In: Civil Engineering
Q3. a) Discuss the factors to be accounted for when specifying connections for structural steel work and highlight their effects on the construction process and structural performance.
The factors to be accounted for when specifying connections for structural steel work are as follows:-
1. Load at the ends of the beam
The type of connection to be designed majorly depends on the type of load the structure is going to carry throughout its design life. For example, If the reactions at the end of the beam is large, then it is recommended to consider stiffened seat connections because it has adequate capacity to resist large forces whereas the capacity of unstiffened seat connection is restricted due to limited bending capacity of seat angle leg that stick out horizontally. Also, in welded connections, the weld is subjected to direct shear stress and stress caused by loads on the beam that affect weld pattern. So, these stresses are required to be considered while designing the connection. Also, if the structure is to transfer moments, the connection has to be designed adequate enough.The ability of connections to transfer moments to the columns is based on the degree of fixity of the connections. The higher the degree of fixity of the beam connection, the greater the ability to transfer moments to the columns.
2. Strength of connection
The strength of connections basically means the ultimate load it can carry per unit area throughout its service period. The connection should be capable enough to tackle the design load of the structure including the ultimate loads like wind loads, earthquake loads. The strength of base material plays an important role while designing the connection. The more the yield stress of steel, better is the connection. Also, the strength of connection depends on the orientation and geometry of the column.
3. Panel zone yielding
Panel zone yielding is a yield mechanism that causes ductility of connections. On the other side, connections with excessive panel zone deformation may have premature connection fracture and reduced ductility. Therefore, panel zone yield deformation is an important factor to be accounted for specifying connections. Beam depth and span length affect the ductility and performance of connections.
The effects of these factors accounted while designing connections are-