Analysis of construction sub-processes for the evaluation of the real performance of tower cranes

Con en om his wo k may be used unde he e ms o heC ea i eCommonsA ibu ion 3.0 licence. Any u he dis ibu ion o his wo k mus main ain a ibu ion o he au ho (s) and he i le o he wo k, jou nal ci a ion and DOI. Published unde licence by IOP Publishing L d WMCAUS 2021 IOP Con . Se ies: Ma e ials Science and Enginee ing 1203 (2021) 022132 IOP Publishing doi:10.1088/1757-899X/1203/2/022132 1 Analysis o cons uc ion sub-p ocesses o he e alua ion o he eal pe o mance o owe c anes Ros isla Doubek, Di a Hořínko á, Ma in Š ě ba, Radka Kan o á B no Uni e si y o Technology, Facul y o Ci il Enginee ing, Ins i u e o Technology, Mechaniza ion and Cons uc ion Managemen , Ve eří 331/95, 602 00 B no, Czech Republic doubek. @ ce. u b .cz Abs ac . The p oduc i i y o wo k pe o med a cons uc ion si es is p ima ily dependen on he e ec i e deploymen and use o cons uc ion machine y. Ne e heless, manu ac u e s do no s a e he ac ual pe o mance o hei machine y because i is di icul o de e mine due o i s dependence on he speci ic condi ions p esen a each cons uc ion si e. One o he mos impo an machines used in he cons uc ion o buildings is he owe c ane, which p o ides seconda y anspo o ma e ial onsi e. In o de o e alua e he e ec i eness o he use o such machines using a de e minis ic o s ochas ic app oach, a ela i ely ex ensi e and exac se o da a desc ibing he ac i i ies o a gi en owe c ane needs o be p epa ed. These da a desc ibe he eal equi emen s o ongoing cons uc ion sub-p ocesses wi h ega d o he u ilisa ion o owe c anes. This con ibu ion conce ns he analysis o key cons uc ion sub-p ocesses du ing he building o monoli hic ein o ced conc e e s uc u es in connec ion wi h seconda y anspo a he cons uc ion si e; in pa icula , i desc ibes he p epa a ion and p ocessing o his da a o he e alua ion o eal ime equi emen s placed on owe c anes. 1. In oduc ion Cu en mode n echnical cons uc ion p ocesses canno unc ion wi hou he pe o mance o de ailed planning and ca e ul p epa a ion be o e building p oduc ion commences. An impo an aspec o hese echnically- ocused p epa a o y ac i i ies is he c ea ion o a ime schedule, and he ela ed e ec i e deploymen o cons uc ion machine y. This has a di ec and signi ican e ec on he smoo hness and cou se o he en i e cons uc ion p ojec , and hus also he o e all inancial cos s o he unde aking. A numbe o app oaches ha e been de eloped ha design and op imise me hods and p ocedu es o he e ec i e use and deploymen o machine y in cons uc ion. The p oposals deal wi h he op imisa ion o he loca ion o cons uc ion machine y ( owe c anes in pa icula in he case o building cons uc ion), and also wi h he e ec i e deploymen o machine y in e ms o ime, pe o mance and hus also inancial cos s. In o de o be able o assess he wo k e iciency o cons uc ion machines and hei eal wo k pe o mance, i is no longe possible o ely solely on indica i e me hods and app oxima e indica o s. An example o he exis ing wo k dealing wi h his issue is he con ibu ion by Ch. Huang, Op imal Selec ion and Loca ion o Towe C ane o he Cons uc ion o P e ab ica ed Buildings wi h Di e en P e ab ica ion Ra ios. This s udy p esen s a me hod o he selec ion and op imisa ion o he placemen o a owe c ane in ela ion o he p e ab ica ion a io in o de o educe cos s and cons uc ion ime. The s udy WMCAUS 2021 IOP Con . Se ies: Ma e ials Science and Enginee ing 1203 (2021) 022132 IOP Publishing doi:10.1088/1757-899X/1203/2/022132 2 p oposes a model and algo i hm aimed a de e mining he scope o c ane deploymen based on he localiza ion ela ionship be ween he loca ion o he c ane and he sou ce and des ina ion o he p e ab ica ed load, as well as he p e ab ica ion a io. The p e ab ica ion a io P o a building is de ined as he a io o he weigh o he p e ab ica ed componen s in he conc e e s uc u e o he o al weigh o he building. O he inpu pa ame e s a e he li ing capaci y o he