MMI has provided structural engineering services related to several derrick crane rooftop installations. These installations served as cost effective solutions for major mechanical and electrical equipment replacement projects at various downtown high rises. The typical structural work involved for this type of project consists of installing a steel frame, elevated above a building’s roof, onto which a derrick crane can be mounted. The temporary steel frame is attached and anchored to the existing structure to allow for the lifting of equipment loads of up to 12 tons such as for cooling towers and electrical substations. Where required, the existing structure is reinforced to provide the necessary lifting capacity.

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A unique feature of these projects includes the constant adaption of a defined crane support system to a building’s existing structure and utility layout.