Info

Discussion and conclusions . .

The wind condition was successfully simulated to provide external pressure values at the opening door and window locatons The building's shape appears to respond well to the prevailing wind directions, with the combination of wing^ and balcon.es providing relative h,gh/«ow pressure areas a. ventilation openings on the upwind and downwind elevations For wind directions other than the prevailing winds, the pressure gradient across the building may be less.

however »» openings along X should provide sufficient control. ___ t.moerature th, stack only situation the ventilation rate , not very high, a, about 1ac/h The internal ex -Wee is greatest (1 V, h.gher, for the stack only case This relatively small'speed ,s *«>vely low ceiling height with respect to the stack effect, does not provide a strong stack force and would not provide a significant comfort cooling effect Unwind the ventilation rates are for the window opening situations, where there are large openings upwind and dow ^ ^^ ^ bftwein high (up to about 30 ac/h) Obviously, this is too high for comfort as the c0"espO g do„n the openings on

04 ** 0.5 m/s, which could give nse to mechanical problems, such as papers moving 6 ^ ? (fepeat) pfovlde uPwind side appears to be the best solution for controlling ventilation For example, controlled ventilation without excessive internal air speeds I,jed in relation to the inlet openings

The pattern of mtemai air movement for w.nd-dnven ventilation appears to be oca ^ ^^ coinc,de with internal herf ** strong paths of air-flow originating from the inflow openings. app Thcfe may ^ the need to consider routes, but there may be much lower air movement in the main occupy zo even|y distributed and

<om. of device that would diffuse the incoming air 'jet', such that the ven.Haton a ^ ^ ^ ^ ,deHec1or-11 any short-arcu.ting between supply and exhaust openings. This might be

^^ near to the openmgs . wlde for low wind and calm condi-

ventkation strategy should be to ensure that windows and doors can be ope ■ and hlgh wind conditions

^ but that they can have adjustaWe openings to allow them to be operated ^ close down on the

^ to curves ,n table 3) During medium to high wind situations it appears to be ad ^ ^ ^ on|y , secondary openings to a mm,mum. It appears that the openings on the o ^^ ^ movemen, . 0n filiation rates although they may have a larger influence on patter ^ daU

A ^ and graph of window opening guidance has been extrapolated from

X-we« law relation for varying M Mlth h,tgM

X-we« law relation for varying M Mlth h,tgM

M OÍ Vwevkr,

figure 5

In plan

figure 6

wind-shutters closed wind-shutters closed figure 7

wind-shutters open figure 8

wind-shutters open figure 8

Window opening related ^^^ ^

Z^TZ'Zn^. fe the piling wind dlr^ figure 9

Z^TZ'Zn^. fe the piling wind dlr^ figure 9

umno tower

Puten Sh.reen (University of Brighton)

daylight studies daylight simulations level 9 10.00am

Climate data on solar radiation also shows that it is about 4 00pm u> direct/diffuse radiation (and also temperature) start to significantly drop' ty51*1' angles for this time shows about 18-20 deg)

What is recommended is a shading system with two main components

1 one whose dimensions/cross section can be derived from the present one

2 a 'separate' component dealing with the high intensity incident of the cur,«a.

To deal with the intensity of direct radiation (2) should either be 1 a vertical shading system that cantilever about 2 or 1 75 x the 'length of the existing frame of present shading system possibly made with perforated metal to admit usable amounts of daylight level 8 10.30am level 7 9.00am

Dubai, United Arab Emir;

owner Dub.n Municipality. United Arab Emirates location Dubai. United Arab Fmir.itr-, latitude 25 1 N

no» of storeys up to 18 storeys (over 27 blocks) date start 1998 (design) completion date areas total built-up area 863,550 sq m gross

Site area 124,688 sq m plot ratio 1 4 5

design features • The project is located m a prominent waterfront site between five famous sector-, in central Dubai Clock Tower. City-center. Dubn International CoH Club. Alkhor Park and AIMaktoum Bndge

The site en|oys panoramic views across the river to Alkhor and Alkhor Park to the south and Alkhor Park and the Colt Clut. to the south-east

The site has an area ot over 1 3 million sq It with a permissible Floor Area Ratio (FAR) ot 1 5. which gives thr development grr.1t flexibility in design and use. and high potential economic returns However, there is a building height restriction of 11 Storeys or 55 m which places a constraint on the site s building massing

The site is located in a heavy traffic /one area at thr crossing of AIMaktoum interchange expansion with Ban.yds mam road Due to its proximity the intersection, the site has limited vehicular access points off the main toad The toad frontage also limited as the south-western boundary is taken up by the water front

