Two Chicago concrete construction projects have a number of things in common. They are both dramatic examples of the significant role which reinforced cast-in-place concrete is playing in the field of high-rise apartment buildings; they both employ a Linden climbing crane imported from Denmark; and they both make use of a central concrete core for elevators, stairs and utilities. Another interesting feature of the Chicago projects is the use of prefabricated fiberglass-reinforced plastic forms for the central core, columns, beams and slabs. The forms are reinforced with metal along the edges where parts are bolted together and the outer sides are stiffened with wood bracing.