Page 58 - Structural Steel Designers Handbook AISC, AASHTO, AISI, ASTM, and ASCE-07 Design Standards

Brockenbrough_Ch02.qxd 9/29/05 5:01 PM Page 2.20

FABRICATION AND ERECTION*

2.20 CHAPTER TWO

FIGURE 2.3 Crawler crane.

One of the most common machines for steel erection is the crawler crane (Fig. 2.3). Self-propelled,
such cranes are mounted on a mobile base having endless tracks or crawlers for propulsion. The base
of the crane contains a turntable that allows 360° rotation. Crawlers come with booms up to 540 ft
high and capacities up to 1000 tons. Self-contained counterweights move the center of gravity of the
loaded crane to the rear to increase the lift capacity of the crane. Crawler cranes can also be fitted with
counterweights on attached mobile carriages or ring attachments to increase their capacity.
Truck cranes (Fig. 2.4) are similar in many respects to crawler cranes. The principal difference
is that truck cranes are mounted on rubber tires and are therefore much more mobile on hard surfaces.

FIGURE 2.4 Truck crane.

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