Adapted from: Braham M, Jaspart JP. Is it safe to design a building structure with simple joints, when they are known to exhibit a semi-rigid behaviour? Journal of Constructional Steel Research, 60, 2004, 713-723.
This report evaluates the assumption that joints which display semiPurpose rigid behaviour can be modelled as frictionless pinned joints in building design calculations. The idealisation is evaluated by Method
comparing computer simulations incorporating this assumption with experimental test data for the actual structure. The results Results
show that the idealisation is safe and is usually conservative in estimating the structural strength; however these conclusions are limited to cases where the joints display large deformations before rupture of the bolts or welds. Only in few, probably unrealistic Conclusion
cases will this assumption lead to unsafe results which overestimate strength. It is recommended that three conditions are necessary for the safety of semi-rigid joints: joints must show enough ductility, Recommendations welds must be well designed in order to avoid premature fracture and the design of the joint must be such that the rotation is practically possible.
Problem / issue
In building design, joints are classified as pinned, semi-rigid or rigid depending on their stiffness relative to the framing in which they are used. Engineers consider some joints as pinned in their structural analysis, even though it is common knowledge that all joints exhibit some rotational constraint. For example beam-tocolumn joints made with a thin and non-extended end plate are actually semi-rigid but are modelled as frictionless pinned
Until recently there has been no reliable evidence that the
idealisation of such joints is a safe building design practice. Even in the absence of definite proof the above assumption continues to be...
References: Eurosteel on Steel Structures, Coimbra, September 19–20, 2002, Portugal. 2002, p. 1079–
(D). Version 2000R19, 2000. Commercialised by ICCS bv (NL).
Sample & abridged Aerospace Engineering report
Please join StudyMode to read the full document