| 摘要 |
PROBLEM TO BE SOLVED: To apply pretension, corresponding to design conditions, to trussed girders of a greenhouse and a vinyl plastic hothouse, and to simplify operations for applying the pretension to the trussed girders. SOLUTION: Respective diagonal members 21-24 are predesigned in such a manner that dimensions thereof are shorter by predetermined amounts than necessary dimensions in a truss forming state, and truss forming fittings 40 are screwed to upper and lower chords 11 and 12. Subsequently, a first strut material 31 is mounted in the state of being temporarily tightened with a bolt, and the first-fourth diagonal members 21-24 are mounted in the state of being temporarily tightened with a bolt. One end is rotatably supported while second and third strut materials 32 and 33 are obliquely inserted into the truss forming fitting on which inside ends of the third and fourth diagonal members 23 and 24 are mounted in a temporarily tightened state; the other end is fitted between the front and back plates of the other truss forming fitting while being rotated in a vertical state; and both ends are fixed in the temporarily tightened state by means of the bolts. Finally, each of the bolts in the temporarily tightened state is finally tightened. COPYRIGHT: (C)2009,JPO&INPIT
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