Seismic Retrofit of Container Cranes

Transcription

1 Seismic Retrofit of Container Cranes Erik Soderberg, S.E. Liftech Consultants Inc. 1 of 35

2 Historic Seismic Performance Kobe - Liquefaction 2 of 35

3 Crane Evolution Circa 1970 Modern Jumbo 3 of 35

4 50 Gage Crane CLE Response 4 of 35

5 50 Gage - Close-up 5 of 35

6 100 Gage Crane CLE Response 6 of 35

7 100 Gage Close-up 7 of 35

8 Wheel Uplift U plift, in ' Landside 50' Waterside 100' Landside 100' Waterside WHEEL DISENGAGES FROM RAIL WHEEL ENGAGED ON RAIL Time, s 8 of 35

9 Lateral Force on Rail 400 Lateral force, kips / side ' Landside 50' Waterside 100' Landside 100' Waterside Time, s Note: Wheels engaged with rail. If one side disengages, the shown forces may be up to double at the engaged wheels. 9 of 35

10 Tipping Forces 1000k Circa k 3000k Modern Jumbo 1360k 10 of 35

11 Tipping Leg Moments 680 k 27,200 k-ft 150 k 4,500 k-ft 30' Moment 40' Moment 150 k Circa k Jumbo 11 of 35

12 Recent Liftech Design Criteria Changes Pre 2006 Force-based design elastic response for 0.2g lateral loading 2006 to present Performance-based design consistent with current wharf design practices 12 of 35

13 New Crane Design Criteria Operating Level Earthquake: Elastic strains no damage Contingency Level Earthquake: Tipping load no damage Ductile yielding some damage Isolation no damage Reference: 13 of 35

14 Design for Tipping 14 of 35

15 Design for Ductile Yielding A B A B AISC SEISMICALLY COMPACT A-A B-B 15 of 35

16 Design For Isolation Isolation Between Main Equalizer and Sill Beam Mitsubishi Heavy Industries 16 of 35

17 Design For Isolation Isolation Between Lower Leg and Portal Beam Liftech 17 of 35

18 Isolation Detail Isolation Between Lower Leg and Portal Beam Liftech 18 of 35

19 What about Existing Cranes? 19 of 35

20 Some Retrofit Questions 1. How will the existing crane perform? 2. Is significant damage acceptable in an operating level earthquake? 3. At what magnitude earthquake is collapse acceptable? 4. Should different criteria be used for different cranes? 5. Should cranes be upgraded when the wharf is upgraded? 20 of 35

21 Cost vs. Performance New Construction and Retrofit Retrofit + Damage New + Damage Cost Retrofit New Damage Performance 21 of 35

22 Factors Affecting Seismic Risk Location Seismicity Rail Gage Ductility of the Portal Frame Mass Portal Strength Portal Stiffness Trolley Mass 22 of 35

23 Rail Gage 300k 1360k 1000k 3000k 50 Gage 100 Gage or Larger 23 of 35

24 Ductility Connection strength > member strength Close stiffener spacing to limit local buckling. Ductile weld details FILLET SIZE t/4 BUT AT LEAST taws MIN. 24 of 35

25 Mass, Portal Strength, and Stiffness 25 of 35

26 Evaluating Existing Cranes Suggested Steps Check if the portal structure can support the tipped crane Check if the portal structure can deflect laterally 30 without collapse considering secondary effects and multiple load cycles. Perform time history analysis 26 of 35

27 Retrofit Options Option Strengthen structure Improve ductility and strength by adding stiffeners Add isolation mechanism Pro Reduces probability of damage Least costly, avoids collapse No damage Con May reduce portal clearance or be expensive Probability of damage unchanged Expensive 27 of 35

28 Strengthen Portal to Carry Tipped Crane Temporary Jacking Frame Pipe Braces 28 of 35

29 Add Plate Stiffeners to Improve Ductility External Angle Stiffeners Original Reinforced 29 of 35

30 Add Isolation Mechanism Isolation Between Lower Leg and Portal Beam 30 of 35

31 Other Gantry Structures Bulk Loader 31 of 35

32 Loader Damage Aticu, Peru of 35

33 Time History Analysis 33 of 35

34 Summary Be aware of seismic risk. Use state-of-the-art performance criteria when purchasing new cranes. It is practical to evaluate seismic risk. Retrofit is an option and is most practical when making other modifications. 34 of 35

35 Thank You This presentation with speaker notes will be available for download on our website: 35 of 35

36 Liftech Consultants Inc. file data: N:\Papers & Presentations\!Working\2007_AAPA_Seismic_ES\Seismic_Retrofit_Cranes_06_AD.ppt Copyright 2007 by Liftech Consultants Inc. All rights reserved. This material may not be duplicated without the written consent of Liftech Consultants Inc., except in the form of excerpts or quotations for the purposes of review. The information included in this presentation may not be altered, copied, or used for any other project without written authorization from Liftech Consultants Inc. Anyone making use of the information assumes all liability arising from such use. Quality Assurance Review: Author: Erik Soderberg Editor: Michael Jordan Principal: Erik Soderberg 36 of 35