Rafter

The main beam supporting the roof system.

Rail (Crane)

See “Crane Rail”.

Rails (Door)

The horizontal stiffening members of framed and paneled doors.

Rake

The intersection of the plane of the roof and the plane of the end-wall.

Rake Angle

Angle fastened to purlins at rake for attachment of end-wall panels.

Rake Trim

A flashing designed to close the opening between the roof and end-wall panels.

Rated Capacity (Crane)

The maximum load (usually in tons) which the crane is designed to support safely.

Reactions

The resisting forces at the column bases holding the structure in equilibrium under a given loading condition.

Reinforcing Steel

The steel placed in concrete as required to carry the tension, compression and shear stresses.

Remote-Operated Crane

A crane controlled by an operator not in a pulpit or in the cab attached to the crane, by any method other than pendant or rope control.

Retrofit

The placing of new metal roof or wall systems over deteriorated roofs or walls.

Rib

The longitudinal raised profile of a panel that provides much of the panel’s bending strength.

Ribbed Panel

A panel which has ribs with sloping sides and forms a trapezoidal shaped void at the side lap.

Ridge

The horizontal line formed by opposing sloping sides of a roof running parallel with the building length.

Ridge Cap

A transition of the roofing materials along the ridge of a roof; sometimes called ridge roll or ridge flashing.

Rigid Connection

See “Moment Connection”.

Rigid Frame

A structural frame consisting of members joined together with moment connections so as to render the frame stable with respect to the design loads, without the need for bracing in its plane.

Roll-up Door

A door that opens by traveling vertically.

Rolling Doors

Doors that are supported at the bottom on wheels which run on a track.

Roof Covering

The exposed exterior roof surface consisting of panels.

Roof Live Load

Loads that are produced:

• during maintenance by workers, equipment, and materials.
• during the life of the structure by movable objects and do not include wind, snow, seismic or dead loads.

Roof Overhang

A roof extension beyond the end wall or side wall of a building.

Roof Slope

The tangent of the angle that a roof surface makes with the horizontal, usually expressed in units of vertical rise to 12 units of horizontal run.

Roof Snow Load

That load induced by the weight of snow on the roof of the structure. Usually obtained by taking a fraction of the “Ground Snow Load”.

Ropeseal

See “Sealant”.

Runway Beam

See “Crane Runway Beam”.

Runway Bracket

A bracket attached to the column of a building frame which supports the runway beam for top-running cranes.

Runway Conductors

The main conductors mounted on or parallel to the runway which supplies electric current to the crane.