Download - 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