TREND OF COUNTERMEASURES AGAINST LARGE-SCALE EARTHQUAKES DAMAGES AT HIGH PRESSURE GAS FACILITIES IN JAPAN

Transcription

1 UN/OECD Workshop Natech Risk Management Natural Hazards Triggering Technological Accidents 05 to 07 September 2018 at Potsdam, Germany, Kongress Hotel TREND OF COUNTERMEASURES AGAINST LARGE-SCALE EARTHQUAKES DAMAGES AT HIGH PRESSURE GAS FACILITIES IN JAPAN 1 Takashi OHNO The High Pressure Gas Safety Institute of Japan

2 OUTLINE 1. Introduction seismic damage for high pressure gas equipment in japan in 2011 Investigation into the cause of accident Current earthquake assumption objective ~ revise the seismic design standard? ~ 2. Damage estimation against earthquakes 1 Estimate acceleration 2 Evaluate design margin 3. Discussion of Future design Standard 4. Summary 2

3 1.INTRODUCTION Huge earthquake hit East Japan (March.11th.2011) Fire and explosion accident (LPG spherical tank was collapsed ) Investigation into the cause of accident the 2011 Great East Japan Earthquake Epicenter of Main shock date and time : 2011/3/11 14:46:18 magnitude : Epicenter of Max. After shock date and time : 2011/3/11 15:15:34 magnitude : 7.6 Accident 2 :Spherical tank support broke Accident 1:Spherical tank collapsed

4 1.INTRODUCTION Huge earthquake occurred in Japan (March.11th.2011) Fire and explosion accident (LPG spherical tank was collapsed ) Investigation into the cause of accident Short brace member Accident 1 Brace Spherical shell Upper column Upper column Long brace member 4 Column Lower column column Collapsed spherical tank Fig. Spherical Tank with steel pipe brace and column structure Accident 2 Steel pipe brace breaking

5 1.INTRODUCTION Huge earthquake occurred in Japan (March.11th.2011) Fire and explosion accident (LPG spherical tank was collapsed ) Spherical tank support was broken Investigation into the cause of accident 5 Gusset plate Diap Diaphragm accident causation : strength poverty of intersection of braces need reinforcing intersection of braces Intersection of braces gusset plate 3-diaphragms/rings 2-diaphragms/rings 1, 0 Already reported at NATECH , 0 Validation: Fracture mechanism and deformation behavior 4, 0 1 Study:Effectiveness of reinforcement and seismic capacity of spherical tank post-action measure *A manufacture use 2 method Joint of Upper column and braces Inserted 1-diaphragm/ring Inserted 2-diaphragms/rings Inserted gusset plate Inserted gusset plate and 1-diaphragm Rib plate Counter measure : reinforcing intersection of braces by Gusset plate or daiphragm 1 1 4

6 1.INTRODUCTION the Great East Japan Earthquake exceeded the assumption About 20,000 dead / missing people Fix assumption Large-scale earthquakes in future Nankai Trough Earthquake Tokyo Inland Earthquake 6 Hypothetical source fault zone by Cabinet Office fault region of strong motion Nankai Trough Earthquake(2012) the Great East Japan Earthquake(2011) Nankai Trough Earthquake(2003) Area km km km 2 Magnitude M W Increasing crisis awareness of large-scale earthquakes Advance measures are required

7 1.INTRODUCTION 7 Consideration for In-Advance measures against large scale earthquake 1How much acceleration is a large earthquake? 2How much the equipment withstand acceleration? 1Estimate acceleration of assumed large-scale earthquake. 2Evaluate design margin of high pressure gas equipment by numerical analysis simulation and shaking test. It was discuss that necessity to revise the seismic design standard or not.

