Main Frame
An assemblage of rafters and columns that support the secondary framing members and
transfer loads directly to the foundation.
Main Wind Force Resisting System
A structural assembly that provides for the overall stability of the building and receives
wind loads from more than one surface. Examples include shear walls, diaphragms,
rigid frames, and space structures.
Mansard
A steep sloped (almost vertical) real or mock roof element on the perimeter of a
building. Originated by the French architect, Francois Mansart.
Manufacturer
A party who designs and fabricates a Metal Building System.
Manufacturer's Engineer
An engineer employed by a manufacturer who is in responsible charge of the structural
design of a Metal Building System fabricated by the manufacturer. The manufacturer’s
engineer is typically not the Engineer of Record.
Masonry
Anything constructed of materials such as bricks, concrete blocks, ceramic blocks, and
concrete.
Mastic
See "Sealant".
Material Safety Data Sheet (MSDS)
A written description of the chemicals composing a product, and other information,
such as safe handling and emergency procedures. In accordance with OSHA
regulations, it is the manufacturer’s responsibility to produce an MSDS and the
employer’s responsibility to communicate its contents to employees.
MBMA
Metal Building Manufacturers Association.
MCA
Metal Construction Association.
Mean Roof Height
Average height of roof above ground.
Metal Building System
A complete integrated set of mutually dependent components and assemblies that form
a building including primary and secondary framing, covering and accessories, and are
manufactured to permit inspection on site prior to assembly or erection.
Mezzanine
An intermediate level between floor and ceiling occupying a partial area of the floor
space.
Mill Duty Crane
Cranes with service classification E and F as defined by CMAA.
Miter
The joint produced by joining two diagonally cut pieces, or the act of making such a
cut.
Model Codes
A building code that is accepted in a large number of states. (See Building Codes.)
Moment
The tendency of a force to cause rotation about a point or axis.
Moment Connection
A connection designed to transfer moment as well as axial and shear forces between
connecting members.
Moment of Inertia
A physical property of a member, which helps define strength and deflection
characteristics.
Monolithic Construction
A method of placing concrete grade beam and floor slab together to form the building
foundation without forming and placing each separately.
Monorail Crane
A crane that travels on a single runway beam, usually a "S" or "W" beam.
Multi-Gable Building
Buildings consisting of more than one gable across the width of the building.
Multi-Span Building
Buildings consisting of more than one span across the width of the building. Multiple
gable buildings and single gable buildings with interior columns are examples.
Multiple Girder Crane
A crane that has two or more girders for supporting the lifted load.