Composite Design with Lightweight Aggregates on Building Projects

Composite design using concrete slabs, steel beams and girders with various types of shear connectors has been used with some limitations for the past thirty or thirty-five years. Most of the applications of composite construction have been for highway bridge construction and only since the late 1940s and early 1950s has its application been accelerated in the building field. Increasing use of ultimate strength design methods, development of various types of shear connectors, and extensive research in composite design in the past twelve years has advanced this type of construction and has allowed the structural designer to justify savings over conventional elastic and non-composite techniques. This paper centers itself around building projects using composite design with a type of concrete that is unusual since it is lightweight with densities ranging from 90 to 110 pcf instead of the normal density of 150 pcf. This type of concrete has structural characteristics and physical properties similar to normal weight concrete.