New line-up for UK Green Construction Board
The refreshed Green Construction Board recently held a meeting chaired by Mike Putnam, CEO of Skanska UK. He said: “I am looking forward to continuing in the role as the Chair of the Green Construction Board and to working with a wide selection of industry leaders to deliver on our ambitious and challenging priorities. There is a clear need for leadership and action from the industry if we are to deliver a low carbon future and I believe we are well placed to do this.”
The industry-led GBC GCB is the sustainability workstream of the Construction Leadership Council and its role is: ‘To provide leadership and action to enable the whole value chain (clients, contractors, product manufacturers, suppliers and others) to become more environmentally sustainable, more productive and better placed to exploit the growing global market.’
The meeting focused on how the GCB will deliver on its priorities:
- Championing, leading and supporting action to reduce greenhouse gas emissions from infrastructure, domestic (housing) and non-domestic built environment sectors, in line with the pathway outlined in the Low Carbon Routemap (reductions of greenhouse gases by 50% by 2025 and 80% by 2050) and report on progress.
- Supporting the construction sector to move towards a circular economy business model to improve resource efficiency and productivity.
Commenting on the new line-up, Skills Minister and Co-Chair of the Construction Leadership Council, Nick Boles said: “The new Green Construction Board members bring together some of the best expertise in industry. The refreshed Board will build on the work of the new Construction Leadership Council, delivering its sustainability agenda to help the UK achieve a more low carbon built environment.”
The members of the Green Construction Board are:
George Adams - Director for UK Energy & Engineering, Spie
Mark Bew - Chair of the UK BIM Task Group
Tim Chapman - Director / Leader for Infrastructure London Group, Arup
Louise Clarke - Group Sustainability Manager for Berkeley Group and Chair of CIC 2050 Group
Alan Couzens - Director, Infrastructure UK, HMT
Munish Datta - Head of Facilities Management and Plan A, M&S
Louise Ellison - Head of Sustainability, Hammersons
David Hancock - Head of Construction, Cabinet Office
Julie Hirigoyen - Chief Executive of the UK Green Building Council
Peter Hunt - Chief Operating Officer for the Lighting Industry Association Chief Executive Lumicom Ltd and Vice President of Lighting
Rob Lambe - Managing Director, Willmott Dixon Energy Services
Chris Newsome - Director of Asset Management, Anglian Water
Rob Pearce - Consultant to Haskoll Architects & Designers
David Purdy - Director for Energy Efficiency Deployment Office, DECC
Mike Putnam - President and CEO of Skanska UK
Peter Schofield - Director-General for Neighbourhoods, DCLG
John Sinfield - Managing Director for Knauf Insulation Northern European and Chairman of the Construction Products Association
Lynne Sullivan - Co-founding partner, SustainableBYdesign
Robin Webb - Deputy Director, Retail, Construction & Rail, BIS
Peter Williams - Technical Director, European Hub, Laing O’Rourke
Why engineers must always consider human-induced vibration
Human induced vibration, or more accurately vibrations caused by human footfall, often conjures images of Millennium Bridge-style swaying or collapsing buildings.
But in reality, the ‘damage’ caused by human-induced vibrations is less likely to ruin a structure and more likely to cause discomfort in people. Though not as dramatic as a structural failure, any good engineer wants to make sure the people using their structures, be it bridges or buildings or anything in between, can do so safely and comfortably. This is why human-induced vibration must be considered within the design process.
Resonance v Impulse
There are two ways that human-induced vibrations affect structures: resonant, and impulse or transient response. Put simply, resonance occurs when Object A vibrates at the same natural frequency as Object B.
Object B resonates and begins to vibrate too. Think singing to break a wine glass! Although the person singing isn’t touching the glass, the vibrations of their voice are resonating with the glass’s natural frequency, causing this vibration to get stronger and stronger and eventually, break the glass. In the case of a structure, resonance occurs when the pedestrian’s feet land in time with the vibration.
On the other hand, impulse or transient vibration responses can be a problem on structures where its natural frequencies are too high for resonance to occur, such as where the structure is light or stiff. Here the discomfort is caused by the initial “bounce” of the structure caused by the footstep and is a concern on light or stiff structures.
Engineers must, of course, design to reduce the vibration effects caused by either impulse or resonance.
Potential impacts from human induced vibration
Human induced vibration can lead to a number of effects upon the structure and its users. These include:
- Interfering with sensitive equipment Depending on the building’s purpose, what it houses can be affected by the vibrations of people using the building. Universities and laboratories, for example, may have sensitive equipment whose accuracy and performance could be damaged by vibrations. Even in ordinary offices the footfall vibration can wobble computer screens, upsetting the workers.
- Swaying bridges One of the most famous examples of human-induced resonance impacting a structure occurred with the Millennium Bridge. As people walked across the bridge, the footsteps caused the bridge to sway, and everybody had to walk in time with the sway because it was difficult not to. Thankfully, this feedback can only occur with horizontal vibrations so building floors are safe from it, but footbridges need careful checking to prevent it.
- Human discomfort According to research, vibrations in buildings and structures can cause depression and even motion sickness in inhabitants. Tall buildings sway in the wind and footsteps can be felt, even subconsciously by the occupants. It has been argued that modern efficient designs featuring thinner floor slabs and wider spacing in column design mean that these new builds are not as effective at dampening vibrations as older buildings are.
- Jeopardising structural integrity The build-up of constant vibrations on a structure can, eventually, lead to structural integrity being compromised. A worse-case scenario would be the complete collapse of the structure and is the reason some bridges insist that marching troops break step before crossing. Crowds jumping in time to music or in response to a goal in a stadium are also dynamic loads that might damage an under-designed structure.
How to avoid it
As mentioned, modern designs that favour thinner slabs and wider column spacing are particularly susceptible to all forms of vibration, human-induced or otherwise, but short spans can also suffer due to their low mass. Using sophisticated structural engineering software is an effective method for engineers to test for and mitigate footfall and other vibrations at the design stage.