Annex A: actions on tent structures A.1 Backgroun ollowing te ublication o Guiance on certiication scemes an management o construction rojects or ortable tents an structures, August 014, iscussions wit te arties involve ave sown tat tere is a nee or clariying te guiance wit resect to te saety o te structures in question. In aition, a nee as been ientiie or seciying more recise win actions tat inclue te eect o te comliance o structures wen etermining te caracteristic values, wic is an issue tat te resent rovisions o te Eurocoe o not eal wit consistently. Te esign is base on te Eurocoe system, incluing te saety rovisions given in EN 1990 an te Eurocoe on win actions, EN 1991-1-4, an teir National Annexes. Te ollowing clauses eal wit te etermination o te overall win actions on tents an te associate saety an win loa actors, an rovie a roosal or a ocumentation ormat. A. actions Te overall esign win orce, w, acting on te structure is etermine using te exression, see te Eurocoe: w, q c c c s A re were is te orce artial actor, q is te eak velocity ressure, c is te orce coeicient, c sc is te structural actor, an A re is te reerence area o te structure. Te eak velocity ressure is taken as q q c, 0 season were q, 0 is te eak velocity ressure witout te season variation, an c season is te seasonal actor. Te orce coeicient, c, is taken as c c e, 10 c i were 10 e, c is te external ressure coeicient or loae areas o 10 m an i c is te internal ressure coeicient.
A.3 Loa classes Te calculation o te structure can be base on loa classes. Table A.3.1 illustrates te coice o eak evacuation sees, seasonal actors an artial actors or te 5 loa classes. In te table, te secon row rom te bottom escribes te basis o te calculation o te eak velocity ressure. Loa class 1 covers normal saety an loaing; loa class covers normal saety or a structure set u uring te erio rom May to Setember. Te eak velocity ressure eens in aition o te rougness o te surrouning terrain. Te Eurocoe ivies te terrain into 4 terrain categories, I-IV, see clause A.4. Table A.3.1 Loa classes an associate coeicients Peak evacuation see, v, [m/s] * evak Seasonal actor, c [-] season 1. All year No evacuation. May-Setember 3. Hurricane Evacuation is necessary 4. Violent storm 5. Storm - - 3,7 8,5 4,5 1,0 0,8 1,0 1,0 1,0 Partial actor, [-] 1,5 1,5 1, 1, 1, Peak velocity ressure q base on Evacuation requency Return erio o 50 years Return erio o 50 years - - v, evak v, evak v, evak Arox. once every 10 years Arox. once every year * base on an agricultural country corresoning to terrain category II accoring to te Eurocoe an at a eigt o 10 m. Several times every year Were loa classes 3 to 5 are alie, monitoring o win conitions by means o weater reorts an/or an anemometer will be necessary. Monitoring is combine wit an emergency evacuation lan. I te weater reort reicts tat te ermissible win orce will be exceee, te tent sall be evacuate an constructive measures sall be taken to ensure tat te tent oes not resent a anger to te surrounings. Examles o constructive measures inclue reucing win actions: oening o te sies o te tent; increasing te strengt: aition o extra guy lines an imrovement o tent ancorages. Wit resect to te items seciie above, it is necessary to ientiy wo is resonsible or monitoring, evacuation an constructive measures. Te measures sall be escribe in etail in te ocumentation o te structure an te ocumentation intene or te user.
A.4 Terrain categories Extracts rom Eurocoe 1 Te value o te eak velocity ressure, q, eens on te rougness o te surrouning terrain, see te Eurocoe. Te terrain rougness is consiere by assigning te area were te structure is set u to terrain categories I to IV. A escrition o te 4 ierent terrain categories is given below. Descrition Terrain category I Lakes or lat an orizontal area wit negligible vegetation an witout obstacles. Illustration Terrain category II Area wit low vegetation suc as grass an isolate obstacles (trees, builings) wit searations o at least 0 obstacle eigts. Terrain category III Area wit regular cover o vegetation or builings or wit isolate obstacles wit searations o maximum 0 obstacle eigts (suc as villages, suburban terrain, ermanent orest). Terrain category IV Area in wic at least 15 % o te surace is covere wit builings an teir average eigt excees 15 m. 3
A.5 Peak velocity ressure Te eak velocity ressure eens on te terrain category an te reerence eigt, see Eurocoe 1. Te eak velocity ressure may be ivie accoring to loa classes, see Table A.5.1 or te reerence eigt z = 10 m. Table A.5.1 Peak velocity ressure, Terrain categor y No evacuation 1. All year. May- Setember q [kn/m ], at a eigt o 10 m 3. Hurricane Evacuation is necessary 4. Violent storm 5. Storm I 1,00 0,80 0,79 0,60 0,44 II 0,85 0,68 0,67 0,51 0,38 III 0,6 0,49 0,49 0,37 0,7 IV 0,4 0,34 0,33 0,5 0,19 or oter reerence eigts tan z = 10 m, te eak velocity ressure is multilie by te actor erive rom igure A.5.1 or te seciic terrain category in Eurocoe 1. Te igest oint o te tent is tyically taken as te reerence eigt. igure A.5.1 Correction actor eening on te reerence eigt, z, an te terrain category 4
