Sfobb Dec08

The Survey for the New San Francisco Oakland Bay Bridge

December 1st, 2008

ASCE Dallas Branch Meeting

Presentation Topics

An Introduction to the Project Key Bridge Components Geodetic Surveying and Tectonic

Considerations Transition Span OBG’s Footings (T1 & E2) SAS Tower SAS OBG’s

Project Limits

San Francisco

Oakland

Treasure Island

Yerba Buena Island

Introduction The New Bridge

Designed by Ty Lin and Moffett Nichol JV Constructors - American Bridge/Flour JV

SAS Components

Surveying Challenges

Unique single tower design requires extreme survey accuracy

Complex OBG Deck Geometry (e.g., pre-camber)

Primary geodetic control network (Order B) Steel component fabrication tolerances (1 mm

→ 3 mm depending on specific dimensional criteria)

Thus survey accuracies must be 5 x to 10 x better than the tolerances

Project Area sits on a single tectonic plate No discernable scale or rotation seen in the HTDP output Presented Results to Client

HTDP OutputHTDP (version 2.9) OUTPUT

VELOCITIES IN MM/YR RELATIVE TO NAD_83(CORS96)

EE-75LATITUDE = 37 49 25.53939 N NORTH VELOCITY = 24.11 mm/yrLONGITUDE = 122 19 13.74167 W EAST VELOCITY = -19.59 mm/yrELLIPS. HT. = 0.000 m UP VELOCITY = 0.00 mm/yrX = -2697037.344 m X VELOCITY = -8.65 mm/yrY = -4262916.207 m Y VELOCITY = 22.97 mm/yrZ = 3890010.703 m Z VELOCITY = 19.04 mm/yr

RECEIVE RESET 1970LATITUDE = 37 48 36.74206 N NORTH VELOCITY = 25.14 mm/yrLONGITUDE = 122 21 40.44261 W EAST VELOCITY = -20.13 mm/yrELLIPS. HT. = 0.000 m UP VELOCITY = 0.00 mm/yrX = -2700562.314 m X VELOCITY = -8.76 mm/yrY = -4261776.122 m Y VELOCITY = 23.79 mm/yrZ = 3888822.196 m Z VELOCITY = 19.86 mm/yr

Primary Geodetic Control and Related Issues, e.g., Tectonic Motion

Transition Span Survey For Caltrans

USA Steel Fabrication Verification - Portland Transition Spans First Survey Attempt by Others Failed Original Fabricator went out of Business

Conventional Precision Survey Methods

Conventional Network

95% confidence regionsexceed project tolerance (3 mm)

State of the Art Technology

Laser Tracker

Primary Control

Applied Technology Precision prisms Drift nest tools Circle tools Edge tools Hidden point tools Etc.

Leica Laser Tracker and 1.5″ PreciseSphere

Laser Tracker Survey of the Transition Span OBG’s

T1 Footing Survey – Corpus Christi Five Elements

Dimensions Pile Sleeve Radii and Orientation Dowel Locations Location and Axis of 438 Bolt Holes Dowel and Bolt Hole Template

Pile SleeveAnalysis

T1 FootingPile SleeveAlignment and KeyDimensions

T1 FootingOrganizedChaos

T1 Footing Survey – Corpus Christi Use a Laser Tracker Work at Night

Minimize ambient conditions flux Easier access with minimal other work Network based on 63 surveyed dowel

locations

Dowel Survey Results

Template Survey Results

T1 Footing at KOS

T1 Footing Delivery

Driving the Piles

T1Footing inPlace

T1 Footing Installed

ZPMC Fabrication Facility Shanghai

ZPMC

Tower Survey - China Tower FabricationGetting Oriented (no pun intended)

The Basic Tower Design

Tower Mock-up Surveys China Tower/Deck Fabrication – First Survey

The Project Site Steel Fabricator in Shanghai Mock up Survey

• 3 Elevations of the Tower• To Prove Capability• Actual Sections 40 M• Survey for

– Dimensions– Flatness– Orthogonality– Torsion– Alignment

Tower Survey

China Tower Fabrication Survey Using Laser Tracker

Tower Shaft Survey China Tower Fabrication

Performing the Survey

Tower Shaft Survey China Tower Fabrication

Performing the Survey

Control Network and Object Observations Network Design Point Cloud

Maximum Residual found was 0.023mm (0.0009’)

Survey Report (Shaft Dimensions)

Survey Report (Shaft Skin Analysis)

Results Flatness

CI = 0.5 mm

(1/50th inch)

Survey Report (Stiffener Locations and Orthogonality)

Survey Report (Shaft Torsion Analysis)

Alignment at Shaft Splice

OBG Jig Survey Use of jigs to maintain OBG fabrication geometry

Jig Under Construction

OBG Survey

Ice Cream Break

Shanghai Surveys Towill Engineer with Buddy from Shanghai Hash

House Harriers

Thank You