12.10.1
Ordinary moment frames (OMF) should be shown to withstand inelastic deformation corresponding to a joint rotation of 0.02 radians without degradation in strength and stiffness below the full yield value ( ). Ordinary moment frames meeting the requirements of this section shall be deemed to satisfy the required inelastic deformation.
12.10.1.1
Ordinary moment frames (OMF) shall not be used in seismic zones IV and V and for buildings with importance factor greater than unity (I >1.0) in seismic zone III.
12.10.2 Beam-to-Column Joints and Connections
Connections are permitted to be rigid or semi-rigid moment connections and should satisfy the criteria in 12.10.2.1 to 12.10.2.5.
12.10.2.1
Rigid moment connections should be designed to withstand a moment of at least 1.2 times of either the full plastic moment of the connected beam or the maximum moment that can be delivered by the beam to the joint due to the induced weakness at the ends of the beam, whichever is less.
12.10.2.2
Semi-rigid connections should be designed to withstand either a moment of at least 0.5 times the full plastic moment of the connected beam or the maximum moment that can be delivered by the system, whichever is less. The design moment shall be achieved within a rotation of 0.01 radians. The information given in Annex F may be used for checking.
12.10.2.3
The stiffness and strength of semi-rigid
connections shall be accounted for in the design and the overall stability of the frame shall be ensured.
12.10.2.4
The rigid and semi-rigid connections should be designed to withstand a shear resulting from the load combination 1.2DL + 0.5LL plus the shear corresponding to the design moment defined in 12.10.2.1 and 12.10.2.2, respectively.
12.10.2.5
In rigid fully welded connections, continuity plates (tension stiffener, see 8.7) of thickness equal to or greater than the thickness of the beam flange shall be provided and welded to the column flanges and web.