Slides for discussionSOPAC/UCSD/UA

From Press Release Inertial Force-Limiting Floor Anchorage Systems for Seismic Resistant Building Structures UA/UCSD

Objectives

• Phase1: new friction dampers between walls and floors, expect lower accelerations (force) but larger displacement with increasing intensity

• Phase2: traditional wall-floor PSA connections, expect higher accelerations, more out of plane motion

• Question – if energy is dissipated in displacement, why doesn’t Phase1 have higher displacement than Phase2

Displacement comparison BE05 MCE

• Berkeley Design Basis Earthquake : • M6.9 1989 Loma Prieta earthquake recording at Los Gatos Presentation Center station• Distance: 4 km from fault• Actual recorded motion: 0.97g PGA

• For this experiment, scaled to 0.61g • (Value for Berkeley from PSHA map, expected acceleration level at 2% probability)• Design Basis Earthquake motions are MCE scaled by 1/1.5• Period scaled by 1/sqrt(2) for 1/4 scale building

RFNW Berkeley MCE Event (1.5xDBE)Phase1- New IFLFA vs Phase2- traditional PSA

Peak displacement is similar

Out-of-plane displacements are much larger for traditional PSA (bigger than EW!)

Displacement comparison BE05 DBE

• Berkeley Design Basis Earthquake : • M6.9 1989 Loma Prieta earthquake recording at Los Gatos Presentation Center station• Distance: 4 km from fault• Actual recorded motion: 0.97g PGA

• For this experiment, scaled to 0.61g • (Value for Berkeley from PSHA map, expected acceleration level at 2% probability)• Design Basis Earthquake motions are MCE scaled by 1/1.5• Period scaled by 1/sqrt(2) for 1/4 scale building

RFNW Berkeley DBE EventPhase1- New IFLFA vs Phase2- traditional PSA

East

North

IFLFA damped after 7 s

Peak displacement is smaller for IFLFA

Out-of-plane Displacements are much larger for traditional PSA

Why 7 sec? Why isn’t peak displacement smaller for DBE or MCE?

RFNW Berkeley DBE EventPhase1-IFLFA vs Phase2- traditional PSA (EAST)

Integrated accelerations are significantly out of phase

Integrated accelerations give different answer than GPS, because of rotation

RFNW Berkeley DBE EventPhase1-IFLFA vs Phase2- traditional PSA (North)

Integrated accelerations are significantly out of phase

Integrated accelerations give different answer than GPS, because of rotation

Plans

• Plot displacement comparisons for other pairs• Calculate drift using GPS displacement at roof minus

integrated acceleration (?) at base• Plot drift as a function of acceleration • Look at rotation

Phase1 roof displacement (not drift)

Phase2 roof displacement (not drift)

Rotations

• Much more out of plane motion and greater rotation for Phase 2 traditional PSA

Phase 2 traditional PSA connections

Phase 1 new IFLFA connections

Earthquake ground motions

• Seattle Maximum Considered Earthquake: • Moderate Intensity • 1979 Imperial Valley earthquake record• M6.6• 0.36 g PGA • El Centro Array #5 station• Distance: 28 km from fault• Scaled to 0.59g• Period scaled by 1/sqrt(2) for 1/4 scale building• Design Basis Earthquake motions scaled by 1/1.5

• Berkeley Maximum Considered Earthquake: • High intensity • 1989 Loma Prieta earthquake recording• M6.9• 0.97g PGA • Los Gatos Presentation Center station• Distance: 4 km from fault• Scaled to 0.61g• Period scaled by 1/sqrt(2) for 1/4 scale building• Design Basis Earthquake motions scaled by 1/1.5

Source: SOPAC

NEES/UCSD LHPOSTInertial Force Limiting Anchorage

System Experiments (December 2013 – January 2014)

Four-Story Building

Base Station

Middle of Building Roof – Site MIDG

SIO MEMS Accelerometer

Trimble NETR9

Site MIDG

LHPOST: Large High Performance Outdoor Shake Table