تالار شهر لندن

زمانی که تونی بلر در انگلستان بر سر کار آمد گفت: «این دولت نماینده بازگشت به مدرنیسم است.» او از جامعه ای سخن میگفت که نگاهش رو به آینده است. بر اساس همین دیدگاه بحث ایجاد ساختمانی در لندن به عنوان شهرداری لندن مطرح گردید که نماد چنین تفکری باشد.

ادامه در ادامه مطلب

تالار شهر یا (city hall) مکانی است برای کلیه امور اجتماعی شهر. این تالار در درجه نخست فضای استقرار انجمن ها و شوراهای شهر و سپس مرکزی برای گردهم آیی های عمومی و ارتباط و تعامل میان مردم در عرصه مسائل شهری است. نقش این فضا در دنیا گردهمآوری شهروندان و ترغیب آنها برای مشارکت در امور شهری است. تالار شهر متعلق به همه مردم شهر است و نماد معمارانهای از دموکراسی است. (متأسفانه در ایران تالار شهر وجود ندارد)

این طرح در جنوب رود تایمز واقع شده است. نورمن فاستر به همراه تیمی گسترده از مهندسین، سازه ی تخم مرغی شکلی طراحی کرد که شهرداری و شورای شهر لندن را در خود جای داده اند. ساخت این پروژه از سال ۲۰۰۰ شروع شد و تا سال ۲۰۰۲ ادامه یافت. از زمان شروع این پروژه آشکار بود که تیم طراحی و ساکنان آتی آن بر آنند تا ساختمانی پدید آورند که مثالی برای یک ساختمان با مصرف پایین انرژی باشد. مصرف انرژی در این بنا تا ۷۵ درصد نسبت به ساختمان های مشابه کمتر است.

موضوع اصلی در طراحی پوشش این ساختمان محدود کردن بارهای سرمایش و گرمایش بود. هندسه نامتعارف سازه GLA طوری طراحی شده که هر دیواره شیشه ای با زاویه متفاوتی نسبت به دیگری قرار گیرد. این دیواره ها با استفاده از تحلیل های نورپردازی سه بعدی و روش شبیه سازی نور روز طراحی شدند. هدف این بود که بیشترین جذب گرمای خورشیدی درنما وجود داشته باشد.

هوای تازه از طریق دریچه های مشبک جاسازی شده در کف سطوح اداری تأمین می شود. در زمستان یک چرخه حرارتی رطوبت پذیر برای رطوبت دهی به هوای مکیده شده استفاده میگردد. در تابستان وقتی دمای هوای خارج از هوای داخل زیادتر است، همان چرخه حرارتی هوای تازه ورودی را از قبل خنک می سازد. تهویه کنندههای بازشویی در محیط اداره ها نیز تهویه طبیعی را به عهده دارند. دیوار های عایقبندی شده هم نقشی مناسب خود ایفا می کنند.

آب گرم این ساختمان توسط دو گرم کننده گازی با کارایی بالا تأمین می شود. آب گرم با روش همرفت بخش های اداری، اتاقهای جلسات و لابی ورودی را گرم می کنند.

در تابستان علاوه بر چیلر برقی، درجه حرارت توسط تیرهای سرد خنک نگهداشته میشود. این تیرها در سقف قسمت اداری قراردارند. آب اصلی خنک شده از اعماق چاه ها توسط دو پمپ زیر آبی تأمین
میگردد و بعد از خنک سازی ساختمان در فلاش تانک های سرویس بهداشتی و آبیاری فضای سبز بیرون به کار می رود. آب مازاد به درون رود تایمز تخلیه می گردد.

ساختمان در جهت شمالی و جنوبی متقارن است. انحنای این ساختمان در جهت شمالی جنوبی به گونهای است که حداقل سطح را در ضلع جنوبی در معرض تابش مستقیم خورشید داشته باشد. همچنین در این ضلع، حالت پله ای طبقات موجب می شود هر طبقه روی طبقه زیری خود سایه بیندازد و تابش مستقیم تعدیل شود.

سازه نگهدارنده این فرم حاصل تعامل معماران و مهندسان است. ستونهای مایل نیروهای بزرگیکه به این شکل منحنی با شیب تند وارد می شوند را کنترل میکنند. شبکهای از تیرهای فولادی به هسته بتنی مرکزی بسته شده است، نیروهای افقی مورد نیاز برای تثبیت ستونها را تحمل میکند. در سازه فولادی از گره دوکی استفاده شده است.

پوسته شفاف و شیشه ای ساختمان نماد شفافیت دولت است. مردم می توانند در داخل ساختمان حرکت کنند از قسمت های تفریحی آن استفاده کنند در رمپ ۵۰۰ متری آن حرکت کنند و نمایندگان خود را در حال کار ببینند.

