Initially, our project scope was to verify the structural integrity of an existing 64'-0'' square, rooftop Heli-Stop that was damaged during landing operations atop an eleven-story hospital. Ultimately, our services included field verification of existing conditions; review of original construction plans, specifications, and reports; review of regulatory agency (local, PennDOT, NTIS, FAA) requirements; determination of design and operating loads; structural analysis of existing systems; determination of the Heli-Stop load-carrying capacity; recommendations for remedial construction; and, preparation of a findings report.

For reference, the Heli-Stop consist of a 64'-0'' square concrete bearing pad supported by composite structural steel framing. twelve structural steel column stubs bearing on the steel building frame support the composite steel framing system. According to original contract documents, the original Heli-Stop was designed to support a 5,000 pound gross weight helicopter.

We modeled the Heli-Stop structure utilizing RAMSteel, a structural analysis software package that permitted analysis using various load combinations. The baseline helicopter configuration used for analysis was the Aerospatiale 365N, which is comparable to the "Life Lion" helicopter utilized for the 1987 design of the Heli-Stop. There was no significant damage to the Heli-Stop, and the limiting design consideration was the composite steel framing allowable bending stresses. Our analysis determined that the Heli-Stop had adequate load-carrying capacity to support a 10,000 pound gross weigh helicopter.