More Than a Model: The Golden Gate Bridge at 1:80 Scale · The Golden Gate Bridge at 1:80 Scale Sylvester T. Black Engineer, Robert Silman Associates Princeton University Department

More Than a Model: The Golden Gate Bridge at 1:80 Scale

Sylvester T. Black Engineer, Robert Silman Associates

Princeton University Department of Civil and Environmental Engineering

June 21, 2012

More Than a Model

Dimensions:

• Main span 52.5 ft • Side span 14.1 ft • Arch 4.1 ft • Total Length 85 ft • Tower Height 9.3 ft

More Than a Model

Loads:

• Self weight • Wind • Seismic • Corrosion • Pedestrians

More Than a Model

• Gravity Load Analysis Sylvester Black Thesis 2009

• Wind Load Analysis Gavin Daly Thesis 2010

• Seismic Load Analysis Michelle Lau Thesis 2012

More Than a Model

Loads:

• Self weight • Wind • Seismic • Pedestrians • Corrosion

More Than a Model

1:80 Scale Steel Prototype -- “Teenage Load Test”

More Than a Model

Loads:

• Self weight • Wind • Seismic • Pedestrians • Corrosion

Materials & Fabrication

Materials & Fabrication

Stainless Steel Duplex 2205: • More corrosion resistant than SS316 • Stronger & more stiff than Aluminum • Cheaper & easier to fabricate than Titanium

Materials & Fabrication

Water-Jet Cutting • Lessons learned from the

Candela exhibition

Materials & Fabrication

Materials & Fabrication

Materials & Fabrication

Water-jet cutting • Lessons learned from the

Candela exhibition

Connections:

A Multi-Variable Optimization Problem

Connections- An Optimization Problem

Criteria: • Normal service loads • Highly concentrated, extreme-

event loads • Machinable Material • Corrosion- Resistant Material • Easy to assemble • Easy to maintain

• Adjustability

Connections- An Optimization Problem

Criteria: • Normal service loads • Highly concentrated, extreme-

event loads • Machinable Material • Corrosion- Resistant Material • Maintain Suspender straightness • Easy to assemble • Easy to maintain

• Adjustability

• NO LARGER THAN A MARBLE!

Connections- An Optimization Problem

Public Works for Public Learning- Applications

Takeaway Points for PWPL

“Large Model” Projects:

Public Works for Public Learning- Applications

1. Not a model of the Golden Gate Bridge…

- A Bridge that looks like the Golden Gate

2. If you build it, they will climb:

Public Works for Public Learning-Applications

3. Set a clear hierarchy of goals:

Lifespan (public use/abuse, corrosion, maintenance) Aesthetic precision: Which ideas are most important to communicate?

Public Works for Public Learning-Applications

4. Not all “Large Models” are the same…

Consider geometry of the real structure when selecting a scale to model it at.

1:80 scale model of Golden Gate Bridge

Deck-Suspender-Cable connection

• Cable band

• Suspenders

• Cable clamps & separators • Swaged or threaded connection

• Balancer/Assembly tools

__________________________ • Permutations of components

Cable Band

• 3 Types, ½”- ¾” length • Attach cable band in-shop • Length & height reduced • Final design to conform to

suspender size

1:80 scale model of Golden Gate Bridge

1:80 scale model of Golden Gate Bridge

Deck-suspender connection

• Current design items: • Smaller suspender spacing • Adjustability in-field • Eliminate galvanic conflicts

• Alternate solution: Reduce rod

diameter

1:80 scale model of Golden Gate Bridge

Deck-suspender connection

• Balancer component • Designed for wire rope • Modify for rods