Project Brief
Shadow casted over site
Main Circulation for construction transportation
The project site is situated in the south-east part of London Borough of Islington. Islington was initially an agriculture land in the 18th century and slowly turned into a town that accommodates residents and shops nowadays due to industrialization and gentrification. The proposal is to prevent the culture lost tha slowly vanished throughout time by having a program of tannery which imply the industry of agriculture. The making of leather in the tannery involve various processes and hence it the project may need to change some spaces of the site in order to obtain the spaces needed.
Site
Introduction
Site Context & Demolishment Strategy
A combination of programs were originally sited. As extra spaces were needed for the tannery to sit in, existing structures may need to be amended for obtaining spaces. A study of programs, erection years and materiality of them is shown and they are the key elements of considerating the demolishment of them. As the conference centre and offices are newly built in 20th century comparing to the others, they are the main part of demolishment as to retain the essence of old buildings around, suiting the program of traditional tannery. Victorian Brick House Stone Cladding on concrete
20th century Brickwork Factory Brickworks
Render finishing on brickworks
As the proposal is sitting within structures and buildings in the site, the shadows produced by them may possibly affect the natural lightings obtained for the proposal. Special angles may needed to be implemented for different uses of spaces.
Residential
Average Wind direction & Strength on site
Restaurants Grennery Conference Centre
Smells produced by the tannery may need suitable ventilation. Shown is the average wind strength and direction throughout a year in Islington. SW is the dominant wind direction which may benefit the ventilation with openings situated towards SW & NE.
Studio Office
20th century Brickwork
Stone Cladding with steel framing structure Victorian Brick House with 21th century amendment on South side
21th century Brickwork
Chun-yin Kavika Lau AD 672 Technology University of Brighton
Sunpath Diagram
230°
Altitude80°62° max 70°
11:00
60°
50°
Sunlight range on 1st July
Vast amount of sunlight from South in daytime
40° 30°
8:00
15°
7:00 6:00
120°
105° 1st March 90°1st April
30° 5:00
1st February
55° 45°
75°
1st May 60°
In order to obtain as much sunlight as possible for the Reception & Office area, the whole spaces and the windows are orietated towards the South for receiving whole range of sunlight in the daytime in all seasons.
2
N
55°
N
Wind Direction Diagram
From the sunpath diagram, it can be the SW direction of wind Direction seenisthat the dominanting direction, meaning wind are most likely to blow from South West. by taking the advantage from it, Single-sided Ventilation, Cross Ventilation & Ventilation Stack could be created to suit different programs in the proposal.
Positive Pressure Zone Negative Pressure Zone Dominant Wind from South West Air flow induced
The dehairing area needs certain ventilation for people who work in it. Single-sided Ventilation is then used. By the dominanting South West wind, the pressure difference is easily created. Then with the positive & negative pressure zones, air flow is then induced inside the dehairing area.
Dehairing Area
Glass (LUX)
Frosted Glass (LUX)
1
3
50
2
24
74
3
125
82
Wood Log Storage office Space
N
Tanning Pools Tower
Wood Chip Storage
Skin Drying Product Storage
Oiling
Leather Trimming
Product Storage
LUX reading were taken at each point 1 2 3 in the space with Glass skylight and Frosted Glass skylight with constant altitude, i.e. 60°, and with constant lighting, based on tests carried out by lighting software. By the result of tests, Frosted Glass is chosen for better spreading of light over the Tanning Tower.
Drying Area
Positive Pressure Zone Negative Pressure Zone Dominant Wind from South West Cross Air flow induced
Ventilation
Tanning Pools Tower As light is always needed for working in the tanning tower, and sunlight will not affect the effectiveness of chemical used in the tanning process, obtaining certain amount of sunlight for work is chose but artificial lighting. As the sunlight is always from the South, the windows facing the south has the most in quantity. The skylight was also considered to be an opening to obtain sunlight, but as the direction of sunlight is always tilted in altitude (ranging from 16° in winter to 62° in summer), material for diffusion effect (Frosted glass) was chosen in order to improve the spread of light down the tower. A system to control tilting angles of frosted glass skylight is designed to provide different uses of light needed at different stages of tanning, e.g. constant light diffusion on whole area OR spotlight-liked of lighting on different areas. The heat produced in the tower by sunlight will also need to be considered and will be further dicussed in the section of ventilation.
The process of leather drying needs a rapid ventilation over the area as the humid air created by evaporated water from the leather needs to be brought out. dry air is also needed to continue the drying. As the outer air in London is relatively dry, it could be used as the dry air being drawn into the space for drying. And with the help of dominanting South West Wind, cross ventilation is used to create large amount of dry air flowing through the space by differences in prussure induced by the wind.
