Wabash Bridge Competition

69
Wabash Bridge Competition Bridge Engineering Todd Wilson, B.S., E.I.T. Traffic Engineer - DMJM Harris

Transcript of Wabash Bridge Competition

Page 1: Wabash Bridge Competition

Wabash Bridge Competition

Bridge Engineering

Todd Wilson, B.S., E.I.T.Traffic Engineer - DMJM Harris

Page 2: Wabash Bridge Competition

In 1904, the Wabash Bridge opened to carry the Wabash-Pittsburg Terminal Railroad over the Monongahela River. In

1948, the bridge was removed. The piers still remain.

Page 3: Wabash Bridge Competition

Now it is up to you to design a pedestrian bridge or structure to bring new life to the old abandoned bridge piers.

Page 4: Wabash Bridge Competition

Overview

• Definitions• Engineering

– Forces– Type– Configuration– Form

• Classification Challenge• Other Design Considerations

Page 5: Wabash Bridge Competition

Definitions

• Abutment - support at beginning or end ofbridge integrated with the ground

• Pier - intermediate support• Span - the bridge between two supports• Girder - a tall, narrow beam• Support Structure - the part of the bridge

that carries the load

Page 6: Wabash Bridge Competition

Engineering - Classification of Forces

• Function of bridge: to carry a load across adistance

• Due to gravity, all loads have a downwardforce (weight)

• All bridges can be classified into thefollowing basic types based on how theycarry the weight:– Compression– Tension– Tension/Compression (Both)

Page 7: Wabash Bridge Competition

Compression Bridges

• Compression is the “push” force• Compression causes an object to get shorter• Stone and concrete are strong in

compression

Page 8: Wabash Bridge Competition

Compression Bridges - Arch• A bridge that supports a weight in compression is

an arch bridge• The circular arc in compression supports the road• The arch can be below the road or above the road

Page 9: Wabash Bridge Competition

Compression Bridge - Arch

Photo: Todd Wilson

Page 10: Wabash Bridge Competition

Tension Bridges

• Tension is a “pull” force• Tension causes an object to get longer• Wire rope and chains are strong in tension

Page 11: Wabash Bridge Competition

Tension Bridge - Suspension• A suspension bridge features a long cable strung

over towers and anchored on both sides• Smaller cables are hung from the main cables and

connect to the road deck• The cables in tension support the road

Page 12: Wabash Bridge Competition

Tension Bridge - Suspension

Photo: Todd Wilson

Page 13: Wabash Bridge Competition

Tension Bridge - Cable Stayed• A cable stayed bridge features cables that connect

directly from a tower to the road• The cables in tension support the road

Page 14: Wabash Bridge Competition

Tension Bridge - Cable Stayed

Photo: Todd Wilson

Page 15: Wabash Bridge Competition

Tension/Compression Bridge

• A beam bends under the weight of a load• When the beam bends, the top half is in

compression and the bottom half is in tension• The taller the beam, the stronger it is

Page 16: Wabash Bridge Competition

A Beam Bridge…

Page 17: Wabash Bridge Competition

Now let’s add vertical rods to help you see whatis going on. They serve no structural purpose.

Page 18: Wabash Bridge Competition

The top rods are pushed together incompression

The bottom rods are pulled apart in tension

Page 19: Wabash Bridge Competition

Tension/Compression - BeamPhoto: Todd Wilson

Page 20: Wabash Bridge Competition

Tension/Compression - Truss

•As a beam gets taller and taller, itbecomes too costly and too heavy

•Solution: build a truss•Trusses have the same function as

beams, but are composed of triangles

Page 21: Wabash Bridge Competition

Tension/Compression - Truss– Top composed of thick beams (compression)– Bottom composed of thin eye-bar chains (tension)

Photo: Todd Wilson

Page 22: Wabash Bridge Competition

Truss Types

• Bowstring• Lenticular• Pratt• Double Intersection

Pratt (Whipple)• Baltimore• Parker

• Pennsylvania• Warren• Double Intersection

Warren• Warren Quadrangular

(Lattice)• K Truss

Page 23: Wabash Bridge Competition

Truss Type - Bowstring

Photo: Todd Wilson

Page 24: Wabash Bridge Competition

Truss Type - Lenticular

Photo: Todd Wilson

Page 25: Wabash Bridge Competition

Truss Type - Pratt

Photo: Todd Wilson

Page 26: Wabash Bridge Competition

Truss Type - Double Intersection Pratt

Photo: Todd Wilson

Page 27: Wabash Bridge Competition

Truss Type - Baltimore

Photo: Todd Wilson

Page 28: Wabash Bridge Competition

Truss Type - Parker

Photo: Todd Wilson

Page 29: Wabash Bridge Competition

Truss Type - Pennsylvania

Photo: Todd Wilson

Page 30: Wabash Bridge Competition

Truss Type - Warren

Photo: Todd Wilson

Page 31: Wabash Bridge Competition

Truss Type - Warren

Photo: Todd Wilson

Page 32: Wabash Bridge Competition

Truss Type - Warren

Photo: Todd Wilson

Page 33: Wabash Bridge Competition

Truss Type - Warren

Photo: Todd Wilson

Page 34: Wabash Bridge Competition

Truss Type - Double Intersection Warren

Photo: Todd Wilson

Page 35: Wabash Bridge Competition

Truss Type - Warren Quadrangular

Photo: Todd Wilson

Page 36: Wabash Bridge Competition

Truss Type - K

Photo: Todd Wilson

Page 37: Wabash Bridge Competition

Tension/Compression Configurations

• Simple– Beam or truss rests on one support on each end

• Continuous– Beam or truss continues over at least one support

between the end supports• Cantilever

– One (or both) ends of a beam or truss are projectedpast the end of a support - the projected anchor spans

