SPECIALIST SERVICES TRANSPORT BOND STREET AND BEYOND
PEDESTRIAN FLOWANALYSIS
BY PAUL SPEIRS Technical director, WSP
At peak times, up to 19,000 passengers an hour will move through the new Bond Street Crossrail station, so it’s critical that we make sure that movement through the station is efficient, comfortable and safe. Pedestrian flow analysis allows us to do exactly that.
Our specialist pedestrian flow analysis team has used industry-leading Legion software to build 4D dynamic models of the new station, which include every single person, their interactions and their combined impact on its operational performance. On Crossrail, there is stringent guidance on passenger comfort and crowding. Using dynamic modelling tools, we tested our design against forecast passenger demand to demonstrate that density remains at acceptable levels throughout peak periods.
The software uses complex algorithms to account for a range of human behaviours, such as walking speed and crowd interactions. But the results are readily understandable, even to a lay person. We can see interactions in real time from street level down to the platforms in one holistic model, showing the ebb and flow of passengers and the build-up and breakdown of queues and bottlenecks. This highlights where refinements are required, and allows us to demonstrate how our solutions have eased or removed problems.
Crowd density is measured on the Fruin Level of Service (LoS) scale, and colour- banded density maps illustrate the conditions through six grading levels from good to very poor. Histograms tell us how long the poorer conditions last and how many individuals are affected, and space utilisation maps show the strongest desire lines and the dead space. With our experience in interpreting these outputs, we can quickly understand what decisions need to be made.
Jem Biggins, technical director at WSP and lead traffic engineer at Bond Street, was responsible for explaining the model to the wider team. “There were many emotive and difficult conflicts, which needed a clear-cut evidence base,” he says. “The pedestrian flow analysis team provided me with definitive answers and powerful graphics, which made my job a lot easier.” WSP’s models were used to support key decisions on escalator and ticket gateline configurations, to assess corridor
and platform widths and measure evacuation times. We could highlight design concerns and identify a range of solutions which we then put to the test. By demonstrating that the final design met the Crossrail standards, this gave confidence to the many stakeholders and the design team. The pedestrian modelling team worked with the architects, with structural, vertical transportation and fire and life safety engineers, and London Underground, to name but a few.
“Pedestrian flow analysis is an invaluable design tool,” says Tim Peet, senior technical director at WSP and lead engineer on Bond Street. “The two most important things underpinning a safe and operable station design are the fire and evacuation strategy, and the Legion modelling report. The many physical constraints in Mayfair have presented a significant challenge, and any slight change has had a domino effect on the design. Pedestrian modelling has been a very effective tool for demonstrating compliance.”
Christine Palmer, principal engineer at WSP and Bond Street’s lead pedestrian modeller, had to tackle many interfaces between the new station and surrounding elements. “Our job was to future-proof the design, while ensuring it linked up with the existing London Underground station. We held workshops with LU to aid the flow of information and to brainstorm solutions to potential crowding issues. The real-time simulations were a great way to express our work and helped to make the sessions interactive and successful.”
During the last six years, WSP’s growing pedestrian flow analysis team has worked around the world on projects as diverse as stadiums, shopping centres, skyscrapers, schools, airports and even restaurants. We pride ourselves on creating solutions, influencing design and providing confidence to help our clients deliver on their aspirations.
paul.speirs@wspgroup.com
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