Structural Systems with Enhanced Seismic Resiliency Using High-Performance Materials Konstantinos A. Skalomenos Specially Appointed Assistant Professor, Kyoto University Masayoshi Nakashima President of Kobori Research Complex and Professor Emeritus of Kyoto University Kazuhiro Hayashi Assistant Professor, Toyohashi University of Technology Hiroyuki Inamasu Doctoral Assistant, Swiss Federal Institute of Technology PESDES 2017 Tongji University, Shanghai, China
Resilience 2 100% Function Reduce Vulnerability Damage Vulnerability Recovering time Disaster = + Time Prevention Robustness, Redundancy Earthquake-resistant systems Seismic Isolation, etc. Recovery Resourcefulness, Rapidity Reconstruction Decision-making, etc. Resilience = Prevention + Recovery Disaster Prevention Research Institute (DPRI), Kyoto University Feb. 21-22, 2017 PESDES, 12-15 Oct. 2017, Shanghai, China
Why seismic resilience 3 Earthquake is the deadliest natural disaster Earthquakes create great economic losses Konstantinos Skalomenos, Masayoshi Nakashima, Kazuhiro Hayashi, Hiroyuki Inamasu
Damage from Earthquakes 4 Disaster Prevention Research Institute (DPRI), Kyoto University Feb. 21-22, 2017 PESDES, 12-15 Oct. 2017, Shanghai, China
To Enhance Seismic Resilience 5 Operational Immediate Occupancy Life Safety Collapse Prevention Operational Extended Immediate Occupancy LS CP Structural systems that secure an extended Immediate Occupancy level would be a good choice in strengthening our seismic resiliency Structure can retain to its pre-earthquake situation, damages can be easily and economically repaired even under rare earthquakes Konstantinos Skalomenos, Masayoshi Nakashima, Kazuhiro Hayashi, Hiroyuki Inamasu
Self-centering Rocking Frames
To Enhance Seismic Resilience We need a structural system that offers: Quick Recovering Adequate Capacity to Absorb Seismic Energy Repairability Low-Cost Scenarios STRATEGY New High-performance materials Engineering technology 7 Disaster Prevention Research Institute (DPRI), Kyoto University Feb. 21-22, 2017 PESDES, 12-15 Oct. 2017, Shanghai, China
Self-Centering plus Rocking 8 Building tends to return on the initial situation by tension force High strength steel bar Uplifting reduces inter-story deformation Small deformation Uplift Tension force Self-centering Rocking Feb. 21-22, 2017 Konstantinos Skalomenos, Masayoshi Nakashima, Kazuhiro Hayashi, Hiroyuki Inamasu
Seismic Performance 9 Service Level Earthquake No uplift Design Base Earthquake Small uplift Small deformation Maximum Considered Earthquake Large uplift Small deformation Self weight Self weight Uplift Uplift Tension Disaster Prevention Research Institute (DPRI), Kyoto University Feb. 21-22, 2017 PESDES, 12-15 Oct. 2017, Shanghai, China
Energy dissipation 10 Ductile and replaceable steel fuses: Made of Low Yield steel (LY100) Well-distribution throughout the building Steel Fuses Konstantinos Skalomenos, Masayoshi Nakashima, Kazuhiro Hayashi, Hiroyuki Inamasu
Large Axial Force 11 F PTbar mg + F PTbar Concrete Hollow PT Bar Inner steel tube Disaster Prevention Research Institute (DPRI), Kyoto University Feb. 21-22, 2017 PESDES, 12-15 Oct. 2017, Shanghai, China
Two Quasi-static Tests 12 Double-skin CFT column Disaster Prevention Research Institute (DPRI), Kyoto University Self-centering frame Feb. 21-22, 2017 PESDES, 12-15 Oct. 2017, Shanghai, China
Self-Centering Frame 13 1000 Column Section 2400 (mm) 50 HS steel 150 Fixed Base Uplift Pre-tension force PC bar = 26mm Konstantinos Skalomenos, Masayoshi Nakashima, Kazuhiro Hayashi, Hiroyuki Inamasu
Self-Centering Frame 14 W Moment Drift Relationship Elastic region Moment PC bar yielding M A W yptbar PT y PT Uplifting Moment M FW uplift Frame drift w/o Energy Dissipation Pre-tension force F i i Disaster Prevention Research Institute (DPRI), Kyoto University Feb. 21-22, 2017 PESDES, 12-15 Oct. 2017, Shanghai, China
SC Frame with Dissipating Fuses MRF with SC composite frame 15 Fuse Fuse element Rotation Point T-shaped beam Fuse Connection MRF with Fuses Self-Centering Composite Frame Konstantinos Skalomenos, Masayoshi Nakashima, Kazuhiro Hayashi, Hiroyuki Inamasu
SC Frame with Dissipating Fuses MRF with SC composite frame 16 Fuse Moment PC bar yielding + Fuse strength MCE DBE Uplifting SLE Fuse yield point Frame drift MRF with Fuses Disaster Prevention Research Institute (DPRI), Kyoto University Self-Centering Composite Frame Feb. 21-22, 2017 PESDES, 12-15 Oct. 2017, Shanghai, China
SC Frame with Dissipating Fuses
Test Results Loops 18 Test Model (kn*m) (kn*m) (kn*m) Bar Yield Uplift (rad) (rad) Base Plate Base Plate Conventional Steel (kn*m) (kn*m) (kn*m) (rad) (rad) (rad) Stopper Stopper Low Yield No Pre-tension Pre-tension MRF-SC with fuses Disaster Prevention Research Institute (DPRI), Kyoto University Feb. 21-22, 2017 PESDES, 12-15 Oct. 2017, Shanghai, China
