Stefan Kaczmarczyk

Professor of Applied Mechanics

The Dynamic Behaviour ofLift Ropes and Components under Seismic Excitation

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Outline Introduction

LiftsInstallations tractionlifts

Seismicexcitation

Seismicdamagesinliftinstallationcomponents

Dynamicmodelsandsomeresults

Safetycodes/preventivemeasures

Introduction

Lift Engineering @NorthamptonResearch and Education programme: MSc/MPhil/PhD LiftSystemsEngineering SystemsDynamicsandVibration Control LiftTrafficAnalysis SafetyCodesandStandards

Openaccesspeerreviewedjournal

Annualliftandescalatorconference

BiannualSymposiumTheMechanicsofSlenderStructures

Lift installationsLifts:nonstructuralbuildingcomponents,themaintypes:

TractionDrive

HydraulicDrive

Rack&PinionDrive

Screwdrive

Pneaumatic drive

Traction lift

Suspension ropes

Machine/ drive unitHoistway with guide rails

Car/ sling assembly

compensating cables

Counterweight assembly

Buffers in the pit

Fx

Fx

Fx

FxFxFx

Fy

Fy

FyFy

Fy FkFkFk

Hoistway with guide rails

1999 Elevator World Inc.

Traction lift: ropingMachine room

Travelling cables

1:1 Reeving 2:1 Reeving1:1 Reeving 2:1 Reeving

Traction lift: safety gearRocking armoverspeed governor

Pivoted bob weightoverspeed governor

Cam typesafety gear

Captive rollerinstantaneoussafety gear

Progressivesafety gear

Governor tension weight

Rocking armoverspeed governor

Pivoted bob weightoverspeed governor

Cam typesafety gear

Captive rollerinstantaneoussafety gear

Progressivesafety gear

Governor tension weight

1999 Elevator World, Inc.

Governor rope

Governor rope

1852,ElishaOtis,thesafetyelevator

Seismic damage to lift installation Guiderailbrackets/anchorage

Bentguiderails

Rollerguidesbroken/loose

Counterweightsderailed/collidedwiththecars

Machineroomequipmentmoved/damaged

Suspensionropesdamaged/jumpedoutofthetractionsheave/diverterpulleys

Compensatingcablesdamaged/outoftheirgrooves

Travellingcablesbroken/hungup tangledinthehoistway

Rope dynamics / vibration

u, u, u

w, w, w v, v, v

Longitudinal Lateral Out-of-plane

Lateral in-plane

Tall buildings and structures: base excitation

x(t)

s(t)

m

Tall buildings and structures (3) Tallbuildings/towersswayatlowfrequencies. Anadversesituationariseswhenthebuildingstructureisexcitednearitsnaturalfundamentalfrequency.

Thebuildingswayisthemaincauseoflargemotionsofsuspension/compensatingropes.

Theyoccurduetolongperiodgroundmotions (e.g.MidNiigataPrefectureEarthquakein2004, GreatEastJapanEarthquakein2011).

Atbuildingsitesfarawayfromtheepicentreconventionalseismicdetectionsystems(switches)oftendonotregisterthelowacceleration/lowfrequency(below0.5Hz)longperiodgroundwaves.

Tall buildings and structures (5) Thegroundaccelerationatasitefarfromtheepicentremaynotbesufficientlyhightotriggerseismicdetectors.

However,theswayoftallbuildingsincreases,andelevatorropesresonatewiththebuildingmotion.

Lateralropevibrationmaythencauseentanglementintheelevatorshaftordamagetoshaftequipment.

Compensating sheave

Whirling motion

Frequency (Hz)0 0.5 1 1.5 2 2.5 3

0

0.02

0.04

0.06

0.08Freq. of the rope Lateral In-Plane (Model)

simulation modelx

(m)

x (m

)

expriment

Simulation model

M

L1

1x

2x

2u

1u1u

v2

ww1

Mcar

E1 A1m

E2 A2m

L3

w (t)w0

2

1

q M1

qM3comp

L4

Z0

MqM2

cwt

L2

ground

v (t)v 0

3x

x4

v1

ww2 z

r

Equations of motion developed for each section of the suspension and compensating system

Deterministic models and stochastic models

svsw

Simulationmodel:frequenciesvslength

1 20 34 0 36. Hz; . Hz

M

L1

Mcar

L3

comp

L4

Z0

Mcwt

L2

ground

Thenaturalfrequenciesoftheliftropesystemvarywiththelengthoftheropes.

Simulation model: animation

M

L1

1x

ww1

Mcar

w (t)w0

q M1

qM3comp

Z0

ground

v (t)v 0

v1z1

Simulation model: animation

M

L1

Mcar

L3

comp

L4

Z0

Mcwt

L2

ground

Codes and Standards / Technical Reports

ASME/ANSIA17.1CSAB44SafetyCodeforElevatorsandEscalators

SECTION8.4:elevatorsafetyrequirementsforseismicriskzone2orgreater

EN8177definesadditionalrequirementstoEN8120/50coveringliftsinseismicconditions

ISO/TR25741:2008providesacompilationofrelevantsafetystandardspertainingtoprotectionoftheuserandverticaltransportationequipmentduringseismicactivity.

ASMETRA17.18.42013GuideforElevatorSeismicDesign

Mitigating measures Optimizationofthesuspensionropeandcompensationrope,governorropetensionstoshifttheresonancefrequencyregions

Liftwell:protectionofsnagpoints Ropeguardstopreventropesjumpingfromthesheaves/pulleys Compensatingropesheavetiedown Seismicswitches/detectionsystems

Uponactivationofaseismicswitch,allelevatorswithtractionmachines,counterweights,andselective,collective,orgroupautomaticoperationthatareinmotionshallproceedtothenearestavailablefloor,opentheirdoors,andshutdown(A17.1).Allregisteredcarandlandingcallsshallbecancelled.Newcallsshallbeignored;Aliftinmotionshallreducethespeedorstopandproceedtothenextpossiblelandingawayfromthecounterweightorbalancingweightwithmaximum0.3m/scarspeed.(EN8177).

CounterweightdisplacementdetectorsWhenthecounterweightdisplacementswitchisactivated,theelevator,ifinmotion,shallinitiateanemergencystopandthenproceedawayfromthecounterweightataspeedofnotmorethan0.75m/s(150ft/min)tothenearestavailablefloor,openthedoors,andshutdown(A17.1).

Positionrestrainers tothecarandcounterweightframes Reinforcedguiderails

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THANK YOU

stefan.kaczmarczyk@northampton.ac.uk