The diagrams indicate the amount of shading on site throughout the year. It can be seen that the site is not overshadowed nor does it overshadow any nearby buildings. The site would be perfect to orient a building facing the south to maximise solar gain. Summer Shadows
10am
1pm
4pm
Winter Shadows
10am
1pm
4pm
1pm
4pm
August 26th
November 26th
August 26th
November 26th
Proposed building shadows show that the proposal does not affect the rights to light of any surrounding buildings.
Proposed Building Shadows Summer 10am
1pm
4pm
Proposed Building Shadows
Winter
10am
Cumulative shadows show where maximum shading is present on site. The overpass creates the most shadows on site but otherwise there are no natural lighting issues.
Cumulative Shadows
February 26th
August 26th
November 26th
Cumulative Building Shadows
February 26th
It can be seen that the overpass may only be a problem with rights to light in the very early hours of the morning when the sun is far in the east
Site Plan Views
February 26th
August 26th
November 26th
Plan Views
February 26th
Insolation diagrams from summer and winter show that building zones facing the south-east will receive the most sunlight, whereas the northern and western faces of the proposal will receive the least amount of sunlight. This will help establish exactly where inside my building specific rooms will be located. Flooding is an issue on the site; it is situated adjacent to the tidal river Avon, and is particularly prone to flooding after a wet solstice. The map below highlights low tide, high tide and flood levels along with flood-prone areas (circled). The site lies directly within one of the major flood-risk zones. The tidal range is up to nine metres in height with the average low tide river level rising two metres above sea-level. The tidal river is a strong focus of the design, and will be heavily utilised for power generation. Maximum Insolation Zones
Summer
Minimum Insolation Zones
Summer
Maximum Insolation Zones
Winter
Minimum Insolation Zones
Winter
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River Level
Low Tide
S.L. +2.00m
High and low wind pressures across the site, high pressure displayed in orange. There is a direct correlation between high insolation levels and high wind pressure. The broad range in wind pressure across site will enable the use of passive ventilation strategies. The prevailing wind blows in from the Atlantic, from the south-west. The landscape is very open to the site with not much protection from the elements. The prevailing wind cools slightly as it crosses the river creating a bigger range in pressure. The central diagrams show the prevailing wind direction, speed and frequency in Bristol over the four seasons. The Beaufort Scale is overlaid in orange, and starts from 0 at the bullseye radiating out to force five on the perimeter.
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River Level
High Tide
S.L. +9.00m
Flood Level
S.L. +12.00m
The site can make good use of the ample water supply in the vicinity. Water can be collected from the floating harbour in abundance, filtered, and distributed throughout site via the main plant room.
The wind patterns are barely affected by the proposal on site. It seems the design is an extension of the existing environment and is very passive in concept. Below centre: There is currently no drainage on site, when it rains the water simply flows into the adjacent locks and river. Standing water could be an issue.
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Dead Loads
Live Loads
Naturally the geology on site is incredibly poor. The earth immediately surrounding the river is soft silt and traditional construction methods would be inadequete for the location. For this reason continous flight auger piles have been chosen for the primary foundations, and 149 seven metre piles are spread across site. These are drilled down to the bedrock for stability. The man-made island upon which the site sits is filled with loose rubble, and again would be unsuitable for traditional foundations. Not only will piles be used but underground retaining anchor bolts will keep the lock walls straight and prevent buckling under the immense weight of the new build. The diagram to the right shows the spread of piles (in orange) across the site. Primary concrete ctructure is shown in grey while the principal load bearing roof beams are shown in red. These range in length from 12m up to the maximum of 20m.
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Axonometric showing structural hierarchy of detention centre cell block. Construction method is typical throughout. Green - Green roof Beige - Primary structural system, 300mm reinforced concrete Red - Secondary structural system, 40mm steel bars and 300mm reinforced concrete. The upper floor has been allocated as a secondary structure as it is a load bearing component, however it is also bearing its load onto the bracing walls and floor below. Yellow dictates the bracing elements. Although the concrete is itself already internally braced, the highlighted walls further brace the structure as a whole and gives it much more rigidity.
In summary the roof supports the green flora adorning it, which is supported by the principal concrete beams atop the load bearing walls, which carry the loads through the structure and down the foundations into bedrock. The surplus walls give the structure rigidity and will endlessly aid with the relentless elemental pounding the building will receive in its exposed location. The below diagrams show dead and live loads acting upon the structure. The last two diagrams describe the effect of such a mass of weight atop the poor soil conditions, and the solution to this problem can be found with the anchor bolts, which will neutralise the lock walls’ urge to spread.