– A subsequent beam or truss is connected to theprojected spans - the suspended span

Page 38: Wabash Bridge Competition

Configuration - Simple

Photo: Todd Wilson

Page 39: Wabash Bridge Competition

Configuration - Simple

Photo: Todd Wilson

Page 40: Wabash Bridge Competition

Configuration - ContinuousPhoto: Todd Wilson

Page 41: Wabash Bridge Competition

Configuration - Continuous

Photo: Todd Wilson

Page 42: Wabash Bridge Competition

Configuration - Cantilever

Photo: Todd Wilson

Page 43: Wabash Bridge Competition

Configuration - Cantilever

Photo: Todd Wilson

Page 44: Wabash Bridge Competition

Configuration - Cantilever

Photo: Todd Wilson

Page 45: Wabash Bridge Competition

Bending - Simple• A simple bridge bends the most at the midpoint

between supports• Simple bridges are often thickest in center

Photo: Todd Wilson

Page 46: Wabash Bridge Competition

Bending - Continuous• An intermediate support causes bending• A continuous structure becomes thicker over a pier

Photo: Todd Wilson

Page 47: Wabash Bridge Competition

Bending - Cantilever• Each projected span bends over a pier• Weight of suspended span applies a weight to the

ends of the projected spans• This also causes bending• Cantilevers are thickest over pier to resist bending

Photo: Todd Wilson

Page 48: Wabash Bridge Competition

Classification of Form

• Bridges are classified based on location ofstructure relative to the road (deck)– Deck: (structure beneath road)– Pony: (structure next to, but not above road)– Through: (structure above road)– Half Through (structure above and below road)

Page 49: Wabash Bridge Competition

Classification of Form - Deck

Photo: Todd Wilson

Page 50: Wabash Bridge Competition

Classification of Form - Pony

Photo: Todd Wilson

Page 51: Wabash Bridge Competition

Classification of Form - Through

Photo: Todd Wilson

Page 52: Wabash Bridge Competition

Classification of Form - Half Through

Photo: Todd Wilson

Page 53: Wabash Bridge Competition

Classification Challenge

• For each bridge, try to classify it!• Use the following categories:

– Form: deck, pony, through, half through– Type: tension, compression, tension/compression– Style: arch, suspension, cable stayed, beam,

truss– Beam Configuration (if applicable): deck, pony,

through, half through• Note: Some bridges will be combinations of

styles we discussed

Page 54: Wabash Bridge Competition

Cable Stayed

Photo: Todd Wilson

Page 55: Wabash Bridge Competition

Simple Through Truss

Photo: Todd Wilson

Page 56: Wabash Bridge Competition

Continuous Deck Girder (Beam)

Photo: Todd Wilson

Page 57: Wabash Bridge Competition

SuspensionPhoto: Todd Wilson

Page 58: Wabash Bridge Competition

Cantilever Through Truss

Page 59: Wabash Bridge Competition

Cantilever Deck Truss

Photo: Todd Wilson

Page 60: Wabash Bridge Competition

Cantilever Through Truss & Arch

Photo: Todd Wilson

Page 61: Wabash Bridge Competition

Through ArchPhoto: Todd Wilson

Page 62: Wabash Bridge Competition

Tied ArchPhoto: Todd Wilson

Page 63: Wabash Bridge Competition

Materials

• Steel– Weathering– Galvanized

• Iron• Wire Rope• Wood• Concrete• Reinforced Concrete• Masonry (stone)

Page 64: Wabash Bridge Competition

More Design Considerations

ß Impact on area– Traffic– Railroad– Pedestrian

• Implementability• Signage• Lighting

• Marketing• Maintenance• Security/Crime• Size• Liability (Lawsuits)• Clearance• Attractiveness

Page 65: Wabash Bridge Competition

ADA Requirements

• Bridge or structure must be handicappedaccessible

• Maximum slope: 1 ft rise per 12 ft run• Maximum rise between landings: 2.5 ft• 5 ft x 5 ft landing required where ramp

changes direction• Handrails required:

– Rise greater than 0.5 ft.– Run greater than 6 ft.

Page 66: Wabash Bridge Competition

Some Bridge Websites• www.pghbridges.com• www.venangoil.com/bridges.html• www.oldohiobridges.com• www.historicbridges.org• okbridges.wkinsler.com• www.iceandcoal.org/bridges/bridgefront.html• bridgehunter.com• www.bridgemeister.com• en.structurae.de/index.cfm• memory.loc.gov/ammem/collections/habs_haer/index.html

Page 67: Wabash Bridge Competition

Bridge Design Software

• http://bridgecontest.usma.edu/• Free bridge designer software

Page 68: Wabash Bridge Competition

Good Luck!!!

Page 69: Wabash Bridge Competition

Questions?

[email protected]@dmjmharris.com