Single-sided Ventilation
Crane Residential space
3
N
Reception & Office Dominant Wind
Frosted Glass Lux Levels Tests
10°
N
128°
1
128° 20°
9:00
135°
Glass
345°
10:00
150°
{
Altitude 16° max in winter
12:00
165°
Skylight Material
Altitude 62° max in summer
307°
sunlight range on 1st January
N
environmental performance
According to the sunpath diagram, sunlight mostly comes from South Max Sunlight Range direction. Windows in the Reception & Office area is then designed to 1st November 1st October 1st December 255° obtain more sunlight from the 270° 240° 1st January South as it requres certain 230° 225° 285° amount of light for 1st September working without using 210° 300° artificial lighting in 1st August the daytime, in 18:00 19:00 June 1st 17:00 order to make 16:00 195° 315° 307° the most from 15:00 1st July daylight for 14:00 Altitude 16° sustainability max S 330° issue. 13:00
Cleaning / Sandwich Tanning Pulping Dehairing
Frosted Glass Tilting System
N
Flat (Closed) Frosted Glass
Angled (Opened) Frosted Glass
Sunlight from South Air flow induced by Stack Effect Stack Height
N h
Within the tanning process, there are strong smell of tanning chemical and also possibly harmful evaporated chemical floating around. In order to remove the strong smell and the toxic air from the tanning tower, continuous air flow during daytime working must be induced for best quality of space. The increased quatity in windows facing the South and reduced quantity of them facing the North help the best induction of air flow through the space by the principle of Solar Chimney. The tanning tower itself forms a solar chimney which takes up sunlight and heat up the interior air. By heating up the interior air, the Thermal Buoyancy increases which enhance the stack effect in the chimney. In order to maximize the stacking effect, with the help of the equation ∆P=0.043H∆T, it is known that when the value of H is larger, ∆P value would be larger as well. Stack Height (H) could then be taller for having the most vertical pressure difference (∆P) within the tanning tower. The windows at the South side are then lowered as much as they can towards the ground to maximize the Stack Height above. The South West prevailing wind hits the tower causing a high pressure on the side it hits, and a low pressure on the other side. The difference in pressure then benefits the pulling of air through the tower, which is known as Cross Ventilation, in conjunction with the Stack Effect.
Tanning Pools Tower Ventilation Stack - Solar Chimney + Cross Ventilation
∆P=0.043H∆T
N
∆P:Vertical pressure difference across a Stack ∆T:Temperature difference between interior & exterior H:Stack Height Chun-yin Kavika Lau AD 672 Technology University of Brighton
Site development scheme with proposal evolvement Void
Void
Free Site Generated
Proposal
Void as site
First proposal
1st Proposal in void
Structure
Transition Layer
Context Removal Strategy
The 1st proposal was aiming to make use the voids in the site, as to not affecting the ground circulation in terms of form and programs. It was then decided to be parasited on top of a building that generated a void with the surrounding context. As the form of the 1st proposal is so different from the surrounding context, a transition layer made of steel is put between the existing and the proposal in order to have them separated. The layer is formed by steel truss for strong support of the proposal. Extra support may also be added in the existing to take the weight of the proposal above.
1st Proposal
Context Retaining from Removal
Final Proposal
Context Retaining Strategy
2nd Proposal
2nd Proposal Horizontal Structures In the 2nd Proposal, there are many floor slabs within the buildings that need certain support. The floor slabs in Tanning Tower are mostly only for workers to walk on and always having no more than 1 person per floor, meaning the slabs does not need to take a lot of weights. On the other hand, the spaces in the main building contains many heavy machines and workers are working at the same time in the same spaces. Great amount of weights are being taken up by the slabs. With the consideration of weights being taken, different kind of structure for floors are investigated in depth. The structures are mainly divided into 2 categories, first the One-way Structure and second the Two-way Structure. Both of them have different combinations in arrangement and on cooperations with different materials. They are drawn below and each of them were considered not only by weights taking but also the best material for the spaces.
Main Building
Tanning Tower
Transition Layer [Steel Truss]
One-way Structure
Two-way Structure
Supporting framework for context under Weight One-way Plate
Weight One-way Beam
One-way Structure System
Concrete Slab on Metal deck & Steel Joists
Two-way Beam
Tanning Tower
Direction of weights spread on slab
Plywood deck on wood joists
Two-way Plate
As there are always only 1 person per floor slab working in the Tanning Tower, meaning not a lot of weigh needed to be taken by the floor, One-way Structure are chosen. In the Tanning Tower there are many tanning pools which make the spaces very moisturing and wet, Plywood floor will then absorb the moisture and affecting the effectiveness of it, it is then not considered. Concrete may not be effectively prevent slippery caused by wet floor, hence steel grating floor are chosen over concrete slab with the support of One-way beams. One-Way Concrete Slab
One-Way Beams
One-Way Rib Slab
Two-way Structure System Direction of weights spread on slab
Main Building In the main building, there are lots of heavy machineries and workers working in the spaces. A rigid and strong structure was chosen for taking up the heavy duty. The Two-way Waffle Slab could also cooperate with metal decking and concrete on top which could make the structure even stronger.
