SDEE: Lecture 1

StructuralDynamics

& EarthquakeEngineering

Dr AlessandroPalmeri

Motivations forthis module

Introduction tothe module

Equations ofmotion forSDoFoscillators

Structural Dynamics& Earthquake Engineering

Lecture #1: Introduction

Dr Alessandro Palmeri

Civil and Building Engineering @ Loughborough University

Tuesday, 2nd February 2016

StructuralDynamics






Why bother about Structural Dynamics?

http://www.youtube.com/watch?v=uzdQer1gvsU

http://en.wikipedia.org/wiki/Tacoma_Narrows_Bridge_(1940)

The 1940 TacomaNarrows Bridge

It was a steel suspension bridgein the US state of Washington.Construction began in 1938, withthe opening on 1st July 1940From the time the deck was built,it began to move vertically inwindy conditions (constructionworkers nicknamed the bridgeGalloping Gertie).The motion was observed evenwhen the bridge opened to thepublic.Several measures to stop themotion were ineffective, and thebridge’s main span finallycollapsed under 64 km/h windconditions the morning of 7thNovember 1940.





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http://www.youtube.com/watch?v=eAXVa__XWZ8

http://en.wikipedia.org/wiki/Millennium_Bridge,_London

The Millennium Bridge

It is an iconic steel suspensionbridge for pedestrians crossingthe River Thames in London.Construction began in 1998, withthe opening on 10th June 2000.Londoners nicknamed the bridgethe Wobbly Bridge afterparticipants in a charity walk toopen the bridge felt anunexpected and uncomfortableswaying motion.The bridge was then closed foralmost two years whilemodifications were made toeliminate the wobble entirely.It was reopened in 2002.





StructuralDynamics







http://dx.doi.org/10.1063/1.2963929

http://www.enea.it/en/en/research-development/new-technologies/materials-technologies

Shaking Table Tests

The video shows the last,destructive shaking table testconducted in 2007 on a 1:2scale model of a masonrybuilding resembling a specialtype (the so-called Tipo MistoMessinese), which is proper tothe reconstruction of the city ofMessina after the 1783 Calabriaearthquake.The model, incorporating a noveltimber-concrete composite slab,has been tested on the mainshaking table available at theENEA Research CentreCasaccia in Rome, both beforeand after thereinforcement with FRP materials.

Colfiorito-DeCanio.avi

http://dx.doi.org/10.1063/1.2963929

http://dx.doi.org/10.1063/1.2963929





StructuralDynamics







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Aim of the Module

This module is aimed at:developing knowledge and understanding ofvibrational problems in structural engineeringand to provide the basic analytical and numerical toolsto assess the dynamic response of structureswith special emphasis on theseismic analysis and design to Eurocode 8

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Intended Learning Outcomes of the Module

On completion of the module you should be able to:Discuss the equations ruling the free and forcedvibration of single-degree-of-freedom (SDoF) oscillators... and multi-degree-of-freedom (MDoF) structuresIllustrate the role of damping and ductility in SDoF andMDoF systemsExploit the concepts of mode of vibration andRayleigh’s quotientCalculate the dynamic response of SDoF and MDoFsystems...

StructuralDynamics






Intended Learning Outcomes of the Module

... And also to:Interpret provisions of Eurocode 8Evaluate the seismic performance of frame structuresusing linear modelsCompare the behaviour of structures under static anddynamic loads.Critically assess advantages and disadvantages ofdifferent options for the analysis and design ofengineering systems under dynamic loads

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Module Description: Part 1

Dynamics of single-degree-of-freedom (SDoF) systems

Equations of motion for SDoF oscillatorsModelling and evaluation of damping in SDoFoscillatorsDynamic response of SDoF oscillators in both time andfrequency domains

StructuralDynamics







Dynamics of multi-degree-of-freedom (MDoF) systems

Equations of motion for MDoF structuresModal analysis and mode superposition methodClassically and non-classically damped MDoFstructuresDynamic response of MDoF structures in both time andfrequency domains

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Earthquake engineering

Engineering seismology (basics) and seismic action onstructuresElastic response spectrum and ductility-dependentdesign spectraLateral force methodResponse spectrum methodDesign options to improve the seismic performance ofexisting and new buildingsA look into the (near) future: performance-basedearthquake engineering (PBEE)

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Assessment of Module

2-hour examination (75% of the module)Section A (50% of the exam marks) on Parts 1 and 2

Solving 2 out of 3 questions (each one weighting 25%)Section B (50% of the exam marks) on Part 3

Solving 1 out of 2 questions (including somediscursive reasonings, NEW with respect to previousyears)

Coursework comprising an group written assignmentbased on Part 1 (25% of the module)

Issued in Week 4 (Tuesday 23rd February 2016)Handed in Week 9 (Monday 25th April 2016)Returned in Week 12

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Schedule of the Module

Lecture #1 Lecture #2 Tutorial

Week 1 Introduction Equation of motion for SDoFoscillators

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Week 2 Fourier analysis for structuraldynamics applications

Frequency response functionfor SDoF oscillators

Part 1

Week 3 State-space formulation forSDoF oscillators

Energy dissipation devices forvibration control

Part 1

Week 4 ? Equations of motion forundamped MDoF structures

Modal analysis Part 1

Week 5 Classically and non-classicallydamped MDoF structures

Newmark-β method Part 2

Week 6 State-space formulation forMDoF structures

4th-order Runge-Kutta method Part 2

Week 7 Basics of engineeringseismology

Strong motion characteristics Part 2

Easter break

Week 8 † Elastic response spectrum Ductility µ, behaviour factor qand design spectra

Part 3

Week 9 Lateral force method Part 3Week 10 Response spectrum method Part 3Week 11 Performance-based earthquake engineering Part 3Week 12 ‡ Revision —

? Coursework brief is issued in Week 4† Group report is handed in Week 9 (after Easter) – On Monday 25th April 2016‡ Feedback is given in Week 12 (before the Exams)

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Questions?

SDEE: Lecture 1

Education

Transcript of SDEE: Lecture 1