A computerized model to optimize location of a group of tower cranes is presented

A computerized model to optimize location of a group
of tower cranes is presented. Location criteria are balanced workload, minimum likelihood of bridge gantry crane with each other, and high efficiency of operations. Three submodels are also presented. First, the initial location model classifies tasks into groups and identifies feasible location for each crane according to geometric ‘‘closeness.’’ Second, the former task groups are adjusted to yield smooth workloads and minimal conflicts. Finally, a single-tower-crane overhead gantry crane model is applied crane by crane to search for optimal location in terms of minimal hook transportation time. Experimental results and the steps necessary for implementation of the model are discussed.  Crane location models have evolved over the past 20 years. Warszawski (1973) established a time-distance formula by which quantitative evaluation of location was possible. Furusaka and Gray (1984) presented a dynamic programming model with the objective function being hire cost, but without consideration of location. Gray and Little (1985) optimized crane location in irregular-shaped buildings while Wijesundera and Harris (1986) designed a simulation model to reconstruct operation times and equipment cycles when
handling concrete. Farrell and Hover (1989) developed a database
with a graphical interface to assist in crane selection and location. Choi and Harris (1991) introduced another model to optimize single tower crane location by calculating total transportation times incurred. Emsley (1992) proposed