u2-l2

U2-L2

March 11, 2008

QUIZ FRIDAY – Architecture Styles

QUIZ WEDNESDAY – Construction Methods

Also, be able to match vocabulary with definition or picture.

U2-L2

STYLES / VOCAB QUIZ FRIDAY

Be able to identify all styles and at least 3 characteristics.

U2-L2

PRINCIPLES OF CONSTRUCTION

BACKGROUND

Principle – a rule or code of conduct

• Humans were nomadic– Natural caves or portable tents made of animal skins

• Settled down in fixed locations near fertile areas– Bearing Walls – solid walls that provide support for

each other and for the roof– Post-and-Lintel – a horizontal beam (lintel) across at

least two vertical posts

U2-L2

PRINCIPLES OF CONSTRUCTION

Post-and-Lintel

• Problem– In the West, stone was material used most often. – Stone is heavy, so space between posts was limited.

U2-L2

PRINCIPLES OF CONSTRUCTIONBACKGROUND

• Romans – used stone

– Arch – smaller, lighter blocks of stone supported by leaning on the keystone in the center

– Vault – a series of arches that forms a continuous arched covering• Barrel Vault

• Cross Vault

– Dome – many arches arranged so their based form a circle and their tops meet in the center

U2-L2

PRINCIPLES OF CONSTRUCTIONBACKGROUND

U2-L2

PRINCIPLES OF CONSTRUCTION

BACKGROUND

• Gothic Arch – pointed at top

– Bearing structure

– Buttress (pilaster) – added support at the base

– Flying buttress – supports side of wall without added weight

U2-L2

PRINCIPLES OF CONSTRUCTION

• Buildings are divided into 3 types:

–Bearing-Wall Structures• Solid walls that support the weight of the walls, floors, and roof

–Post-and-Beam

–Skeleton-Frame Structures• Open, self-supporting framework covered by an outer,

nonbearing surface

Principle – a rule or code of conduct

U2-L2

Structural ForcesNewton’s 3 Laws of Motion:

1. Inertia: objects at rest stay at rest;

objects in motion stay in motion

2. F = ma

3. Action/Reaction: for every action there is an equal and opposite reaction

U2-L2

Structural Forces

• Another way to look at it:– How much do you weigh?– You are pushing down on the earth that amount of force.– The earth is pushing up on you with an equal amount.

• What would happen if the earth were pushing up with more force?

• Less force?

U2-L2

Structural Forces

• Structural stability is based on the strength and placement of structural members.

• Four types of force exert stress on building materials:–Compression – push; tends to flatten/buckle–Tension – pull; tends to stretch–Shear – slide; material fractures–Torsion – twist; twist out of shape or fracture

U2-L2

Structural Forces

Tension

U2-L2

Structural Forces

Compression

U2-L2

Structural Forces

Torsion

U2-L2

Structural Forces

Shear

U2-L2

Structural Forces

Compression

Tension

Structural Forces

Loads:1. Live Loads: the weight of all moveable objects,

such as people and furniture; includes weight of snow, ice, and force of wind

2. Dead Loads: the weight of building materials and permanently installed components.

• Lumber, brick, glass, nails

The total weight or mass of all live and dead loads is the Building Load.

U2-L3

U2-L3

Structural Forces

A building supports the following loads in the middle of winter:• 10,000 lbs of lumber• 1000 lbs. of snow and ice• 40,000 lbs of brick• 300 lbs of wind• 600 lbs of glass• 200 lbs of nails

1. Calculate the Live Load.

2. Calculate the Dead Load.

3. Calculate the Building Load.

U2-L3

Structural Forces

Lateral (horizontal) loads:

1. Wind

2. Earth (next to the foundation)

3. Earthquakes

U2-L3

Structural Forces

Methods of counteracting lateral loads:

1.

Roof

Methods of counteracting lateral loads:

2.

Diagonal

ties add

Rigidity

U2-L3

Structural Forces

Methods of counteracting lateral loads:

3.

Added

Reinforcement

U2-L3

Structural Forces

Methods of counteracting lateral loads:

U2-L3

Structural Forces

U2-L3

Structural Forces

Roof Loads

• High-pitch roofs

contribute to high

wind loads

U2-L3

Strength of Materials

• Strength of a construction material is the capacity to support loads by resisting the 4 structural forces.

• Strength depends on material– Type

– Size

– Shape

U2-L3

Strength of Materials

• Strength depends on material– Shape

U2-L3

Strength of Materials

• Deflection – bending that results from both tension and compression acting on a member at the same time.

– Vertical

– Horizontal

U2-L3

Strength of Materials

• Deflection – bending that results from both tension and compression acting on a member at the same time.

– No deflection

U2-L3

Strength of Materials

• Cantilever – when only one end of a horizontal member is supported

– Center-supported – center supports equal dead loads on all sides

– Eccentric (off center) – cantilevered on only one side• Causes TORSION