c ane and he weigh o he li ed load. The s udy also includes he calcula ion o c ane cos s and he calcula ion o load li ing ime [1]. In his a icle, au ho S. M. Biju desc ibes a newly de eloped applica ion, “C ane Loca o ”, which will make he p ocess o placing a c ane easie . The so wa e use de ines all o he objec s on he cons uc ion si e (posi ion, dimensions) and he maximum weigh o he li ed load. The ou pu om he applica ion is a posi ion o he c ane (a cons uc ion si e equipmen d awing), as well as he numbe , model and ype o c ane [2]. BIM echnology is also used when designing he e ec i e use o machines and hei localiza ion. In his pape , B. Daso ic p esen s he use o BIM o he op imum placemen o owe c anes and s o age su aces on cons uc ion si es. He desc ibes he me hod o expo ing he equi ed da a om he BIM and he me hod o impo ing i in o he op imisa ion model. The inpu pa ame e s o he op imisa ion model a e he coo dina es o ma e ial s o age a eas on he cons uc ion si e and he des ina ions o anspo ed ma e ials, he coo dina es o possible owe c ane posi ions, he numbe and ype o a ailable owe c anes, he coo dina es o he building and he pe ime e o he cons uc ion si e. The aim is o sho en he wo k cycle o he c ane and sa e on inancial cos s [3]. P o . J. Gašpa ík uses mo e de ailed inpu da a in he p oposed p ocedu e called he “me hod o op imizing he selec ion o machines”, which he applies when selec ing a se o machines. The basic inpu da a o selec ing he mos sui able se o machines a e he dimensions o he inal p oduc o he cons uc ion p ocess (e.g. cons uc ion pi s), he ype and class o soil, he o al olume o exca a ed soil, anspo dis ance, equi ed du a ion o wo k and ype o oad su ace. I desc ibes he design o he “Machine Selec ion” applica ion o he selec ion o a machine which was c ea ed o suppo he so wa e o he me hod desc ibed in his pape . The ou pu o he applica ion is a lis showing all he a ian s o se s o machines which a e capable o dealing wi h he ask wi hin he equi ed ime. The use o his applica ion will inc ease he e iciency o he selec ion o cons uc ion machine y in e ms o he key op imisa ion c i e ia: quali y, ime and ene gy consump ion [4]. In his wo k, K. Schabowicz deals wi h he de e mina ion o he p oduc i i y o cons uc ion machines and se s o ea hmo ing machines using an a i icial neu al ne wo k. Exca a o s and dump ucks a e conside ed as se s o machines he e. The inpu da a o he c ea ion o he neu al ne wo ks a e he echnical pa ame e s o he machines and hei pe o mance. These pa ame e s a e, o example, he loading ime o he uck, he capaci y o he exca a o bucke , he capaci y o he loading pla o m o he uck, e c. [5]. Ano he au ho who deals wi h op imisa ion calcula ions o he use o ea hmo ing machines is B. S. Kim. He has de eloped a me hod acco ding o which i is possible o selec di e en combina ions o machines wi h ega d o de ined c i e ia and he di e ence in hei signi icance. The inpu pa ame e s o he selec ion o a se o machines a e he cycle ime o each machine, he ypes o machines and hei ene gy consump ion, he olume o exca a ed and anspo ed soil, he ype o soil and he anspo dis ance. The me hod is demons a ed using a hypo he ical case s udy which p esen s he dependence o he impac s o cons uc ion on he en i onmen depending on he choice o machine y, cons uc ion ime and cos s [6]. P o . M. Kozlo ská om he Uni e si y o Technology in Košice deals wi h he compa ison o de e minis ic and s ochas ic app oaches o he speci ica ion o he echnical and ope a ional pe o mance WMCAUS 2021 IOP Con . Se ies: Ma e ials Science and Enginee ing 1203 (2021) 022132 IOP Publishing doi:10.1088/1757-899X/1203/2/022132 3 o cons uc ion machine y in he wo k New app oaches o speci ying pe o mance o cons uc ion machine y om 2015. To compa e he app oaches, a case s udy ocused on he p ocess o conc e ing using a owe c ane and a c ane bucke . The inpu pa ame e s a e he echnical pa ame e s o he used cons uc ion machines, anspo