Introduction
The material waste has been recognized as a major problem in the construction industry and has important implications for industry efficiency and environmental impact of projects( Formoso 2002). However, the early stages of product development process have been failing in defining product solutions that meet the rationalisation of production aimed at avoiding waste of high-value materials and low productivity of manpower. This gap is more harmful to the social housing projects where the reduction of costs and time is significantly important. There are two variations of the industrialized construction system approached in this research: Light Wood Frame( LWF) or Light Steel Frame( LSF). Both of them prove to be an alternative technology with potential for the rationalisation of the construction process, especially for low-income housing projects. The main benefits to the production process are:( 1) the possibility of a significant reduction in the lead time, which is an important issue in social housing;( 2) the opportunity to simplify the tasks carried out in the construction site; and( 3) the reduction of material waste if the design takes account of the components’ connections; and( 4) the insertion of the pipe building facilities( electrical, water and sewage) in the empty space between two wood structural panels( OSB- Oriented Strand Board). This last benefit has implications also in the elimination of the interdependence between production tasks and the reduction of waste, since it eliminates the need to demolish walls for the insertion of building facilities and for the maintenance in the use phase. In this research, LWF is the construction system studied. Its main characteristic is the wall’ s configuration which is composed of a continuous sheathing made of wood structural panels( OSB- Oriented Strand Board) nailed on a light wood frame. The exterior and internal finishes are attached on the OSB. This system is suitable for the construction of buildings up to five floors( LPBRASIL 2011). Both construction systems, the light steel frame and light wood frame, can be performed using three construction methods: stick, panels or modular( Freitas and Crasto 2012). In the stick method, all stages of production are carried out on site, since the assembly of framing until the sheathing with the wood structural panel, finishing, and the passage of installations. In the panels’ method, the production of walls, slabs and roofs is performed at the factory and assembled on the construction site. The use of this method increases the dimensional precision and reduces the tasks carried out on the site, allowing a higher production speed. The modular method corresponds to units completely pre-manufactured that are delivered on site with all the finishes, insulations, windows, bathroom components( toilet, sink, and shower) and piping. The possibility of rationalisation, especially the reduction of lead time, increases as the steps of the production process are transferred from site to the factory. These industrialized construction systems enable the designers to achieve minimum levels of material waste. However, the effective rationalisation depends on the quality of design and planning, which should ensure the best utilization of high-value materials. A wide variety of components may impair the rationalisation of the construction process. Thus, there should be a concern in the definition of the wall panels to reduce the material waste( OSB and finishing boards), in addition to maintaining a low variation of panels to be produced in the factory. This aspect should be intensively considered in mass production. It was not possible to find scientific papers discussing design solutions for reducing material waste of panels. Therefore, the aim of the present study is to present design solutions for reducing material waste of the wall panels. The study was carried out during the development of the product design. The data of material waste and its causes allowed the analysis of the design
334 ZEMCH 2015 | International Conference | Bari- Lecce, Italy