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October 2018

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Sebastian Desand

Wind can impact property value: 3 real-life cases

By simulating wind early in the design process, predicted flow behaviour will lead to a better and smarter design.

Comfort and safety

The picture above shows pedestrians trying to cross the street in front of Bridgewater Place Tower. The building in the city of Leeds, UK, has such bad aerodynamics that crossing the street is not only difficult, but also dangerous. At one point, rugby players were even hired to help people cross the street. The wind effects of the building caused a truck to overturn by the wind in 2011, tragically killing a man. Wind speeds between 67 m/h and 79 m/h were recorded there.

The answer to such a behaviour is based on simple aerodynamics. The full force of the prevailing high-speed winds at 70-100 metres heigh hits the side of the building and is pushed downwards (Downwash) and around to the side. The building then acts like a funnel, squeezing a large volume or air into a smaller space, forcing the wind speeds to accelerate more than 5 times. You can visualise this effect below:

Simulation by Ingrid Cloud

It’s well-known that the specific building design is responsible for this dangerous scenario. Architects and constructors could have avoided it by performing an accurate flow simulation in early stages of the design process. Access to reliable wind information and predicting its effects on pedestrian comfort and safety allows for design optimisation. Ledges on the building's side would most likely have redirected the wind and mitigated the Downwash effect.

Look how a different design choice could have changed the aerodynamics of the building. The round corner from the original design increases wind speed when the flow hits the main façade of the building:

1-windeffects_leeds_original

While a sharp edge makes the wind speed significantly lower:

2-windeffects_leeds_modified

1 - Bridgewater Place Towers, England

  • Total cost: 850 million dollars (USD).
  • 32 storeys for office and residential spaces.
  • Building amendments for mitigating wind effects: 1M USD. 

Underestimating wind analysis

Not only high-rise buildings are affected by aerodynamic forces. Significant wind effects can be caused by buildings no more than 50 metres high. Look at this 26 storey mixed-use development in Stockholm, Sweden.

In this top view simulation video, the wind speeds up near the corners of the structure and in the passage are a result of the Venturi effect. Pedestrian discomfort can also be caused by turbulence such as the one that can be seen in this visualisation:

3-two_towers_wind_effect

Windy and unpleasant surroundings make pedestrians find alternative routes, which in turn reduces the number of potential customers for retail establishments in the impacted area, for example.

The value of a property is very much based on the rental income. If the retail establishment's renting premises in the building starts losing customers and revenue due to low levels of pedestrian comfort, the market value of the location will drop, which will in turn lower the rental income and the overall value of the property.

The consequence of underestimating wind analysis during the design process can easily go unnoticed during the entire design and construction phase of a building. But sooner or later, reality hits you in the face like a cold winter's storm. That risk is not worth taking, considering the wind simulation tools and services available.

2 - Tuletornen, Sweden

  • 26 storeys for residential use and commercial areas at ground level.
  • Low pedestrian comfort at ground level impacts surrounding retailer’s revenue.

Structural savings

Wind analysis can also provide input for other savings in an urban project. The Chinese skyscraper, Shanghai Tower, is well known for studying the building's aerodynamics in order to increase cost efficiency while maintaining comfort and safety.

The twisted form reduces wind loads by 24%, offering significant savings in overall building material. That’s a $58 million in savings.

Let’s see what the wind has to say about this design choice: The streamlined representation of the air shows that by twisting the shape, less turbulence is caused, and the wind flows without strong interruptions. Wind loads are also mitigated by the design's optimisation:

 

 

3 - Shanghai Tower, China

  • Total cost: $2.4 billion dollars (USD).
  • 128 storeys, one of the tallest buildings on earth.
  • Savings in material due to design optimisation: $58 million.

Understand the wind. Use it. Don’t fight it

By simulating wind early in the design process, accurate data will lead to a better and smarter design. So, do NOT underestimate the impact of wind.

Ingrid Cloud is an affordable and automated software for wind simulations. It is used by experts in Computational Fluid Dynamics and wind analysis, as well as by non-specialists who understand the value of predicting the effects of the wind. Register an account and get started within minutes. It’s easy, fast and accurate. We also offer expert consultation to interpret the simulation results in order to draw the right conclusions.