DRILL 1 What is structural technology 2 What

DRILL 1. What is structural technology? 2. What comes to mind when you hear the word “structure”? U 3 j - L 1

Structural Technology • The technology of putting mechanical parts and materials together to create supports, containers, shelters, connectors, and functional shapes. Example applications: • Legs on a chair, • City water tower, • Swimming pool, • Roadways and Bridges, • Bicycle spokes • Airplane wing, • Satellite antenna disc. U 3 j - L 1

UNIT 3 – Engineering Design Engineering, the systematic application of mathematical, scientific, and technical principles, produces tangible end products that meet our needs and desires. U 3 j - L 1

Structural Technology PURPOSE OF SUB-UNIT • To familiarize students with the functioning and applications of structural technology systems. U 3 j - L 1

Technology What is technology? The application of knowledge, tools, and skills to solve problems and extend human capabilities. What is a technology system? A Technology System is a group of subsystems working together to solve problems and extend human capabilities. U 3 j - L 1

Structural Technology Structural engineers are responsible for structural integrity. 1. Structural failures do not occur very often, but when they do, we hear about it: a. Tacoma Narrows bridge (1940) b. Challenger Space Shuttle (1986) c. Columbia Space Shuttle (2003) d. Chernobyl Nuclear Reactor (1986) e. 2007 Missouri bridge collapse 2. As late as 1870’s and 1880’s, 25 bridges a year collapsed on the American roadways. 3. Many people can be killed when engineered structures fail. U 3 j - L 1

Structural Technology Almost everything is a structure of some kind: Humans Plants Animals Houses Vehicles Tables Bottles U 3 j - L 1

The “First Modern Engineer” • • • Galileo Galilei (1564 – 1642) The “Father of Modern Physics” The “Father of Modern Science” Research into the strengths of materials Prior to Galileo, the size and shape of most structures was determined by the traditions and rules of highly skilled craftsmen. U 3 j - L 1

Structural Technology • • • Structural designs advanced by trial and error until modern engineers were able to anticipate the characteristics of new buildings, bridges, and other structures. Engineers apply science and mathematics to the problem of designing safe structures. Many engineering principles are based on common sense. U 3 j - L 1

Structural Technology Newton’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 U 3 j - L 1

Structural Technology • 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? U 3 j - L 1

Strength of Materials • Strength of a construction material is the capacity to support loads by resisting the 4 structural forces. Strength depends on materials’: • – – Type Size Shape Placement U 3 j – L 1

Structural Forces • 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 U 3 j - L 1

Structural Forces Tension U 3 j - L 1

Structural Forces Compression U 3 j - L 1

Structural Forces Torsion U 3 j - L 1

Structural Forces Shear U 3 j - L 1

Structural Forces Compression Tension U 3 j - L 1

Strength of Materials Is bending one of the structural forces? • Deflection – bending that results from both tension and compression acting on a member at the same time. – – Vertical Horizontal COMPRESSION TENSION U 3 j - L 1

Strength of Materials – No deflection U 3 j - L 1

Structural Forces A structure must contend with two types of loads: 1. Dead Loads: permanent loads that do not change. The weight of building materials and permanently installed components: Lumber, nails, or steel beams, Thebrick, totalglass, weight mass of concrete all live and 2. Live Loads: weight of all. Total moveable objects, deadthe loads is the Load. such as people and furniture in a house, vehicles on a bridge. Includes weight of snow, ice, dead leaves, and force of winds. U 3 j - L 1

Structural Forces A building supports the following loads in the Live Load: 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. 1000 lbs. + 300 lbs. 1, 300 lbs. Dead Load: 10, 000 lbs. 40, 000 lbs. 600 lbs. + 200 lbs. 50, 800 lbs. U 3 j - L 1

Structural Forces 1. Live Load = 1, 300 lbs. 2. Dead Load = 50, 800 lbs. 3. Calculate the Total Load: Total Load = Live + Dead Load = 1, 300 lbs. + 50, 800 lbs. Total Load = 52, 100 lbs. U 3 j - L 1

Research Project • Select one engineering structural failure. • For that failure address the following: – Where the structure was built – Purpose of the structure – How the structure failed – Who was responsible for the construction of the structure – Who took the blame for the failure – How many people were injured or killed U 3 j - L 1

1. Work on your Research Project 2. Rough draft sketch of poster and information due Tuesday!! U 3 j - L 1