2. Semi-continuous and braced frames

Figure 19 in the article [C 2560] has already shown the wide variety of possible mixed connections (including ductile reinforcement) for semi-continuous frames. In cases (b), (d) and (e) of this figure, the connection of the metal part is not fundamentally different from that of a hinged steel frame, so that in the construction phase, the mixed connection resembles a nominally hinged connection. It is only in the final mixed phase, when the action of the reinforcement is combined with that of the metal connection, that the connection acquires significant rigidity and strength.