Research On Attachment Device Of SP7525 Flat-arm Tower Crane In Golden International Plaza

At present,tower cranes used in super high-rise buildings in China need to install attachment devices in order to ensure the rigidity and stability of the tower crane itself.The attachment device allows the tower crane to perform its intended function through the constraints provided for the tower crane.The current domestic technical standards for tower cranes mainly focus on the design,manufacture and use of tower cranes.The design of the attachment device is missing in the current standard,even if there are provisions for the design of the attachment device,is also principled,with poor operability,and related companies also lack technical personnel with design capabilities.Based on the above situation,this subject takes the tower crane SP7525 of Shandong Gold International Plaza as the research object,through strain monitoring,parameter simulation and theoretical derivation to study the attchment force characteristics,attchment force calculation and force calculation of the attachment rod when the attachment device is in working state.It is hoped to provide a method reference for the research of attachment devices in the future,so that attachment devices can play a better role in construction projects.First,monitor the strain of the attachment rod,record the strain generated by the tower crane operating at a uniform speed for one week when lifting different loads,and analyze the stress characteristics of the attachment rod according to the monitored data.Secondly,used the 3D3 S finite element software to perform finite element modeling on the tower and the attachment device,and the monitoring results were verified to prove the correctness of the model,which is ready for the next analysis of the tower crane attachment device under complex load.Thirdly,the finite element software is used to study the influence of the three parameters of the load combination,rotation angle and number of attachment channels of the tower crane attachment.The load combination includes: constant load+ Live load + wind one,constant load + live load + wind two(the directions of wind one and wind two are different,wind one is perpendicular to the front,wind two is parallel to the wall);The rotation angle is 0°,45°,90°…315°,8 angles in total;The number of attached channels includes: one,two,four,six,eight,and nine.Through research,it is found that:(1)Under the first load combination,theattachment force is the smallest at the rotation angle of 0 °,and the attachment reaction force is greater when the rotation angle is around 180 °;Under the second load combination,the attachment reaction force is smallest when the rotation angle is around 90°,and the attachment reaction force is greater when the rotation angle is around 270°.(2)When the wind load and the direction of the lifting bending moment are close(±45°),the attachment force is the largest.(3)When the total number of attachments is determined,the uppermost attachment reaction force(the ninth channel)is the largest,the eighth attachment reaction force is opposite to the ninth channel,and the remaining attachment forces of the remaining channels are smaller and close to the value;The uppermost(ninth)attachment device bears 90% torque and the eighth attachment bears 10% torque.(4)With the increase of the number of attachment channels,the uppermost adhesion force R is increasing,because the total wind load is increasing,but it does not increase linearly.The torque carried by the uppermost attachment device is not accompanied by the change in the number of device channels,and on average bears 94% of the torque.(5)Rod A obtains a maximum value of 0.93 R at a rotation angle of 0°(R is the maximum attachment force under the first load combination),rod B obtains a maximum force of 1.45 R at a rotation angle of 90°,and rod C at a rotation angle of 45° obtain a maximum force of 1.13 R,rod D obtains a maximum force of 1.63 R at a rotation angle of 270°,and the strength of the attached rod force should not be less than the attachment force during design.Finally,based on the above research,this paper proposes a calculation method for transforming the tower body into a solid-web bar through the comparison of the calculation methods of adhesion reaction force.Through the calculation of two methods and verification with finite element method,it is proved that this method is feasible and simple.Based on the calculation method of adhesion reaction force,the force calculation formula of the attachment rod of the attachment device is given by the force method.