Optimization of reinforcement steel supply to precast concrete plants

Abstract

In addition to aggregates, cement, and water, reinforcing steel is one of the key building components of precast products. Steel price fluctuations observed on global markets have a large impact on the cost of production of precast products made of reinforced and prestressed concrete. An important issue is, therefore, the proper planning of steel orders and deliveries to the precast concrete plants. A significant number of competing warehouses and construction warehouses offer diversified steel prices, which are subject to frequent changes in relatively short periods. This results in a problem in the selection of an appropriate procurement strategy by precast concrete plants. An additional unfavorable factor is the ordering of reinforcing steel that is too large in relation to the demands of the precast concrete plants, resulting in high costs of its storage in the warehouses or storage yards. In this paper, the issues of optimal planning and delivery of plain, ribbed, and prestressing steel were discussed. For the research and calculation purposes, supplies of steel from four wholesalers to four different precast concrete plants were assumed. In addition, the types of steel and the class of bars used to reinforce the elements were discussed. A different level of unit prices for the purchase and delivery of steel in each warehouse and a different demand for each of the four concrete plants were also assumed. As a result of the analyses carried out, a model was developed, including the strategy of purchasing and supplying plain, ribbed, and prestressing steel with the assumption of minimum costs.