Building Our Bridge to Fun! BOG-AAA123- Building Our Bridge to Fun! Civil Engineering in the Classroom Image source: http://iipdigital.usembassy.gov/st/english/inbrief/2012/05/201205316562.html#axzz2McRZsqR4

Main Goals of this Activity BOG-AAA123- Main Goals of this Activity Learn about how bridges are used and why we need them Identify forces acting on a bridge Hands-on activity: build two type of bridges (with two type of materials) Measure deflection of a span using LEGO ultrasonic sensor Gather data (load vs. deflection) Image sources: Left: http://www.nps.gov/glca/historyculture/navajobridge.htm Right: http://news.tn.gov/node/2523

Introduction What is a bridge? Why do we need build bridges? BOG-AAA123- Introduction What is a bridge? Why do we need build bridges? Water supply Image sources: Left: http://en.wikipedia.org/wiki/File:Pont_du_Gard_Oct_2007.jpg Center: http://schools.nyc.gov/SchoolPortals/23/K647/default.htm Right: http://apps.roads.maryland.gov/WebProjectLifeCycle/ProjectPhotos.aspx?projectno=FR4185110 Crossing rivers or water bodies Traffic

Engineering for bridges BOG-AAA123- Construction Materials: Concrete Steel Wood Stone Brick Bridges are structures to provide passage over water, roadways, and more! Image source: http://www.mtc.ca.gov/news/transactions/ta_spring_2011/sfobb.htm

Engineering for bridges: History BOG-AAA123- Primitive People: Logs Slabs of Rocks Intertwined Vines or Ropes Roman Empire—First Great Bridge Builders Timber Truss Bridges Masonry Arch Bridges Nineteenth Century Modern Long Bridges Moveable Bridges Europeans Followed Roman Empire style until iron and steel was used Image sources: Top left: http://commons.wikimedia.org/wiki/File:Bridge_Astore.jpg Top right: http://www.p12.nysed.gov/ciai/socst/ghgonline/turnpoint/cities5.html Bottom left: Eric Jones http://commons.wikimedia.org/wiki/File:Porth_Mawr_or_East_Gate_-_geograph.org.uk_-_269876.jpg Bottom right: http://www.nasa.gov/offices/oce/appel/ask/issues/39/39s_big_dig.html

Engineering for bridges: Primitive Bridges Rock Bridges Rope Bridges Image sources: Top left: Humphrey Bolton http://commons.wikimedia.org/wiki/File:Rock_Bridge_-_geograph.org.uk_-_1281307.jpg Center: http://commons.wikimedia.org/wiki/File:Puente_de_hamaca.JPG Bottom right: http://commons.wikimedia.org/wiki/File:Log_bridge_on_Kunar_river1.jpg Log Bridges

Engineering for bridges: Loads Primary Loads acting in a bridge Weight of the bridge DEAD LOAD Traffic: cars, trucks, people LIVE LOAD Wind, snow Dynamic: earthquake and vibrations

Engineering for bridges: Primary forces Tension: magnitude of the pulling force that acts to lengthen an object, usually by a string, cable, or chain. Compression: a pushing force that acts to shorten the thing that it is acting on. Opposite to tension.

Engineering for bridges: Primary forces Demo: Use a sponge to represent a beam. When loaded with weight, the divots (holes) on top _________ and the divots (holes) on bottom _________ Conclusion: close open compression tension compression The top of a beam experiences __________. The bottom of a beam experiences _______. tension

Engineering for bridges: Type of Bridges Fixed Moveable Other Beam bridge Truss bridge Continuous truss Arch bridge Cantilever Suspension Cable-Stayed Swing bridge Bascule bridge Vertical lift bridge Bailey bridge Pontoon bridge

Type of Bridges: Fixed Truss Bridges Beam Bridges BOG-AAA123- Type of Bridges: Fixed Beam Bridges Truss Bridges Beam bridge strengthened by trusses A truss is a structure joined to form triangles with tie rods Lighter than ordinary beam sections of equal length Useful for longer bridges Two parallel beams with flooring supported by piers Used for highway over and underpasses or small stream crossings Image sources: Left: http://www.fhwa.dot.gov/bridge/prefab/if09010/appd.cfm Right: http://parkplanning.nps.gov/projectHome.cfm?projectID=15822

