Economic Rebar Order Quantity Model for Construction Project

Abstract

Planning and ordering construction materials is a highly complex problem in the construction industry as it has to order the right type of material in the right quantity and at the right time. Otherwise it will cause losses and consequences. This study is to develop an Economical Order Quantity Model for Construction Projects. By reducing the limitation of the current method to calculate by ordering the same amount every time and have the same frequency this may result in higher expenses, for example the cost of storing the remaining rebar after ordering in excess of daily demand. Therefore, the researcher has studied and developed a Modified Economic Order Quantity Model in order to calculate the timing of ordering rebar in accordance with the project schedule to reduce the ordering cost, holding cost, delivery cost, handling cost, opportunity cost, penalty cost, indirect cost and idling cost and reduce delays in construction activities by using a Genetic Algorithm to help find the best answer for the time and quantity to order construction materials. This method has the advantage of helping to find the closest answer to the best answer can find the trend of improved answers and help create a plan for ordering steel bars in many forms the above methods have been used to experiment with case study projects, both of which consider the fastest time and the case that takes into account the cheapest cost. It was found that the modified economic order quantity model method compared to EOQ with Planned Shortage and EOQ with quantity discounts found that it can help reduce the time and cost to be less.