Research On ZSL1700 Loom Type Tower Crane Attachment Device Of IFC

In recent years,with the continuous rise of super high-rise buildings,the use of large-scale external boom tower crane is more and more extensive.In the traditional design method,it is considered that the force transmitted from the tower body to each node of the attachment device is evenly distributed,but there is uncertainty in the distribution of reaction force and acting force at each point of attachment of the tower crane in the actual loading.However,scholars have little research on the attachment device of luffing tower crane,and the field monitoring lacks scientific and accurate guidance.Therefore,taking the 428m super high-rise project of Shandong International Financial Center as an example,the overall modeling of the ZSL1700 tower crane and the method of field monitoring are used to analyze the simple load of the tower crane（vertical force N;torque T;bending moment M;horizontal force V;wind load q）,complex load（combination of M,N,T,q）and the distribution law of the support force of the attachment device and the force of the tower body on each point of the attachment device.Simplified calculation model of the total reaction force and the calculation method of the related reaction force and acting force.Firstly,the strain of each monitoring point of the attachment device was monitored when the tower crane was at different rotation angles.Secondly,the numerical simulation software 3D3S was used to modeling and analyze the tower crane and attachment device with different rotation angles.At last,the simplified calculation model of the total reaction force of tower crane and the related calculation methods of reaction force and acting force are studied.The results show that:（1）The vertical force N is not evenly distributed at each point of the lower attachment frame,and the difference is large,which is harmful to the tower body;the horizontal force of the upper attachment frame is small,and the lower attachment frame is large.（2）The torque T is mainly borne uniformly by the two points of the main beam CD of the upper attachment frame,and the acting force is perpendicular to the wall surface.The value can be approximately T/b,while the lower strut and the side strut hardly participate in the torque bearing.（3）The horizontal force generated by the bending moment is jointly borne by the upper and lower adhesion reaction forces,and the tower feet will generate two-way bending moments M_bx and M_by under the action of the bending moment.（4）For the analysis of adhesion reaction force and acting force under the action of bending moment,the side brace can be ignored,and the relevant reaction force and acting force can be obtained by using the simplified model.（5）Under the action of horizontal force V,V is borne by the upper attachment frame.（6）Under the action of q,q is jointly borne by the upper and lower attachment frames.（7）According to the law of the adhesion reaction force analysis under simple load,a simplified calculation model of the total adhesion reaction force is proposed,that is,the two attachment frames are simplified into horizontal spring k_y and rotating spring r_x respectively.（8）Under the action of rotating moment,the reaction force of the support presents a s-shaped change trend.The reaction force at the main beam of the upper and lower attachment frame is larger,and the reaction force at the vertical strut and the lateral strut is smaller;the force near the wall end node is larger,and the force far away from the wall end node is smaller.Through the analysis of the reaction force and acting force of the tower crane under the complex load,it can be seen that:（9）The variation rule of the acting force of the tower body on each point of the main beam is s-shaped curve,point AB is less than point CD,point EF is less than point GH,and point up is less than point down.（10）In the reaction force of the support at each point of the attachment frame,the reaction force at points 1and 2 is the largest,and the reaction force is smaller in x,y and z directions at points 3,4,5 and 6,and the maximum value is less than 6kN;in the lower attachment frame,the reaction force at points 7 and 8 is the largest,and the reaction force at points 9 and 10 is same as y and z directions,and the reaction force at points 11 and 12 is smaller in x,y and z directions,and the maximum value is less than 40kN.Compared with the reaction force of the upper and lower attachment frames,the reaction force of the lower attachment frame is significantly greater than that of the upper attachment frame.（11）When q is parallel to the forearm of the tower crane,the acting forces of the tower body on the main beam at ABCD and EFGH as well as the adhesion reaction,are basically greater than when q is perpendicular to the wall,with an increase rate about 22%.