Type of Bridges: Fixed Continuous Truss Bridges Simple Truss Bridges BOG-AAA123- Continuous Truss Bridges Simple Truss Bridges Image sources: Top: http://www.nyc.gov/portal/site/nycgov/index.jsp?epi-content=GENERIC&wcproxyurl=http%253A%252F%252Fwww.nyc.gov%252Fhtml%252Fdot%252Fhtml%252Fbridges%252Fqueensboro.shtml&beanID=1173395690&viewID=proxy_view_secondary Bottom: http://www.fhwa.dot.gov/nediv/bridges/cherry.htm

Type of Bridges: Fixed Arch Bridges Aqueduct One or more arches BOG-AAA123- Arch Bridges Aqueduct One or more arches Masonry, reinforced concrete or steel Roadway on top of arches or suspended by cables Spans can be longer than beam or truss Image Sources: Left: http://www.fhwa.dot.gov/publications/publicroads/05sep/03.cfm Center: http://www.dot.nd.gov/imgs/bridge08/pages/rainbow%20arch%20bridge-valley%20city.htm Right: http://en.wikipedia.org/wiki/File:Pont_du_Gard_Oct_2007.jpg

Type of Bridges: Fixed Cantilever Bridges Suspension Bridges BOG-AAA123- Cantilever Bridges Suspension Bridges Roadway hangs from vertical cables supported by overhead cables chained between two or more towers Longest spans, costly and challenging to design Highly susceptible to winds and swaying Cables can be up to three feet in diameter Double-ended brackets supporting a center span Shore end of each cantilever firmly anchored Center supported by pier Image sources: Left: http://www.iowadot.gov/subcommittee/bridgeterms.aspx Center: Martin St-Amant, http://en.wikipedia.org/wiki/File:125_-_Qu%C3%A9bec_-_Pont_de_Qu%C3%A9bec_de_nuit_-_Septembre_2009.jpg Right: http://www.fhwa.dot.gov/infrastructure/asstmgmt/cswa0701.cfm

Type of Bridges: Fixed Cable-Stayed Bridges Image sources: BOG-AAA123- Cable-Stayed Bridges Suspended by cables that run directly down to roadway from central towers Less costly than suspension Quickly constructible Spans must be limited in length Image sources: Left: http://openi.nlm.nih.gov/detailedresult.php?img=3292090_sensors-09-07943f2&req=4 Center: http://www.nasa.gov/offices/oce/appel/ask/issues/39/39s_big_dig.html Right: http://www.dhs.gov/shield-activated

Type of Bridges: Moveable BOG-AAA123- Type of Bridges: Moveable Swing Bascule Vertical Lift Central span turned 90 degrees on pivot pier placed in the middle of the water way One or two sections are not supported by piers Balanced on one end by counterweights Section jack-knifes up to allow passage of ships Most common type of highway drawbridge Central span extends between two towers Balanced by counterweights Image sources: Left: http://www.fhwa.dot.gov/infrastructure/asstmgmt/bmcs705.cfm Center: http://www.groton-ct.gov/depts/plandev/BridgeProject.asp Right: http://en.wikipedia.org/wiki/File:Tower_Bridge_Sacramento_edit.jpg

Let’s start building our bridges: Two Designs: a. A three-span beam bridge made with paper b. A simple truss bridge made of spaghetti (recommended) or any other design is also welcome

Paper Bridge: BOG-AAA123- Image sources: Eduardo Suescun

Spaghetti Bridge: Identify tension and compression forces Learn how to strengthen a single beam bridge Measure deflection using a LEGO MINDSTORMS EV3 ultrasonic sensor

BOG-AAA123- THANK YOU ! Image source: http://www.dot.ca.gov/hq/esc/Structure_Design/SD/bd1.html