SR99 Bored Tunnel-Assessment of Settlement Impacts ... - SCATnow

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List of TablesTable E-1. Level 1 Monitoring ..................................................................................................................... 15Table E-2. Level 2 Monitoring ..................................................................................................................... 16Table E-3. Level 3 Monitoring ..................................................................................................................... 16List of FiguresFigure E-1. Monitoring/Alert Mechanism Schematic .............................................................................. 12The Alaskan Way Viaduct & Seawall Replacement Program March 2010Proposed SR 99 Bored Tunnel - Assessment of Settlement Impacts to BuildingsE-iiPublic Disclosure Request 11-0123 for Elizabeth Campbell - 2nd installment
1.0 IntroductionThe potential ground movement associated with open cut excavations and tunnelboring operations may affect adjacent buildings, utilities, and other elements at ornear the existing ground elevation. Surveys of the pre-construction conditions,monitoring settlements and tilt during construction, and plan "trigger levels" atwhich contingency plans may be enacted for these items. The discussion within thisappendix is focused on monitoring impacts to building structures along the tunnelalignment. It does not provide input for all of the instrumentation and monitoringrequired for the construction of the tunnel.The exact implementation of monitoring points and types will be a balance betweencosts, risk management, and practical considerations. Potential equipment formonitoring is outlined below.Tilt meters are relatively inexpensive per location for one location/direction and givecontinuous information on tilt. However, one is needed for each direction at aparticular location, and no direct information is gathered for the settlement values.Hence multiple tilt-meter locations need to be carefully chosen to provideinformation for the vulnerable points. Shearing mode deformations causing diagonaltension cracking in walls do not trigger tilt alarms unless a beam element is added tospan a wall and the tilt meter is placed on that beam element. Careful placement oftilt meters is essential, such as on beams for framed buildings with sheardeformations and at maximum expected tilting locations for walls with bendingdeformations.GPS Rover stations provide direct settlement information as long as relativelyunobstructed satellite exposure is available. However, they have significant cost perlocation for monitoring, and multiple locations may be required on a building.Rover stations get their accuracy with the aid of one or more fixed (not settling ormoving) base stations near the project site. A few base stations are required for thewhole project to achieve the desired accuracy at the Rover stations, depending on themanufacturer or work progress. Hence the two terms “Base Stations” and “RoverStations” are used various times in the report, both being essentially GPS stationsproviding X, Y, Z coordinates, but the rover stations being moved around tolocations where direct settlement information is required, and the base stationsproviding a fixed reference.Prisms fastened to building exteriors as part of an Automatic Robotic Total Stationmonitoring systems (sometimes called Robotic Total Stations) have even betteraccuracy than GPS Rover stations, yet they have incremental costs of only roughly1/10 that of the GPS Rover stations. However, they require line-of-sight to theTotal Station equipment, which can have significant cost. The line-of-sightrequirement is not a problem for settlement monitoring inside a tunnel but is moredifficult in a downtown environment.The Alaskan Way Viaduct & Seawall Replacement Program March 2010Proposed SR 99 Bored Tunnel - Assessment of Settlement Impacts to Buildings E-1Public Disclosure Request 11-0123 for Elizabeth Campbell - 2nd installment
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Table of Contents1.0 EXECUTIVE SUMM
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Proposed SR 99 Bored Tunnel -Assess
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The damage classification for the r
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2.0 Program Description & Backgroun
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2.2 Tunnel Project DescriptionThe T
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2.2.3 North Access Project Descript
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3.0 Building AssessmentThe tunnel a
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. History of settlement - based upo
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4.0 Settlement and Ground Movement4
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Figure 3. Generalized Transverse Se
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5.0 Building Response to Excavation
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Table 2. Building Damage Classifica
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tunnel axis), the settlement trough
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6.0 Results of Structural Analyses6
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Therefore, high-rise buildings alon
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Table 4. Summary of Building Damage
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PROPERTY IDPROPERTY ADDRESSAPPROXIM
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PROPERTY IDPROPERTY ADDRESSAPPROXIM
Page 41 and 42: PROPERTY IDPROPERTY ADDRESSAPPROXIM
Page 47 and 48: 7.0 ReferencesAttewell, P.B.; Yeate
Page 49 and 50: Appendix ATunnel Alignment Plan She
Page 51 and 52: A1Legend! ! SeawallPiersAreawaysTun
Page 53 and 54: T161NOTES :1) ASSESSMENT OF DAMAGE
Page 55 and 56: A3LegendMONORAILEBIAreawaysTunnelTu
Page 57 and 58: Appendix BBuilding Damage Classific
Page 59 and 60: Figure B-1. Graphical Illustration
Page 61 and 62: Appendix CBuilding Assessment Forms
Page 63 and 64: List of Abbreviations Used in Build
Page 65 and 66: Distance to Tunnel:• Horizontal o
Page 67 and 68: example, T311 and T312 are the same
Page 69 and 70: Appendix DBoscardin and Cording Ana
Page 71 and 72: Table of Contents1.0 B&C ANALYSIS M
Page 73 and 74: 1.0 B&C Analysis MethodThe building
Page 75 and 76: Offset, Yδε hLβDeparture from tu
Page 77 and 78: Figure D-1. Building Location Coord
Page 79 and 80: 1.00.90.80.7G((X-XT)/KZ)0.60.50.40.
Page 81 and 82: 2.0 B&C Damage ClassificationsTable
Page 83 and 84: 3.0 E/G RatioE/G is based upon Tabl
Page 85 and 86: 4.0 Building HeightBuilding height
Page 87 and 88: 5.0 Foundation DepthThe analysis to
Page 89 and 90: Appendix EMonitoringThe Alaskan Way
Page 91: Table of Contents1.0 INTRODUCTION .
Page 95 and 96: 2.0 Basic MonitoringManual survey p
Page 97 and 98: 3.0 Tilt Meter Monitoring3.1 Goals3
Page 99 and 100: 4.0 GPS Monitoring4.1 Goals4.2 Impl
Page 101 and 102: 5.0 Automated Monitoring Total Stat
Page 103 and 104: 6.0 Distributed Data Acquisition6.1
Page 105 and 106: The emerging capability of wireless
Page 107 and 108: 7.0 Levels of MonitoringEach buildi
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