Design of Structures for the Effects of Falling Objects

Many times, design engineers come across situations when the effects of the impact of falling objects are considered of significance to the safety of a structure. Some of the situations may include rock fall protection structures, accidental fall of elevator counterweights, design of protective structures around construction sites or existing buildings where building components are reported to fall off the building, moving of heavy loads suspended from gantry cranes, and any other objects falling at high speed. A simple method suitable for design office practice using the principles of conservation of energy will be presented. The derivation of the Energy Equation will be presented based on widely recognized principles of motion of objects. It is assumed that the striking body is rigid such as a steel object, and the struck object is a flexural member such as a structural steel beam or a reinforced concrete slab or beam. The design objective is to provide strength and ductility so that the kinetic energy delivered by the falling object may be resisted by the strain energy developed by the structural elements. A design example will be provided to demonstrate the use of the procedure