THE DIGITAL SIMULATION OF STEEL TRUSS STRUCTURE LOW-POSITION LIFTING

Low-position lifting refers to that the design height of the lifting platform is low，and structure installation height is above the lifting platform，in the process of lifting，structure needs to be out of the lifting platform． Notable features of the low lifting is the lifting platform lower than the structure position，the first lifting，truss structure only installed the part above the middle chord，hence the stiffness of the structure can not meet the design requirements． Therefore，two hoisting points should be set in the truss structure region to ensure truss structure stability in the whole lifting process． After the lower chord installation completed，the temporary hoisting points should be removed，and replacing the lifting equipment to the second other lifting point，at the same time，low hoisting points within the truss area would be set from the original string position to the bottom，hanging point displacement has become the focus of the second lifting． With the actual situation of the lifting，MIDAS software was used to conduct two lifting digital analysis，the structure offset in the whole lifting process was got，and through pre adjusting the steel net set up value， with which two low-position liftings of steel truss structure were realized smoothly．