NEESR-SG: Controlled Rocking of Steel-Framed Buildings with Replaceable Energy Dissipating Fuses Greg Deierlein, Paul Cordova, Eric Borchers, Xiang Ma, Alex Pena, Sarah Billington, & Helmut Krawinkler, Stanford University Jerome Hajjar, Kerry Hall, Matt Eatherton, University of Illinois Mitsumasa Midorikawa, Hokkaido University David Mar, Tipping & Mar Associates and Greg Luth, GPLA

Shortcomings of Current Approaches Throw-away technology: Structure and Architecture absorbs energy through damage Large Inter-story Drifts: Result in architectural & structural damage High Accelerations: Result in content damage & loss of function Deformed Section – Eccentric Braced Frame

New System Shear Fuse Post-tensioning Develop a new structural building system that employs self-centering rocking action and replaceable* fuses to provide safe and cost effective earthquake resistance. *Key Concept – design for repair

Design Concept & Applications Enhanced alternative to conventional steel-braced frame RC wall systems 2. Retrofit of existing steel or RC frame buildings 3. Extensions to other building and structural systems

Rocking Design Parameters Design Variables PT: Post-tensioning force Vp: Fuse shear strength Dimensions A & B Vp Column Base Reactions R1 = PT - Vp R2 = PT + Vp Vp Overturning moment (& base shear) Mot = PT·(A) + Vp·(A+B) Limiting Values To ensure self-centering: PT > Vp·(1+B/A) To ensure dual rocking: PT > Vp PT Now I know you’ve been just itching for some equations, so it’s time to do little bit of math, but nothing too complicated. [click through equations and talk about them…] PT R1 R2 A B

Pretension/Brace System Fuse System Base Shear Drift a,f b c d e g PT Strength Frame Stiffness Fuse System Base Shear Drift a b c d e f g Fuse Strength Eff. Fuse Stiffness b c Origin-a – frame strain + small distortions in fuse a – frame lift off, elongation of PT b – fuse yield (+) c – load reversal d – zero force in fuse e – fuse yield (-) f – frame contact f-g – frame relaxation g – strain energy left in frame and fuse, small residual displacement Base Shear 2x Fuse Strength d a PT Strength e f PT – Fuse Strength g Drift Combined System

OpenSees Simulation Model

Cyclic Response DESIGN with R = 8.0 A B Global Behavior 4% shear strain cap A B PD Fuse Behavior DESIGN with R = 8.0 Vd = 0.125W PT = 1055kN, Vp,fuse = 1687kN br = 1.0 Pinching 50% residual

Maximum Interstory Drift vs. Sa(T1) 2.7% 2/50 Level Inelastic Time History Analyses: 20 EQ record pairs, scaled to increasing intensities Primary EDP: interstory drift structural limit states - column lift-off (rocking) fuse yielding/damage PT yielding 1.6% 10/50 Level PT Yielding Unscaled records The yellow squares represent the median, 16th and 84th percentile response.

Research Scope System Design Development Subassembly Frame/Fuse Tests - parametric design studies - shear panel fuse design and testing - building simulation studies Subassembly Frame/Fuse Tests - quasi-static cyclic loading - PT rocking frame details & response - panel/frame interaction - model calibration Shake Table System Tests - proof-of-concept - validation of simulation models Stanford NEES - Illinois E-Defense

Shear Fuse Testing - Stanford Attributes of Fuse high initial stiffness large strain capacity energy dissipation Candidate Fuse Designs ductile fiber cementitious composites steel panels with slits low-yield steel mixed sandwich panels damping devices Panel Size: 400 x 900 mm

Trial Steel Fuse Configurations thickness t h a L b B Rectangular Link Panel Butterfly Panel KEY PARAMETERS: Slit configuration b/t and L/t ratios Butterfly – b/a ratio Out of plane bracing

Trial Fuse Designs: Rectangular Slits #4 R56-10BR #3 R56-10 #4 R56-10BR

Subassembly Frame Tests (NEES-Illinois) Test Configuration 1/3 scale planar rocking frame with realistic details quasi-static System Response structural details & PT various fuse types indeterminate shear-fuse/frame interaction Simulation model validation NEES - Illinois

NEES-Illinois Subassembly Tests (1/2 scale) Front View Side View

Controlled Rocking System Replaceable energy dissipating fuses Post-tensioning strands Stiff braced frame (elastic) Pivoting collector beam connection Rocking base trough

ROCKING FRAME DETAILS Rocking Base Detail

SPECIMEN DETAILING – PT Top Anchor

Shake Table Validation Test (E-Defense) Large (2/3 scale) frame assembly Validation of dynamic response and simulation Proof-of-Concept construction details re-centering behavior fuse replacement Collaboration & Payload Projects

E-Defense “Testbed” Structure 2.7m Section – Testbed & Frame Plan View (Shake Table)

Rocking Braced Frame w/Post Tensioning Orinda City Offices Architect: Siegel and Strain Architects

Rack Storage Structure w/ protective rocking 次にトラス柱構造の地震応答解析について報告します。 解析の対象とするトラス柱構造を示します。用途はラック倉庫，高さ49.7m， 1次固有周期は2.73です。入力地震はHachinohe EW 50kineです。 ダンパー継ぎ手は静的解析をもとに中小地震に対し ダンパー継ぎ手のフランジが塑性化しないような位置へ配置しました。 Rocking Joint Height: 50 m Prof. Akira Wada - Japan

Innovation and Design Research Thematic Concept Life Cycle Design for Earthquake Effects damage control & design for repair Engineering Design Features controlled rocking & self-centering energy dissipating replaceable fuses Performance-Based Engineering Framework quantification of decision variables (losses, downtime) integration of hazard, response, damage, loss Development & Validation testing and analysis