May 16, 2020

AECOM joins the Campbell Institute as a Charter Member

AECOM
US Construction
Health & Safety
Global Construction
Admin
2 min
The buyout will see the emergence of a substantial conglomerate
AECOM has been chosen to join the Campbell Institute as a Charter Member following a thorough review of its approach and superior performance by the ins...

AECOM has been chosen to join the Campbell Institute as a Charter Member following a thorough review of its approach and superior performance by the institute’s partnership and steering committees.

Grounded in the belief that safety, health and environmental (SH&E) management is at the core of business vitality and intrinsic to operational success, the Campbell Institute is the SH&E centre of excellence at the US National Safety Council (NSC).

As a member, AECOM joins a group of like-minded organisations that are SH&E leaders and serve as the core of the Campbell Institute. 

AECOM Chief Safety Officer Andy Peters said: “This is a tremendous opportunity that recognises our SH&E best practices among top organizations that focus on integrating safety into their business models.

“Our journey towards a safer and more-sustainable world is accelerated through the thought leadership and knowledge sharing that this honourable organisation ignites.”

Safety is a core value at AECOM, supported by the belief that non-compliance with safety standards creates a poor work environment that not only endangers the lives of employees, contractor employees and members of the public, but also damages a company’s reputation and undermines its financial performance. AECOM’s strong corporate commitment to safety provides a key advantage when pursuing work globally.

Deborah Hersman, President and CEO of the NSC, said: “We are proud to welcome AECOM, one of America’s largest companies serving clients around the globe, to the Campbell Institute.

"As a Campbell Institute member, AECOM is taking its influence to the next level by joining with other world-class organizations to share SH&E experience, knowledge and best practices.”

As part of the NSC’s annual congress, Peters recently provided a keynote address as part of the institute’s Executive Forum, sharing his vision and experience enhancing AECOM’s safety culture and programs to advance its goal to achieve zero incidents in the workplace.

Through events, partnerships, research, as well as the sharing of knowledge and expertise, the Campbell Institute is a transformative force in SH&E leadership and is committed to creating a roadmap for all organizations striving to achieve safety excellence.

AECOM is a premier, fully integrated professional and technical services firm positioned to design, build, finance and operate infrastructure assets around the world for public- and private-sector clients. With nearly 100,000 employees including architects, engineers, designers, planners, scientists and management and construction services professionals serving clients in over 150 countries around the world, AECOM is ranked as the number one engineering design firm by revenue in Engineering News-Record magazine’s annual industry rankings.

More information on AECOM and its services can be found at www.aecom.com.

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Jun 17, 2021

Why engineers must always consider human-induced vibration

Vibrations
Engineering
design
Structuralintegrity
Dominic Ellis
3 min
Human-induced vibration can lead to a number of effects upon the structure and its users

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.

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