A.6 orce coeicients Extracts rom Eurocoe 1 Te orce coeicients given in tis clause are base on Eurocoe 1. acting on acaes Te orce coeicient is base on rectangular lan structures. Plan e = b or, wicever is smaller b: crosswin imension Elevation or e D E b A B C e e/5 4/5e -e Elevation A B C Elevation or e Elevation or e 5 A B A e/5 -e/5 A B A Table A.6.1 Recommene values o external ressure coeicients, c e, 10 [-], or vertical acaes o rectangular lan structures Zone / A B C D E 5-1, -0,8-0,5 +0,8-0,7 1-1, -0,8-0,5 +0,8-0,5 0,5-1, -0,8-0,5 +0,7-0,3 5
acting on uoitc roos θ = 0 e/4 Uwin ace Downwin ace Pitc angle ositive θ = 0 α 0 Uwin ace Vin α α Downwin ace G H J I b e = b or, wicever is smaller b: crosswin imension e/4 e/10 e/10 θ = 90 e/4 e/4 G G H H Rige I I b e/10 e/ 6
Table A.6. External ressure coeicient, c e, 10 [-], or uoitc roos Pitc angle Zone or = 0 Zone or = 90 5 15 30 45 G H I J G H I -1,7-1, -0,6-0,6 +0, +0,0 +0,0 +0,0-0,6-0,6-0,9-0,8-0,3-0,4-1,0 +0, +0, +0, +0,0 +0,0-0,5-0,5-0, -0,4-0,5 +0,7 +0,7 +0,4 +0,0 +0,0 +0,0 +0,0 +0,0-0, -0,3 +0,7 +0,7 +0,6 +0,0 +0,0-1,6-1,3-0,7-0,6-1,3-1,3-0,6-0,5-1,1-1,4-0,8-0,5-1,1-1,4-0,9-0,5 60 +0,7 +0,7 +0,7-0, -0,3-1,1-1, -0,8-0,5 75 +0,8 +0,8 +0,8-0, -0,3-1,1-1, -0,8-0,5 Linear interolation or intermeiate itc angles o te same sign may be use between values o te same sign. At = 0 te ressure canges raily between ositive an negative values on te winwar ace aroun a itc angle o α = +5 to + 45, so bot ositive an negative values are given. or tose roos, our cases soul be consiere were te largest or smallest values o all areas, G an H are combine wit te largest or smallest values in areas I an J. No mixing o ositive an negative values is allowe on te same ace. Te internal ressure coeicient, c i, is taken as te more onerous o +0, an -0,3, wen te structure oes not ave ominant oenings. A.7 Structural actor Te structural actor takes into account bot te loa reucing eect o te nonsimultaneous occurrence o te eak win ressures on te suraces o te structure an te vibrations o te structure. or te structures consiere, vibrations are not ecisive an in tis case te structural actor accounts rimarily or te eect o te non-simultaneous occurrence o te largest win ressures on te suraces o te structure an te eect o te comliance o te structure. Wen win loa on te winwar ace is combine wit tat on te leewar ace, te structural actor also takes into account te non-simultaneous occurrence o winwar ressures an leewar suction. Te non-simultaneous occurrence o winwar ressures an leewar suction contributes consierably to te loa reuction inclue in te structural actor. Te comliance o te structure will result in reuce eects o win. or te esign o rame structures an lit o te structure, te structural actor is unerestimate by not alying c sc = 0,80. 7
A.8 Proosal or a ocumentation ormat Te conclusion o te calculation o te tent may be base on veriication o te resistance were R E R is te esign resistance, an E is te loa eect wic inclues te win loa. Table A.8.1 seciies te conormity o te resistance o te tent wit te loa classes. Te colours inicate wen te esign resistance o te tent, R, is larger or smaller, resectively, tan te esign loa eect, E. Table A.8.1 Conclusion or certiication o te tent structure Terrain category No evacuation 1. All year. May- Setember 3. Hurricane Evacuation is necessary 4. Violent storm 5. Storm I R < E R < E R < E R < E R > E II R < E R < E R < E R > E R > E III R < E R < E R > E R > E R > E IV R < E R > E R > E R > E R > E Te loa eect may inclue secial esign situations, suc as rolle-u tent sies an irectional actors, but tis will not be a tyical situation. In aition to Table A.8.1 were te tent structure is arove, minimum values o te loa caacity or all tent ancorages to te groun are given. Te loa caacity can e.g. be given as te mass o ballast or te number, size an angle o groun ancors. Table A.8. contains an examle o te communication o minimum values o te ancorage loa caacities. Ancorages 1 N may inicate guy lines an rame legs. 1 may e.g. inicate all ancorages at rame legs at te corners o te tent structure. Te table may be sulemente by igures illustrating te ositions an tyes o ancorages. 8
Table A.8. Minimum loa caacities or ancorages accoring to te loa classes in Table A.8.1 or R > E Loa class 1. Terrain category 1 3 N I - - - - II - - - - III - - - - IV - - - - I - - - -. II - - - - III - - - - IV I - - - - 3. II - - - - III IV I - - - - 4. 5. II III IV I II III IV In aition to ocumentation in te orm o static calculations, it may contain guiance on setting u te tent an oter inormation. 9