The Structural Engineer's Corner

Eng. Onorio Francesco Salvatore

Structural design of steel pipe racks

Written By: Lexatus - Sep• 28•14

Pipe rack - Onorio Francesco Salvatore

Pipe racks are structures used in the petrochemical, chemical and power plants industries. They are meant to support pipes, power cables and instrument cable trays. Sometimes, pipe racks support mechanical equipment, vessels and valve access platforms. Basically, they are a connection between equipment and storage or utility areas.

The main structural components of the pipe rack superstructure are:

transverse beams (supports for piping, etc.);


longitudinal struts;

vertical bracing.

When designing pipe racks, the Structural Engineer shall take into account the maintenance, allowing a clear access under the pipe rack. For this reason, moment resisting frames (MRF) are used or the bracing is limited only to few bays.

There are primarily two types of pipe racks:

– Strutted;

– Unstrutted.

The first type, strutted, has longitudinal struts between the transverse frames. This addition provides stiffness in the longitudinal direction. In addition, diagonal bracing can be added in order to act together with the longitudinal struts to resist the horizontal loads. This arrangement is very common.

The unstrutted pipe rack doesn’t have the longitudinal struts, hence the columns act as cantilevers to resist lateral loads longitudinal to the pipe rack.

Strutted pipe rack - Onorio Francesco Salvatore


Usually, if using strutted pipe racks, the columns shall normally be designed with pinned or fixed base, depending on the lateral drifting requirements.

For unstrutted pipe racks, columns shall be considered pinned in the transverse direction and fixed in the longitudinal direction. The major axis of columns should be perpendicular to the longitudinal direction of the pipe rack.

For any issues or questions, you can contact the author at:

Eng. Onorio Francesco Salvatore

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