The paper describes especially the typical behavior of two active spectators crowds involved in two substantially different sporting events, namely, ice hockey games and a biathlon world cup competition. In both cases, spectators behavior was observed together with grandstand structure dynamic response to their cheering activities. The experimental results obtained during both events were mutually compared and discussed whether the dynamic loading and its effects on the grandstand structures are similar for the two compared spectators crowds

Verner, Martin

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CTU Open Journal Systems (Czech Technical University, Prague / České vysoké učení technické v Praze)

doi:10.14311/APP.2020.26.0139Acta Polytechnica CTU Proceedings 26:139–143, 2020 © Czech Technical University in Prague, 2020available online at https://ojs.cvut.cz/ojs/index.php/appTHECOMPARISON OF TWO DIFFERENT SPORTING EVENTSBASEDONTHETYPICALBEHAVIOROFTHEACTIVESPECTATORSAND GRANDSTAND VIBRATIONS INDUCED BY THEMMartin VernerCzech Technical University in Prague, Faculty of Civil Engineering, Department of Mechanics, Thákurova 7,166 29 Prague 6, Czech Republiccorrespondence: martin.verner@fsv.cvut.czAbstract. The paper describes especially the typical behavior of two active spectators crowdsinvolved in two substantially different sporting events, namely, ice hockey games and a biathlon worldcup competition. In both cases, spectators behavior was observed together with grandstand structuredynamic response to their cheering activities. The experimental results obtained during both eventswere mutually compared and discussed whether the dynamic loading and its effects on the grandstandstructures are similar for the two compared spectators crowds.Keywords: Behavior of fans, grandstands, vibrations of grandstands.1. IntroductionHereinafter, the research of the dynamic response ofthe steel construction induced by audience of differentsport events is emphasized. Actual research, whichfollows the one focused on dynamic response of thetribune induced by football fans [1], is focused ontwo different winter sports – ice hockey and biathlon.Selection of these sports is not accidental. Ice hockeyis one of the most popular sport in Czech Republic.Biathlon was chosen because of the unique mountedconstruction which has been considered and the at-tendance of biathlon races which is still growing innumbers in Czech Republic. The goal of the observa-tion was to find out, if the behavior of the audienceis recurrent as well as their influence on the responseof the construction. For both sports the followingassumption is taken – audience does not induce con-struction by the jumping in contrast to football etc.,audience induces construction by the applause, hand-clapping.2. Measurement methodThe piezoelectric sensors Brüel&Kjær type 4507 B005were used for all the experiments. Pilsen, the four sen-sors were placed on the bottom flange of ice arena con-struction. Two sensors, No. 1 and 3, measured hori-zontal acceleration of the girders. Another two sensorsinstalled in the middle of the transverse girder/beam.Sensor No. 2 and No. 4 were used for measuring hori-zontal and vertical acceleration respectively see Fig 1.Number of the measurement sensors was limited tofour sensors by the character of the measurement link.Nine sensors were installed, two measurement linkswere applied (4 and 5 channel) in Nové Mvˇsto naMoravě. Acceleration in all directions measured onthree points of the construction, In accordance withexperiment in Pilsen. Two construction points, no.Figure 1. Location of sensors at the grandstands [2].1 and 3, were located on the stands of the steel con-struction and one point, No. 2, was located in themiddle of the plank span see Fig. 2.The behavior of the audience was recorder usingthe camera. The installation placement of the camerawas chosen in accordance to not to raise suspicionof the audience. The camera was installed on theopposite tribune nn Pilsen,. The camera was installedon the television tower left from construction in NovéMěsto na Moravě. The distance between camera andrecorded place was approximately 100 m in both cases.2.1. Description of construction2.2. Ice arena PilsenThe construction of the ice hockey