Two-Way Concrete Plate
Two-Way Concrete slab on edge beams
Two Way Concrete slab on drop panels
Two-way beams
Two-way Waffle Slab
Chun-yin Kavika Lau AD 672 Technology University of Brighton
Floor Slab Construction
[Method 1] Waffle / Honeycomb Floor Step 1
Step 2
Step 3
Step 4
Step 5
[View from Below]
Bounding Mould
Rib Reinforcement inserted
GRP Waffle Mould Inserted
Steel Rebar Bar Dia.: 20mm Weight: 4.928lbs/m
Concrete poured in situ
Waffle / Honeycomb floor made
Waffle floor mould Base size: 800mm x 800mm Depth: 300mm
50mm thick in situ topping reinforced with welded fabric
R.C. edge beam
Main Floors
Construction
Rib Steel Reinforcement Bar
In the structure part, it is decided to use the Two-way structure / Two-way Waffle slab to be the floor structure for the main building as lots of workers and machineries will be put on top. The construction of waffle floor slab is then look into detail in this section. Other than the construction procedure introduced above, some details of mould are as well looked into and be considered. GRP (Glass Reinforced Plastic) is chosen to be the material of mould as it is strong, lightweight to resist the lateral concrete loading during concreting. The Waffle moulds are inclined in order to ease striping of the moulds from the slab after drying. a hole on the underside of the mould is made for receiving compressed air as shown above to help stripping after concrete hardens. Maintenance of moulds is essential before re-use as they are easily be scratched as scratched moulds would produce poor finish of concrete.
Initial floor slab design on 3/F
Detail of unit mould
[Method 2] Prestressed Concrete Slab
Wires and strands anchored with barrels and wedges on anchor plate
Mould inside steel frame
Choice 1:Pre-tensioning
Tension variation
Stage 2
Long-line production
Standard Strand
Standard Strand
Drawn Strand
Drawn Strand
Direction of Tension in tendon
Stop-end Temporary Sturts
Steel Anchorages
End of post-tensioned element
Decision for main building floor slabs
Anchorages
Direction of Tension in tendon
19-wire strand
Anchorages
Anchor Plate
Stage 3
7-wire strand
Macally Bar
Stage 3
Steel joists Anchor Plate
Wire
Dywidag Bar
Stage 2
Concrete
Generated 3/F Floor slab
Drawn Strand
Tendon
Barrels and wedges anchoring wires or strands
[View from Below]
Standard Strand
Tendon Duct Concrete
End plate in mould
Tension variation
in situ ribs at 800 c/c
Types of tendons General types
Stage 1 Hydraulic jacks for detensioning
Stage 1
Choice 2:Post-tensioning
Honeycomb shape left by moulds
Jacking end
Fixed Abutment
Floor Level
Tendon Duct
Prestressed Post-tensioning Two-way Waffle Concrete Slab Drawn 7-wire Strand Radius: 4mm
Pre-tensioning equipment arrangement Steel Beam section as abutment fixed to each side of mould
Dividing plates or spacers
Concrete cast around stressed tendons
Abutment Steel anchor plate
Steel Tendons stressed before concrete is placed
Anchor secured before stressing commences
Direction of Tension
Hydraulic Jack Precision metal mould
Steel Anchor Plate Steel Channel Bearer
Floor Level
Support piers to raise mould to reasonable working height
As heavy weights are put on the concrete floor slabs, extra support from the reinforcement within could be implemented. As concrete is strong in compression but weak in tension, prestressed concrete is used or provide extra strength. Two types of prestressing are introduced above which have different method of tensioning the tendon within the structure. But as Pre-tensioning only applies to precast elements and Post-tensioning could be cast in-situ, whereas the floor slabs are very large and different with each other in shapes, casting in-situ is preferred. Post-tensioning is then decided. When looking at the types of tendons to be used in post-tensioning, Dywidag Bar and Macally Bar are excluded as they could not be bent and insert into the duct. Wire is obviously too weak in strength and being considered. As the proposal has only 3 levels in the main building unlike skyscrappers, Drawn 7-wire with commonly used 4mm in radius strand is used.
Chun-yin Kavika Lau AD 672 Technology University of Brighton
ZINC CLADDING
OUTDOOR ASPHALT WATERPROOF MEMBARNE
LADDER CAGE
STORAGE RACK
CLADDING FIXINGS
SERVICES LADDER STEEL GRATING MAIN STRUCTURAL I-BEAM
TANKING WATERPROOFING MEMBRANE
SECONDARY STRUCTURAL I-BEAM
BUILDING FINISHES
WATERPROOFING MEMBRANE INSULATION LAYER
ASPHALT WATERPROOFING MEMBRANE SHEAR REINFORCEMENT
EXTRA REINFORCEMENT TIES
steel studded floor plate
CONCRETE TANKING
TANKING WATERPROOFING MEMBRANE FOUNDATION ASPHALT WATERPROOFING MEMBRANE
REINFORCEMENT CONCRETE FOUNDATION Chun-yin Kavika Lau AD 672 Technology 1:20 Section University of Brighton