ed olumes o ma e ials and he anspo dis ance. The s udy concludes ha he s ochas ic app oach is mo e accu a e and be e e lec s eal condi ions on si e [7]. The exac assessmen o he pe o mance o cons uc ion owe c anes lies among he subjec s in es iga ed by B no Uni e si y o Technology s a . The esul s can be ound in, e.g. he wo k o M. Š ě ba, L. Klempa, J. Š as ný and V. Mo yčka [8, 9]. I conce ns a new app oach o he assessmen o he ime u ilisa ion o owe c anes using a simula ion model whose calcula ions a e based on de ailed inpu da a. The ini ial condi ions and inpu da a o he c ea ion o he model a e: a binding cons uc ion schedule, a modelled ime uni (e.g. one wo k shi ), he o al olume o wo k o he indi idual cons uc ion sub-p ocesses, concu encies be ween cons uc ion sub-p ocesses; c ane ype, he posi ion o ma e ial s o age si es and deposi ion si es in ela ion o he posi ion o he c ane, and he olume o wo k in he indi idual cons uc ion sub-p ocesses in he indi idual assessed wo k cycles. Based on he inpu da a, he designed so wa e will choose speci ic sui able ypes o c ane om he da abase and he equi ed numbe o hem o he speci ic cons uc ion condi ions and implemen a ion ime. The p oposed se s o machines will hen be compa ed om he economic and ecological poin o iew. The inpu da a a e: he loca ion o he cons uc ion si e, he shape and dimensions o he s uc u e o be buil , he shape and weigh o he li ed elemen s, he cha ac e o he cons uc ion si e, and he equi ed speed o cons uc ion. The so wa e also e alua es he op ions o anspo ing he c ane o he cons uc ion si e and he possible me hod o i s placemen and assembly a he si e. The aim is o achie e he as and e icien selec ion o li ing mechanisms o a speci ic cons uc ion si e, and also he compa ison and e alua ion o a ious al e na i es. The wo ks lis ed abo e a e examples o possible app oaches o he issue. They p o ide con i ma ion ha i is no longe possible o use app oxima e inpu da a o exac calcula ions when dealing wi h he e iciency o cons uc ion machines. I is gene ally ue ha a ious app oaches o he solu ion o his issue equi e he p epa a ion o ele an inpu da a, which a e a p e equisi e o exac ma hema ical modelling and enable he acquisi ion o esul s ha a e usable in eal-wo ld p ac ice. Such da a a e essen ial o he meaning ul assessmen o de e mina ion o he eal pe o mance o machines o se s o hem, and hei op imum use. I is clea ha a numbe o bounda y condi ions ela ed o he na u e o cons uc ion p ojec s a e in ol ed in he de e mina ion o he eal pe o mance o cons uc ion machines, and i is no always possible o cap u e all o hese ci cums ances exac ly in a model. Ne e heless, he quali y o he p epa a ion o he inpu da a o use in model calcula ions a ec s hese ou pu s signi ican ly. A e i s pa ag aph, o he pa ag aphs a e inden ed as you can see in his pa ag aph. A e In oduc ion, di ide you a icle in o clea ly de ined and numbe ed sec ions. 2. De ini ion o he in es iga ed ask This con ibu ion desc ibes he design o a p ocedu e o he p epa a ion o inpu da a o he exac assessmen o he eal pe o mance o cons uc ion machines and he e alua ion o he ime u iliza ion o machines du ing he execu ion o cons uc ion sub-p ocesses. Speci ically, i deals wi h he p epa a ion o inpu da a o he e alua ion o he eal pe o mance o owe c anes. The analysed inpu da a conce ns he cons uc ion o ein o ced conc e e mul i-s o ey buildings. Fi s , he ypical wo k cycle o he owe c ane is analysed, a e which he selec ed cons uc ion sub-p ocesses ha ha e a decisi e in luence on he cons uc ion p ocess a e also s udied. Thei analysis is pe o med wi h ega d o hei seconda y supply ole du ing cons uc ion. WMCAUS 2021 IOP Con . Se ies: Ma e ials Science and Enginee ing 1203 (2021) 022132 IOP Publishing doi:10.1088/1757-899X/1203/2/022132 4 In he nex pa o he pape , a p ocedu e o he expe imen al e i ica ion o he analysed da a in he con ex o execu ed cons uc ion p ojec s will be desc ibed, and he conclusions