Test Results Loops 19 Test Model (kn*m) (kn*m) (kn*m) Bar Yield Uplift Satisfactory seismic performance (rad) (rad) Base Plate Base Plate Effective to reduce permanent deformation (kn*m) (kn*m) Conventional Steel (kn*m) Energy dissipation. Conventional (rad) fuses fractured at first floor in 1.5%. No fracture Stopper at LY steel fuses Stopper up to the end. (rad) Low Yield (rad) MRF-SC with fuses Konstantinos Skalomenos, Masayoshi Nakashima, Kazuhiro Hayashi, Hiroyuki Inamasu
Test Results Photos
Key Features 21 The large restoring forces and self-weight loads are directly transmitted to the strong and stiff double-skin HS CFT columns which remain elastic High performance materials, such as the HS and LY steel, improve the seismic performance of the proposed SC frame PC bars can be connected directly to pile foundations for transmitting the large tensile axial forces A uniform dissipation of seismic energy can be achieved for a better control of structural deformation Disaster Prevention Research Institute (DPRI), Kyoto University Feb. 21-22, 2017 PESDES, 12-15 Oct. 2017, Shanghai, China
Steel Braces
Conventional Steel Braces 23 Steel braces are often used as the main earthquake-resistant system, since they provide very large strength and stiffness in structures Disaster Prevention Research Institute (DPRI), Kyoto University Feb. 21-22, 2017 PESDES, 12-15 Oct. 2017, Shanghai, China
Conventional Steel Braces 24 Strength - Stiffness dependent design (i.e. larger base shear) Low post yielding stiffness Soft story failure mechanism High Stress/Strain concentration in the middle low ductility Low Post-yield Stiff. Initial Stiffness fracture Local buckling Uplifting force Konstantinos Skalomenos, Masayoshi Nakashima, Kazuhiro Hayashi, Hiroyuki Inamasu Rupture Brace Deformation
Proposed Brace New Concept: Intentional Eccentricity along the Brace length 25 Pin-ended member End plate Conventional Brace Load Steel tube Pin connections Eccentricity Disaster Prevention Research Institute (DPRI), Kyoto University Proposed one Feb. 21-22, 2017 PESDES, 12-15 Oct. 2017, Shanghai, China
Proposed Brace 26 New Concept: Intentional Eccentricity along the Brace length Pin-ended member End plate Without eccentricity With eccentricity Load Steel tube Pin connections Eccentricity BIE Konstantinos Skalomenos, Masayoshi Nakashima, Kazuhiro Hayashi, Hiroyuki Inamasu
Deformation mechanism of proposed brace In tension 27 Large + Section + N + = - M N+M Small Yield Fiber Fracture Fracture Eccentricity decreases Pure tension Plastic hinge Disaster Prevention Research Institute (DPRI), Kyoto University Axial load Pure tension Yield CBB BIE Axial deformation PESDES, 12-15 Oct. 2017, Shanghai, China
Deformation mechanism of proposed brace 28 In compression Large Section - - + = N M N+M + Small Axial deformation CBB BIE Yield Axial load Buckling Konstantinos Skalomenos, Masayoshi Nakashima, Kazuhiro Hayashi, Hiroyuki Inamasu
Strain distribution in each steel 29 Eccentric force Conventional Steel (CS) e ycs Pin CS Conventional Steel (CS) Section Strain distribution (N+M) CS Eccentric force + LYS/HSS Low yield steel (LYS) e yly e ycs e yhs Pin LYS High strength steel (HSS) Section Strain distribution (N+M) Disaster Prevention Research Institute (DPRI), Kyoto University HSS Feb. 21-22, 2017 PESDES, 12-15 Oct. 2017, Shanghai, China
Brace Configuration 30 1. Apply Intentional Eccentricity e 2. Use Advanced Steel Materials - Combination of Low-yield and High-strength Steels Low Yield Steel (LYS) High Strength Steel (HSS) Konstantinos Skalomenos, Masayoshi Nakashima, Kazuhiro Hayashi, Hiroyuki Inamasu LYS HSS e Eccentricity S t e e battens 30
Cyclic test 31 The Gusset Plate uniformly rotates as a pin Disaster Prevention Research Institute (DPRI), Kyoto University Feb. 21-22, 2017 PESDES, 12-15 Oct. 2017, Shanghai, China
Hysteretic behavior 32 32 Conventional Steel Brace Proposed Steel Brace Konstantinos Skalomenos, Masayoshi Nakashima, Kazuhiro Hayashi, Hiroyuki Inamasu
Hysteretic behavior 33 MCE DBE SLE CBFs New braced Frame Disaster Prevention Research Institute (DPRI), Kyoto University Feb. 21-22, 2017 PESDES, 12-15 Oct. 2017, Shanghai, China
Conclusions 34 1. A new brace member which overcomes some deficiencies of conventional steel braces is proposed. 2. The new brace offers independent design for strength and stiffness. 3. Large post-yielding stiffness is provided (~16% of the initial stiffness) and high ductility. 4. Both local buckling and fracture were delayed. These failures occurred at two times larger story drifts than those of conventional steel braces. Konstantinos Skalomenos, Masayoshi Nakashima, Kazuhiro Hayashi, Hiroyuki Inamasu
Mt. Fuji Thank you for your attention