8 2. DAMAGE ESTIMATION AGAINST EARTHQUAKES 1ESTIMATE ACCELERATION Evaluation of Design Acceleration Estimated basement acceleration by the Cabinet Office Basement acceleration waveforms throughout Japan (1km1km mesh) Design Acceleration of Seismic Design Standard Maximum ground surface acceleration :600gal Convert base acceleration to ground surface acceleration by Conversion formula At several points, Conversion value verification by 1D nonlinear response analysis (SHAKE) Nankai Trough Earthquake Red zone Over 600gal Tokyo Inland Earthquake 8

9 2. DAMAGE ESTIMATION AGAINST EARTHQUAKES 2EVALUATE DESIGN MARGIN Maximum response displacement [cm] 9 1Estimate acceleration 2Modeling <1D non-linear analysis> <Modeling by 3D-FEM and shaking test> Acceleration wave Equipment on ground surface Subsurface layer Engineering Basement surface Basement acceleration waveforms by the Cabinet Office K:Stiffness Ground surface C:damping Spherical tank (tie rod brace) Spherical tank (pipe brace) reinforced, reinforced 3Response calculation < 1 mass system nonlinear Time history analysis> Equipment 4evaluation of damage Estimate the collapse acceleration (response calculation at tens of thousands ) Damage occurred Flat bottom cylindrical tank Horizontal cylinder tank Limited displacement Acceleration wave on ground surface Maximum ground surface acceleration [cm/s/s] Vertical cylindrical tank Leg Rag Tower Skirt

10 2. DAMAGE ESTIMATION AGAINST EARTHQUAKES 2EVALUATE DESIGN MARGIN Boring data K: Stiffness C: damping 10 1Estimate acceleration Calculation example of 1site(Nankai Trough Earthquake) < 1D non-linear analysis > Basement acceleration wave Ground surface acceleration wave 2Modeling For time history calculation Calculation case = tens of thousands points 9 type equipment An easy-to-calculate model is required Shaking test + 3D-FEM (dynamic) + 3D-FEM (static) 1 mass system model Equipment m Ground surface

11 Maximum response displacement [cm] 2. DAMAGE ESTIMATION AGAINST EARTHQUAKES 11 2EVALUATE DESIGN MARGIN Evaluation result of one case for Spherical tank(tie rod brace) 3 Response calculation 2 Response displacement max. Ground surface acceleration wave Limit state Maximum ground surface acceleration [cm/s/s] limit displacement 4 evaluation of damage No. High Pressure Gas Equipment Ground surface acceleration limit acceleration design standard Design margin A/B A(gal) B(gal) 1 Spherical tank (tie rod brace) Spherical tank (reinforced pipebrace) Spherical tank (pipe brace) Flat bottom cylindrical tank 5 Vertical cylindrical tank 6 Horizontal cylinder tank Tower (Skirt) Tower (Leg) Tower (Rag) Earthquake response depends not only on the Maximum ground surface acceleration but also on periodic characteristics and phase characteristics.

12 Acc. 加速度応答スペクトル response spectrum [cm/s/s] α (gal) Acc. response spectrum [cm/s/s] 3.DISCUSSION OF FUTURE DESIGN STANDARD Design standard Current SA 600gal A 480gal B 420gal Nankai Trough Earthquake Change regional classification? Need region classification Every assumption review Every earthquake High cost Change? Change design spectrum? Setting safety side uneconomical design 100 第 1 種地盤 10 第 2 種地盤第 3 種地盤第 4 種地盤 固有周期 Period [s] T (s) Top 50 Spectrum Period [s] Reasonable Set design ground motion for each point

13 3.DISCUSSION OF FUTURE DESIGN STANDARD How to set design ground motion for each point? Fundamental formula (, ) (,, ) (, ) k ik i Strong motion prediction method U Y = T X Y D X d 13 Engineering basement Source characteristics Propagation Characteristic Ground characteristics Seismic basement Deep ground structure The Headquarters for Earthquake Research Promotion Strong ground motion prediction method for earthquakes with specified source faults (in Japanese)

14 4. SUMMARY 14 The earthquake damages in 2011 were examined and the direction of countermeasures against large scale earthquakes was showed. The seismic motion of the assumed large-scale earthquake were estimated. The design margin of the high pressure gas equipment were evaluated. The way of future seismic design standard was discussed.

15 ACKNOWLEDGMENT This presentation used the results to verify the seismic performance of the High pressure gas equipment in Research Committee of the Ministry of Economy, Trade and Industry commissioned project in I would like to express the deepest appreciation to committee members and participator.

16 16 THANK YOU FOR YOUR KIND ATTENTION.