ha can be d awn om he esul s hi he o achie ed will be p esen ed. 3. Analysis o inpu da a o he e alua ion o he ime equi emen s o seconda y anspo using owe c anes Basic e ms and inpu da a. In o de o he inpu da a o be analysed, hey mus i s be iden i ied and de ined. The supply o building ma e ial on a cons uc ion si e mainly akes place in cycles. The moni o ed inpu da a o he s a ed pu poses a e hus alues exp essing he du a ions o p edominan ly cyclical cons uc ion sub-p ocesses, which a e di ided in o he du a ion o a c ane’s wo k cycle and he du a ion o wo k pe o med wi hou se ice om a c ane [10]. Buil s uc u es and hei elemen s a e c ea ed ia p oduc ion p ocesses. A cons uc ion sub-p ocess is a pa o he p oduc ion p ocess, ca ied ou by one wo k eam, and i s p oduc is a buil s uc u e [11]. The pe iod o one wo k cycle o a cons uc ion sub-p ocess is u he ma ked as T. I is composed o wo main ime alues, he pe iod o he wo k cycle o he c ane, c, and he pe iod when he se ice o he owe c ane is no equi ed, p. I can be w i en down as he ollowing equa ion: T = c+ p (1) The ime o one wo k cycle T is hus he ime in e al be ween he indi idual equi emen s o he e alua ed cons uc ion sub-p ocess o he supply o building ma e ial. The ypical wo k cycle o a owe c ane. C anes a e machines ha wo k in cycles. Gene ally, he wo k cycle o a c ane can be illus a ed as shown in he image below. Figu e 1. Wo k cycle o a owe c ane To de e mine he calcula ed du a ion o he c ane wo k cycle ( igu e 1), n ( igu e 2), he pe iod is di ided in o h ee pa s acco ding o he ollowing equa ion: n= j+ m+ a (2) n – calcula ed du a ion o he c ane wo k cycle, j – ime needed o anspo a uni quan i y o ma e ial, m – ime needed o hook up and disconnec he anspo ed ma e ial, a – c ane se ice ime. WMCAUS 2021 IOP Con . Se ies: Ma e ials Science and Enginee ing 1203 (2021) 022132 IOP Publishing doi:10.1088/1757-899X/1203/2/022132 5 Figu e 2. Diag am o he ime di ision o he owe c ane wo k cycle The alue o quan i y j is based on he ypical wo k cycle and can be de e mined on he basis o he echnical pa ame e s o he machine by, e.g. using he C i ical Pa h Me hod. The alue o quan i y m can be ob ained om he p o essional li e a u e, e.g. [12], and can hen be checked by moni o ing such ac i i ies a he cons uc ion si e. As ega ds alue a – c ane assis ance ime, i is no s a ed in he p o essional li e a u e a all, and had o be de e mined ia moni o ing a cons uc ion si es To de e mine he wo k cycle o a c ane, o he objec i e and subjec i e in luences on p oduc i i y should also be conside ed (e.g. wea he condi ions, he layou o he si e, he pe o mance and expe ience o he c ane ope a o , e c.) These in luences, which a e di icul o de e mine p ecisely, a e assessed in he li e a u e [12] and a e lis ed in he ollowing able (Table 1). Table 1. Examples o coe icien s o he in luences chosen cons uc ion sub-p ocesses ha e on p oduc i i y Cons uc ion sub-p ocess Value o p oduc i i y in luence coe icien ks Fo mwo k 1.2 Rein o cemen 1.1 Conc e ing – solid s uc u es 1.1 Conc e ing – hin-walled s uc u es 1.4 Fo mwo k emo al 1.2 A e aking in o accoun he men ioned in luences, he du a ion o he owe c ane wo k cycle o he moni o ed cons uc ion sub-p ocess can be exp essed by he ollowing equa ion (Eq. 3): c= n+ ks (3) c – du a ion o he c ane wo k cycle, n – calcula ed du a ion o he c ane wo k cycle, ks – coe icien o in luences on p oduc i i y. Analysis o selec ed cons uc ion sub-p ocesses. A cons uc ion sub-p ocess is composed o wo ime in e als: ime c ( he wo k cycle du a ion o he owe c ane) and ime p ( he ime when he uni quan i y o ma e ial is p ocessed wi hou equi ing se ice om he owe c ane); see Eq. 1. The de e mina ion o ime T can be based on he a ailable ime consump ion s anda ds o indi idual cons uc ion sub-p ocesses, o al e na i ely on a binding ime schedule o a speci ic cons uc ion p ojec . I is based on he idea (assump ion) ha he cons uc ion p ocess akes place WMCAUS 