Construction materials constitute a major cost component in any construction project. Construction projects can be accomplished utilizing management processes. These processes include planning, organizing, executing, monitoring, and controlling (Ahuja et al 1994). During any construction project the three inter-related factors of time, money, and quality need to be controlled and managed. Successful completion of projects requires all resources to be effectively managed. Materials management is considered as a means to achieve better productivity, which should be translated into cost reduction.
The total cost of installed materials (or value of materials) may be 50% or more of the total cost (Stukhart 1995, Bernold and Treseler 1991), even though the factory cost may be a minor part of the total, probably less than 20-30%. This is because the manufactured item must be stored, transported, and restored before it is put in place or "consumed" at the site. The total cost of materials will include, in addition to the manufacturer selling cost, the cost of procurement (cost of placing processing and paying the material, physical distribution, the distributor's cost, and the transportation of materials), and the site-handling costs (cost of receiving, storage, issuing, and disposal). The efficient procurement and handling of material represent a key role in the successful completion of the work. It is important for the contractor to consider that there may be significant difference in the date that the material was requested or date when the purchase order was made, and the time at which the material will be delivered. These delays can occur if the contractor needs a large quantity of material that the supplier is not able to produce at that time or by any other factors beyond his control. The contractor should always consider that procurement of materials is a potential cause for delay (Willis, 1986). Poor planning and control of materials, lack of materials when needed, poor identification of materials, re-handling and inadequate storage cause losses in labour productivity and overall delays that can indirectly increase total project costs. Effective management of materials can reduce these costs and contribute significantly to the success of the project.
BACKGROUND
The Webster's dictionary defines materials as "the elements, constituents, or substances of which something is composed or can be made." Ballot (1971) defines materials as the physical materials that are purchased and used to produce the final product and does not suggest that materials are the final product. In other words, materials are the parts used to produce the final product.
Bailey and Farmer (1982) define materials as the goods purchased from sources out of the organization that are used to produce finished products. Stukhart (1995) defines materials as the items that are used to produce a product and which include raw materials, parts, supplies and equipment items. Chandler (1978) states that construction materials can be classified into different categories depending on their fabrication and in the way that they can be handled on site. He classifies the materials into five categories. They are:
Bulk materials- these are materials that are delivered in mass and are deposited in a container.
Bagged materials- these are materials delivered in bags for ease of handling and controlled use.
Palleted materials- these are bagged materials that are placed in pallets for delivery.
Packaged materials- these are materials that are packaged together to prevent damage during transportation and deterioration when they are stored.
Loose materials- these are materials that are partially fabricated and that should be handled individually.
Table 2.1 presents some examples of commonly used materials in construction and their classification.
Table 2.1: Classification of Materials (Adopted from Chandler, 1978)
Material
Bulk
Bagged
Palleted
Packaged
Loose
Sand
X
Gravel
X
Topsoil
X
Paving Slabs
X
Structural Timber
X
Cement
X
X
X
Concrete
X
Pipes
X
X
Tiles
X
Doors
X
Electrical Fittings
X
Stukhart (1995) states that the main categories of materials encountered in a construction project are engineered materials, bulk materials, and fabricated materials.
Bulk materials- these are materials manufactured to standards and are purchased in quantity. They are bought in standard length or lot quantities. Examples of such materials include pipes, wiring, and cables. They are more difficult to plan because of uncertainty in quantities needed.
Engineered materials- these materials are specifically fabricated for a particular project or are manufactured to an industry specification in a shop away from the site. These materials are used for a particular purpose. This includes materials that require detailed engineering data.
Fabricated materials- these are materials that are assembled together to form a finished part or a more complicated part. Examples of such materials include steel beams with holes and beam seats.
Stukhart (1995) defines material management as the activities involved to plan, control, purchase, expedite, transport, store, and issue in order to achieve an efficient flow of materials and that the required materials are bought in the required quantities, at the required time, with the required quality and at an acceptable price. Plemmons and Bell (1995) define material management as the plan and control of all activities to ensure the correct quality and quantity of materials and equipment to be installed as specified in timely manner, obtained at reasonable cost and are available when needed. Dobler and Burt (1996) state that material management is designed to improve the activities related to the flow of materials. They add that material management should coordinate purchasing, inventory control, receiving, warehousing, materials handling, planning, and transportation.
STATEMENT OF PROBLEM
SCOPE AND LIMITATION OF STUDY
The scope of this study is focused on finding out the material management practices used by contractors at the pre contract and post contract level of construction projects in Ghana and accessing the major challenges. The research is done within the context of the following;
It focuses on random selected Ghanaian Contractors.
The respondents are Ghanaian Construction firms resident in Ghana only.
Data is collected from professionals at senior management level or personnel who are relevant to decision making of the firm.
AIM OF STUDY
The main aim of this study is to investigate the material management practices used by contractors at the pre contract and post contract level of construction projects in Ghana.
OBJECTIVES OF STUDY
The aim of this research can be broken down into the following objectives:
Find out existing material management practices used at the pre contract and post contract level by the Ghanaian contractor.
Identify problems faced by the Ghanaian contractor in managing materials for construction works.
Recommending better material management practice as well as solutions to some of the major problems the contractors face at the pre contract and post contract level.
METHODOLOGY OUTLINE
The research is conducted through the following stages:
First stage: Literature Review
Materials management related literature was reviewed to identify the main topics and concepts that related to this research.
Second Stage: Field Survey
A survey of the local materials management practices of contracting companies in Ghana was made. A structured questionnaire was used and the person in charge of managing construction materials in the company was interviewed. Statistical analysis for questionnaires was done by using Statistical Package for the Social Sciences (SPSS). Discussion for the obtained results was also made.
Third Stage: Model Formulation and Evaluation
A better material management practice system was developed based on the results obtained from the field survey. This system was evaluated by experienced contractors after applying it on ongoing projects.
