Modelling waste generated during construction of buildings using regression analysis.

The building industry is responsible for a large amount of waste, and the measurement and modelling of this waste could be used to develop better waste management plans. Several theoretical models explain the relationships between waste and building characteristics, but local practices may result in different behaviours. This study aimed to measure and analyse the waste generated through construction. It was based on the analysis of 18 building sites located in the region of Porto Alegre, Brazil. Waste was measured at these sites, and the results showed an average waste generation rate of 0.151 m3 m-2. A regression analysis of the collected data presented a satisfactory performance in two models. The first model was developed to explain total waste generation, including the effects of certain attributes, with an R2 = 0.81. The changes in waste generated during construction were estimated. The second model considered time schedules and examined the effect of the construction stage on waste generation, and reached an R2 = 0.91. The model with time indicated an S-shaped relationship. The models presented satisfactory statistical parameters and could be used to produce better waste management plans in the preconstruction stage.

Factors influencing temporary wood waste generation in high-rise building construction.

In Brazil, the use of wood in construction is primarily temporary, and it can represent a great percentage of construction waste. It is typically discarded with minimal reuse or recycling. As landfill wood disposal could result in methane emissions and/or leaching of hazardous constituents polluting water or soil, the implementation of temporary wood waste reduction strategies must be a critical issue for local construction companies. To manage and control wood waste generation, including setting some reduction goals, it is necessary to identify the influencing factors and ways to quantitatively predict their relative contributions. This study uses a multiple regression statistical model to estimate the amount of temporary wood waste generated in the construction of high-rise buildings by considering the influencing factors related to the design/construction as well as site and safety installations. The case study includes 22 high-rise residential buildings. The regression model predicted approximately 89% of the factors involved in the generation of wood waste in similar constructions. The dependent variables that had an influence on the amount of wood waste are related to design features ('number of floors'), structural construction system ('in situ moulded concrete volume'), and site and safety installations ('site wood fence' and 'wood use rate'). Ways of minimising wood waste generation and the contributions of each type of temporary wood use were discussed.