2021 IOP Con . Se ies: Ma e ials Science and Enginee ing 1203 (2021) 022132 IOP Publishing doi:10.1088/1757-899X/1203/2/022132 6 smoo hly, and ha acco ding o he binding cons uc ion schedule [13] he planned amoun o ma e ial needs o be eloca ed o he gi en cons uc ion sub-p ocess. The uni quan i y o ma e ial o be hois ed by he c ane in one wo k cycle is de e mined. I is hen possible o calcula e he numbe o wo k cycles o a cons uc ion sub-p ocess equi ed o he moni o ed ime in e al (e.g. o one wo k shi ) and hus also o one wo k cycle T. The inpu da a o he analysis o he indi idual cons uc ion sub-p ocesses hus include:  he amoun o ma e ial ans e ed du ing he e alua ed pe iod (e.g. one wo k shi ),  he uni quan i y o ma e ial mo ed by he owe c ane in one wo k cycle,  he numbe o wo k cycles in he e alua ed pe iod (e.g. one wo k shi ),  he ime T o one wo k cycle o he moni o ed cons uc ion sub-p ocess,  he ime c o which he se ice o a owe c ane is equi ed by he cons uc ion sub-p ocess du ing one wo k cycle,  he ime o which he cons uc ion sub-p ocess does no equi e he se ice o a owe c ane du ing one wo k cycle The decisi e cons uc ion sub-p ocesses o he execu ion o monoli hic ein o ced conc e e s uc u es we e analyzed in de ail in his way, and he abo e-men ioned inpu da a conce ning he in es iga ed ype o monoli hic s uc u e we e g adually calcula ed. These include he o mwo k used o e ical and ho izon al s uc u es, he ein o cemen and conc e ing o such s uc u es, o mwo k emo al and he laying o he mason y o load-bea ing and pe iphe al s uc u es [14]. 4. Expe imen al moni o ing o he wo k o owe c anes To e i y he analyzed inpu da a ob ained ia calcula ions, ex ensi e expe imen al moni o ing o he wo k o owe c anes was pe o med a selec ed cons uc ion si es. A b ie desc ip ion o he moni o ed s uc u es. The ypes o moni o ed s uc u es we e selec ed on he basis o hei s uc u al design, he layou o he cons uc ion si e and he wide su oundings o he si e, as well as accessibili y wi h ega ds o he ci ies o B no and B a isla a. Adminis a i e buildings, apa men buildings and combina ions o hese we e among he moni o ed monoli hic ein o ced conc e e s uc u es. Examples o he moni o ed s uc u es a e lis ed and b ie ly desc ibed below. An o ice building wi h en ed comme cial space ( igu e 3). One o he moni o ed examples is a building in he sou he n pa o B no, which is a densely popula ed pa o ha ci y. The building consis s o a basemen and eigh loo s. Figu e 3. The load-bea ing monoli hic ein o ced conc e e s uc u al sys em o he moni o ed s uc u e WMCAUS 2021 IOP Con . Se ies: Ma e ials Science and Enginee ing 1203 (2021) 022132 IOP Publishing doi:10.1088/1757-899X/1203/2/022132 7 The ounda ion o he building u ilises d illed piles and a base pla e. The load-bea ing s uc u e is a combina ion o monoli hic in e nal ein o ced conc e e columns, and in e nal and pe iphe al walls. I includes walls in he s ai co es and ele a o sha s. The monoli hic ein o ced conc e e ceiling slabs a e he same o all loo s. The monoli hic ein o ced conc e e co es o he s ai case a e made up o monoli hic landings wi h p e ab ica ed ligh s. The moni o ed elemen s we e ein o ced conc e e columns on he 6 h loo and he ceiling on he 7 h loo . The deployed li ing machines ha handled hem we e Liebhe 81 K.1 and 71 K s a iona y owe c anes. Apa men buildings wi h en ed comme cial space ( igu e 4). The buildings a e pa o he densely popula ed no he n sec o o he ci y o B no. They all ha e a basemen and ou loo s. Figu e 4. Cons uc ion o he moni o ed apa men building 5. Design o he me hods and ools o be used o expe imen al moni o ing [15] Fo p ac ical easons, he expe imen al measu emen s (moni o ing) we e aken di ec ly a he cons uc ion si e wi h he aid o a eco ding de ice. Because he p ocedu es o he acquisi ion (and adminis a ion) o da a ob ained du ing he moni o ing had o be epea ed, i was necessa y o design a se o da a measu emen and adminis a ion me hods which includes p ocedu es o be pe o med in ch onological o de as well as he necessa y equipmen o wo k wi h he eco ded da a. Desc ip ion o he me hods: 1) De e mina ion o he in es iga ed esea ch plan – The echnical pe o mance o li ing mechanisms in cons uc ion p ocesses. 