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Reservoir In Inspection and Str tructural Analysis is Pete Boone, - - PowerPoint PPT Presentation
Reservoir In Inspection and Str tructural Analysis is Pete Boone, - - PowerPoint PPT Presentation
Reservoir In Inspection and Str tructural Analysis is Pete Boone, PE, PLS Tualatin Valley Water District Pete Slocum, PE, SE OBEC Consulting Engineers Why is this import rtant nt? See anything ng? Co Considerati erations ons wh
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Co Considerati erations
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when planning inspecti ction
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- Safety
- What are we looking for?
- Steel vs. concrete
- Interior vs. exterior
- How do we get a good look at the roof?
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Safety ety
- Confined space entry
- Fall hazard
- Water hazard
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What t are we we looking for?
- Steel tanks
- Paint failures
- Corrosion
- Algae
- Concrete tanks
- Cracks and crumbles
- Exposed rebar
- Rock pockets
- All tanks
- Ladders
- Piping
- Hatches
- Vents
Things that look bad
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Interi terior
- r inspectio
tions ns Full Reservoir
- Roof inspection by boat
Drained reservoir
- Wash down walls and floor
- Visual inspection from floor
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Boat t inspecti ction
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Safety considerations
- Lockout/tag out for reservoir valves
- Air monitor and radio communication
- Retrieval system and harnesses
- Lifejackets and second raft deployed
- Rescue plan and coordination with local fire dept.
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Bo Boat at in inspe pections tions
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Boat t inspecti ction
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Boat t inspecti ction
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Concret rete e roof configurat guration
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Network of beams and columns
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Co Concrete rete roof configurati guration
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Columns and drop panels
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Co Concrete rete roof configurati guration
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Columns and drop panels
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Co Concrete rete roof inspecti ction
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Looking for cracked, spalled, or crushed concrete
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Spalling
Beam breaking free of roof slab Spalling from beam/beam pocket friction
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Beam and slab cracki king ng
Vertical cracks in center from bending Diagonal cracks near ends from shear White stuff is called efflorescence
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Beam failure re
Beam breaking free of roof slab This began as a shear crack When crack hit longitudinal bars, they peeled free
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Be Beam am fa fail ilur ure
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De Developin ping g beam failures res
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Marki king ng cracks ks in be beams
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Ro Roof to wa wall ll connecti ction
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Ro Rock pockets ts in in colu lumns
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De Deteriorating riorating concret ete wa wall ll coating ing
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Hatches
- Hinges
- Latches
- Locks
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Ladders
- Corrosion
- Attachment
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Piping
- Corrosion
- Attachment
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Ex Exterior erior in inspecti ctions
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Ex Exterior erior in inspecti ctions
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De Deteriorating riorating pain int
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Starting rting a reservoir voir inspecti ction
- n program
am
- Safety planning
- Gather information
– As-builts – Previous inspections
- Documentation
– Photos – Inspection reports
- Evaluation and analysis by structural engineers
- Plan for repairs
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Pete Slocum, PE, SE
Reservoirs– Structural Analysis and Retrofits
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Pete Slocum, PE, SE
Appropriate Inspection Program
In addition to those applicable and mentioned previously by TVWD (Pete Boone)
- Nondestructive testing (NDT)
- Inspect the Roof
- Inspect the Wall
- Observation Below Grade
- Sample and test Shotcrete
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Pete Slocum, PE, SE
Appropriate Structural Analysis and Retrofit Strategies
Analysis
- Analysis of the existing structure
- Review available documents
- Determine the era of tank construction
- Determination of load rating capacity
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Pete Slocum, PE, SE
Appropriate Structural Analysis and Retrofit Strategies
Evaluation
- Identification and prioritization of deficiencies and
repairs
- “Short-term” versus “long-term” repairs and risks
- Alternatives for "short-term" repairs
- Preliminary cost estimates
- Previous loadings
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Pete Slocum, PE, SE
Appropriate Structural Analysis and Retrofit Strategies (cont’d)
- Seismic structural analysis is based on:
- Field inspections
- Available design, construction, and past inspection report
documentation.
- Knowledge of construction techniques at the time of construction
- Current code
- All failure mechanisms
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Pete Slocum, PE, SE
Understand the Causes
- Deterioration
- (don’t just cover it up!)
- Spalled shotcrete cover
- Rusty, deteriorated & broken
wrap wire
- Concrete carbonation
- Leakage & freeze/thaw damage
at wall top
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Pete Slocum, PE, SE
What a Water District needs to know about Seismic Loads on your Reservoir
- Tank, anchorage and foundation under distress.
- Possible failures: anchorage breakage, buckling, pipe connections
and soil liquidfaction.
- Older reservoirs are undercapacity for the current Code levels.
- Taller, narrower tanks have more issues.
- All nonstructural features need bracing.
- Install shut-off valves.
- Locate all ponds and basins down slope from tank.
- Earthquake levels: 2% probability of being exceeded in 50 years.
- Seismic Slosh and Required Freeboard.
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Pete Slocum, PE, SE
Also Consider…
- Decisions must include non-
seismic considerations and life-cycle costs
- Piping connections, soil
capacity, anchorages, design codes, size .
- Economical ways to reduce
load and deterioration
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Pete Slocum, PE, SE
Geotechnical Considerations
Site specific information is necessary to accurately identify the true vulnerability including
- landslide potential,
liquefaction of the soils
- ground rupture (based on
proximity of the closest mapped fault)
- stability of the site.
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Pete Slocum, PE, SE
Repair Examples
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Pete Slocum, PE, SE
Corrective Measures
Epoxy Injection
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Pete Slocum, PE, SE
Corrective Measures
External Stirrups
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Pete Slocum, PE, SE
Corrective Measures
External Stirrups
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Pete Slocum, PE, SE
Corrective Measures
Scaffolding Support
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Pete Slocum, PE, SE
Questions?
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Co Contact act Inform
- rmation