نورمن فاستر در واقع ساختمان های عمومی و دولتی را به محلی برای تحقیق و نوآوری با هدف احداث سازه هایی با حداقل میزان انتشار گاز کربنیک درآورده در طراحی تالار شورای شهر لندن،مخروطی کروی شکل را برای راس سازه و محل برگزاری جلسات شورای بیست و چهارنفره شهر لندن در نظر گرفت باتوجه به این واقعیت ریاضی و هندسی که یک کره، ۱۸ درصد سطح دیوار کمتری از یک فضا با دیوارهای تخت و مساحت مساوی دارد، میزان تابش نور و گرمای خورشید بر سطح سازه کاهش محسوسی یافته است.

ضمناً مایل بودن نمای سازه به سمت جنوب درحالی که بعضی از طبقات انگار از روی هم لغزیده و جابجا شده اند در این کاهش سطح برخورد با اشعه خورشید موثر است.در بخش دوم توافق با کارفرمای دولتی، فاستر محافظه کاری سنتی ارگان های دولتی و سیاستمداران انگلیسی را به چالش طلبید و با طراحی یک رمپ معلق که از طبقه هشتم و از گنبد تخم مرغی عظیم ساختمان به پائین لغزیده و دسترسی راحت و آسان مراجعان به اعضای شورای شهر مستقر در طبقه هشتم را تسهیل می کند.

شفافیت حرف های دولتمردان را در عمل به شعار دولت شفاف و ارتباط نزدیک با ارباب رجوع به بوته آزمایش می گذارد.
افکار و ایده های فاستر در دو ساختمان برلین، ارزش های اساسی و عرف های بنیادین هنر و اعتقادات ژرمن ها مبنی بر شعار «هنر در خدمت ترقی جامعه» را زیر سوال برد. اعتقاداتی که باعث شعله ورشدن آتش دو جنگ جهانی از آن خطه شد. در طراحی و معماری داخلی ساختمان شورای شهر لندن هم، فاستر زیبایی را فدای ایده آل ها نکرده است. در سالن زیبای جلسات، چشم انداز شمالی از ورای شیشه هایی مخصوص با مقطع سفید و آبی رنگ (مقطع شیشه های معمولی سبزرنگ است) نوری زلال، طبیعی و ملایم، درست مثل نقاشی های ورمیر را به درون تالار پاشیده است.

ساختمان شورای شهر لندن همچنین بیادآورنده عادات اروپاییان در صرفه جویی مصرف انرژی و کاهش میزان گازهای گلخانه ای است. درحالی که معماران آمریکایی در بند فرم های ناموفق دهه هشتاد خود گیر کرده اند، اروپا سالهاست که در تعامل با نیازهای اقتصادی و زیست محیطی تطابق پذیر نشان می دهد.

فاستر ۶۸ ساله همچنان در پروژه های متعدد حال حاضر خود از تکنیک های بهینه سازی مصرف سوخت و کاهشمصرف انرژی بهره می جوید و در این زمینه پیشتاز است.

Height of the building:	45m
No. of floors:	10 floors above the ground
Gross floor area:	185,000 sq ft/18,000 sq m (approx)
Nett lettable floor area:	130,000 sq ft/12,000 sq m (approx)
Steelwork:	Structural frame – ۲۱۰۰ tons Reinforced – ۱۹۵۰ tons
Concrete (core):	13,100 sq m
Cladding:	7,300 sq m of triple glazed low emissivity coated clear glass, incoporating shading devices
Heat insulation:	Average value = 0.7-0.8 W/m_.k
Angle of glass front inclination:	31 degrees
Diameter of circular glass facade:	45m
Environmental strategy:	Windows open for natural ventilation, bore hole water cooling, heat recovery, displacement ventilation system, no chillers required
Energy consumption:	Energy consumptions for GLA’s environmental systems is less than half levels in DETR good practice office guide. The radical shape of the building minimses the surface area (approx 25 per cent less than an equivalent rectangular building). is self shading and the high performance facade ensures excellent energy efficiency.
Electrical consumption:	Greatly reduced as a result of using cold ground water instead of refrigeration to air condition the building. Saving use of mains water, the water is extracted through two bore holes from the water table beneath London and is used to cool the building and is then used for flushing the toilets.
Architect:	Foster and Partners
Construction Managers:	MACE
Structural, services, facade, fire, communications and acostics engineers:	Arup & Partners
Cost consultants:	Davis Langdon & Everest and Mott Green & Wall
Landscape architects:	Townshends

Decadence has its attractions, obviously. You would be inhuman not to be impressed by some of these spaces, though the debating chamber feels as though it is tilting backwards – an illusion caused by the oval spiral ramp (in fact a shallow staircase) above it. This winds upwards to the viewing gallery and function room on top. It is the building’s most effective one-liner, and it certainly keeps you fit. By the time you have walked from the bottom to the top and back again, you have covered exactly a kilometer. Packing all that walking distance into such a small and compact building is another of Foster’s curiously irrelevant achievements here. It could be done, so it was.

