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The concept of a materials passport is a healthy sustainability solution for structural engineers. Nothing is lost, everything is re-created, everything is reused.

Traditionally, structural engineers have followed optimisation procedures to reduce material usage, increase the efficiency of designed systems, and consequently reduce negative environmental impacts.

Recently, a new procedure, termed healthy sustainability has emerged, aimed at creating positive rather than reducing negative environmental impact. An example of a healthy sustainability approach is a building whose elements can be reused in the same or different project or product at any time under its operational service or at the end of life.

Reusing structural elements not only has the potential to significantly reduce embodied energy, but also addresses recourse limitation issues, and brings a cost-effective solution to construction value chains, governments, and end-user benefits.

 

Research that drives #sustainablesteel

Material passports are sets of data that describe specific features of materials in products that give them value for recovery and reuse [1]. As a result, waste will be reduced, and fewer virgin resources will be used [2].

HERA is working to develop a steel circularity passport based on this principal in an effort to better facilitate structural steel reuse. This will be the first material passport in the Australasian construction sector of its kind, and serve as a proof of concept to significantly assist the New Zealand construction sector to develop material passport capability for other building components and materials.

This is based on a strategy of healthy sustainability – known as cradle to cradle to cradle (C2C2C). Implementing a C2C strategy requires the development of a circular economy [3], and transformation to a circular economy requires both a C2C strategy and design for reconstruction.

 

Priority approaches to prevent and minimise waste in construction are to [3]:

  1. reuse in the original system;
  2. maintain/refurbish;
  3. reuse in new systems; and
  4. recycle/reprocess.

 

Options 1, 2, and 4 are globally common practices, whereas reusing structural elements in new contents (option 3) is rare.

This is significant for the steel industry as structural steel is reusable and can be recycled infinitely. Steel buildings are generally dismountable via reversible connections and therefore comparatively simple to re-use. It is possible to cut and reshape structural steel elements, which normally have predefined cross-sections and grades. Visual, acoustic, and load testing can also be used to determine the capacity of steel elements [3].

This development is also part of a broader HERA research program (Structures As Steel Banks (HERA-SASB)) aimed at addressing broader research gaps and considering industry needs for even greater participation in the circular economy.

sasb-chart
kaveh-andisheh
Kaveh Andisheh

General Manager Structural Systems

Our key focuses:

Bridging the gap of understanding

HERA Report R4-159: Common language in Structures as Steel Banks

In raising the idea of a materials passport for steel in structures, we have found one of the key barriers is that many are unaware of, or do not understand the key concepts underpinning it. This impedes clear communication in an interdisciplinary grouping where each expert is accustomed to using their own terminology.

To address this, one of the first focuses we have had, was to identify, review and redefine the common language used so it reflects steel construction and its practice in New Zealand more clearly.

In essence, putting the concept into familiar terminology used in steel construction to bridge the gap of understanding and communication.

hera-report-r4159
Click here to find out more.

Making steel the low-carbon choice

This project investigates the challenges relating to the use of structural steel, to meet the New Zealand Government’s targets of achieving 50% carbon reduction by 2030 and net zero by 2050.

It outlines the challenges and opportunities to achieving those goals, as well as identifying solutions relating to the design and use of structural steel, to achieve the lowest whole-of-life carbon usage in a typical building or bridge structure.

It identifies critical development of the design tools and guidance that will change the way how practitioners approach the design of structures. In reality, what is being changed is the whole philosophy relating to humans’ relationship with the built environment and nature.

This project concludes that by harnessing innovations in the construction of our built environment, including recycled and more sustainably manufactured steel, designers and engineers are well placed to deliver solutions that will drive down emissions and help lessen the impacts of climate change.

An online corrosion category map

HERA has recently developed a GIS model covering the whole of NZ with shapefiles of the corrosion categories, based on Table 2 from TS3404 overlaid on the more general dataset that has been developed by NIWA and HERA and used for the maps in TS3404.

The resultant tool will enable users to search by address and determine the corrosion classification based on Table 2. This will also identify how close a site is to the boundary of a corrosion classification. Such sites may require more in-depth investigation before allocating a classification.

This tool will assist engineers to improve the specification of steel coatings for the correct macroclimate corrosion zone and therefore support the correct specification and also improved durability.

Enhancing steel durability will improve and facilitate its reusability.

Development of numerical indentation simulation to facilitate structural steel reuse

Steel re-use has the potential of saving up to 96% of environmental impacts compared to new steel, so it significantly improves construction sustainability.

One of the hypothesised barriers to steel reuse is a concern related to steel properties. To reuse structural steel elements, it must be verified that they have not been subjected to their yield stress. To determine this, lab testing is required or conservative re-use assumptions must be made. Lab testing is intrusive and costly, so it likely to be amongst the most important barriers to structural element reuse.

This research will investigate the feasibility of non-intrusive, cost-effective approaches to estimate mechanical properties of structural steel to facilitate reuse.

 

This will include:

  1. development of required finite element models;
  2. sensitivity analysis of the numerical simulations results; and
  3. study of the role of non-intrusive test data, finite element analysis and mathematical frameworks in the estimation of steel mechanical properties.

[1] Building as Material Banks (BAMB)- MP video- https://youtu.be/9pB6axd7gQk

[2] Buildings as Material Banks (BAMB)- https://www.bamb2020.eu/

[3] Fivet, C., & Brütting, J. (2020). Nothing is lost, nothing is created, everything is reused: structural design for a circular economy. The Structural Engineer, 98(1), 74-81.