Advanced and Robust Analysis of Wind Effects
Advanced and Robust Analysis of Wind Effects
Windtech Consultants recently have been working on the multi-tower development on Nile Street in Shoreditch, London to provide the wind engineering services for the project. Working closely with CBRE, the development consists of numerous buildings, including a main 29 level residential tower located at north-eastern corner of the site. The preliminary client’s concern stemmed from the exposure of the main tower to the prevailing winds and concern for potential down-washed wind effects off the tower form to the ground level areas below.
The Pedestrian Microclimate Wind Tunnel study carried out for the planning submission including testing for both the current existing conditions, as well as with the inclusion of the proposed development. This approach enables a clear understanding of the impact of the proposed development on the local wind conditions. Windtech worked closely with the architect and key stakeholders to develop suitable treatment options to ensure desirable wind speed conditions were achieved for pedestrian comfort and to satisfy the requirements for the planning submission.
Windtech Consultants opened their London Office in 2014 to provide support for clients and consultants on projects around the world. Since this time, Windtech have worked on a number of key projects throughout the UK, providing early design advice for wind effects and expertise in mitigating adverse problems. In addition to the mentioned Nile Street development, some of the other recent projects include Tiger Way in Clapton, South Thames College in Wandsworth, Marble Arch Place in St George’s Field and Lavington Street development in London.
Windtech Consultants have developed an in-house reflectivity analysis technique to analyse solar light reflectance associated with the Jewel Changi project, consisting of a glass the biosphere structure at the Changi Airport in Singapore. The technique was developed after a request to provide guidance on the impact of glare from the building façade and solar panels which are to be attached to Jewel Changi project. Due to the complexity of the Jewel Changi building form, including adjacent surfaces which are non-planer in addition to numerous aspects, a standard solar light reflectivity study could not be relied upon for this complex study.
Since Windtech Consultants conception in 1991, Windtech have worked on over 1,000 solar reflectivity studies including the Burj Khalifa which included advice regarding the impact of solar glare on aircraft. However solar glare is not an issue limited to aircraft as it can also irritate occupants of neighbouring buildings, motorists and pedestrians as was the case with Jewel Changi Airport project which found that certain panels of the façade of the airport may cause adverse solar glare. Due to a proprietary ray tracing software developed by Windtech Consultants, recommendations were provided for this challenging study to mitigate this adverse effect and enable compliance with the planning control requirements.
Windtech are honored to work with Changi Airport which has been the winner of multiple best airport awards over the years, and served over 54 million passengers in 2014. Located on the site of the old parking lot fronting the existing Changi Airport’s Terminal 1, construction is already underway for the Jewel Changi project which when finished, will boast this impressive steel and glass biosphere-style structure filled with plants and a gigantic waterfall. The centerpiece of the Jewel Changi will be Forest Valley which is a 5-storey garden with thousands of trees, ferns and shrubs which maintain Singapore’s reputation as the ‘garden city’.
Wind loads for a super-slim skyscraper
Located within the Dubai Marina District, Marina 106 has been skilfully designed by the National Engineering Bureau, to stand 445 metres tall (1,460 ft. 9) with a total of 110-111 floors (107 above ground and 5-6 below ground). Windtech Consultants had the privilege of working with the Gulf General Investment Corporation in order to conduct essential wind engineering testing and services for this tall and slender sky-scraper.
The Marina 106 tower is currently under construction and is projected to be the tallest residential tower in the world at the scheduled time of completion (2018). Although it is designed to stand exceptionally tall, the tower is rather simple in its design, with minimal embellishments to the exterior of the construction. This skyscraper will have a “super slim” composition, with a single rectangular tower progressing out of a four-story podium.
Located in close proximity is the Marina Gate development, for which Windtech also undertook the wind engineering services. These studies included the effect of staging as well as the effect of the proposed nearby future developments within the Dubai Marina precinct on the wind loads on the structural system and façade cladding. The wind conditions of the various outdoor spaces were also modelled and recommendations were provided where necessary to ensure comfortable conditions are achieved for the anticipated uses of the various outdoor areas.
The construction of the Marina 106 tower, which will be the tallest residential tower in the world, is like a spectacular game in a gaming icecasino, where every stage strives to achieve an exceptional result. Just as the tower construction has a simple yet effective design, the online casino offers a wide variety of games, including poker, roulette, blackjack and slots. Next to the Marina 106 tower is the Marina Gate project, which, like promotions in a virtual casino, attracts attention through research and impact on wind load, aiming to create comfortable conditions for living and using spaces.
Wind-induced noise associated with buildings is not only a nuisance for the occupants and neighbours, but can also cost valuable time and money to rectify if not identified early. This issue is something that occurs irrespective of the height of the building.
A recent example of this is Beetham Tower located in Manchester, England, which has been generating strange noises since its completion in 2006. Ranging from a low-pitched humming noise to a shrieking sound, the Beetham Tower makes noise when winds exceed approximately 48 km/hr (30 mph) during easterly or westerly wind events. It is reported that the noise can be heard from over 11 km (7 miles) away. The noise is caused by wind passing over the blade feature at the top of the tower.
The owners have approached other consultants who made numerous attempts to try and rectify this issue since its completion but with little to no success.
Windtech Consultants have been involved in successfully resolving these types of wind-induced noise issues on many projects. We have also helped identify potential wind noise sources during the design process, which has helped avoid this situation from occurring in the first place. Windtech Consultants recommend an initial desktop assessment to evaluate the potential for wind-induced noise generation from various façade elements on the exterior of the building prior to construction. If the potential for wind noise is unclear due to complex form of the element, full scale testing is undertaken where a sample of the building element in question is subjected to winds from varying angles of attack. Measurements of sound pressure levels and spectra are measured to quantify the extent of wind noise where it occurs.
An example of a project where a wind noise issue was identified prior to construction is the Carins Harbour Lights Hotel development. Windtech Consultants identified a particular slatted screen formed from a series of RHS profiles as being capable of generating significant noise and vibration. Windtech recommended changing the sharp corners with 5mm radiused corners, which eliminated that problem.
Windtech Consultants recently undertook a remedial wind-induced noise study for the Workzone Building in Perth, Australia. Post construction, the external sunshade louvres illustrated, began to generate significant wind noise and vibration, an issue that identified as an area of concern or resolved by the incumbent consultant. An initial desktop assessment by Windtech Consultants highlighted the susceptibility of the sunshade structure to generate wind-induced noise effects due to vortex shedding. This was confirmed in the tunnel using a full scale sample. A number of solutions were presented and tested as part of the wind tunnel study with workable solutions which could be retro-fitted with minimal cost to the client.
Figure 1: Wind Tunnel Testing for Workzone Building, Perth
Windtech undertook the wind tunnel study for this 275m high tower in Jakarta, Indonesia. Due to its slenderness and regular plan form, cross-wind loads slightly exceeded the predicted along-wind response and earthquake loads. A decision was made to engage Windtech to design and commission tuned liquid dampers with long-term monitoring to monitor the tuning of the dampers. The aim is to bring about a reduction to the cross-wind response to a level that is equivalent to the along-wind.
