THE PREFLEX TYPE AND LOADING DEVICE WITH 3 LOADING POINT

摘要

A preflex type loading device with three loading points is provided to cut down construction cost by adjusting thickness of steel material according to distribution, and to improve structural stability without torsional deformation, local deformation or horizontal buckling by distributing load into three points. A preflex steel girder is manufactured by applying bending deformation to the steel girder with a reaction bar(2) by hydraulic jacks(3) at both ends, and load is applied to a center point of the steel girder. Load is applied alternately to the center point and both ends, and the center point is accurately dropped within the permissible limit range by applying preflex load according to change of strength of a joint portion. A loading bar(13) fixed to the ground by an earth anchor(18) is installed in the center point of the steel girder, and a lower flange(15) of an upper frame of the loading bar and a hydraulic jack(16) are mounted to the loading bar by bolting. The preflex girder is manufactured by applying load with the hydraulic jack of the loading bar.