stadium in Pilsenbegan in 1950. The overall reconstruction of thestadium took place including roof construction andstand reconstruction in 1969. Since 1969, amongother reconstructions, the building envelope has beenreplaced and the concrete construction rehabilitated.Construction of the stadium is made of reinforcedconcrete skeleton/frame see Fig.3.139Martin Verner Acta Polytechnica CTU ProceedingsFigure 2. Location of sensors at the grandstands andmeasuring axis sensors [3].Figure 3. Construction of the stands of the ice sta-dium.The main girders are fixed to the columns. The gird-ers support transverse panels of a L-shape. There is noevidence of any project documentation of the ice arena.Therefor the basic level of documentation – passportwas drawn up where the basic construction elementsare described including dimensions. Based on thepassport the whole construction is considered to be-come monolithic. The modal analysis was performedand the first measured eigenfrequency of the standwas 12.5 Hz (evaluated by the software MeScope).2.3. Biathlon stadium Nové Město naMoravěIn the biathlon stadium there is a permanent rein-forced concrete grandstand. Audience capacity of thestadium could be extended by the temporary steelstands. These steel stands are based on modularscaffold pieces, steel planks and poles and could bebuilt up to 14 m above ground. In accordance withsafety requirements the jumping on the steel stand isforbidden see Fig 4.Figure 4. Construction of prefabricated stands.There is no reliable mathematical model describingdynamic behavior of the jumping crowd based onthe information of the scaffold stand manufacturer.According to the only technical readout focused ondynamics of scaffold stands – British standard, theevaluation of the dynamic load has to be performed ifand only if the first eigenfrequency is smaller than 8 Hz.The modal analysis of the steel stand was performedand the first measured eigenfrequency of the standwas 3.0 Hz (evaluated by the software MEscope).2.4. Spectators behaviorSpectators behavior was assessed using the videorecording see Fig 5. Different types of behavior wererecognized on the record. The total time of each140vol. 26/2020 The Comparison of two different sporting eventsFigure 5. Position of the camera relative to the monitored area [4, 5].The type of spectatorbehaviourThe time duringfor the game [%]Static state 23.6Walking and running 5.5Jumping – all type -Bouncing 1.1Swaying 15.9Hand clapping – all types 51.3Goal scoring 2.6Mexican wave -Table 1. Behavior of fans HC Škoda Plzeň vs. HCKometa Brno (2.10.2015).The type of spectatorbehaviourThe time duringfor the game [%]Static state 23.6Walking and running 5.5Jumping – all type -Bouncing 1.1Swaying 15.9Hand clapping – all types 51.3Goal scoring 2.6Mexican wave -Table 2. Behavior of fans IBU NMN 2019 – WomenMass Start (18.12.2016).behavior type was added up through the whole record-ing.The seven behavior types were recognized duringthe hockey matches. Static state – spectators arestanding on the tribune without any other activity;Walking and running – recorded at the beginningand at the end of the match when spectators walkin and out of the stadium; Bouncing – bouncing ofknees when heels do not loose contact with the floor;Swaying – the spectators rock their bodies back andforth and to the sides; There were recognized 3 typesof Hand clapping – 1) normal applause, clapping handin front of the chest, 2) clapping hands over head,3) clapping hands move from the place in front ofthe chest above head, all of them are considered asone type behavior Hand clapping; Goal scoring andMexican wave (the sitting spectators are rising, onerow after another and wave their hands above theirheads) see at the Tab 1.The four behavior types were recognized duringbiathlon races see at the Tab 2. There are two typesexcluded. Jumping is forbidden on the biathlon com-petitions and therefore was not recognized. And sec-ond type – Goal scoring is excluded inherently. Theexperiment did not consider Mexican wave becausethis type of behavior took place during competitionbreaks when the crowd was not recorded.3. Response of standThe main part of the experiment was focused on thedynamic response of the stand. Fourier transforma-tion on the measured