Partial factors for wind actions considering hidden safety due to time invariant components

Author(s):  
M Holický ◽  
J Retief ◽  
C Viljoen
Keyword(s):  
10.14311/370 ◽  
2002 ◽  
Vol 42 (4) ◽  
Author(s):  
M. Sýkora

A steel frame with haunches is designed according to Eurocodes. The frame is exposed to self-weight, snow, and wind actions. Lateral-torsional buckling appears to represent the most critical criterion, which is considered as a basis for the limit state function. In the reliability analysis, the probabilistic models proposed by the Joint Committee for Structural Safety (JCSS) are used for basic variables. The uncertainty model coefficients take into account the inaccuracy of the resistance model for the haunched girder and the inaccuracy of the action effect model. The time invariant reliability analysis is based on Turkstra's rule for combinations of snow and wind actions. The time variant analysis describes snow and wind actions by jump processes with intermittencies. Assuming a 50-year lifetime, the obtained values of the reliability index b vary within the range from 3.95 up to 5.56. The cross-profile IPE 330 designed according to Eurocodes seems to be adequate. It appears that the time invariant reliability analysis based on Turkstra's rule provides considerably lower values of b than those obtained by the time variant analysis.


Author(s):  
Andrei Sokolov ◽  
Andrei Sokolov ◽  
Boris Chubarenko ◽  
Boris Chubarenko

Three dumping sites located at the south-eastern part of the Baltic Sea (Kaliningrad Oblast) at shallow depths are considered. The first one is located to the south of the Vistula Lagoon inlet in front of a permanently eroded open marine shore segment. The second one is located to the north of the Vistula Lagoon inlet, and is used now for disposing of dredged material extracted from the Kaliningrad Seaway Canal. The third dumping site is located near the northern shore of the Sambian Peninsula to the east of the Cape Gvardeijski and assigned for disposing the dredged material extracted from the fairway to the Pionerskij Port located nearby. The last site is planned to be used for disposing of dredged material from the future port that should be constructed there before the beginning of the FIFA World Cup 2018. All three dumping sites are located not far from the eroded segments of the shore. The question behind the study is: would it possible that disposed material will naturally transported from the damping site to the shore and accumulate there to protect it from erosion? A numerical hydrodynamic-transport 3D model (MIKE) was used to model sediment transport under different wind actions. The winds with the speed stronger than 15 m/s complete wash out disposed material from the dumping site and spreading it over the wide area with a negligible layer thickness. Winds of about 7-10 m/s transport material along the shore at a distance of few kilometers that may be useful for shore protection. The first location of the dumping site (to the south of the Vistula Lagoon inlet) looks very ineffective for potential protection the shore nearby. At the other hand, the second and especially the third locations are favorable for transport of disposed material to the shore, the most favorable conditions are at onshore or alongshore currents.


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