BSG: COVID-19 site breaches in decline in UK
The Building Safety Group (BSG) reports a considerable decline in the amount of COVID-19 breaches reported on construction sites.
The report, commissioned by the UK’s largest construction safety group, BSG, has reported a 41% decline in the number of COVID-19 safety breaches on construction sites around the United Kingdom.
The figure is based over a three month period. The decline is thanks to construction companies implementing more stringent COVID-19 safety measures. These include strict social distancing measures.
The report is based on a total of 4400 independent site visits which were conducted by Building Safety Group between the beginning of June and the end of August.
Although most breaches which were measured were minor, there were more than 50 major breaches during June 2020, reducing to around 20 in August. The total number of non-compliances measured sank to around 75 during August 2020, compared to well over 120 in June.
It has been estimated by The Building Safety Group that the figure surrounding breaching the guidelines will reduce even further as construction companies and contractors become more accustomed to different working conditions relating to COVID-19 for the rest of 2020 and beyond.
The Building Safety Group has revealed some of the most common non-compliances that it reported on-site over the last quarter. The most common issue surrounded social distancing, which management and operatives not following the guidelines. Other breaches included inadequate welfare facilities on-site combined in insufficient cleaning regimes.
BSG also observed insufficient segregation amongst staff in canteens and other communal areas. A lack of hand sanitizing stations and PPE use were also highlighted in the report, in addition to outdated Site Operating Procedures found on site.
Stephen Bell, BSG’s Managing Director, said: “We are pleased to see that Covid-19 breaches have fallen since we began risk assessing companies’ prevention measures to counter the coronavirus. Although we expect this downward shift to continue, now is not the time to become complacent so it is vital that our industry remains vigilant and continues to follow government Site Operating Procedure (SOP) guidelines.”
About The Building Safety Group
Working as the United Kingdom’s largest construction safety organization, BSG operates across the nation with a goal of improving health, safety and environmental performance on construction sites. It is a not for profit organisation and currently has over 800 members which are spread across 3500 workplaces, all over the UK.
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.