multiple structures in a system.

•Abstract notion describing interrelationship of elements

•Many different representations (verbal, graphical, mathematical).

MY FAMILY SYSTEM

Mother Father Foster mother

MeBrother SisterBrother in Law

Sister in Law Wife

Nephew Son Daughter NieceDaughter in Law

Son in Law

GranddaughterGrandson

STRUCTURE of MARRIAGESMATHEMATICAL REPRESENTATION

Foster Sister Daughter

Mother Mother Wife Daughter Sister in Law in Law

Father 1 1 0 0 0 0 0Me 0 0 1 0 0 0 0Son 0 0 0 0 0 0 1Son in Law 0 0 0 1 0 0 0Brother 0 0 0 0 0 1 0Brother in Law 0 0 0 0 1 0 0

PARENTAGE STRUCTURE

Mother Father Foster mother

MeBrother SisterBrother in Law

Sister in Law Wife

Nephew Son Daughter NieceDaughter in Law

Son in Law

Grandson Granddaughter

GRAPHICAL REPRESENTATION

A SIMPLE BUILDING PLAN

Exterior

Corridor

Reception

SecretaryBoss Room 1

Hall

Room 2Room 3Room 4

CIRCULATION STRUCTURE

Reception

Secretary

Boss

Corridor

Exterior

Room 1

Hall

Room 2

Room 3Room 4

WHY BUILDINGS?

•Security (predators, pests, enemies, etc.)

•Meso-environment (thermal, acoustic, light)

PROBLEMS in BUILDINGS

• Problem specific structures

• Problems and factors

• Nearly all elements involved

HUMAN FACTORS

• Cultural (meanings, use patterns, etc.)

• Psychological (spatial perception, spatial cognition)

• Physiological (thermal comfort)

• Social (spatial layout)

ENVIRONMENTAL FACTORS•Climatic (thermal, radiation, wind, rain, snow, etc.)

•Topographical (slopes, vegetation)

•Geological (gravitation, earthquakes, materials, foundations)

•Economic (materials, labor, finance)

MECHANICAL FACTORS

•Foundations

•Mechanics (forces and motions)

•Loads (gravitation, wind, earthquakes)

LOAD CARRYING SYSTEM(LCS)

• Elements + connectivity structure

• STRUCTURE of building

• Structural problems

A SIMPLE BUILDING LCS

Slab

Beam 1 Beam 2

Beam 3Beam 4

Col

umn

1

Col

umn

2 Col

umn

3

Col

umn

4

Wall 1 Wall 2

BUILDING ELEMENTS

C1 C2 C3 C4

Slab

Wall 1 Wall 2

B1

B2

B3 B4

STRUCTURE of CONNECTIVITY

Slab

B1 B2 B3 B4

Wall 1 Wall 2

C1 C2 C3 C4

Edge connection End connection

STRUCTURAL REQUIREMENTSof LCSs

• Restraint (sufficient members and supports to provide for equilibrium)

• Strength (sufficient material to prevent rupture)

• Rigidity (sufficient resistance to deformation)

• Ductility (sufficient capacity for energy absorption)

COMPATIBILITY REQUIREMENTS

of LCSs• Spatial layout (e.g. hotels, bearing walls)

• Materials (e.g. masonry and vaults)

• Services (integration of services)

• Construction (e.g. bearing walls, integral forms, tower cranes)

STRUCTURAL BEHAVIOR

•Displacements/deformations

LoadInternal force

Load

•Internal forces

•Energy storage

•Language of description is mechanical.

UNDERSTANDING BEHAVIORof LCSs

•Modeling of LCS

•Prediction of loads

•Analysis of mechanical forms

•Understanding in terms of basic modes

DIRECTION of PREDOMINANT LOAD

•Vertical (gravitation)

•Horizontal (wind)

•Combination (earthquake)

GEOMETRIC FORM

•3D forms - solid, systems of 1D and 2D forms

•Dimensionality

•1D forms - rod, planar curve, spatial curve

•2D forms - plane, surface, systems of 1D forms

•Orientability

MECHANICAL FORM

•Combination of geometric form and load

Orientation

Load

Geometric

Form

•Mechanical form = Oriented and loaded geometric form

MECHANICAL FORMS(BEAM and COLUMN)

Geometric Form = ROD

Load Orientation Load Orientation

BEAM COLUMN

MECHANICAL FORMS(ARCH and CURVED BEAM)

Geometric Form = PLANAR CURVE

Load

ARCH

Load Orientation

Load

Load Orientation

CURVED BEAM

Arch

Curved Beam

Spatial

Curved Beam

MECHANICAL FORMS(SLAB and WALL)

Geometric Form = PLANE

Load

WALL

Load Orientation

Load

Load Orientation

SLAB

Slab

Folded Plate

MECHANICAL FORMS(SHELL)

Load

Shell

Dome

UNDERSTANDING SPECIFICBUILDING LCS’s

•Resolve hierarchy of structural problems

•Determine scale of problem (overall building, breakdown of main structure, detail elements)•Resolve structure of elements

•Recognize the MF of elements

World Trade Tower

s

SKYSCRAPER(overall building scale)

Gravitation

MF = COLUMN

Windor

Earthquake

MF = BEAMGF = ROD

SKYSCRAPER(main structure scale)

GF = PLANE GF = PLANE

Gravitation

MF = SLAB

MF = WALL

Gravitation

MF = WALL

Earthquake

Sears Towe

r

SKYSCRAPER(detail scale)

GF = PLANEGF = ROD

LateralLoad

MF = BEAM

Weight

AxialLoad

MF = COLUMN

AxialLoad

Weight

MF = SLAB

BEHAVIOR of the BEAM

BENDING MOMENT SHEAR

INTERNAL FORCES

BEHAVIOR of the COLUMN

Compression Tension

INTERNAL FORCES

COMPRESSIVE AXIAL FORCE

TENSILE AXIAL FORCE

BEHAVIOR of the COLUMN (BUCKLING)

BENDING MOMENT

INTERNAL FORCE

Load

DESIGN for BENDING•Provide material away from the center.

I beamRC beam

•Provide the right kind of material.

DESIGN for SHEAR

Truss

Provide diagonals

I beam

Castella beam

Welding

DESIGN for COMPRESSION

AGAINST BUCKLINGProvide this material away from the center.

Provide the necessary material in axial form.

TWO BASIC PROBLEMS

1. Space enclosure.

2. Provision of horizontal levels.

Planes of equal potential energy

CONCLUSION

•Look at a building LCS hierarchically.

•Identify the predominant loading.

•Identify the geometric form.

•Identify the mechanical form.

•Estimate the behavior.