1.Which of Newton’s three laws of motion is most applicable in structural technology? Why? 2.Sketch an example of each of the four types of structural forces. May 6, 2008 DRILL U3i – L2 Law #3: Action / Reaction The supports, containers, shelters, connectors, and functional shapes all counteract loads on them and the materials contained within.

U3i – L2 Structural Technology Is the force against these objects a pulling force or a pushing force? Which is a tension structure and which is a compression structure TENSION STRUCTURE COMPRESSION STRUCTURE PULLING FORCE PUSHING FORCE

U3i – L2 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. Structural Technology

U3i – L2 Structural Technology Almost everything is a structure of some kind: Humans Plants Animals Houses Vehicles Tables Bottles

U3i - L1 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. The “First Modern Engineer”

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 U3i – L2

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 Strength of Materials U3i – L2

Strength of Materials –No deflection

U3i - L1 Beams are horizontal structural members Posts are vertical structural members Wood and stone beams have been used for bridges, boats, and roofs since ancient times. Beams and Posts POST BEAM

U3i – L2 Strength of beam –Type –Size (depth of beam) –Shape –Placement How do type, size, and shape affect the strength of these materials? Beams and Posts

U3i - L1 Trusses – an assemblage of beams forming a rigid framework Benefits over beams: –Lighter –More resistant to shear Strength comes from triangular shape Trusses

U3i – L2 Goal: make a truss as light as possible without making it too flexible and unstable. Trusses

U3i – L2

Bridge Piers 1.Piers are vertical structural members 2.Construct two structures that support a bridge. 3.Your grade will be determined by two things: U3i – L2