sixteen seismic design Earthquake Design Earthquake Design Earthquake Design dynamic vs. static loading hazard types hazard types: ground shaking

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APPLIED ARCHITECTURAL STRUCTURES: STRUCTURAL

ANNE NICHOLS FALL 2017 lecture sixteen dynamic

affect time duration acceleration & velocity

Lecture 17 F2009abn Seismic Design 2 hazard

tsunamis (sea waves) hazard types: ground

1 APPLIED ARCHITECTURAL STRUCTURES: STRUCTURAL ANALYSIS AND SYSTEMS DR. ANNE NICHOLS FALL 2017 lecture sixteen dynamic vs. static loading amplification of static affect time duration acceleration & velocity seismic design Reuters 2004 Seismic Design 1 Lecture 17 F2009abn Seismic Design 2 hazard types surface fault ruptures ground failures tsunamis (sea waves) hazard types: ground shaking Seismic Design 3 Lecture 17 F2009abn Seismic Design 4 1

fundamental considerations building configuration symmetry with respect to mass stiffness or vibration control symmetry with respect to lateral resistance mechanisms member sizes, rigidity, braces,

2 fundamental considerations building configuration symmetry with respect to mass stiffness or vibration control symmetry with respect to lateral resistance mechanisms member sizes, rigidity, braces, dampers anchorage of parts and components seismic joints tie the building together building response Seismic Design 5 Seismic Design 6 building response seismic joints L, T, H shapes bad building response center of mass ex.: W x NS center of rigidity ex. (R = 1/ ): r E R x W NS torsion (eccentricity) y x R y Seismic Design 7 Seismic Design 8 F2008abn 2

Low-Rise Response lateral ground movement drift Frequency and Period natural period of vibration avoid resonance hard to predict seismic period affected by soil

accuracy to ensure a safe and economical building design National Earthquake Hazards Reduction Program (NEHRP) evaluate structural response (spectrum) to

3 Low-Rise Response lateral ground movement drift Frequency and Period natural period of vibration avoid resonance hard to predict seismic period affected by soil short period high stiffness long period low stiffness To ring the bell, the sexton must pull on the downswing of the bell in time with the natural frequency of the bell. Seismic Design 8 Seismic Design 9 codes purpose is to provide a simple uniform method of determining potential earthquake forces in any location with enough accuracy to ensure a safe and economical building design National Earthquake Hazards Reduction Program (NEHRP) evaluate structural response (spectrum) to earthquake (motion vs. time) Seismic Design 10 Loads derived from W & amplification factors at base of structure: Z, zone I, importance ( ) C, stiffness related to period of vibration R W, response modifications for building type (1.25 8) distribution per floor simple vs. tall - Seismic Design 11 W x h x Wh V ZICW R W 3

Loads (ASCE-7) at base of structure: S W, usually dead load but can include some live load C s, seismic design coefficient S C S DS D1 but not greater than S ( R / I )

factor T, building period S 1, mapped one-second spectral acceleration Seismic Design 13 V C W F2012abn Loads (ASCE-7) Seismic Design 14 F2012abn Earthquake-Resistant

concrete redundancy helpful use rigid diaphragms horizontal members fail before verticals Seismic Design 13 Lecture 17 http://nisee.berkeley.

4 Loads (ASCE-7) at base of structure: S W, usually dead load but can include some live load C s, seismic design coefficient S C S DS D1 but not greater than S ( R / I ) T( R / I ) S DS, short period design spectral response acceleration S D1, one second design spectral response acceleration R, response modification factor I, importance factor T, building period S 1, mapped one-second spectral acceleration Seismic Design 13 V C W F2012abn Loads (ASCE-7) Seismic Design 14 F2012abn Earthquake-Resistant Structures absorb energy input from ground motion pins can t, rigid frames can energy goes into forming plastic hinges (ductility) continuous steel, timber or reinforced concrete redundancy helpful use rigid diaphragms horizontal members fail before verticals Seismic Design 13 Lecture 17 F2009abn soft first stories problematic Seismic Design 13 ground level story weaker than those above usually higher reduced strength in vertical elements significantly increased mass above 4

5 want horizontal elements to fail before vertical elements do passive base isolation low stiffness layer between foundation and structure Seismic Design 14 Seismic Design 15 tuned mass damping systems dampers elastomer bearings neoprene or rubber sliding systems friction pendulum systems Seismic Design 16 Seismic Design 17 5

Sendai Mediatheque, Japan, 2011 Damage Levels FEMA Operational minimal or no damage to structure extremely low risk to

safety Wizneko 2011 Seismic Design 19 F2011abn Seismic Design 22 F2013abn Damage Levels FEMA (cont.

Collapse Prevention not suffered complete or partial collapse, may have severe internal damage to structure, likely

6 Sendai Mediatheque, Japan, 2011 Damage Levels FEMA Operational minimal or no damage to structure extremely low risk to life safety Immediate Occupancy minimal to no damage to structure, minor damage to non-structural, very low risk to life safety Wizneko 2011 Seismic Design 19 F2011abn Seismic Design 22 F2013abn Damage Levels FEMA (cont.) Life Safety may have extensive damage to structure, some repair may be economically impractical low risk to life safety Collapse Prevention not suffered complete or partial collapse, may have severe internal damage to structure, likely complete economic loss damage that poses risk to life safety Seismic Design 23 F2013abn Architectural Considerations Seismic Design 18 Video Buildings at Risk 6

SEISMIC DESIGN OF STRUCTURE

SEISMIC DESIGN OF STRUCTURE PART I TERMINOLOGY EXPLANATION Chapter 1 Earthquake Faults Epicenter Focal Depth Focus Focal Distance Epicenter Distance Tectonic Earthquake Volcanic Earthquake Collapse Earthquake