4.2.1
The effects of design action in the members and connections of a structure shall be determined by assuming singly or in combination of the following forms of construction (see 10.6.1).
4.2.1.1 Rigid construction
In rigid construction, the connections between members (beam and column) at their junction shall be assumed to have sufficient rigidity to hold the original angles between the members connected at a joint unchanged under loading.
4.2.1.2 Semi-rigid construction
In semi-rigid construction, the connections between members (beam and column) at their junction may not have sufficient rigidity to hold the original angles between the members at a joint unchanged, but shall be assumed to have the capacity to furnish a dependable and known degree of flexural restraint. The relationship between the degree of flexural restraint and the level of the load effects shall be established by any rational method or based on test results (see Annex F).
4.2.1.3 Simple construction
In simple construction, the connections between members (beam and column) at their junction will not resist any appreciable moment and shall be assumed to be hinged.
4.2.2 Design of Connections
The design of all connections shall be consistent with
the form of construction, and the behaviour of the connections shall not adversely affect any other part of the structure beyond what is allowed for in design. Connections shall be designed in accordance with Section 10.