1 / 16

Tunnel Design, Inspections, and National Standards

Tunnel Design, Inspections, and National Standards . Dan Walsh. Topics. Design of the D Street portal ceiling Tunnel inspections National standards for tunnel finish designs. Project Oversight. Epoxy. Federal Highway Administration. Sika Corporation. MassHighway

dewitt
Télécharger la présentation

Tunnel Design, Inspections, and National Standards

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Tunnel Design,Inspections, and National Standards Dan Walsh

  2. Topics • Design of the D Street portal ceiling • Tunnel inspections • National standards for tunnel finish designs

  3. Project Oversight Epoxy Federal Highway Administration Sika Corporation MassHighway Mass. Turnpike Authority Powers Fasteners, Inc. Design and Construction Bechtel/Parsons Brinckerhoff (B/PB) Gannett Fleming, Inc. Newman Renner Colony, Inc. Conam Inspection, Inc. Modern Continental Construction, Inc.

  4. Design Loads • Anchor designed for 2,600 pounds • Finite element analysis • Model anchor loads • Determine structural redundancy • Examine different “hanger-out” scenarios

  5. Design Loads • Powers Fasteners anchoring system • Average expected load capacity of 25,400 pounds • Safety factor of 4 • Allowable load of 6,350 pounds • Anchor design load of 2,600 pounds

  6. Finite Element Analysis • One hanger removed, loads remained below 6,350 pounds • Two or more hangers removed, loads remained below 25,400 pounds

  7. Responsibility of Consultant • Gannett Fleming • Develop detailed design • Review submittals and prepare responses • Affixed engineer’s professional seal • Evaluation of each component of the ceiling system

  8. Anchor Specification • Failed to account that adhesives creep • Adhesive anchors in pure tension was an atypical application • Adhesives have different properties

  9. Anchor Specification • No specification regarding long-term properties • No requirement for testing for long-term performance • No consideration of service life • No provision for periodic inspection

  10. Anchor Approval • Opportunity to address creep in the approval process • Contractor’s proposed anchoring system • Draft version of ICBO Report ER-4514 • Fast Set epoxy approved for short-term loads only • Gannett Fleming authorized work to proceed

  11. Preaccident Anchor Failures • Opportunities to determine poor long-term characteristics of the adhesive • First opportunity in HOV tunnel (September 1999) • Suspected improper anchor installation • Powers evaluated the anchor installation (October 1999)

  12. Preaccident Anchor Failures • Remove and replace all failed anchors • Proof test to higher load of 6,350 pounds • Higher load would not identify poor long-term load characteristics • Anchor performance should have been monitored

  13. Preaccident Anchor Failures • Additional opportunity in eastbound I-90 connector tunnel (late 2001) • Remedy developed was ineffective • Considered the continuing failures as isolated instances

  14. Preaccident Anchor Failures • Problem attributed to installation, including overtorquing the nuts • Tests showed overtorquing did not reduce load capacity • Powers did not recommend to continue to monitor the anchor performance

  15. Summary • B/PB and Modern Continental should have instituted a program to monitor anchor performance • Powers response to the anchor displacements was deficient

More Related