The brief calls for a mixed-use complex with housing, offices touristic and commercial uses, as well as landscape areas masterplannlng • The pro|ect masterplan overall objective Is to address the street frontage and the river frontage Water is brought into this site to enable access by boat and to contribute to lowering the ambient temperature of the development (see below).

site massing • The massing propr.il for this s< hen« i n. .. the existing site density and height restnction as follows

• All car-parking spaces are located in the basement in ordr • to tree up the ground level lor landscaping and recreational use By placing the cars in the basement, the building height can also be reduced

• Water Is brought into Ihe site to create Internal views and to increase the waterfront recreational space (eg marina water tront promenade, etc)

• The buildings fronting the water is elevated .it ground Irvr^ treeing up extra space for recreational use

• Increase In building height to 70 m Informal dr.. ussions held with the Dept of Civil Aviation suggests that there may be a relaxation in building height restrictions from 55 m to 70 m hotel • The hotel is located at the most visible position from the main road at the northern corner on the site

The hotel is served by a high-class vehicle drop-off with convenient car-parking located underneath The hotel suites has views both to the waterfront to the west and the city centre to the north Its horse shoe shape frame, Ihe swimming pool deck while directing the views towards the creek beyond

The hotel serves the business demand generated by the proposed otllce buildings as well as loumts to this location The nearby tourist attractions such as the City Centre shoppm* mall. Dubai Creek Colt Club and Creekside Park would be turther enhanced by the proposed new waterfront development and shopping mail serviced apartment» • The serviced apartments are connected to the hotel tor central servicing and shared use ol club lacilitles The apartments have direct view, towards the waterfront and new manna bay The hotel and serviced apartments are located on the northern segment ot the site separated by the new manna bay to difteirntiate it from the rest of the development This allows lor better security of its premises apartments • The apartment • located a. tM -vat. • ><

ed«r and command the best views in Ihe

The apartments benefit l-om a close relationship to the off«, towers and retail shopping mall

Each apartment block has a separate car drop oft to the main lobby and are directly accessible -cm the basement car-parking underneath dubal towers

Al Maktoum bridge hotel tower office blocks facing Benlyas Rd public/private marina

axonometric

circulation spine hotel service apartments retail mall offices apartments mosque carpark

Al Maktoum bridge building elements - overall concept axonometric hotel tower

""«"l'ont, office blocks facing Benlyas Rd public/private marina

The Dubai Towers project is essentially very different from Yeang's definitive skyscraper typology, in both its form and location.

set in a distinctive waterfront position, in central Dubai, the site and buildings enjoy panoramic vistas across the river to parkland. The permissible building height i$ restricted to 70 metres maximum, and road access is limited to the linear highway frontage of Baniyas Road.

Yeang's overall design strategy is essentially that of a huge partially buried plinth which houses car-parking and retail shopping mall with a landscaped roof which descends gently to a new waterfront promenade and marina, and which brings water into the site-enhancing views and recreational space. Over this massive landscaped base Yeang has located a series of canted linear-towers, whose ends are lifted above the lower landscape, and are set at approximate right-angles to the waterfront. The towers are separated but linked, for ease of circulation. The overall result of this arrangement is a 'sliced' form which is entirely driven by considerations of wind and natural ventilation and the maximising of the vistas and prospect.

Yeang's summary of the bioclimatic response contained in the formal arrangement makes two significant points: first, that channeled air movement between the linear towers increases air movement and cooling effect, and next that complementary shading between the linear towers lowers radiant air temperature. Coupled with these overall principles Yeang has utilised a traditional concept of the 'wind tower', to ventilate basement car-park levels through to the podium roof. Thus, in overall terms the whole intensive layered form can be seen as a direct conceptual model, which is harnessing wind and hence ventilation, and providing shade over new landscape of planting and water. Yeang's policy is developed in more detail:

"... the proximity of the creek water mass with the city water mass behind the development can give reversal of wind directions during the daily cycle. During the afternoon when the land mass is warmer the cooler sea breeze moves in from the water towards the land. In the early morning when the land and building masses have been cooled with night radiation to the sky, the dense cool air moves towards the water mass." 1 The design is inextricably evolved from this statement, and then enhanced in detail throughout the programme of mixed-uses.

