10-04-2017, 09:20 PM
Fundamentals for the Up-and-Coming Bridge Engineer
Outline
Beam Strength and Deflection
Moment of Inertia
Types of Forces Applied
Young s Modulus (stress and strain)
Optimization
Beam Deflection
Every object acts as a spring it will deflect when a force is applied
Extent of deflection depends on force applied, material properties and object shape
Moments of Inertia
A measure of resistance to deflection
A larger moment of inertia means that the beam will be more resistant to deflection
To Increase the Moment of Inertia
Increase the size:
But as you increase the size, you increase the weight and cost
Change the cross-sectional shape:
A hollow cross-section is stronger for the amount of material used
Differences in Deflection
Types of Forces on a Bending Beam
Compression, Tension, and Torsion
Stress and Strain of Different Materials
Design Optimization
Engineering is not about building the strongest possible bridge
Engineering is about building a bridge that is strong enough and balances cost, strength, time required to build, etc
Engineering is about trade-offs and meeting design specifications
Design Optimization
Engineering is not about building the strongest possible bridge
Engineering is about building a bridge that is strong enough and balances cost, strength, time required to build, etc
Engineering is about trade-offs and meeting design specifications
Summary
Beam strength depends on force applied, material properties and object shape
Important material properties include moment of inertia and Young s Modulus (stress and strain)
Three types of forces are compression, tension, and torsion
These concepts will be helpful in the West Point Bridge Designer