Mathematical Model for Awarding Jobs to Sub-Contractors

The modelling is considered one of the modern dependable methods in the engineering systems which handle many problems in the engineering sector, from here came the research idea to use mathematical modelling in subcontracts assignment in the productive sector for achieving optimization in lower cost or higher profits, and also to ensure fair distribution of the subcontracts according to the experience and cost and excluding non-qualified subcontractors.

Whereas the study included researches studying, former studies and dependable techniques in the assignment and studying linear programming method according to the assignment system, so the necessary data for the study were collected from Al-Zawra'a Public Company which performed the project of supplying and installation electrical substations, these data represent tenders prices whom are introduced by the subcontractors for all the subcontracts and the assigned prices for them.

Eight mathematical models were constructed which represent different study cases that could happen to any project depending on the assignment method in the Hungarian way whereas external effects were introduced like forcing the committees to make one or more of the contractors deliver more than a contract or excluding one of the contractors, the program (Win qsb) was used to solve the models.

The study showed the most important conclusion that the Hungarian way may not give the best results because it is restricted in the method of assigning one contract to each contractor and the improved model for this way which allow assigning more than one subcontract to one contractor gave better results than the Hungarian way according to the cost and in helping to speed up the achieving of the project.