Spatial analysis of urban material stock with clustering algorithms: A Northern European case study

Abstract

A large share of construction material stock (MS) accumulates in urban built environments. To attain a more sustainable use of resources, knowledge about the spatial distribution of urban MS is needed. In this article, an innovative spatial analysis approach to urbanMS is proposed. Within this scope, MSindicators are defined at neighborhood level and clusteredwith k-mean algorithms. The MS is estimated bottom-up with (a) material-intensity coefficients and (b) spatial data for three built environment components: buildings, road transportation, and pipes, using sevenmaterial categories. The city of Gothenburg, Sweden is used as a case study. Moreover, being the first case study in Northern Europe, the results are explored through various aspects (material composition, age distribution, material density), and, finally, contrasted on a per capita basis with other studies worldwide. The stock is estimated at circa 84 million metric tons. Buildings account for 73% of the stock, road transport 26%, and pipes 1%. Mineral-binding materials take the largest share of the stock, followed by aggregates, brick, asphalt, steel, and wood. Per capita, the MS is estimated at 153 metric tons; 62 metric tons are residential, which, in an international context, is a medium estimate. Denser neighborhoodswith a mix of nonresidential and residential buildings have a lower proportion of MS in roads and pipes than low-density single-family residential neighborhoods. Furthermore, single-family residential neighborhoods cluster in mixed-age classes and show the largest content of wood. Multifamily buildings cluster in three distinct age classes, and each represent a specific material composition of brick, mineral binding, and steel. Future work should focus on megacities and contrasting multiple urban areas and, methodologically, should concentrate on algorithms,MS indicators, and spatial divisions of urban stock.

Leonardo Rosado

Associate Professor

Studying cities from an Urban metabolism perspective. Its flows and stocks, its functions and needs. To provide information towards urban planning and circular economy.

Holger Wallbaum

Full Professor, Vice-Head of Department and Vice-Dean for Research

Holger is a Full Professor in sustainable building at the Division of Building Technology, research group Sustainable Building, and in the Area of advance Building Futures. Holger works within sustainable building on concepts, tools and strategies to enhance the sustainability performance of construction materials, building products, buildings as well as entire cities.