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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