acceleration of different part ofthe stand was applied leading to excitation frequen-141Martin Verner Acta Polytechnica CTU Proceedingscies induced by spectators. Each type of behavior isrepresented by different excitation frequency. One cansee similarity in terms of excitation frequency for allthe types of behavior.4. SummaryTwo different sporting events, the ice hockey gamesand biathlon race, were compared mutually in thepaper. The described experiments proved our expec-tations based on previous observations [1, 2].The spectators behaved in similar way during bothcompared sport events. The two most used behav-ior types in the course of the ice hockey games werestatic state and hand clapping. The same two typeswere most often utilized by spectators also during thebiathlon race. Moreover, it is evident that fundamen-tal excitation frequencies for individual behavior typesare very similar for both compared events. It maybe remarked that the first natural frequency of thetemporary steel grandstand (3.0 Hz) is comparableto the basic excitation frequency (2.7 Hz) evaluatedduring the type of behavior – bouncing, see Fig. 9.On the other hand, the level of induced grandstandvibration was quite different. The highest vibrationlevel recorded on the temporary steel grandstand dur-ing the biathlon race was 1.2 m/s2 and It was sub-stantially higher in comparison to 0.18 m/s2 that wasregistered on the reinforce concrete grandstand in thecourse of the ice hockey games.-0,20-0,15-0,10-0,050,000,050,100,150,20240 242 244 246 248 250 252 254Time [s]Ac ce le rat i on [ m·s-2 ]0,00000,00050,00100,00150,00200,00250,00300,00350,00400 5 10 15 20 25 30 35Frequency [Hz]Ac ce le rat i on [ m·s-2 ]Figure 6. Ice-hockey, dynamic response of the stand- Hand-clapping [2].-0,30-0,20-0,100,000,100,200,30255 265 275 285 295 305 315Time [s]Ac ce le rat i on[ m·s-2 ]00,00050,0010,00150,0020,00250,0030,00350,0040,00450,0050 2,5 5 7,5 10 12,5 15 17,5 20 22,5 25 27,5 30 32,5 35Frequency [Hz]Ac ce le rat i on[ m·s-2 ]Figure 7. Ice-hockey, dynamic response of the stand- Scored goal [2].-2,50-2,00-1,50-1,00-0,500,000,501,001,502,002,50270 275 280 285 290 295 300Time [s]Ac ce le rat i on [ m.s-2 ]0,000,020,040,060,080,100,120,140,160,180,200 1 2 3 4 5 6 7 8 9 10Frequency [Hz]Ac ce le rat i on [ m.s-2 ]Figure 8. IBB, dynamic response of the stand –Hand-clapping after shoot [3].142vol. 26/2020 The Comparison of two different sporting events-1,00-0,80-0,60-0,40-0,200,000,200,400,600,801,00115 120 125 130 135 140 145 150 155 160 165Time [s]Ac ce le rat i on [ m.s-2 ]0,0000,0050,0100,0150,0200,0250 1 2 3 4 5 6 7 8 9 10Frequency [Hz]Ac ce le rat i on [ m.s-2 ]Figure 9. IBB, dynamic response of the stand –Bouncing – axes y [3].-0,15-0,10-0,050,000,050,10115 125 135 145 155 165Time [s]Ac ce le rat i on [ m.s-2 ]0,00000,00050,00100,00150,00200 1 2 3 4 5 6 7 8 9 10Frequency [Hz]Ac ce le rat i on [ m.s-2 ]Figure 10. IBB, dynamic response of the stand –Bouncing – axes z [3].AcknowledgementsThis paper has been supported by the Czech Science Foun-dation project No. GA15-15728S. and project of the Fac-ulty of Civil Engineering, Czech Technical University inPrague (SGS project No.16/201OHK1/3T/11).References[1] T. Plachy, M. Polak, M. Verner. An experimentalstudy focused on spectators’ behavior and inducedvibrations of a reinforced concrete grandstand on afootball stadium. Procedia Engineering Oxford: ElsevierLtd) pp. 2871–2876, 2017.[2] M. Polak, T. Plachy, M. Verner. An analysis of the fans’behavior during two ice hockey games and its influenceon the level of grandstand vibrations. 54th InternationalConference on Experimental Stress Analysis 2016 2016.[3] J. Hubka. Dynamic analysis of grandstand, 2017.Master\T1\textquoterightsThesis.[4] BMW-IBU-World-Cup-Biathlon-2020.https://www.ticketlive.cz/cs/event/biatlon-2020.[5] Z. stadion Plzeň.https://www.zimnistadionplzen.cz/arena/plan-haly/.143

THECOMPARISON OF TWO DIFFERENT SPORTING EVENTS BASEDONTHETYPICALBEHAVIOROFTHEACTIVE SPECTATORS AND GRANDSTAND VIBRATIONS INDUCED BY THEM

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THECOMPARISON OF TWO DIFFERENT SPORTING EVENTS BASEDONTHETYPICALBEHAVIOROFTHEACTIVE SPECTATORS AND GRANDSTAND VIBRATIONS INDUCED BY THEM

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