Seismic Retrofitting for School Buildings in Japan Nonstructual Seismic Retrofitting

Transcription

1 Seismic Retrofitting for School Buildings in Japan Nonstructual Seismic Retrofitting for School Buildings in Japan 8 January 2009 Koichi Shinpo Director, Educational Facilities Research Center National Institute for Educational Policy Research(NIER)

2 National Institute for Educational Policy Research The National Institute for Educational Policy Research (NIER) is a national institute dedicated to the broad study of educational policy in Japan Established in 1949 Total staff 158 persons Annual appropriation is approximately 4,100 million yen Organization Director General, Duputy Director General(2) 6 Departments for research 5 Research centers Department of general affairs

3 Educational Facilities Research Center Established in 2004 The latest research center in NIER Objective Implementation of fundamental and special research on educational facilities Collection and analysis of information about educational facilities Recent major research themes Seismic retrofitting for existing school buildings Environmentally friendly renovation for existing school buildings Safety and crime prevention of school buildings Barrier free of school buildings

4 Reference Book on Seismic Retrofitting for School Building Seismic Retrofitting Quick Reference School Facilities that Withstand Earthquakes Examples of Seismic Retrofitting What are the types of seismic retrofitting? Structural slits Is value How much does seismic retrofitting cost? Installing seismic shear walls Published by MEXT in September 2006 Contents - Examples of school buildings damaged by recent major earthquakes - Background information of seismic retrofitting - 8 examples of retrofitted school buildings - Other 14 simple description of seismic retrofitting cases How long does it take to retrofit? Steel bracings Website: What effects does seismic retrofitting have? Ministry of Education, Culture, Sports, Science and Technology

5 Seismic Resistance Capacity Evaluation of Existing Buildings Is (Seismic Capacity Index of Structure) : an index that defines the seismic capacity of existing reinforced concrete buildings Is Eo S T Eo basic structural seismic capacity index calculated by the product of Strength index (C), Ductility index (F) and Story Index ( ) Eo= C F S : reduction factor to modify Eo index due to the difference in structural balance in plan and elevation T : reduction factor allowed for time-dependent deterioration grade Evaluation of seismic capacity by Is When a large scale earthquake occurs Is 0.3 There is high risk of collapsing 0.3 Is 0.6 There is risk of collapsing 0.6 Is There is low risk of collapsing

6

7 [BEFORE] Floor Plan of Model Case (Ground Floor) [AFTER SFB Steel Frame Brace Reinforced Concrete Wall SP Column Reinforcement by Steel Plate SP SP SFB SP SFB SFB SFB SFB SFB SFB

8 [SOUTH] Section of Model Case SFB SFB SFB SFB SFB SP [NORTH] SFB Steel Frame Brace Reinforced Concrete Wall SP Column Reinforcement by Steel Plate ( Is index increased from 0.44 to 0.74 )

9 Earthquake resistant Method (1) Steel Frame Brace A construction method to attach steel frame braces to columns and beams Steel frame braces can be installed outside or inside the building Work at the construction site is comparatively easy Users can utilize the building even under construction

10 Earthquake resistant Method (2) Reinforced Concrete Wall A construction method to add reinforced concrete walls inside the building Construction period is comparatively longer Ventilation and lighting might be disturbed Construction cost is comparatively lower

11 Earthquake resistant Method (3) Column Reinforcement by Steel Plate or Carbon Fiber A construction method to attach steel plate or carbon fiber to columns Construction cost is comparatively higher Ventilation and lighting are not disturbed

12 Earthquake resistant Method (4) Out Frame A construction method to add reinforced components outside the building Ventilation and lighting are less-disturbed Construction inside the building is unnecessary Construction cost is comparatively higher

13 S lower secondary school (Shizuoka Pref.) 3,600 sqm / 4 stories SFB(outside) "Is" About 150 million yen About 41,100yen/sqm (only seismic retrofitting)

14 S elementary school (Chiba Pref.) 2,900 sqm / 4 stories SFB(outside) + "Is" About 455 million yen About 155,000yen/sqm (with improvement in quality)

15 T upper secondary school (Niigata Pref.) 3,200 sqm / 3 stories SFB(inner side) + "Is" About 174 million yen About 54,300yen/sqm (only seismic retrofitting)

16 S elementary school gymnasium (Tokyo) 610 sqm Addition of steel braces "Is" About 14 million yen About 22,000yen/sqm (only seismic retrofitting)

