Building Research & Information

The building sector consumes large quantities of resources and generates high levels of construction and demolition (C&D) waste. From an ‘urban mining’ perspective, the building stock can be seen as a repository of natural resources. In order to manage this repository, evidence is needed on its quantity and dynamics. Although data exist for domestic buildings, little evidence exists for non-domestic buildings. A new method is presented to quantify the material stock of non-domestic buildings – based on the German building stock. The quantification process involves three steps: (1) material composition indicators (MCIs) are calculated with respect to various building types; (2) the country's total floor space is estimated and disaggregated; and (3) the total material stock is calculated. The main results are MCIs and the floor space for both domestic and non-domestic stocks, as well as the material mass in total. In Germany the total material mass of non-domestic buildings is approximately 6.8 billion tonnes, accounting for 44% of the entire building stock. The method can be adapted and validated for use in other countries. These results will assist both policy-makers and the construction industry to understand the potential for moving toward a more circular economy.

The dynamics and metabolism of the built environment are important for understanding the construction, renovation and demolition activities that characterize its long-term physical development. Previous research on building stock development is limited, particularly for developing countries. As one of the most seismically active countries in the world, Chile's built environment is constantly subjected to losses. This study included earthquake vulnerability and damage in a dynamic material flow analysis (MFA) of the Chilean housing stock. Stock and flows of residential floor area were modelled using population and life style parameters. Demolition was modelled assuming a constant demolition rate. By characterizing the building stock according to vulnerability classes and establishing a mass balance per class, the effects of different typology distributions on the overall damage to the stock caused by earthquakes could be assessed. Scenarios with different trends in typology distribution for new construction and renovation suggest that significant potential exists for reducing future earthquake damage in the Chilean housing stock. This is best achieved by gradually reducing the vulnerability of buildings to earthquakes. Legislation, building standards and financial instruments could be used to ensure such reductions in earthquake damage and thereby provide socio-economic benefits in the future.

A huge amount of construction material is required in urban areas for developing and maintaining buildings and infrastructure. Ageing stocks, which were built during a period of rapid growth in Japan (1955–1973), will cause a new waste flow in the near future. In order to assess urban metabolism with regard to building and infrastructure, it is necessary to understand change in its material accumulation both ‘spatially’ and ‘temporally’. In this analysis, material accumulation over time is elucidated using four-dimensional Geographical Information Systems (4d-GIS) data at an urban scale. An approximately 8 km2 urban area of Salford in Manchester, UK, and 11 km2 of Wakayama City centre, Japan, were selected as case study sites. In this analysis, the material stock of buildings, roadways and railways was estimated locally over time, using a 4d-GIS database: (1) to find the spatial distribution of construction materials over time, (2) to estimate the demolition curve of buildings based on characteristics of an area, and (3) to clarify material accumulation with vertical location, such as above and below ground, from the viewpoint of recyclability. By estimation of the demolition curve, the life span of buildings in an urban area was found to be shorter than the national average respectively at both sites: 81 years in the urban area of Salford compared with 128 years for the UK; and 28 years in Wakayama City centre compared with the Japanese national average of 40 years. In 2004, 47% of total construction material was stocked in underground infrastructure in Wakayama City centre. Une quantité considérable de matériaux de construction est nécessaire dans les zones urbaines pour construire et entretenir les bâtiments et les infrastructures. Les parcs bâtis vieillissants, qui ont été construits au cours d'une période de croissance rapide au Japon (1955–1973) occasionneront un nouveau flux de déchets dans un proche avenir. Afin d'évaluer le métabolisme urbain du point de vue des bâtiments et des infrastructures, il est nécessaire de comprendre à la fois dans l'espace et dans le temps les changements intervenant dans son accumulation de matériaux. Dans cette analyse, l'accumulation de matériaux au fil du temps est élucidée en utilisant les données de Systèmes d'Information Géographique quadridimensionnels (SIG-4D) à une échelle urbaine. Un secteur urbain d'environ 8 km2 de Salford, à Manchester, au Royaume-Uni, et 11 km2 du centre-ville de Wakayama, au Japon, ont été sélectionnés comme sites pour cette étude de cas. Dans cette analyse, le parc de matériaux constitué par les bâtiments, les routes et les voies ferrées a été estimé localement au fil du temps, en utilisant une base de données SIG-4D: (1) pour découvrir la distribution spatiale des matériaux de construction au fil du temps, (2) pour estimer la courbe de démolition des bâtiments en se basant sur les caractéristiques d'un secteur, et (3) pour clarifier l'accumulation de matériaux par leur emplacement vertical, tel qu'au-dessus et en dessous du sol, du point de vue de la recyclabilité. Grâce à l'estimation de la courbe de démolition, il a été découvert que la durée de vie des bâtiments dans un secteur urbain est inférieure à la moyenne nationale sur les deux sites, respectivement: 81 ans dans le secteur urbain de Salford, comparé à 128 ans pour le Royaume-Uni; et 28 ans dans le centre-ville de Wakayama, comparé à la moyenne nationale japonaise de 40 ans. En 2004, 47% de la totalité des matériaux de construction, dans le centre-ville de Wakayama, étaient accumulés dans les infrastructures souterraines. Mots clés: parc bâti, Systèmes d'Information Géographique quadridimensionnels (SIG-4D), parc des infrastructures, flux de masse, intensité en matériaux, analyse du parc de matériaux, développement durable, temps, flux de masse urbaine