All steel structural framing systems have some things in common ““ and, not surprisingly, a few differences. Horizontal bracing at the top of the rafter’s compression flange is normally needed to allow the entire structure to function efficiently. Live, dead and snow loads apply force to the highest flange of the major framework to create compression. However, roofing purlins usually furnish sufficient bracing. Bottom flanges require extra reinforcement as this part of the framework contends with the force of wind uplift. The steel building manufacturer’s design department determines the best locations for any flange bracing.

Many steel structure buyers are opting for free span technology, as they allow for the most flexibility in floor plan designs. Since free span designs can cost more, especially in larger buildings, give careful consideration as to whether the extra cost is warranted. For instance, if the building plan calls for permanent partitioning, there is no real reason to assume the additional expense of a free span design. Relatively few steel building manufacturers have the ability to produce and design larger buildings with broad expanses of free-span space.

The question is: What is the purpose of the building There are so many framing options that act as self-reinforcing agents. Larger buildings that can include interior columns without negatively impacting floor lay-outs can utilize a multi-span rigid structural framework system, which result in a significant cost savings over free span structures. This is especially true if there are no expansion plans for the building. The single-span rigid framework with a wide span feature is another choice if interior load-bearing columns are not desired. If the structure is relatively small, cost savings can be realized by using a tapered beam method or a wing unit.

The building buyer, working with a designer or architect, must make an informed decision as to what sort of column provides the best match to the structural framework chosen and for the building’s intended function. This includes the selection of tapered, straight or other style of column application. Straight columns tend to be more expensive, so if a tapered column application is “doable”� you can save some money.

In addition, the endwall structural framework must be determined. Although endwall designs do not vary too much, you must validate that all columns in the structure endwalls are of single or double cold-formed channels made with a minimum density of 14 gauge steel. The endwall’s job is to handle any load resistance and bolster the structural wall girts.

The framing choice is critical for the successful completion of any building project, and to ensure the customer’s satisfaction over the serviceable life of the steel structure.