SEISMIC APPLICATION OF SUSTAINABLE FIBER MATERIAL UEDA Tamon Hokkaido - PowerPoint PPT Presentation

SEISMIC APPLICATION OF SUSTAINABLE FIBER MATERIAL UEDA Tamon Hokkaido University US ‐ Japan Workshop on Life Cycle Assessment for Sustainable Infrastructure Materials, 21 ‐ 22 October 2009, Sapporo 1

Sustainable Infrastructures Minimize the burden to • Natural environment – Lessing burden by making structure durable • Social environment – Financial burden, etc Maximize the benefit to • Natural environment • Social environment US ‐ Japan Workshop on Life Cycle Assessment for Sustainable Infrastructure Materials, 21 ‐ 22 October 2009, Sapporo 2

Sustainable Infrastructure Life Cycle Cost • Initial cost – Still main issue for financial department – Important for social discount rate US ‐ Japan Workshop on Life Cycle Assessment for Sustainable Infrastructure Materials, 21 ‐ 22 October 2009, Sapporo 3

FRP Disadvantage • High material cost � High initial cost US ‐ Japan Workshop on Life Cycle Assessment for Sustainable Infrastructure Materials, 21 ‐ 22 October 2009, Sapporo 4

Necessary Material Property • Strength/Stiffness or Deformability? • Property Necessary for Flexural and Shear Reinforcement of Concrete Structures US ‐ Japan Workshop on Life Cycle Assessment for Sustainable Infrastructure Materials, 21 ‐ 22 October 2009, Sapporo 5

Strength/Stiffness or Deformability? Strength/ stiffness �� Fracturing strain (High cost) �� (Low cost) High cost Carbon/Aramid Low cost high strength and Polyacetal stiffness Polyester high fracturing strain Fig.1 US ‐ Japan Workshop on Life Cycle Assessment for Sustainable Infrastructure Materials, 21 ‐ 22 October 2009, Sapporo 6

Strength/Stiffness or Deformability? Strength/stiffness can be replaced 200 MPa 2000 MPa equivalent strength with strength with 1000 mm 2 100 mm 2 cross section cross section Deformability cannot be replaced • Material with 10% deformability cannot be replaced by material with 1% deformability US ‐ Japan Workshop on Life Cycle Assessment for Sustainable Infrastructure Materials, 21 ‐ 22 October 2009, Sapporo 7

Strength/Stiffness or Deformability? Consequently High deformability could be a better option than high strength/stiffness US ‐ Japan Workshop on Life Cycle Assessment for Sustainable Infrastructure Materials, 21 ‐ 22 October 2009, Sapporo 8

Necessary Property for Member Strength ‐ Flexural Reinforcement ‐ • Case of other material (no yielding with a moderate fracturing strain) – Not only strength but also fracturing strain is required US ‐ Japan Workshop on Life Cycle Assessment for Sustainable Infrastructure Materials, 21 ‐ 22 October 2009, Sapporo 9

Necessary Property for Member Strength ‐ Flexural Reinforcement ‐ What is the strain at flexural strength? Strain compatibility and force equilibrium ⎛ ⎞ k x ′ = − ⎜ ⎟ 2 M bk xk f d fu , c 2 1 c ⎝ ⎠ 2 Stress distribution ( ) ′ ′ ′ ′ − ε + ε + ε 2 A E A E 4 k k b f A E d = s s cu s s cu 1 2 c s s cu x ′ k k b f 2 c 1 2 − Strain at flexural d x ′ ε = ε strength s cu Strain distribution x US ‐ Japan Workshop on Life Cycle Assessment for Sustainable Infrastructure Materials, 21 ‐ 22 October 2009, Sapporo 10

Necessary Property for Member Strength ‐ Flexural Reinforcement ‐ • Thus, fracturing strain ε tu should be greater than strain ε s at flexural strength − d x ′ ε > ε = ε tu s cu x ε s depends on reinforcement amount and concrete strength. US ‐ Japan Workshop on Life Cycle Assessment for Sustainable Infrastructure Materials, 21 ‐ 22 October 2009, Sapporo 11

Necessary Property for Member Strength ‐ Shear Reinforcement ‐ • Similarly, strain ε w of shear reinforcement at shear strength depends on (Sato et al 1997) – Stiffness of flexural reinforcement – Stiffness of shear reinforcement – Concrete strength Reinf’t. strain ε w Reinf’t. stiffness US ‐ Japan Workshop on Life Cycle Assessment for Sustainable Infrastructure Materials, 21 ‐ 22 October 2009, Sapporo 12

Necessary Property for Member Deformability ‐ Flexural Reinforcement ‐ • Steel is an excellent material – Yielding � energy dissipation – High fracturing strain (over 20%) � deformability US ‐ Japan Workshop on Life Cycle Assessment for Sustainable Infrastructure Materials, 21 ‐ 22 October 2009, Sapporo 13

