## 1 Introduction
While this method was a useful tool to predict the waste amount of each construction material, there was an accuracy problem depending upon the waste rate provided by the project manager. Another method is to estimate the construction waste generation based on the constructed area data (weight/m\({}^{2}\) or volume/m\({}^{2}\)). This method is applied to the waste generation rate per square meter by different types of buildings [17; 21; 22; 23]. It would be useful to provide information on bulk waste generation without categorising the construction materials. On the other hand, this method could be difficult to use to compare the amount of construction waste between different construction methods or techniques that require different quantities of construction materials. Furthermore, the accuracy of the estimated waste amount in this method would be dependent upon the regional database and is difficult to apply to other regions [22]. For example, [PERSON] [24] carried out a study to quantify the construction waste generation from new buildings, renovations, extensions, demolition, and informal construction works in the Brazilian context. Moreover, [PERSON] et al. [25] proposed a method to estimate waste streams from various construction stages which would be able to be generally applied to any regions or countries. Similarly, [PERSON] et al. [26] determined the construction waste of new residential buildings as the waste volume (m\({}^{3}\)) in relation to a building's total floor area (m\({}^{2}\)). In construction projects, the main source of construction waste is the loss of construction materials due to the inappropriate use of construction materials by unskilled construction workers. In particular, the typical cast-in-place reinforced concrete is composed of various types of sub-works where the formwork, reinforcement, casting, and curing are carried out on site. When conducting the concrete construction work, the amount of waste generated by the formwork and reinforcement would vary depending upon the skill level of each worker. In order to lower the generation of waste during the construction phase, several construction methods have been proposed. For example, prefabrication is regarded as an efficient method to reduce the construction waste at a site [3; 6; 15; 17]. In this method, components of a building or structure are manufactured in a factory or other manufacturing site and transported to the construction site and assembled on site. According to [PERSON] et al. [15], the application of prefabrication would achieve construction waste reductions of up to 52% on site in the context of Hong Kong. The prefabricated construction method would not only directly affect the main construction works on site but also to reduce the subsequent waste handling activities such as sorting, recycling, transporting, and disposal [6]. In a similar vein, there are several structural design variations to lower cast-in-situ formwork and reinforcement work. A number of studies have claimed that the design of a structural system could not only reduce the amount of building materials but also mitigate greenhouse gas emissions [27; 28; 29; 30]. For example, [PERSON] et al. [28] assessed the carbon dioxide emissions between different structural systems applied in an apartment building in South Korea. Similarly, [PERSON] and [PERSON] [31] indicated that the structural design would have a significant impact on the life cycle carbon emissions of a building based on a comprehensive assessment of embodied carbon and operating carbon. Along with the studies of greenhouse gas emissions from different structural systems, [PERSON] et al. [32] corroborated the construction waste generation of three different structural systems, namely conventional construction, mixed construction, and precast construction. In this study, they claimed that precast construction achieved the lowest waste generation rate with 0.016 tons of construction waste per square floor area in a Malaysian context.