The Tree
Plaza Planting a tree in Hong Kong
Seperating functions
Expected kick drum peaks from the nightclub are in the bass band region where conventional building acoustics is deficient. To preserve the hotel guests their good night sleep, the hotel is therefore decoupled from the nightclub. By separating the different functions flanking transmission is reduced dramatically. Two load-bearing systems are created; the facade carries the offices and nightclub by a complex tree structure, while the hotel is carried by the elevator cores. Since the offices don’t operate at the same hours as the nightclub, it is used to add stiffness to the facade tree.
Nature suffers from urban areas expanding at a far greater speed than ever before. The Tree aims to reclaim some of the urban space by abstracting itself to blend in with the idiom of the city. Rooting in the ground plaza, it gathers nourishment and energy from water before it majestically rises to the sky. A complex branch structure carries the simple cuboid that holds the functions of a typical urban skyscraper. Travelling upwards, the experience becomes more and more appealing as the tree structure encounters the human scale. The grammar of a tree inspires everything from the load bearing system to the finest interior detail. By planting The Tree in Hong Kong, nature will at last get its revenge.
Reducing vibrations
The low frequency vibrations from the nightclub are transmitted through the facade tree structure. Due to impedance mismatch at each branch junction and material damping treatment on the load bearing structure, a natural attenuation provides sufficient vibration isolation at the hotel facade.
HVAC
Absorbing and isolating sound
Wood is loved due to its complex anisotropic structure and variety of uses. It has great acoustical features and is easy to work with, making it possible to accomplish predetermined design objectives. Wood is in a large extent used in The Tree design, e.g. irregular shaped wall diffusors, absorbing slatted wood panel and wood ceiling reflectors. Combined with heavier materials it is also used for isolation purposes.
Nightclub
4 floors
Hotel restaurant // Relax area
Refining the site
Situated in the very dense and somewhat declined district of Mong Kok in Hong Kong, The Tree certainly stands out from the surroundings. Amongst the damp and shady roots of the tree, one will find a welcoming shelter from sun and traffic. This area is built much like a plaza, encouraging people of the city to pass through as well as serving as an embracing entrance for visitors To create a convenient public space with low annoyance, three simple principles are applied:
Hotel
15 floors
o Yim P
a) Lowering the plaza and elevating the surrounding landscape b) Masking noise by water fountains c) Shielding from traffic noise with glass screens towards Yim Po Fong street and the railway.
st Fong
Hotel lobby
1 2 3 4 5
Drop off area Guest lounge Reception Pedestrian passage Loading and laundry facilities 6 Loading area
st Argyle
6
5 4 3 b) 2 a) 1
y Railwa Offices 7 floors
Railway 75-80 dBA MTR+Freight trains
Public plaza Yim Po Fong Street 70 dBA 22000 vehicles/24 h
Public plaza 60 dBA
Argyle Street 80 dBA 48000 vehicles/24 h
c)
Offices
Hotel
The office solution is simple but smart. Logistics runs smoothly through separated areas without disturbing the concentration of the workers. Half of the space on each floor is dedicated to three open office areas that can provide different sound environments depending on the needs of the company occupying the floor. Absorbing wooden cubicles, that hold readily available functions, are used to divide the open offices into larger acoustical islands. With an intention to facilitate for workers, there is a secondary entrance through an elevator shaft isolated from external visitors.
11
11
10
12
10
12 4 4
5
4 4
7 7
3 6
7 7 4 4
5
8
8
8
8
8
11
8
1
2
1 2 3 4 5 6 7 8 9 10 11 12
Creating the impression of a tree house, the luxury hotel is carried by the two elevator cores. An atrium spanning across all of the floors, splits the plan in two and provides daylight and city view to all rooms. Suites are placed in the most attractive corner locations, facing away from the atrium and common spaces. Arriving at the hotel lobby, one will experience the extraordinary feeling of a high-rising space, and have the possibility to transfer to the room by an exclusive atrium elevator. In addition to a reception with associated areas, the lobby floor also holds the great room and a small business centre. The hotel’s restaurant and spa areas are located in the astonishing space on top of the tree houses.
Entrance/Reception Waiting area Kitchen/Lunch area Restroom Storage Copy room Phone room Private office CEO office Konference room Meeting room Open landscape office
1
3
3
1 2 3 4 5 6
4 4
2 2
5
Suites Queen size rooms Storage King size rooms Atrium Atrium elevators
2
2 4 1
2
9
8
6
OFFICE FLOOR 1:400
2
4
HOTEL FLOOR 1:400
Bathrooms are positioned directly adjecent the corridor to prevent pipes from passing through the rooms Wall diffusers are placed where needed to prevent fluttering echo
Bringing The Tree to work
Workstations can be composed in different ways depending on the type of work to be carried out. Placement and direction of chairs are to be taken into particular attention. For individual work it is preferable not to face each other directly, while for team work the isolation of local sound is of certain importance. Perforated wooden boards are used on the sides and above the desks, complemented with bookshelves and reflecting vertical glass screens hanging from the roof to retain transparency.
