1. SAN FRANCISCO – OAKLAND
BAY 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

2. 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

3. 3
- 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

4. 4
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

5. 5
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

6. 6
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

7. 7
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

8. 8
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.

9. 9
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

10. 10
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

11. 11
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

12. 12
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

13. 13
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

14. 14
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

15. 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

16. 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

17. 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, 2013
Assessment, Upgrading and Refurbishment of Infrastructures