2) Acquisi ion o ha dwa e ( ime-lapse came as wi h he equi ed accesso ies, speci ically memo y ca ds, echa geable ba e ies, ipod, PC) and so wa e (ope a ing sys em, media playe , cloud se ice). The speci ic de ice used, which is designed o eco d da a o he execu ion o ield and adminis a i e p oceedings is:  B inno ime-lapse came a ( igu e 5), model TLC 200, wi h a p o ec i e co e and a clamping b acke , WMCAUS 2021 IOP Con . Se ies: Ma e ials Science and Enginee ing 1203 (2021) 022132 IOP Publishing doi:10.1088/1757-899X/1203/2/022132 8 Figu e 5. B inno TLC 200 ime-lapse came a se Figu e 6. The de ice moun ed on a ipod and a clamping b acke  SD memo y ca d, max. 32 GB, 2 pcs. The e is always one in he came a, while da a is s o ed in he second one,  ba e y cha ge and echa geable AA ba e ies, 2 x 4 pcs. The e is always one se in he came a while he o he is emo ed o echa ging,  a ipod, clamping b acke o auxilia y s uc u e o be a ached a he cons uc ion si e ( igu e 6),  a PC wi h an in e ne connec ion, so wa e o playing he eco dings (e.g. VLC Playe ) and a cloud en i onmen , e.g. he Mic oso OneD i e pla o m. 3) De e mine a sui able objec o moni o ing, i.e. a s uc u e ha is o monoli hic ein o ced conc e e cons uc ion and p ima ily composed o load-bea ing elemen s: ceilings, walls, columns. The building mus consis o a leas 4 loo s (1 basemen and 3 abo e-g ound loo s), as in ha case he use o a owe c ane can be assumed. 4) An ag eemen on coope a ion mus be eached wi h he cons uc ion con ac o (o builde ) conce ning hei pe mission o he esea ch o ake place, and he a angemen o he ield moni o ing o he c ane on he cons uc ion si e. WMCAUS 2021 IOP Con . Se ies: Ma e ials Science and Enginee ing 1203 (2021) 022132 IOP Publishing doi:10.1088/1757-899X/1203/2/022132 9 5) I is necessa y o de e mine a sui able posi ion o mo e han one posi ion on a si e o he moni o ing o he ac i i y o he owe c ane and he wo ke s a he place o wo k (o mo e han one place o wo k) wi h ega d o he ele an cons uc ion sub-p ocesses ( o mwo k, ein o cemen , conc e ing, emo al o o mwo k) pe o med o he monoli hic ein o ced conc e e s uc u es o he building. The si e should be chosen in compliance wi h ce ain basic equi emen s:  when ope a ing he de ice, he e mus be no dange o he use alling om heigh , o being hi by alling objec s o anspo ed loads,  mo emen mus ake place only on ma ked and ag eed ou es, wi h he awa eness o he cons uc ion si e managemen ,  he in es iga o mus no endange o he pe sons o p ope y a he cons uc ion si e,  he si e mus be p epa ed in such a way ha he e is an unobs uc ed iew o he moni o ed wo kplace whe e he cons uc ion sub-p ocess ac i i y akes place and also a iew o he ele an moni o ed owe c ane,  choose he si e in such a way ha i is easy o access and he ime-lapse de ice is easy o con ol (changing he ba e ies and memo y ca d should be simple). P o iding he abo e p econdi ions a e me , he equipmen can be se up on sca olding, in an a ic, on a se o con aine s, e c. 6) The means o a achmen o he ime-lapse de ice depends on he abo e-men ioned condi ions. In an ideal case, adjacen buildings (exis ing o newly buil ones) should be used. I hey include lockable spaces (e.g. balconies) hen he de ice can be a ached o he ipod wi hou u he es ic ions (i no sca olding is ins alled on he si e). An al e na i e is o a ach he ipod wi h a chain o elemen s which a e i mly connec ed o he building and hen lock he de ice in a cage ( igu e 7). Figu e 7. Moni o ing de ice in a p o ec i e cage 7) The ope a o o he de ice ca ies ou inspec ions (ha dwa e unc ionali y), changes he memo y ca ds and ba e ies, and pe o ms he ans e o he moni o ing se o ano he loca ion i necessa y.