SAN FRANCISCO – OAKLANDBAY BRIDGE SECOND CROSSING

Ronald F. Middlebrook, S.E.

Roumen V. Mladjov, S.E.

Louie International, San Francisco, California, USA

International IABSE Conference, Rotterdam May 6 - 8, 2013

Assessment, Upgrading and Refurbishment of Infrastructures

REUSE THE EAST BAY BRIDGE

Reuse the abandoned East Crossing structure for the

East Crossing portion of the new Second Bay Bridge

2SFO Bay Bridge Second Crossing. Ronald F. Middlebrook & Roumen V. Mladjov, Louie Intl, San Francisco, CA, USA

Use the abandoned East Crossing Structure for the East Portion of a New Second Bay Bridge

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- Ralph Modjeski et al

- Suspension Spans – 704 m

- Cantilever truss – 427 m

span, tower to tower

- Longest bridge in the world at time

of completion, 7,1 km

- Construction 3 ½ years; 1933 – 1936

- Seismic-Safety East Crossing, by

the end of 2013?

THE ORIGINAL SFO BAY BRIDGE (1936)

SFO Bay Bridge Second Crossing. Ronald F. Middlebrook & Roumen V. Mladjov, Louie Intl, San Francisco, CA, USA

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San Francisco

YBI

Oakland

The 1936 SFO Bay Bridge + 2013 Safety Project

San Francisco – Oakland Bay Original Bridge (1936)

and the East Bay Seismic Safety Project (2013?)

SFO Bay Bridge Second Crossing. Ronald F. Middlebrook & Roumen V. Mladjov, Louie Intl, San Francisco, CA, USA

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The 1936 SFO Bay Bridge:

- West Crossing - San Francisco to YBI twin suspension bridges;

3 140 m, with two main spans 704 m Steel Structures used 97 161

tons

- YBI segment – tunnel and short viaduct

- East Crossing - YBI to Oakland 3 377 m, including:

4 - 88 m steel truss spans + 738 m cantilever truss structure

+ 5 - 155 m through-truss spans

+ 14 - 88 m deck-truss spans Steel Structures used 54 432 tons

-Total Steel structures used 151 593 tons

Original 1936 SFO Bay Bridge Structure

SFO Bay Bridge Second Crossing. Ronald F. Middlebrook & Roumen V. Mladjov, Louie Intl, San Francisco, CA, USA

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SFO Bay Bridge Traffic Lanes 1936 - 2013+

SFO Bay Bridge Second Crossing. Ronald F. Middlebrook & Roumen V. Mladjov, Louie Intl, San Francisco, CA, USA

The original Bay Bridge had from 1936 to 1964 – 6 narrow

lanes on the upper deck and 3 –truck lanes plus 2 – light

rail lanes on the lower deck.

The current Bay Bridge has 5 traffic lanes on

both the upper and lower decks

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The SFO Bay Bridge is listed in the National

Register of Historic Places (NRHP)

The National Register calls the Bay Bridge:

“ One of the largest and most important

historic bridges in the country”.

Former President Herbert Hoover at his

ground-breaking ceremony: “This marks the

physical beginning of the greatest bridge yet

erected by the human race”

SFO Bay Bridge an Historical Structure

SFO Bay Bridge Second Crossing. Ronald F. Middlebrook & Roumen V. Mladjov, Louie Intl, San Francisco, CA, USA

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Loma Prieta Earthquake, 1989

Partial Earthquake Damage

SFO Bay Bridge Second Crossing. Ronald F. Middlebrook & Roumen V. Mladjov, Louie Intl, San Francisco, CA, USA

The East Span suffered local

damage. One edge of a 15 m

section collapsed and dropped

onto the lower deck. This

damage triggered extensive

studies on the existing structure

and its foundations and resulted

in a 12 year construction

Seismic Safety project.

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EAST CROSSING: SKYWAY + SUSPENSION BRIDGE, 2013 ?

