Heavy Movable Structures, Inc., is a not-for-profit technical organization of volunteers focusing on the heavy civil facilities utilized by or for the public benefit, with emphasis on, but not limited to, movable bridges.

HMS is primarily concerned with movable bridges and other large civil engineering structures.

The main mission of HMS is to provide forums for information interchange among bridge owners, government agencies, designers, contractors, suppliers, and other groups involved in movable bridges and heavy movable structures. This includes both privately owned and publicly owned bridges.

It is intended and believed that this information exchange will benefit the public through improved safety and reliability, more cost-effective utilization of public funds through improved design and maintenance practices, and increased awareness and conformance with issues of the environment.

These information exchanges involve scientific principles and practices, various engineering disciplines, current technologies and state-of-the-art crafts related to the industry. The forums of information interchanges utilized are primarily the biennial symposia with the associated publications and other information that the volunteers may therein provide.

The scope or sphere of interest encompassed by HMS, has not been tightly defined by intention. At the present time, HMS is primarily concerned with movable bridges and other larger civil engineering structures such as navigation locks, dams, flap gates, flood control equipment, movable stadium roofs and other structures with large machinery in which most operational speeds are less than critical and forces are large.