What do you think civil engineers do? Pre-Class Monday 1-18-11 What do you think civil engineers do?

“Mechanical engineers build weapons. Civil engineers build targets.” Civil Engineering “Mechanical engineers build weapons. Civil engineers build targets.”

American Society of Civil Engineers The oldest branch of engineering Design and supervise the construction of roads, buildings, airports, tunnels, bridges, and water and sewage systems Main objective: functional, efficient, and durable systems Very environmentally conscious, includes nature (plants), habitats (animals), and society (people) Subsets include: architectural, construction, environmental, structural, transportation, urban planning, and water resource Average salary in 2005: $43,774 Starting salary in 2009: $48,509 (bachelor’s only)

EWB-USA helps create a more stable and prosperous world by addressing people's basic human needs by providing necessities such as clean water, power, sanitation and education. What they do: http://www.youtube.com/watch?v=mW4L9SVk_nc If you want more information, check out their website: www.ewb-usa.org.

Pre-Class Wednesday 1-19-11 How many squares do you see?

Types of Bridges The downward forces acting on a beam bridge are gravity, the weight of the bridge itself, and the load that it carries. The bridge is flat, so the downward forces are evenly spread across the length of the bridge. They can span longer distances by adding middle piers to help carry the weight.

Other Beam Bridges Clapper bridge One of the earliest bridge constructions Used stepping stones found at streams, spanned by stone slabs or logs. Cantilever bridge - Used by early Asian builders - Supported on two levers, weighted by piers - Downward force counteracted by weights Truss Bridge - The covered bridge are among the oldest in America - Designed to hide the trusses holding it up

Arch Bridges The downward forces acting on an arch bridge are gravity, the weight of the bridge itself, and the load that it carries. The downward forces are spread outward by the curve of the arch and concentrated on the end supports. They can span longer distances by additional supports to redistribute the weight.

Other Arch Bridges Developed by the Romans Discovered it could support more weight than a beam bridge, and natural cement helped strengthen it Modern arches reach above the deck of the bridge (typically made of steel)

Suspension Bridges The downward forces acting on a suspension bridge are gravity, the weight of the bridge itself, and the load that it carries. The curve of the suspension ropes or cables concentrate the downward forces inward where there is no support. Typically droop, so not suited for heavy loads (foot traffic) They can span longer distances and support enormous weights with steel cables, concrete anchorages, and steel towers/trusses.

Deliverables Original brainstorming design and sketches (certified signature) Bridge blueprint Mass of bridge Mass of load on bridge (necessary to break it) Efficiency of bridge Final drawing (if different from original sketch and blueprint)

What type of bridge are you building for the project? Pre-Class Thursday 1-20-11 What type of bridge are you building for the project?

What’s a truss? Combination of triangles to strengthen and distribute downward forces Named after the people to first use them

Engineering Efficiency Measure the mass of your bridge (scale). Divide the weight of the load by the bridge mass. Watch your units! This is your efficiency (record this value).

Deliverables Original brainstorming design and sketches (certified signature) Bridge blueprint Mass of bridge Mass of load on bridge (necessary to break it) Efficiency of bridge Final drawing (if different from original sketch and blueprint)

What is a truss? Pre-Class Friday 1-21-11 Be sure to turn-in your weekly pre-classes (4 total) to the Pre-Class tray.

What are the oldest bridges in America? Hint: two possible answers Pre-Class Tuesday 1-25-11 What are the oldest bridges in America? Hint: two possible answers

Bridge Design The building of a bridge is more than just spanning a gap, canyon, or river. Make use of simulation tools before starting: http://www.youtube.com/watch?v=4xcKlGh7Dm4 If done right, the end result can be amazing: http://www.parade.com/news/2010/10/17-the-birth-of-a-modern-marvel.html Ask the question: what purpose does it serve?

Traffic Engineer Objective Procedures Observe the redesign of an intersection Procedures Divide into groups of 4 or 5. Travel to the intersection of Hughes and Eastview. Each group will complete the following: Draw a top view of the intersection and label it. Count the number of cars that pass through a green light for each lane. Determine the cycle time for each road (red, yellow, green, and arrow). Observe the turn lanes to see if they are long enough Once you have completed step #3, answer the following questions: Is there enough time to get every vehicle through in 1 cycle? Are the turn lanes and road size sufficient for the capacity? Do you think the time of day matters? Explain. When would be the best time to check this intersection? What improvements, if any, would you propose to the city of Madison?

Bartlett Efficiency Acceleration of bridge = weight of load mass of bridge The acceleration acting on the bridge if no other force but the load acted on it. Using Newton’s Second Law of motion: F=ma, where F is the force (Newtons, N), m the mass (kg), and a the acceleration (m/s2) Weight equation based off Newton’s Second Law: W=mg, where W is the weight (force in N), m the mass, and g the acceleration of gravity (9.8 m/s2)

Pre-Class Tuesday 1-25-11 What was the biggest challenge in the Bridge Building Project (a.k.a. Civil Engineering Performance test)?

Write: Guest Speaker Gary Chynoweth Pre-Class Monday 8-23-10 Write: Guest Speaker Gary Chynoweth City of Madison Engineer

Fall 2009