1 / 13

A project undertaken by TRANSIT NEW ZEALAND in conjunction with

S E I S M I C S E C U R I T Y O F S T A T E H I G H W AY B R I D G E S I N N E W Z E A L A N D SCREENING & RETROFIT – PROGRESS SUMMARY. A project undertaken by TRANSIT NEW ZEALAND in conjunction with OPUS INTERNATIONAL CONSULTANTS LIMITED APEX PROJECT MANAGEMENT LIMITED

elvis-alexander
Download Presentation

A project undertaken by TRANSIT NEW ZEALAND in conjunction with

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. S E I S M I C S E C U R I T Y O F S T A T E H I G H W AY B R I D G E S I N N E W Z E A L A N D SCREENING & RETROFIT – PROGRESS SUMMARY A project undertaken by TRANSIT NEW ZEALANDin conjunction with OPUS INTERNATIONAL CONSULTANTS LIMITED APEX PROJECT MANAGEMENT LIMITED and REGIONAL BRIDGE CONSULTANTS

  2. OBJECTIVE & STATUS • To identify bridges that justify a more detailed seismic assessment and, possibly, retrofitting • Seismic screening completed • Retrofitting underway

  3. BACKGROUND Project drivers: • Experience from earthquakes – integrity of the roading network is vital • Dramatic improvement in performance often achievable from simple measures, e.g. linkages • Past practice - since 1933, bridges either monolithic or have spans interlinked

  4. BACKGROUND • Past retrofit policy – low cost seismic improvements in conjunction with work to raise service standards • In early 1990s, 8 bridges in regions of higher seismicity retrofitted for linkages

  5. BACKGROUND • Wellington’s Thorndon Overbridge and the Auckland Harbour Bridge retrofitted • A screening procedure was developed Refer 12th World Earthquake Conference (Chapman et al)

  6. RISK ASSESSMENT • Identification of structure vulnerabilities • Classification of risk level for each risk event - likelihood & consequences • likelihood derived from: • peak ground acceleration causing risk event • seismicity of site • consequences derived from: • effect on safety • extent of traffic disruption

  7. ECONOMIC RANKING INDICATOR (ERI) • For “high” and “significant” risks, an “Economic Ranking Indicator” determined • “ERI” was based on factors such as: • traffic volume • duration & probability of disruption • cost of traffic disruption • cost of bridge damage (if significant) • discounted cost (ROC) of retrofit

  8. RANKING • Ranking was based on factors such as: • Route priority • Risk to Life • ERI value • Number of risk events

  9. OUTCOME • 3813 bridges & culverts screened • 2842 (75%) eliminated • 971 (25%) subjected to risk assessment • 381 (10%) “high” or “significant” risk level • 188 (5%) separately identified as having linkage deficiencies • $850 per bridge for 2322 bridges

  10. ASSESSING & RETROFITTING STRUCTURES • Top 50 ranked structures will be assessed • Available specialist resources likely to constrain the timeframe for assessments • Expenditure ~ $5M to ~$6M per annum

  11. Bridge Seismic ScreeningStage 2 • Progress to date • Linkage Retrofit • Detailed Assessments • Detail Design & Construction • Programme Management

  12. Progress to date • Linkage Retrofit • P1 & P2 routes (130 comepleted) • Detailed Assessments • Re-prioritised 50 completed detail assessments • On hold till first 25 bridges addressed • Detail Design & Construction • Retrofits complete 10 • Retrofits under construction 5 • Designs in progress 6 • Recommended for replacement 2

  13. Programme Management • Delegated authority • Project Team • Rudolph/Gavin/John Wood/Howard Chapman • Project Management Framework • Basis of seismic design for existing bridges. • Remaining life of structure & condition • Mode of failure • Performance indicators & risk profile • Retrofit vs. replacement cost • Route importance • Bridge Design Statement

More Related