# Moment Connection Design

**Symbols**

**C _{pr}: **This coefficient takes into account the strain-hardening which is used to compute maximum possible bending moment strength

**F _{u}:** Characteristic tensile strength of steel

**F _{y}:** Characteristic yield stress of steel

**l _{h}: **The distance of between plastic hinge point at the beam end to the column face

**l _{n}:** Beam span between plastic hinge points at the beam ends

**M _{pr}:** Possible bending moment strength

**M _{pri}:** Possible bending moment strength at the left end i of the beam

**M _{prj}:** Possible bending moment strength at the right end j of the beam

**M _{uc}:** Required bending moment strength of the connection at the face of the column

**R _{y}:** The ratio of possible yield stress to the characteristic yield stress

**V _{d}:** Beam shear force computed from vertical loads at the plastic hinge point of the beam

**V _{uc}:** Required shear strength of the connection at the face of the column

### Design Criteria for Moment Connections

Moment connections are classified as rigid and full/partial strength connections.

For rigid connections, end plate and welded connections are classified according to the rotational rigidity which is defined according to the earthquake regulations depending on the ductility level.

#### Guideline for End Plate Connections

The strength of the end plate connection is determined by the assumption that the tensile force of the bolts on a part of the plate and compressive forces of the bolts on the other part of the plate is controlled by the bearing limit state.

If there is no axial load on the connection, the total tensile and compressive forces are equal and opposite in both parts which create force pair.

To simplify the calculations, it is assumed that the center of rotation is in the center of the compression part.

#### Guideline for Splice Connection of Columns/Beams

In order to be suitable for the design under reversible forces such as earthquake forces, symmetrical and equal number of bolts are used on both flanges and webs. ideCAD does not allow asymmetrical connection during modelling.

It is assumed that the flanges carry the moment and web carry the shear force, while the axial force is equally shared between both flanges.

The gap is left in between the beam splices, while for the column splices it may or may not be left.

### Guideline for Moment Connections with TBDY 2018

Depending on the ductility level, the connections need to provide a relative angle of translation of at least 0.04 or 0.02 radians according to the TBDY 2018 9B.1. These connections are End Plate and Flange Plate connections that are designed in ideCAD Structural Steel.

If the design of the connections is preferred to be computed with TBDY 2018, the

method is mandatory in accordance with the earthquake regulations.**YDKT**The required bending moment strength

**M**and the required shear strength_{uc}**V**on the column face of the connections is calculated over the plastic hinges at the end of the beam. The formulas in the figure below are used._{uc}

The

**V**used in the dimensioning of the connection is determined according to the equation in the figure above by summing the shear force determined on the basis of the yielding limit state with the shear force calculated from the combination of_{uc}on the plastic hinge at the end of the beam.**1.2G + 0.5Q + 0.2S**Plastic hinge length is specified separately for each connection in TBDY 2018 and automatic computation is made in accordance with these rules. Details will be given in each connection.

The shear strength required for the panel zone is calculated by using the column shear force generated by the possible plastic moments of the beams connecting to the column.