P 866 – Racking Systems by Optimizing the Construction and the Use of High-Strength Steel
Usually, high-bay racking systems are made from thinwalled, cold-formed and nonstandardised steel profiles of steel grade S350GD+Z. From a height of 20 meters, it is useful to build high-bay racking systems in silo design. If the silo design is used, the room-enclosing roof and wall covering is supported by the rack structure. Due to the boom of the logistics industry and the general shortage of space high-bay racking systems are nowadays build up to 50 meters height. With the rapid increase of height, the current construction practice reaches its static and structural boundaries. Because of the complexity of rack profiles, these profiles cannot directly be calculated according to DIN EN 1993-1-3.
Therefore, the aim of this research project was to analyse and to optimise the supporting structure of highbay racking systems in silo design and to evaluate the usability of high strength steels. For this purpose, both the overall construction of the high-bay silos as well as individual components and connection structures were examined.
In detail, structural design analyses of typical high-bay silos were conducted and the gained finding could be used to elaborate optimisation parameters for the supporting structure. The research comprised extensive experimental analyses on the load bearing behaviour of compressed column profiles and pallet beams under constant bending moment in order to develop design concepts for these profiles in accordance with DIN EN 1993-1-3. In addition, tests on pallet beams with realistic load application via pallets were performed. These tests showed that pallets obstruct the torsional flexural buckling of the beams, thus increasing the load capacity of the pallet beam. However, this load increase is vdecisively dependent on the surface condition of the pallets.
In addition to the analysis of the structural behaviour of the “beam-column” and “diagonal-column” connections experimental tests were carried out. The examinationat the “beam-column” connection has shown that the evaluation method according to DIN EN 15512 obtained conservative results. Therefore, a ecommendation for an alternative evaluation method was given, which achieves higher connection stiffness with a reduced design moment.
In order to assess the possibility of using high-strength steels, comparative tests with the generally used steel grade S350GD+Z in high-bay racking systems and with steel grades HX460LAD and HX500LAD were performed. It was shown that the use of high strength steels can lead to an optimisation of the structural system and the profitability of the construction in different cases.
The research project IGFNo. 16998 N from the Research Association for Steel Application was supported by the Ministry of Economic Affairs and Energy through the German Federation of Industrial Research Associations (AiF) as partof the programme for promoting industrial cooperative research (IGF) on the basis of a decision by German Bundestag. The research project has been carried out at Technischen Universität Dortmund, Lehrstuhl Stahlbau.
Only available in german language.
D. Ungermann, M. Schulze Bertelsbeck