Foster’s partner in charge of this project, Ken Shuttleworth, remarks that the whole of City Hall would fit inside the debating chamber of the Reichstag in Berlin, one of Foster’s most significant projects of recent years. Indeed there is much of the Reichstag condensed into this £۴۰m building. The Reichstag has a circular debating chamber, offices for MPs and staff, and a glass dome on top with a spiral viewing ramp for visitors. In London, these ingredients have all been tipped into the equivalent of the dome alone. Which is then pulled into a funny shape. A shape generated by computer to be the most efficient, climate-wise. As so often with Foster, good or bad, this is a built diagram.

It is commendably energy-efficient not only because of its shape and north-facing orientation but also because it uses London’s abundant ground water to cool it, flush lavatories etc, and recycles heat in winter, rather than depending on wasteful air-conditioning. Every big building in London should do this. Unfortunately City Hall is a pimple of a building sitting in one corner of a vast, £۷۵۰m commercial office and hotel development, also designed by the Foster office. Another similarly huge new Foster office scheme faces it diagonally across the river. These massive buildings do not embody the low-energy principles of the little City Hall, because commercial developers demand more conventional, less up-front-costly cooling systems. If even the mighty Foster office cannot change this short-term thinking in the commercial sector, we’re not going to get very far with saving the planet.

Everything in City Hall comes back to the shape. The cellular offices are wedge-shaped, to fit in with the curve. Functionally speaking, this is not an ideal shape and leads to some clunky internal details, as does the curving of the spiral ramp – which is anything but elegant, close up – and the very clumsy wrapping of the strips of glazing around the outside. The exterior appearance of the building, as nearly always, belies the architect’s computer-derived images of transparency. This is because architects like to believe that glass is wholly see-through. In reality – especially when used on the slant like this – it is like a car windscreen seen from outside. It reflects, it turns solid. Moreover, this is cheap greenish glass. Advanced, optically clear glass is available and has been used with effect by Richard Rogers in his recent City buildings, but that was ruled out here as too expensive. Even had they used it, the weird shape would stop you getting much of a view in. The upshot of all this is that you do not get a transparent dome-like object. You get a grey blob.

City Hall – how the building was chosen

A developer-led approach was used that combined a competition for the best site with a design competition for the building.

Fifty five potential buildings and sites were submitted for consideration. Seven of the initial ideas put forward by developers were put on public display at the Oxo Tower Wharf in September 1998. Visitors were invited to record their views on the seven proposals by completing a questionnaire. These views were fed into the assessment process. Victoria House and More London Bridge were the most popular with the visitors.

The two front-runners were developed further. On 26 February 1999 former Minister for London Nick Raynsford announced that the Government would be going ahead with the London Bridge City scheme – now known as ‘More London’.

After the City Hall design proved to be the public’s first choice following public consultation in September 1998, the Government Office for London (GoL) struck a deal with developers CIT group. As a result, the Greater London Authority has a 25-year lease on City Hall and will pay an annual rent of £۳۶٫۵۰ per square foot (£۳۹۳ per square metre). This is frozen until 2007. The developer will meet the cost of construction and the Government will meet the cost of fitting out the building. The developers expect that overall construction costs for City Hall and related infrastructure will be £۶۵m.

City Hall was delivered on budget and on time, proving a great deal for Londoners.

City Hall – accommodation

City Hall comprises a meeting chamber, committee rooms and public facilities, together with offices for the Mayor, London Assembly Members and GLA staff. It provides 185,000 sq ft (gross) of space on ten levels.

The building offers flexible office space that can be sub-divided into as many cellular offices as required or kept open-plan. Partitions can be solid or transparent. The brief required provision for 54 cellular offices with the remaining space open-plan.

The Chamber allows a number of different uses, configurations and functions. There is fixed seating for 250 members of the public but the floor of the Chamber can be used for an unlimited range of events. The Chamber has extensive views over the river and towards the City of London.

The Scoop

The Scoop is an outdoor area to the west of City Hall: a sunken oval amphitheatre made of grey limestone. It can seat 1000 people, and is a popular space on a sunny day. It can be accessed from the riverside walkway by a curving ramp and by steep steps.

There is an emergency exit from the City Hall cafeteria on the lower ground floor into the Scoop, but no entry for the public from the Scoop into City Hall.

More London are responsible for the Scoop; it is not under the GLA’s jurisdiction.

In summer 2003, More London put on a programme of free entertainment in the Scoop which included lunchtime music and also evening performances of Sophocles’ Oedipus which made imaginative use of the space.

