1. THE VALUE OF STRUCTURAL ENGINEERING TO SUSTAINABLE CONSTRUCTION
Sarah Kaethner: Arup

2. Context

3. UK Built Environment CO2 Timeline
2050

4. Construction Materials are Important
Global C02
Industry
Process optimised for energy = Technology will not solve problem
Construction optimised for cost and time = Market will not solve problem
Lowest cost, fastest construction = More material, less labour

5. Structural Engineering Changes Lives

6. Why we did this research
Structural Engineer’s work is important
Structural Engineers say that clients are not valuing the contribution of Structures
Green Building Rating Schemes are valued by clients

7. Scope & Method

8. Global Project: Many Schemes

9. Structural Team Member
Construction Management
Acoustics
Lighting
Health & Comfort
Energy

10. What do they measure?

11. Evidence based process
Contribution of structure to the schemes
Study of rating schemes from around the world
Study actual project scores
How much should structure be worth?
Literature review & Arup CO2 profiles
Detailed review of credits by topic
Collection of experience through survey
literature review
Recommendations
For scheme
For credits

12. Framework An effective credit would:
Provide incentives for sustainable actions;
Provide a measure of the sustainability of the structure to enable comparison between buildings;
Provide a framework to define sustainable design practices for professionals;
Work as a practical tool which can be deployed cost-effectively during the procurement of buildings.

13. Findings

14. Schemes were not an effective incentive
“In most cases the (BREEAM) Mat1 system is opaque, complicated, counter-intuitive and not linked to significant sustainability improvements..”

15. Materials don’t contribute to high scoring projects

16. Consistency of Credit Topics
Reuse
Recycled Content
Responsible Sourcing
Local Sourcing
LCA
Durability
Efficiency
Adaptation
High Performance
Cement Replacement

17. Individual Topic Assessment
Recycled aggregate example

18. Example: Recycled Aggregate

19. Example: Recycled Aggregate
% of respondents agreeing
BREEAM
>40
20-40
Strengths
Encourages the development of good practice
Does not impact on other aspects of the design
It rewards sustainable actions
The measure is simple and clear
Barriers
Resistance from design and procurement team
Does not respond well to my regional context
Technically difficult
Effort to achieve is not proportional to reward
Too expensive
Measuring the wrong thing/in the wrong way

20. Example: Recycled Aggregate
“It is almost impossible to commercially achieve credit... unless you have lots of hard landscaping to do the % is too high for concrete and misses the opportunities in cement replacement measures which arguably have a much higher impact on sustainability”
“There is some benefit to reduction in waste but aggregates are plentiful in the UK so the impact on resource depletion is... insignificant.”

21. Findings
Low Scores
Common topics
The credit detail is important
Schemes need to support changes in industry not just measure building.

22. Recommendations …..Recycled Content
Super-structure should be excluded from credits which reward whole building recycled content.
If an individual recycled content for structural concrete is included this should include a pre-requisite to reduce Portland cement content, and practical achievable levels of including a known locally available secondary material in the concrete. ……….

23. What has happened since?

24. Life Cycle Assessment more prominent
Additional credits in BREEAM and LEED
Environmental Product Declarations are promoted
Are requirements clear?
Are the tools accessible?

25. Routemap – Carbon Reporting
Now
Develop measurement rules for construction products
Establish databases of performance
Encourage measurement and reporting
Mandatory Environmental Product Declarations (EPDs) for all construction products
Mandatory measuring and reporting of whole life carbon for public buildings through Government procurement
2020+
Set whole life carbon targets in Building Regulations

26. Key issue is Benchmarking
NOT IN BREEAM!

27. Responsible Sourcing Developing

28. Drivers for sustainable design decisions
Materials efficiency/flexibility/durability credits in BREEAM
Little guidance on how to implement in practice

29. Structural Engineer more engaged?
LEED: “One of the things we want to try to do is to initiate a discussion between the designer and the structural engineer in the same way that that energy modelling initiated a discussion between the designer and the mechanical engineer”
(Scot Horst: Chief Product Officer U.S. Green Building Council : 2013)

30. Next Steps

31. Industry BIM for efficiency Life Cycle Assessment, benchmarks and EPDs
Responsible Sourcing
End of Life supply chain

32. Next Steps
Review and guidance for the new credits.
Influence Schemes & Government on important topics e.g. substructure, Building Regulations

33. Structural Engineers
Use WRAP database
Push for EPDs and CO2 tools
Work collaboratively to balance material efficiency, cost and buildability.
Specify to support the material supply chain

34. Structural Team Member