17 Reference Book on Non-structural Seismic Retrofitting for School Building - Published by NIER in December (NIER: National Institute for Educational Policy Research) Non-structural members can cause significant harm to children and others when a large earthquake occurs - Ceiling material, equipment and various fixtures can fall or topple - 19 case studies of non-structural members 1. Ceiling material 2. Window and windowpane 3. Exterior wall and siding 4. Lighting fixture 5. Outdoor unit (air conditioner and heating unit) 6. Elevated water tank and cooling tower 7. Chimney 8. Refrigerator 9. Bookshelf and locker 10. TV and computer 11. Piano 12. Machine tool 13. Storage shelves in special classes 14. Gymnasium equipment and facility 15. Shoe locker 16. Wall and gate post 17. External staircase and surroundings 18. Retaining wall 19. Others Website:

18 Ceiling Material Damage Falling ceiling materials at a special classroom Chuetsu Earthquake, Niigata Pref. - Fallen auditorium ceiling Hokkaido Southwest Offshore Earthquake Walls and columns Retrofitting Tie brace Provide space (gap) Daily inspection Confirm that tie braces are installed Confirm that intervals between hanging bolts are sufficient, and the bolts are tightened. Confirm that ceiling boards are not moved, cracked or deformed, and fasteners are not loosened or rusted. Retrofitting Provide sufficient space between ceiling materials and wall or column. When hanging bolts are long ( 1500 mm) due to the wide space between the roof and the ceiling, horizontal and diagonal tie braces should be installed to prevent the ceiling from moving.

19 Lightning Fixture Damage Retrofitting Fallen 2004 lighting Chuetsu fixture Earthquake, (chain pendant Niigata type) Daily inspection Confirm that lamp brackets and shades are not loose. Confirm that there is no rust or deterioration on brackets and shades. Hanging bolts 2004 Chuetsu Earthquake, Niigata Fallen lighting fixture (pipe hung type) Confirm that sway preventative braces are installed Fluorescent lamp Sway preventative braces Retrofitting Install modified hooks on brackets. Cover lamp chains with plastic tubes. Install sway preventative braces. Fix electrical raceways to columns or walls. Stainless steel wire Example of sway preventative brace

20 Bookshelf and Locker Damage Retrofitting 2004 Chuetsu Earthquake, Niigata Overturned bookshelves and lockers 2004 Chuetsu Earthquake, Niigata Fix and secure bookshelves and lockers Fix bookshelves and lockers to sturdy wall, beam or ceiling with metal brackets. Interconnect the tops among tall or shallow bookshelves. Fix stacked bookshelves or lockers at the base or the joint. Install a latch at the front opening door of the bookshelf or locker Chuetsu Earthquake, Niigata

21 Window and windowpane Damage Damaged windowpane hit by braces. Buckled bracing members stuck out in lateral direction and hit the windowpane. Other Damages - Damages attributed to the windowpane installation method - Damages caused by derailed windows and doors Retrofitting 1993 Hokkaido Southwest Offshore earthquake Prevent windowpanes from falling Apply anti-shattering film on sheet glasses to prevent them from shattering and falling. Confirm the loosening of windows. Adjust fixtures if necessary 2004 Chuetsu Earthquake Niigata Pref. Secure deformation of window members Stop using hard sealants to fix sheet glass to the window frame. Install windowpanes in accordance to the current design provision. Use bracing connections that prevent buckling of tie braces in lateral direction (Right photo).

22 Exterior Sidings (Concrete Block and ALC Walls) Damage Collapsed concrete block sidings Collapsed ALC and precast panel sidings 1995 South Hyogo Prefecture Earthquake Retrofitting 2005 Fukuoka Prefecture West Offshore Earthquake Internal view of the roof directly hit by collapsed block sidings Chuetsu Earthquake, Niigata Collapsed concrete block sidings Daily inspection Confirm that exterior sidings have not decayed such as loosening, uplifting, spalling or cracking Confirm that the shape and dimensions of fasteners are appropriate Prevent sidings from falling Repair spalling and cracked sidings by injecting resin Replace fasteners Reinforce or refurbish with other building methods

23 Piano Damage 2004 Mid-Niigata Prefecture Earthquake Retrofitting Grand piano The wheel restrainer was effective in restraining horizontal movement. Deeper seismic restrainers are more effective. Install a support frame to prevent the grand piano from overturning. Skidded grand piano Roller wheel Rubber seismic restrainer Upright piano Set upright pianos against the wall. Fix the piano on a board to prevent overturning.

24 Thank you for your attention!