From version < 20.1 >
edited by IwonaBudny
on 2018/09/06 15:15
To version < 20.2 >
edited by IwonaBudny
on 2018/09/06 15:15
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273 273  
274 274  = **Summation of static and seismic effects** =
275 275  
276 +(% style="text-align: justify;" %)
277 +The seismic effect’s results can be considered together with static effects in two ways:
276 276  
279 +* seismic forces applied as real static forces in load cases,
280 +* the final results can be combined with a static load combination or taking into account in load groups.
281 +
277 277  == Seismic loads in static load cases ==
278 278  
284 +(((
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286 +Horizontal seismic forces and torsional effects which were calculated using the static method according to EC8 or NS3491-12 additionally can be added to the static load cases. However it is recommended to have the seismic forces in separate load case(s) in order not to mix up them with the normal static loads.
287 +
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289 +[[image:1536239563646-414.png||height="169" width="264"]]
290 +
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292 +In the static calculations, load cases which contain seismic forces behave like the other normal static forces. Consequently they can be inserted in load combinations and load groups. If they are inserted in the load combinations then they can take part in the imperfection and stability analysis. Of course there is no possibility to convert the masses from these load cases. As it can be seen in the table above, this effect can be taken into account by positive or negative sign as well, because the seismic effect means vibration between +/- extreme values, but the results are shown only in positive direction for the sake of simplicity. As it is shown above all the seismic possible cases can be found in the list but only those cases are valid which were calculated in seismic calculation. The calculated static loads from seismic effect can be found among the seismic results in the Equivalent loads.
293 +)))
294 +
279 279  == Final results of seismic effect (Seismic max.) in load combination ==
280 280  
297 +Final results of seismic effect (Seismic max.) always obtained from the total summation of all components. These results which actually means extreme +/- values, can be added to a load combination as a special load case with arbitrary factor and it can be applied in all codes.
298 +
299 +[[image:1536239630246-104.png||height="62" width="298"]]
300 +
301 +(((
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303 +The combination of the Seismic max. and the other static loads results is calculated in a special way. Because the results of the seismic effect are always positive and individual components (e.g. N, My and Mz internal forces in bar) are not simultaneous FEM-Design takes action as follow:
304 +
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306 +(((
307 +All components of the seismic results are added to the components of static results with the sign of static component.
308 +)))
309 +)))
310 +
281 281  == Final results of seismic effect (Seismic max.) in load groups ==
282 282  
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314 +Final results of seismic effect (Seismic max.) can be applied in load groups in all codes. Using EC8 and NS3491-12 program give possibility to have Seismic load type beside Permanent, Temporary and Accidental load type. In all other codes it is recommended to apply the Seismic load type in the Accidental load type. The final results of seismic effect take part with +/- sign automatically in the load group combination.
315 +
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317 +[[image:1536239721199-472.png||height="59" width="249"]]
318 +
283 283  ----
284 284  
285 285  = **Useful tips, which method to use?** =
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