Description of the SRJa node
The SRJa - Standard Roof Joint - is made up of two articulated elements, a rigid support A and a swinging element C joined together by the bracket B. The function of the node is to connect the perimeter beams of the roof to the edge curb. at the top of the masonry or of a possible curb in ca support. The element B, which prevents rotation in the ZX plane, defines the type of behavior of the node that is similar to an imperfect joint. The profiles 170/1, 170/2 and 170/3 can be placed on the SRJa node.
The SRJa knot is made in the workshop in compliance with the UNI standards for the chemical composition of steels and welding processes (UNI EN ISO 4016: 2002, UNI 5592: 1968, UNI EN ISO 898-1: 2001, UNI EN 20898-2 : 1994). The screws and bolts are made of high strength steel class 8.8 and the rest of the elements are steel S355. To guarantee greater durability, all the elements are subjected to a hot-dip galvanizing process.
Compressed stressed joint on the indicated surface constrained in correspondence with the holes connecting the masonry. The hypothesized constraint does not allow rotation in the ZX plane as it is prevented by the vertical bracket B.
The results were obtained with a non-linear analysis of the stress / strain state and of the displacement / deformation behavior performed with a finite element calculation program for incremental load values. The characteristics of the materials are as follows: S355 steel plates; high strength screws and bolts 8.8. The results of the tests carried out refer to the action of a force (F) for four distinct inclinations, arbitrarily chosen; the angle of rotation of the joint is α = 15 °, 30 ° 45 ° and 60 °. The tractive force (F) assumes the following values:
Where: Se = Max stress at the elastic limit.
Ss = Max stress at the complete plasticization of the resistant section.
Results of the force F expressed in Newton (N) equal to 10 N = 1 Kg.