Field Experiment And Numerical Analysis Of Non-ground Tower Crane Foundation

Tower crane is one of the main equipment in building construction.During the development of subway cover,there are difficulties in the horizontal and vertical transportation of materials.It is urgent to develop a non-ground tower crane foundation.The tower crane foundation plays an important role in the safe operation of the tower crane.If the design and construction of the tower crane do not meet the relevant specifications and standards,it will lead to the occurrence of malignant accidents due to tilting or even overturning of the tower crane.Based on the development of the upper cover of Lanzhou metro in this paper,a new type of non-ground tower crane foundation is developed by using reinforced concrete columns and beams of the existing main structure of vehicle segment at Lanzhou metro by aiming at the problem that it is difficult to build a tower crane foundation during the development of the cover.Based on the analysis of the load characteristics and calculation methods of the non-ground crane,the field experiment is carried out in combination with the actual project,and the non-ground crane and tower crane foundation and application are established by using the software Midas/Gen.The finite element space model of the synergy of the library structure analyzes the tower crane under three operating conditions,when the tower arm rotates to different angles(0 °,30 °,45 °,60 °,75 °,90 °).The influence of the non-ground type tower foundation is compared,and the numerical simulation results are compared with the field test results,and the following main conclusions are obtained:(1)When the tower rotates around different angles,the stress of the steel beam measuring point is different.When the tower arm rotates to 45°,the tower crane foundation is at the most unfavorable load position;under the same working condition,When the tower arm rotates from 0°to 90°,the foundation stress of the tower crane generally increases first and then decreases;(2)Under the action of each working condition,the mean value of the difference between the calculated value and the measured value is within 15%,indicating that the calculated value is close to the measured value,indicating that the calculation model can reflect the basic real force;(3)The mean value of the difference between the calculated value and the measured value is within 10%,and the measured values are less than the calculated value,indicating that the calculation model is reasonable;during the rotation of the tower crane arm,the displacement values of the measuring points D1 and D2 increase with the rotation angle.Decrease,the displacement values of measuring points D3 and D4 increase with the increaseof the rotation angle.When the tower arm rotates to 90°,the displacement value at D4 is the largest;(4)When the tower crane is hoisting heavy objects,during the rotation of the tower arm in different directions,the stress of the tower crane foundation steel beam changes with the rotation direction and loading change,and each measurement point shows different pressure or is affected by the force.Pulled state,but the overall trend is the same;(5)When the tower arm rotates to the same angle and the hoisting weight moves along the boom,the stress values of the points are not much different under different working conditions;the stress of the tower crane foundation steel beam is within the design requirements and meets Design requirements,and the maximum stress value is much smaller than the allowable stress of the material,and the safety reserve is large.