OPTIMIZATION MODEL OF MATERIALS AND WASTE REDUCTION IN VOLUMETRIC PREFABRICATED MODULES FOR VERTICAL RESIDENTIAL UNITS

• Main Author: Luh Made Rai Dyah P, Ni
• Format: Theses
• Language: Indonesia
• Subjects: Struktur arsitektur
• Online Access: https://digilib.itb.ac.id/gdl/view/84309
• Institution: Institut Teknologi Bandung

Sustainable development is one of the global commitments aimed at addressing the increasingly uncontrollable impacts of climate change. Similarly, in housing development, sustainability aspects must be considered given the continuously increasing demand for housing year after year, particularly in urban areas. Sustainable-oriented housing development not only positively impacts the environment but also benefits the community by providing healthy, comfortable, and sustainable living spaces for both current and future generations. Therefore, various ongoing efforts and innovations in housing construction are required. This study focuses on innovative housing development efforts through the reduction of construction waste and lowering of embodied carbon (EC) in residential constructions by implementing Design for Disassembly (DfD) scenarios and modular prefabrication construction methods. The primary goal of this research is to reduce embodied carbon and construction waste by applying the principles of circular economy. This study employs the DfD approach and volumetric prefabrication modules, offering potential solutions to mitigate these environmental impacts. Specifically, this research has four main objectives: the first is to identify the key parameters in reducing construction waste and decreasing EC through volumetric modular prefabrication systems and housing units in Indonesia. The second objective is to examine the assumptions of implementing DfD scenarios on volumetric prefabrication modules and apartment units in Indonesia. The third is to compile inventory data and calculation assumptions needed to achieve an optimal volumetric prefabrication module, and lastly, to analyze the comparative impact of emissions from volumetric prefabrication modules in DfD scenarios against apartment units in Indonesia. This study used distributional analysis, descriptive methods, and ANOVA to address the first objective. The second objective was addressed using node-edge graphical analysis methods. The third objective was achieved using experimental simulation methods with a parametric evolutionary simulation approach utilizing Rhinoceros 3D (Rhino), Grasshopper3D (GH), and its plugin 'Wallacei', along with quantitative analysis using the Life Cycle Assessment (LCA) framework. The fourth objective used comparative analysis. The results indicated that the dimensional limits for volumetric prefabrication modules are a width of 2 meters, a length of 12 meters, a height of 3 meters, and a weight of 35 tons. The selection of primary materials did not affect the width of the modules, which ranged from 1.875 to 5.5 meters, but did impact the length of the modules, with ranges from 3.85 to 12.2 meters for steel, 2.1 to 10 meters for concrete, and 6.4 to 12 meters for wood. The height of the modules was influenced by the standards of spatial comfort, ranging from 2.3 to 3.9 meters. The positions of windows and doors were treated as constant variables, while the function of pods was not included in the optimization process. The study also identified the material specifications and dimensions used during assembly. Regarding the Design for Disassembly (DfD) scenarios, the study found that the Four-Sided Steel and Corner Column Steel scenarios could maintain steel materials in the second life cycle, while the Concrete DfD scenario allowed for the retention of concrete materials if wall and floor elements were not dismantled. The Wood and CLT Wood DfD scenarios required new material use for the second life cycle, with CLT unable to maintain concrete materials. Concerning the process of determining the optimal volumetric prefabrication module, three main stages were conducted. The first stage involved setting up experiments with prototype development, design calibration, GHG calculations, and determining fitness objectives. Simulations were performed both jointly and separately for each module type. The second stage involved analyzing experimental results, where the second simulation showed performance improvements for each objective compared to the first simulation. The third stage included a selection process comprising Pareto Front selection, manual evaluation based on efficiency ratios, and geometric analysis, resulting in optimal solutions for each module type. Evaluations indicated a need for adjustments in the corner column steel solutions related to GHG waste, noting that the least waste does not always correlate with module accuracy, depending on the assembly process and material dimensions. In the comparative analysis among the study objects, results from the cradle-to-grave analysis indicated that the highest emission reductions were seen in the four-sided steel module, followed by corner column steel, wood, concrete, and CLT wood units. In a cradle-to-cradle context, wood and CLT wood prefabrication modules showed significant emission reductions, with CLT wood standing out due to its significant and negative biogenic carbon values, indicating its ability to absorb carbon from the atmosphere.