Research On Mechanical Properties Of High Dense Frame-Truss In Storage Racks

Dense frame-truss in storage racks manifestated truss in horizontal, manifestated semi-rigid frame in vertical,its component were densely.Assemble racks was it typical representation.On the basis of preliminary study of our research group,this artical focused on the high racks with spine bracing system, added multilayer racks to compared. Firstly,the system characteristics of integral type connection racks with integral type connections was described, both its stucture loads and transfer path was studied in this paper.Not only disconnect type connections and integral type connections,but also old spine bracing system and new spine bracing system were compared in this paper.Secondly, the impact of bracing brackets with the vertical eccentric to the lateral stiffness, the impact of plan bracing to the upright length factor,the sphere impact of plan bracing in the racks were researched in the article.The reasonable of arrangement form of spine bracing system and the enhance uprights measure in the spine bracing eare were figured out.Thirdly, the range of connection stiffness to the performance impact of single beam was researched.The system performance to the high-non lateral system and the low-lateral system were also described,in basis of this result the suitable range was figured out.The ITC racks and DTC racks were compared,the better structure performance of ITC racks was clear.The impact of damping ratio of 0.035 and 0.05 to the structure performance was analysised.Last but not least,parametric analysis to the best work load of single beam was done.In case of the normal work load,the selection of upright section was listed in the ariticle. Based the reserches above, several main conclusions are obtained as follows:1、Lateral displacement of upright cap and horizontal rotation were increased in case of increasing of bracing brackets with the vertical eccentric. The increasing of bracing brackets with the vertical eccentric made racks in danger. So huge vertical eccentric of bracing brackets should be avoided.2、For ensuring lateral uprights satisfying the condition of strongly braced.Not only spine bracing system but plan bracing per layer should be setted.3、The increasing numbers of spine bracing caused significant limit to the translation, lateral displacement of upright cap and horizontal rotation were decreased.Based economy considering,one spine bracing should be setted in per 4-7 truss,means that single spine bracing may influence 7m-14m.4、The measure of enhancing upright in the spine bracing area and optimizating order uprights could decrease lateral displacement of upright cap and steel consumption,the effect in standard rack were more significant than the single rack.5、The high-non lateral structure and the low-lateral structure,the increasing connection stiffness cause the decrease of fundamental period, Lateral displacement of upright cap, horizontal rotation,the stress ratio of uprights,the effect of the low-lateral system were outstanding than the high-non lateral system, the connection stiffness were 3×10^8N·mm/rad was suitable.6、Lateral displacement of upright cap, horizontal rotation, deflection of the beams, the stress ratio of uprights of ITC racks was reduced than DTC racks, the base shear was increased.7、The damping ratio of 0.05 than 0.035,make a positive decrease in lateral displacement of upright cap, horizontal rotation, the stress ratio of uprights, the base shear; make nouse to translational,modal,deflection of the beams,the stress ratio of beams.8、The high-non lateral structure may save steel quantities according to increasing seismic fortification intensity and conditional characteristic periods,max to 33.8%; The low-lateral system may save steel quantities according to increasing loads,max to 30.3%.