Of all the bioclimatic elements, beyond the wind and ventilation strategy, the landscaping is the most significant, re-introducing organic mass and lowering ambient micro-climate temperatures. The project includes both ground and vertical landscaping, and including water coverage represents 90% of the entire site area. This is largely due to the massive landscaped ground plane extending from the promenade upwards, over the whole podium. Landscaped skycourts are also incorporated into the higher levels of the buildings.

section A-A

" r ^k* Office» are located on the east tide of the development to take advantage of ,hr ^ ™

essential that these offices are very visible from the surrounding streets

The office blocks sit above the retail pod,urn

Each office block has a separate car drop-off on the tower

« ound (promenade, level and are directly «cess,We from the basement carpark,ng underneath retail . The retail shoppmg centre directly faces Ban*,,

Koad and has its mam entrances off the street level

The roof of the shopping centre ,s landscaped with shoppmg pavilions They command panoramic views over the mar,na and creek

The car-parking is located underneath the mall and are directly accessible via escalators and lifts mosque • The mosque is located on an'island'site directly at the waterfront The mosque faces west towards Mecca car-parking • The car-park,ng for th,s development is located on the lower ground and basement levels due to space limitations and he.ght restrictions Very little ground level parking is provided and where this is provided ,t is with dropping VIPs. women and families in mind The top level of the car-parking (lower ground floor) is the drop-off level for the offices This level is semi-submerged and receives natural light and ventilation It is served by a wide and spacious boulevard' road which has views of the water section concept • Pedestrian and vehicular traffic are separated through a device of vertical segregation of people above and vehicles below

In this way. the linkage between building elements is optimised and conflicts with externa) traffic conditions and circulation are avoided bioclimatic aspects landscaping • Landscaping and planting to lower ambient micro-climate temperatures as well as to re-introduce organic mass back into the essentially urban and mostly inorganic location.

Ground and vertical landscaping is used extensively around the development This is achieved by extending the landscaping from the waterfront promenade level up to the retail podium roof In one continuous plane, below the elevated the building blocks. Landscaped skycourts are introduced in the upper floors of the buildings Earth excavated from the new mannas are used to create landscaped mounds between the elevated buildings and the basement carparking roof, reducing costly export of earth from the site The earth acts as thermal insulation for rooftops wind and natural ventilation • The onentation of the building blocks at right angles to the water front encourage free movement of air between the building blocks assisting the natural cooling of the buildings The porosity of the building facades assists in channeling air through the site while vertical gaps act as thermal flues moving air vertically and in doing so cools the building fabric

In traditional buildings this movement of air has been utilised in the use of 'Towers of Wind' to ventilate occupied accommodation This principle is used in the development to ventilate the carpark floors Large light and ventilation wells from the podium roof into the basements tuncbon as w,nd towers, drawing fresh air into the basement and extracting used air out shading • Shading of both pnmary and external >paces is an essential and important part of the design The need ,s there to protect the treated internal environment from direct sola, radiation and in doing so reduce the energy demand of (he building's environmental systems and a. the same time improve the overall comfort ol the spaces. Sunshade structures emanate as external ^

attachments to the tacade of the buildings The ^ between the external scree« and the windows are tooled by wind movement (see external wall secbon)

project area by use

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As well as the natural sun-shading created by the separated r tpwers, sun-shade structures in the form of louvered screen J^ments are extensively applied to the linear facades. On the level

'.program and urban design the pro'ect is inte™vely mixed-use.

extensive Shopping Mall including departmental store, supermarket, ^ court and speciality shops distributed over the basement parking lf\fl5 The linear-towers incorporate both Apartments and Offices, Mother with a stretched 'horse-shoe' form Hotel.

The Hotel is a major 400 bedroom and suite configuration grounding a courtyard with swimming pool and outdoor cafes. The wings of rooms all command a variety of outward views, and the corridors include skycourts for natural light. The accommodation rcludes roof top garden terraces which also have spectacular vistas over both waterfront and park. As with Yeang's skyscrapers, such as the Singapore EDITT Tower, the consideration of outward prospect and view is always a major priority.

The eleven Apartment buildings, in linear-towers are 'thin' forms which encourages cross ventilation through the apartments. The terminal ends of these buildings are cantilevered over the water and include facilities such as gymnasia, coffee-houses and function rooms, together with special penthouses on upper levels. Again outward views are a concern, throughout. The offices have a similar linear-tower form, located above the retail podium. The elongated plan with minimal columns allows both flexibility of sub-division and provides maximum natural lighting to the interiors.

Many other aspects of the project such as structure, access and circulation have been carefully innovated and integrated into the overall concept and layout. The project also includes a Mosque, which is sited on a waterfront 'island', in a tranquil location facing west, towards Mecca.

But, what remains as singularly important to this project is not 'ts formal arrangement alone, rather it is the manner in which the biodimatic-response has driven that arrangement into a natural dimate-controlled result.

m tr

Phasing m phase 1A

A • hotel (300 rooms) B • retail mall (phase 1) C • service apartments

E • apartments (80) F • offices C • offices H • offices I • offices

phase 2

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