Defining infrastructure

The Organisation for Economic Co-operation and Development (OECD) defines infrastructure as ‘transport, communication, electricity, safe water and sanitation, health infrastructure and other basic facilities’24 .

This definition covers both horizontal and vertical infrastructure. While other definitions exist25, the OECD definition distinguishes two categories:

• Horizontal Infrastructure, which is composed mainly of:

- Transportation: roads, railways, and bridges

- Power & Communication: transmission facilities, electric lines, energy generation

- Subterranean: pipelines, sewer, waterlines.

• Vertical Infrastructure, also called Social Infrastructure (buildings and spaces that facilitate the delivery of social services by governments and other service providers):

- Buildings - hospital, public universities, public housing, etc.

- Surface - parking areas, subsurface or structured facilities - Structure - any building foundation and site work that facilitate the delivery of buildings

The infrastructure sector is highly diverse. As a result, the efforts around resilience, carbon mitigation and circularity are different across sectors, markets and stakeholders.

Although the infrastructure and building sectors vary, they are certainly interdependent and have areas of overlap, primarily:

• Interdependency in use – despite their difference in purpose, together buildings and infrastructure comprise a shared urban ecosystem.

• Shared construction supply chain – buildings and infrastructure use broadly similar materials and operate similar processes of design of construction, with a shared material supply chain.