Complex and contradictory. That is how Robert Venturi, the Philadelphia architect, defined post-modern architecture 35 years ago. Norman Foster is not by any normal stretch of the imagination a postmodernist, yet City Hall – the brand new home of the Mayor of London and the London Assembly – is as close to postmodernism as Foster has ever got. This singular and tautly drawn building is truly complex and contradictory. And on many levels.

By day, City Hall appears as a tight ball of architectural muscle. All of a piece, standing alone and at once light and shadowy dark like a suit of armour, it seems mysterious and alien, with something of a spaceship about it. At night, though, the building is transformed. As it lights up, its dramatic interior is revealed, shining through the structure’s steely skin. A theatrical assembly chamber emerges into the night, wrapped in a quite fantastical ramp that winds up around it through an extraordinary computer-generated geometry to reach a great glazed viewing gallery and platform at the top of the building. It hardly seems to be the same building.

A friend described City Hall as being like a clenched fist. This might sound overly aggressive, yet it is an apt metaphor. By day, the building does have an intense, compact and withdrawn quality; at night it opens up, like a fist relaxing. Perhaps the assembly will enjoy working late into the night; perhaps the mayor has somnambulent habits. Whatever, City Hall appears, at first glance, to be happier by night than by day.

The clenched fist does seem a rather happy description of the home of a mayor and city assembly that have had to fight a long battle against the forces of Thatcherism for their right to exist. London was surely the only capital city in the world in recent history to have been denied its own government, and for so long. The clenched fist says central government cannot have it all its own way. Local democracy matters.

Equally, the clenched fist is a reminder in the age of a triumphal Jean-Marie Le Pen across the Channel that democracy is a delicate creature that needs to be fought for; the metaphor made me think of the battle of Cable Street that took place just across Tower Bridge from City Hall. It was fought between Oswald Moseley and his fascist Blackshirts and a gloriously London alliance of Jewish tailors, Irish dockers and at least one London Transport tram driver, who stopped his vehicle across the fascists’ path at Aldgate. City Hall might be seen to represent London’s fight for democracy and those who attempt to thwart it. No pasaran .

The great surprise, though, is the building’s interior. From the outside, with its regular bands of triple-glazed windows, you might expect serried ranks of office floors for local authority bureaucrats, but the interior is like a hollowed-out pod. It is remarkably light. There are views out at every turn. And, with its asymmetrical ramp and curved form, City Hall appears to have more twists and turns than a helter-skelter.

Without doubt, this is an exciting building to be in. The riverside entrance leads into a great lobby capped with the assembly chamber. A ramp curves down from the lobby to an exhibition hall and to committee rooms and a cafe that lead out into an open-air auditorium. This is one of the finest and most symbolic features of the building. Where you imagine the building to be utterly hermetic, it suddenly breaks out into the open. Not into any open, but into a happy representation of an ancient Greek assembly, a meeting place for Londoners and their politicians. They will share the cafe here and sit on the same auditorium steps. Hopefully, they will even talk to one another, out of the wind that whips along the tidal Thames.

Back inside, the ramp winds around and above the assembly chamber, appearing to criss-cross itself, so that the seats around the mayor’s (including a ring of 250 for the public) look up into a modern version of Guarino Guarini’s breathtaking baroque vaulting at the Chapel of the Holy Shroud in Turin. If debates ever get boring (as if) eyes will be drawn high into this magical space.

Offices arranged around six floors look out across London and in down to the assembly chamber. The idea is clear enough: the democratic process must be seen to be working and we all have a part to play in it. Whether members of the public or GLA staff will be allowed to wander up and down the ramp, as if enjoying politics’ equivalent of New York’s Guggenheim, when the assembly is in action remains to be seen. It seems unlikely, which, frustratingly, might mean that the ramp remains a high day, holiday and night-time experience only.

The public, will, however, have access to the top floor gallery. This will be used for special events and hired out for parties and so on, but much of the time it will be a place for Londoners to come and look out across their city, standing on the heads of the politicians they elect to serve them. This is an idea Foster has transferred from the Berlin Reichstag. There, the great glazed dome is a public meeting place and viewing gallery; the top is gained by complex, interweaving ramps.

Up here, City Hall’s complex curved profile is pronounced. The shape derives ultimately not from some political gesture, but from largely environmental concerns. By creating a kind of asymmetric sphere, Foster has shaped a building that receives a little direct southern light and as much direct northern light as possible in the height of the summer. This means that a highly glazed building, exposed on all sides, can be be kept cool naturally. Combine this with a water-cooling system that draws from a bore hole sunk deep into the soggy London soil and City Hall has little need of air conditioning. So none of those perpetually whirring chiller units that deface the tops of so many London office buildings and refuse to keep quiet at night.

منابع:

kotam.wordpress.com

abbas-valadi.persianblog.ir

تالار شهر لندن

City Hall – how the building was chosen

City Hall – accommodation

The Scoop

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