CONSIDERATION OF STOCHASTIC IMPACTS IN THE CONSTRUCTION SCHEDULING

Abstract

There is show an experience of modern methods of scheduling in construction. There are reviewed existed scheduling methods: Critical Path Method, Constraints Programming, Job Shop Scheduling. Additionally there were reviewed methods with special edition for construction industry: shortest path planning, continue development frontline volume method, continue resources utilization method. All reviewed methods are simplified and don’t consider stochastic factors. Specific of the construction operation is a especially strong influence of stochastic factors to the construction production processes. There were reviewed methods of time reserve utilization, which appears in different stages of operations. This time reserve could be used, in particular, for minimization of negative aftereffects of stochastic factor influence on elements of construction. For these purpose was created target function of negative aftereffects minimization task, which describes dynamic and stochastic loses. The contribution of stochastic factors is expressed by exponential functions. There is shown, that redistribution of time reserve allows without any dynamic loses, to decrease contribution of stochastic loses. There is shown, that in approximation of independent works, the optimal schedule is that, which considers increasing of time reserve on critical directions. There is showed on individual example of algorithm for negative factors aftereffect minimization. Using this algorithm allows to make schedule with details of minimal approximated stochastic loses. In opposite, having a possibility of resources redistribution to directions, associated by high risks and loses, the optimal schedule plan will be alternative schedule plan, considering a possibility of operative redistribution, even through risks rise on non-critical directions.