Distraction distance (rd)= 3 m Privacy distance (rp) = 22 m
2
rd
4
8
16
rp
32
Distance (m)
The speech transmission index STI (0-1) describes the quality of speech with respect to intelligibility.
Open office cubicles
2000
4000
125
RC30 Achievement hotel room
500
1000
2000
Octave band centre frequency (Hz)
4000
Hotel room
Sound Preassure level (dB)
2x12 mm gypsum board 50 mm air gap 50 mm batt inslutaion 200 mm reinforced concrete
Elevator nois
250
An equivalent traffic noise level of 70 dBA is expected at the hotel facade. The hotel room criteria (RC30) is achieved by combination of facade glass and hotel room windows. The floating floor combined with a resilient ceiling improves the impact insulations from footsteps.
Wall construction STC70
Hotel room
-60 -40 -20 0 20 40 60 80
Sound Preassure level (dB)
-40 -20 0 20 40 60 80 100
1000
Office cubicle
20 mm gypsum 35 mm wool insulation 35 mm air gap with wooden studs (75x35 mm) 16 mm absorbing board
Facade towards hotel room
125
Facade construction STC36
Traffic noise at facade RC30 Achievement hotel room
250
500
1000
2000
Octave band centre frequency (Hz)
4000
Outer facade
500
Cubicle, STC45
Footfall noise in the corridor is reduced by a heavy carpet and hair pad on a wood fiber board glued to the concrete
Staggered doors contribute to the acoustical privacy of hotel rooms located along the two sides of a corridor.
Elevator shaft
RC30 Achievement office cubicles
Outer facade
Sound Preassure level (dB)
Traffic noise at facade
Damping carpet
Hotel room
20 mm hardwood floor Waterproof membrane 13 mm plywood Air gap with sleepers 50x50 mm 25 mm Glass-wool quilt 150 mm reinforced concrete 100 mm batt insulation with spring hangers 2x12 mm gypsum board with deflection spring isolator
Sound isolating doors with caulked gaps and perimeter absorption.
Careful placement of doors
A demanding noise for the hotel room is generated by the elevator. The hotel room criteria (RC30) is achieved by high sound isolating walls between hotel rooms and elevator shaft.
Floor construction, STC78, IIC64
Sealed doors
To reduce the flow noise induced by the ventilation system, the ducts are placed above the corridor with mufflers between each room. When a large duct penetrates the wall, the opening is oversized and filled with fiberglass board. The ends are capped with drywall, closely fitted to the penetrating body and caulked.
Elevator shaft towards hotel room
An equivalent traffic noise level of 75 dBA is expected at the office facade. The office room criteria (RC30) is achieved by high sound isolating walls and double windows.
Octave band centre frequency (Hz)
Duct and pipe penetration
80 100
Free field attenuation. Background noise level
The room acoustic quality of the open office has been evaluated according to ISO3382-3:2012. STI-values below 0.5 are classified as non-distractive while values below 0.2 classify privacy. These metrics are shown in distraction distance rd and privacy distance rp . Normal speech at 57 dBA is experienced in the adjacent workstation but is not perceived as disturbing. The decay rate along the line of receivers is below the free field attenuation, indicating a good barrier effect from the wooden boards. In the “quiet” area, the speech is hardly perceived, indicating high privacy as needed for tasks requiring total focus.
20 40 60
1
Sound transmission index, STI open office
250
Natural convection along the facade gives the hotel visitors the opportunity to alternate the sound level and temperature in the room by opening a window
0
60 50
1
SPL at workstations
40
0,48
Open office achievements
30
0,44
Sound Pressure level (dBA)
0,37
125
The air gap between the glass facade and the hotel rooms acts as a resonant absorber
0,16
20
0,15
Slatted wooden panel functions as an absorber to reduce the noise in the atrium and in the hotel rooms
Providing flexible working environments
The tree recurs several times in the interior with its irregular shape and rugged surface. A remarkable feature that can be added to the office is a custom made absorbing tree furniture that creates an exciting informal working experience, suitable for reading or simple computer work. The wooden cubicles, that separate the open office, contain meeting rooms in different sizes as well as “phone booths“, aiming to isolate the human sound source and thereby creating a better working environment.
Diffusing and absorbing artwork made out of wood connects to the concept of the tree
2x9 mm laminated facade glass with 200 mm air gap 1000 mm atrium air gap
Windows STC34 5 mm laminated glass 13 mm air gap 9 mm laminated glass
Wall construction STC65 30 mm wooden slit absorbers 40 mm air gap with wooden studs Absorbing material 150 mm reinforced concrete 2x12 mm gypsum board
Nightclub The nightclub offers an experience that cannot be found anywhere else in the world. Elevators carries visitors to the last stop in the building, letting them enter in a lobby that reveals a magnificent view of the city through dense load bearing branch structure climbing the facade. The nightclub is constructed as an isolated box with four floors serving as five parted spaces for events as well as ordinary restaurant- and bar activities. The spaces include a lobby with double roof height, a panorama bar with scenery in three directions, a multipurpose room for big events, and a rooftop bar with an adjacent roof terrace.
