Testing of “simple” joints and their characterisation for structural analysis

Is it safe to design a building structure with simple joints, when they are known to exhibit a semi-rigid behaviour?

“…It can be seen that the initial stiffness and the "plastic" resistance are in perfect agreement with the test results. The failure mode obtained from the calculation, a large deformation of the end-plate, is also confirmed by the test, as is shown in [8].…”

“…The behaviour of the joints of this structure, in terms of characteristic momentrotation curves (so-called M-φ curves) has been evaluated by means of Eurocode 3 Annex J. However, one of the actual joints had previously been submitted to testing [8]. Therefore a "Eurocode 3 model -test" comparison has thus been made in order to evaluate the level of accuracy of the Eurocode 3 calculation for the other joints, which are similar but not identical.…”

“…As the structure is braced, no wind load has been considered. The joints of beams B1 to the central column have been submitted to test and their behaviour is reported in [8]. …”

“…The end-plate thickness is always 10 mm, and 4 bolts of quality 8.8 are used. The joint "EP2" (see Figure 2) has been submitted to test [8]. The others, showing different beam or column profiles, different steel qualities, were not submitted to test.…”

“…It can be seen from the Figure 3 that the ductility of the joint is more than sufficient; -the welds must be well designed, possibly oversized in order to avoid premature fracture and allow the joint to rotate as required (because in reality, the joints transfer bending moments); -the design of the joint must be such that the rotation is practically possible. There are indeed cases where the rotation could be prevented after a certain amount of rotation (see for example joints FP5 and FP6 in [8]). …”