What is a Frame?

Members Make Up a Frame

Frames are a collection of individual components called members. These may be a series of beams and columns arranged in some configuration.

The construction of these components will entirely depend on the function of the frame. 

For instance, if we are to design a frame structure for a temporary warehouse:

• It must be capable of carrying all sorts of structural loads - dead loads, live loads, and lateral loads.
• It must be lightweight so that it's easy to assemble and disassemble.

Joints Connect Members

The members of the frame are connected at their ends by joints. These connections can be rigid, semi-rigid, or flexible. 

When discussing structural frames, one usually assumes that its joints are stiff unless otherwise stated.

The construction of joints will depend on the material and its structural purpose. For instance:

• For structural steel frames, joints can be riveted, bolted, or welded. Depending on the section and configuration of these connections, it can be any of the three types. For instance, when we fuse the flange and web of an I-beam to a column, it is a rigid connection.
• For reinforced concrete frames, rigid joints are formed by monolithically pouring concrete on member connections.

How Do Frames Behave?

Knowing how the frame behaves is crucial in structural analysis. Later on, we'll discover that the members and joints of a structural frame will experience all types of internal forces: axial, shear, moment, and torsion.

Summary

The frame is a structure composed of members connected by joints.

There are two components for frames: members and their connections at their ends called joints.

The joints are usually rigid but may be semi-rigid or flexible.

The structural frame will experience all internal forces: axial, shear, moment, and torsion.