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2 1 3 8
2
3
8 9
3 4
1 2 3 4 5 6 7
Nightclub entrance Coat room Accessible restrooms Ladies restroom Men’s restroom Cleaning supplies Mechanical room/ local climate control Panorama bar VIP area
1 2 3 4 5 6
6
1 6
2
Stage Stall/Dance floor Greenroom Catering area Dressing room
3
4 4
Restroom
1
7
5
ENTRANCE FLOOR 1:400
MEZZANINE FLOOR 1:400
MULTIPURPOSE ROOM 1:400
Optimizing sound distribution
Handling low frequency
An adjustable ceiling, inspired by the shape of a tree, provides early reflections for optimum sound distribution without enhancement. The variable ceiling reflector plates can be adjusted to also function as absorbers tuned to desired frequencies
Tree top bar // Sky terrace
Perforated gypsum panels for low frequency absorption with additional base traps in corners
Absorbing sound
Absorbing wall to avoid late reflections
Diffusing sound
Preventing sound from spreading
The irregular shape of the tree is successfully used on the side walls to diffuse the sound in the room
Glass sluice with sound absorptive treatment on walls and ceiling to prevent sound from spreading from the multipurpose room when opening the door
0
A highly flexible room
Catering // Stage
1
2 Ceiling plates
As the name reveals, the multipurpose room can host many different kind of events. The design of the room and the flexible ceiling enables both enhanced and acoustical performances. The ceiling is equipped with a control system that allows the plates to vary from highly reflecting to absorbing.
150
Lpeq nightclub
100
Background levels in nightclub lobby Background levels in “panorama bar“
Reverberation time (s)
0
T30 range
1000 2000 125 250 500 Octave band centre frequency (Hz)
4000
4 dB
Wall construction STC72 2x9 mm gypsum board 50 mm batt insulation 20 mm air gap with metal studs 100 mm reinforced concrete 20 mm air gap with metal studs 50 mm batt insulation 2x9 gypsum board
20 mm parquet Waterproof membrane 13 mm plywood Air gap with sleepers 50x50 mm Dry sand layer 10 mm viscoelastic layer PVC 250 mm reinforced concrete 100 mm batt insulation with spring hangers 2x12 mm gypsum board with deflection spring isolator
50 125
4000
Reflecting ceiling Absorbing ceiling
7 dB
6 dB
4 dB
10 dB
Floor construction STC90, IIC80
0
Adjustable air springs, consisting of stacked air filled rubber ellipses, are placed in clusters between the elevator shaft and the load bearing concrete level plane. This reduces the flanking transmission within the construction to about zero and keeps the vibrations out of the hotel.
Sound Preassure level (dB)
Smart air springs
80 mm heavy conrete inertia base 100 mm floating floor concrete 150 mm structural concrete 50 mm batt insulation 25 mm deflection spring isolators Resilient mountings 2x20 mm gypsum board
1000 2000 125 250 500 Octave band centre frequency (Hz)
Nightclub lobby
Floor construction STC94, IIC82
No extension (0)
Multipurpose room
300 mm reinforced concrete, steel I-beam sprayed with viscoelastic damping compound 20 mm mastic caulking Steel profile secured in load bearing structure by bolts: Neoprene gasket 2x9 mm laminated glass with 200 mm air gap Mastic caulking
Half extension (1)
In spite of the loud sound levels expected in the multipurpose room, acceptable background levels are achieved in the nearby facilities. Multilayer walls and wooding floating floor on a sand layer, combined with a resilient ceiling, provides sufficient sound and impact isolation above the base range.
Vibrating machinery is placed on a inertia base on resilient mounts, creating a mass spring system with resonance frequency below 10 Hz. The structural concrete slab is rigidified for increased vibration isolation.
The load-bearing structure consists of a steel core surrounded by viscoelastic damping layers and reinforced concrete. The vibrational energy is dissipating in the damping layer and the total loss factor of the load-bearing structure is increased from 10-3 to 10-1.
0
By increasing the foam volume behind the perforated plate, the absorption is increased and variety of room damping combinations is achieved. A damped room is suitable for dance floor and loud performances while full reflection is appropriate for quieter stage acts.
Reverberation time, T30 Full extension (2)
Multipurpose room
Mechanical room
Facade construction
Absorption 0 0,2 0,4 0,6 0,8 1
The room is equipped with two loudspeaker systems that can be combined: - A central cluster loudspeaker system to enhance quiet stage performance - An equalized ceiling distributing system to direct very high sound levels towards the dance floor.
Absorption coefficient (α)
Nightclub entrance// Panorama bar // Coat room // Restrooms
Adjustable panels
Hollow wooden plates Compressable absorbing foam Thin paper for high flow resistivity Laser perforated wooden plate
0,25 0,5 0,75 1 1,25
Kitchen // Mezzanine floor
Food lift
5
4
7
Mezzanine Offices Storage room Restroom Kitchen
6
5 6
1 2 3 4 5 6
2
250
500
1000
2000
Octave band centre frequency (Hz)
4000
Panorama bar
Strenght (G) Multipurpose room
The sound strength, Gmid describes the sound distribution in the multipurpose room without enhancement. The result indicates an even distribution of early reflections from the ceiling reflectors when they are at full reflection mode.