Optimizing Mass Timber Bay Size in terms of Costs and EC Emission

Abstract

The built environment accounts for the largest portion of global carbon emissions. In particular, carbon emissions known as embodied carbon (EC) emitted from traditional building structures such as concrete and steel frames accounts for one-third of the total emissions. In the future, the proportion of EC is expected to increase further and in response to this, a significant amount of studies suggest the use of mass timber structure as a low carbon solution. However, the cost of mass timber is still relatively high compared to traditional material, which is a primary reason that mass timber is still under-utilized. In addition, studies on optimization of mass timber bay size, which can be an effective method to lower costs and EC emission, are limited. That makes it difficult to identify the optimal alternatives in terms of cost and EC emission under current mass timber design processes. To fill this knowledge gap, this study aims to develop a new approach—named the timber bay cost and carbon optimization approach (TBCCOA)—which can support effective comparison between various mass timber alternatives in terms of volume, cost and EC emission in the initial design stage. To demonstrate the validity and usability of the TBCCOA, I developed two scenarios, and valuable findings on optimization of mass timber bay size were discovered by comparing the cost and EC emission of diverse virtual structure alternatives. The key findings of the scenarios include that (1) 6 m à 6 m is the optimal bay size for mass timber structure in terms of volume, cost and EC emission in general and (2) the application of square bay is more efficient than the rectangular bay. These results of the present study can support project stakeholders, when adopting mass timber as building structure, to reduce construction costs and EC emission of buildings at the initial design stage, as a way to mitigate global climate change. In addition, future researchers can utilize the information derived from this study as a stepping stone for bay size standardization of mass timber buildings.