T.Y. Lin International, Moffat & Nichol Engineers, Weidlinger

Associates, Donald MacDonald Architects

Total Length 3,513 m, Cost $6,45 Billion

East Crossing B.B. - Seismic Safety Project

Skyway, Multiple Spans 160 m SAS, Span 386 m

SFO Bay Bridge Second Crossing. Ronald F. Middlebrook & Roumen V. Mladjov, Louie Intl, San Francisco, CA, USA

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Bridge Element Original Bridge Replacement Bridge

Total Length (meters) 3 377 3 513

Main Span (meters) 427 385

Secondary Spans (meters) 155 160

Traffic Lanes 10 10

Vehicles per Day 280 000 300 000 +?

Construction Time (years) 3.5 12 ?

Completed/Estimated 1936 2013

Steel (kg/m2) 416 1843

Cost USD 78 M (non comparable) 6450 M

Bay Bridge East Span Replacement

EAST SPAN REPLACEMENT 77 YEARS LATER

SFO Bay Bridge Second Crossing. Ronald F. Middlebrook & Roumen V. Mladjov, Louie Intl, San Francisco, CA, USA

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Traffic Capacity:

5 lanes Eastbound from San Francisco to Oakland

5 lanes Westbound from Oakland to San Francisco

The traffic capacity remains the same from

1964 to 2012 and will not change in 2013

when the replacement of the East Crossing

is put into service.

The average daily traffic reached 280,000 vehicles

in the early 1990’s and was already creating heavy

congestions.

Bay Bridge’s Insufficient Traffic Capacity

SFO Bay Bridge Second Crossing. Ronald F. Middlebrook & Roumen V. Mladjov, Louie Intl, San Francisco, CA, USA

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Insufficient traffic capacity of the SFO Bay Bridge will not

improve after the Seismic-Safety replacement of the East

Crossing is completed in late 2013. The situation will only get

worse with the continuing increase of the Bay Area population.

Considering the possible options – the best one is to build a new

Second Bay Bridge along side the original structure

A Solution for Bay Bridge Traffic Problem

SFO Bay Bridge Second Crossing. Ronald F. Middlebrook & Roumen V. Mladjov, Louie Intl, San Francisco, CA, USA

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Bay Bridge Second Crossing Alignment

Proposed Second Crossing Alignment

SFO Bay Bridge Second Crossing. Ronald F. Middlebrook & Roumen V. Mladjov, Louie Intl, San Francisco, CA, USA

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This new bridge should be a highly efficient bridge, designed and built to

the best standards of today’s sophisticated bridge engineering

community.

The direction is given by David P. Billington, Professor at

Princeton University in Civil Engineering, March 1990:

“There are three principles of good bridge design:

• Efficiency (materials)

• Economy (cost and time)

• Elegance (slenderness)…

The least expensive bridge is the best bridge with all

other factors the same”

SFO Bay Bridge Second Crossing. Ronald F. Middlebrook & Roumen V. Mladjov, Louie Intl, San Francisco, CA, USA

Selecting a Bridge Type for the Second Crossing

What are the possible structural systems for the new

West Crossing? Suspension, cable-

stayed, or a combination of the two.

760740 740

760740 740

15SFO Bay Bridge Second Crossing. Ronald F. Middlebrook & Roumen V. Mladjov, Louie Intl, San Francisco, CA, USA

Selecting a Bridge Type for the Second Crossing

What are the possible structural systems for the

new East Crossing?

Selecting a Bridge Type for the Second Crossing

The best solution for the Second East Crossing is to build

foundations on a new alignment alongside the existing bridge

and to rebuild onto these foundations the existing 1936 bridge

in large portions using powerful jacks and temporary piers

installed on barges. 16SFO Bay Bridge Second Crossing. Ronald F. Middlebrook & Roumen V. Mladjov, Louie Intl, San Francisco, CA, USA

SAN FRANCISCO – OAKLAND BAY BRIDGE SECOND CROSSING

FOR MORE INFORMATION, PLEASE SEE THE

WEB-PAGE “SAVE THE BAY BRIDGE”

www.SavetheBayBridge.com

EMAIL YOUR COMMENTS, QUESTIONS OR SUGGESTIONS TO:

Ronald Middlebrook at ronfranco@gmail.com

Roumen Mladjov at rmladjov@louieintl.com

International IABSE Conference, Rotterdam May 6 - 8, 2013Assessment, Upgrading and Refurbishment of Infrastructures