Necessary Property for Member Deformability ‐ Shear Reinforcement ‐ • Shear reinforcement with a high fracturing strain and without yielding gives carbon, etc � Ductile shear failure Best! steel ε w • Examples of such material – Polyacetal Fiber (PAF) with 6-9% fracturing strain – Polyethylene Terephthalate (PET) with 13.8% fracturing strain US ‐ Japan Workshop on Life Cycle Assessment for Sustainable Infrastructure Materials, 21 ‐ 22 October 2009, Sapporo 14

Necessary Property for Member Deformability ‐ Shear Reinforcement ‐ • New design concept for shear – Shear failure is no longer brittle � Shear failure is can be treated as flexural failure (same safety factor) US ‐ Japan Workshop on Life Cycle Assessment for Sustainable Infrastructure Materials, 21 ‐ 22 October 2009, Sapporo 15

New Retrofit Method • To enhance deformability by shear reinforcement with high fracturing strain – A ‐ P Jacketing (Duplex jacketing) • Material with high deformability in hinge zone (PET) • Material with high stiffness in other zone (Aramid) US ‐ Japan Workshop on Life Cycle Assessment for Sustainable Infrastructure Materials, 21 ‐ 22 October 2009, Sapporo 16

New Retrofit Method • Enhancement of deformability and strength in shear Reference specimen Specimen with carbon Shear dominant case Flexure dominant case US ‐ Japan Workshop on Life Cycle Assessment for Sustainable Infrastructure Materials, 21 ‐ 22 October 2009, Sapporo 17

New Retrofit Method • PET shows good performance – Confining cover concrete – No fracturing I n a specimen we found a fracture of steel tie reinforcement but no fracture of PET sheet US ‐ Japan Workshop on Life Cycle Assessment for Sustainable Infrastructure Materials, 21 ‐ 22 October 2009, Sapporo 18

New Model for Ultimate Deformation ‐ Strength Model ‐ • Potential shear strength – Depending on stiffness of flexural and shear reinforcement stiffness – If it becomes less than flexural strength, it controls member strength Potential flexural strength dominant Potential shear strength dominant US ‐ Japan Workshop on Life Cycle Assessment for Sustainable Infrastructure Materials, 21 ‐ 22 October 2009, Sapporo 19

New Model for Ultimate Deformation ‐ Deformation Model ‐ • Shear deformation – Expanded version of model before flexural yielding (Ueda, et al 2004) – Truss deformation Deformation of compression and tension strut US ‐ Japan Workshop on Life Cycle Assessment for Sustainable Infrastructure Materials, 21 ‐ 22 October 2009, Sapporo 20

New Model for Ultimate Deformation ‐ Deformation Model ‐ • On ‐ going work – Flexural deformation model in hinge zone US ‐ Japan Workshop on Life Cycle Assessment for Sustainable Infrastructure Materials, 21 ‐ 22 October 2009, Sapporo 21

Cost Comparison and Practical Application • There are practical applications. – Seismic retrofit of railway viaduct JR Line at Shin ‐ Sapporo station Tobu Line JR Line at near Tokyo Osaka station US ‐ Japan Workshop on Life Cycle Assessment for Sustainable Infrastructure Materials, 21 ‐ 22 October 2009, Sapporo 22

Cost Comparison and Practical Application • Competitive to conventional fiber material ■ A&P Jacketing ■ Jacketing with Aramid Direct construction cost （ Yen/m 2 ) Direct construction cost （ Yen/m 2 ) Shear span to depth ratio, L a / D Shear span to depth ratio L a / D 800 × 800 mm section 1000 × 1000 mm section p t =0.86% p w =0.17% σ N =1.0MPa p t =1.00% p w =0.21% σ N =1.0MPa US ‐ Japan Workshop on Life Cycle Assessment for Sustainable Infrastructure Materials, 21 ‐ 22 October 2009, Sapporo 23

Concluding Remarks • Sustainable infrastructure materials should be durable so that life cycle cost of infrastructure would be less. • Many FRP materials have an advantage to steel due to the non ‐ corrosiveness. However, the high material cost of FRP prevents the practical application from being spread widely. • The new type of fiber materials, whose fracturing strain is high and cost is low, could be a good solution to reduce initial cost so as to reduce the barrier against FRP application. • Furthermore, the fiber with high fracturing strain can provide a better solution for obtaining good seismic performance of structures than conventional fiber materials and steel. US ‐ Japan Workshop on Life Cycle Assessment for Sustainable Infrastructure Materials, 21 ‐ 22 October 2009, Sapporo 24

ACKNOWLEDGEMENT • The author would like to show his sincere gratitude to Mr Hiroshi NAKAI of Maeda Kosen Co. Ltd. who kindly provided him the information on the cost and practical applications of seismic retrofit with PET fiber sheet. US ‐ Japan Workshop on Life Cycle Assessment for Sustainable Infrastructure Materials, 21 ‐ 22 October 2009, Sapporo 25