UNDERSTANDING the

LOAD CARRYING SYSTEM

of BUILDINGS alias

STRUCTURE

SYSTEM

•Method of approach to understanding •Collection of interrelated elements •Various aspects of elements and relationships •Problems related to the whole system

STRUCTURE

•Abstract notion describing interrelationship of elements •Many different representations (verbal, graphical, mathematical).

•Multiple structures in a system.

MY FAMILY SYSTEM Mother Sister in Law Nephew Brother Me Father Wife Son Grandson Daughter in Law Son in Law Daughter Granddaughter Sister Foster mother Brother in Law Niece

Father Me Son Son in Law Brother Brother in Law STRUCTURE of MARRIAGES MATHEMATICAL REPRESENTATION Mother 1 0 0 0 0 0 Foster Mother 1 0 0 0 0 0 Wife 0 1 0 0 0 0 Daughter 0 0 0 0 0 1 Sister 0 0 1 0 0 0 Sister in Law 0 0 0 1 0 0 Daughter in Law 0 0 0 0 1 0

PARENTAGE STRUCTURE GRAPHICAL REPRESENTATION Mother Sister in Law Nephew Brother Me Father Wife Son Grandson Daughter in Law Son in Law Daughter Granddaughter Sister Foster mother Brother in Law Niece

A SIMPLE BUILDING PLAN Secretary Reception Corridor Boss Room 4 Room 3 Room 1 Room 2 Hall Exterior

CIRCULATION STRUCTURE Exterior Hall Room 4 Room 3 Corridor Room 1 Room 2 Boss Reception Secretary

WHY BUILDINGS?

•Meso-environment (thermal, acoustic, light) •Security (predators, pests, enemies, etc.)

PROBLEMS in BUILDINGS

• Problems and factors • Nearly all elements involved • Problem specific structures

HUMAN FACTORS

• Psychological (spatial perception, spatial cognition) • Physiological (thermal comfort) • Social (spatial layout) • Cultural (meanings, use patterns, etc.)

ENVIRONMENTAL FACTORS

•Climatic (thermal, radiation, wind, rain, snow, etc.) •Economic (materials, labor, finance) •Geological (gravitation, earthquakes, materials, foundations) •Topographical (slopes, vegetation)

MECHANICAL FACTORS

•Mechanics (forces and motions) •Loads (gravitation, wind, earthquakes) •Foundations

LOAD CARRYING SYSTEM (LCS)

• Elements + connectivity structure • STRUCTURE of building • Structural problems

A SIMPLE BUILDING LCS

BUILDING ELEMENTS C1 C2 C3 C4 B2 B1 B3 B4

STRUCTURE of CONNECTIVITY Slab B1 B2 B3 B4 Wall 1 Wall 2 C1 C2 Edge connection C3 C4 End connection

STRUCTURAL

REQUIREMENTS of LCSs • Restraint (sufficient members and supports to provide for equilibrium) • Strength rupture) (sufficient material to prevent • Rigidity (sufficient resistance to deformation) • Ductility absorption) (sufficient capacity for energy

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

•Internal forces Load Internal force Load •Displacements/deformations •Energy storage •Language of description is mechanical.

UNDERSTANDING BEHAVIOR of 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

•Dimensionality •Orientability •1D forms - rod, planar curve, spatial curve •2D forms - plane, surface, systems of 1D forms •3D forms - solid, systems of 1D and 2D forms

MECHANICAL FORM

•Combination of geometric form and load •Mechanical form = Oriented and loaded geometric form Load Orientation

MECHANICAL FORMS

(BEAM and COLUMN) Geometric Form = ROD Load Orientation BEAM Load Orientation COLUMN

MECHANICAL FORMS

(ARCH and CURVED BEAM) Geometric Form = PLANAR CURVE Load Load Load Orientation ARCH Load Orientation CURVED BEAM

Arch

Curved Beam

Spatial Curved Beam

MECHANICAL FORMS

(SLAB and WALL) Geometric Form = PLANE Load Load Load Orientation WALL Load Orientation SLAB

Slab

Folded Plate

MECHANICAL FORMS

(SHELL) Load

Shell

Dome

UNDERSTANDING SPECIFIC BUILDING 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 Towers

SKYSCRAPER

(overall building scale) Gravitation Wind or Earthquake GF = ROD MF = COLUMN MF = BEAM

SKYSCRAPER

(main structure scale) GF = PLANE Gravitation GF = PLANE Gravitation Earthquake MF = SLAB MF = WALL MF = WALL

Sears Tower

Axial Load Lateral Load GF = ROD

SKYSCRAPER

(detail scale) GF = PLANE Weight MF = COLUMN Axial Load MF = BEAM Weight MF = SLAB

BEHAVIOR of the BEAM

INTERNAL FORCES BENDING MOMENT SHEAR

BEHAVIOR of the COLUMN

Compression Tension INTERNAL FORCES COMPRESSIVE AXIAL FORCE TENSILE AXIAL FORCE

BEHAVIOR of the COLUMN

(BUCKLING) Load INTERNAL FORCE BENDING MOMENT

DESIGN for BENDING

•Provide material away from the center.

•Provide the right kind of material.

I beam RC beam

Castella beam

DESIGN for SHEAR

Provide diagonals Truss I beam Welding

DESIGN for COMPRESSION

Provide the necessary material in axial form.

AGAINST BUCKLING Provide this material away from the center.

TWO BASIC PROBLEMS

1. Space enclosure.

Planes of equal potential energy 2. Provision of horizontal levels.

CONCLUSION •Look at a building LCS hierarchically.

•Identify the predominant loading.

•Identify the geometric form.

•Identify the mechanical form.

•Estimate the behavior.