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Service distribution across the cell block, highlighted red is the location of the turbines, left
The building utilises different principles in its energy production. Bi-directional hydroelectric turbines are a main feature of the detention centre. These are submerged twice daily and produce energy from the incoming and outgoing tide. Another way of capturing tidal energy is through the conversion of the lock into a tidal lagoon. This captures water inside at high tide and releases it throughout the day via a sluice gate with hydroelectric turbines inside. The main way of creating energy on site, however, is through punishment. Exercise in the gym is a daily mandatory requirement, and every exercise machine is hooked up to a dynamo which creates electricity. Energy produced by inmates at Bristol Borstal could be used as the principal currency in the complex. On average it costs ÂŁ55,000 per year for every young offender detained. This scheme could therefore drastically reduce the cost of incarceration. Diagram left shows the sewerage system in the vicinity. Although it is shown that other buildings dump their waste directly into the river, the sustainable nature of this build would not allow this as an option, and so additional sewer pipes are to be laid on site.
Above displays the service distribution throughout the cell block. Cyan is the delivery of water from the floating harbour, via the main plant room, to every sink and toilet throughout the complex. Orange displays the foul water service runs, culminating in the secondary plant room next to the hydroelectric turbines. The building makes the most of the abundance of light on site, and can even afford to play with it. The cell blocks are oriented so that they get early morning indirect sunlight, whereas the care homes on the other side of the complex are arrayed to watch the setting sun. The adjacent render shows the morning sun in the cell block. The cell block relies on natural lighting, whereas the admin block and the classrooms must rely on artificial lighting. The reason for this is that the classrooms must be multifunctional, therfore able to adapt to accommodate lectures, presentations and meetings. Education is key here, and so it is not important to provide distracting vistas to distract the mind.
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Building Programme Detention Centre - 10 cells housing total 64 inmates. Early morning indirect sun. Harsh material environment Classrooms - 3x, Artificially lit, multipurpose spaces, able to adapt. Much storage, flexibility. Low natural light levels
Orange arrows show means of escape and distances. The heightened security means some of the travel distances are longer than permitted, and this will have to be addressed. The green rooms highlighted below have a 60minute fire safety rating. These are compartment zones which means that if a fire erupts in any of these rooms it will be contained for at least an hour. The rooms have been considered to be compartmented due to their purposes. For instance, all of the plant rooms are compartment zones, as is the kitchen, as are the workshops. Fires are most likely to start in these places.
Workshops - 3x, Mid morning/afternoon indirect sunlight, reduce glare from metal implements. Barren but inviting. Dining Hall - Open space, indirect light throughout the day Kitchen - Industrial sized, staff on 10. North facing, ample indirect sunlight, no direct sun. Reception - Intimidating, first port of call for new arrivals. Sparse, inhospitable. Hard acoustics. Gym - Soft acoustics, soft flooring. Must be large enough to accommodate 16 people and changing room. Morning sunlight Isolation Cells - 8x, grimy 1-man cells. Specifically for punishment, hard acoustics, dank, below ground level. Ample sunlight throughout the day, feature windows to publicly display offenders Secure Care Homes - the exact opposite, calm, warm, inviting, an achievement to work towards. Soft acoustics, low level artificial lighting, ample evening sun Plant Room - No sunlight required. Private space, no acoustic requirements. Staff Room - North facing towards the city, away from the offenders. Low light level amended with use of light wells. Must have sufficient light, Admin Office - North facing towards the city, away from the offenders. Low light level amended with use of light wells. Must have sufficient light, Medical Room - Light wells provide ample light to medical room. Perhaps the most important room to light properly. Soft acoustics, the third room to enter upon arrival, must be inviting Psych Room - small room for holding quiet personal conversations with inmates. Dark room preferred, low light, low artificial light.
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Roof Detail 1:10 1 1.5mm zinc parapet capping zinc UDS connector breather membrane 18mm exterior grade plywood fixed to concrete upstand Timber batten and rubber filler Roof Detail 1:10
The timber battens and rubber filler support aluminium flashing which will make the gutter, and ensures the flashing is level 18mm plywood is rigid enough to support the aluminium flashing Breather membrane is glued directly onto the plywood board Zinc UDS then connected to the membrane so as to connect the parapet capping to the rest of the building 2 aluminium gutter tray waterproof membrane Aluminium tray diverts water from the roof into rainwater collecting tanks
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The waterproof membrane overlaps the underlying roof slab membrane, forming a watertight seal 3
sedum and wild grass roof 150mm reinforced concrete roof slab 80mm board insulation waterproof foil membrane 80mm reinforced precast concrete roof panels 75mm mineral board insulation 75mm pigmented concrete render
The roof is heavily insulated to aid in retaining heat within the massive walls
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Wall/Floor Detail 1:10
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7 Wall/Floor Detail 1:10 4
300mm reinforced concrete 75mm mineral board insulation 75mm pigmented concrete render
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expanded polystyrene insulation
In order to prevent cold bridging insulation is placed between the external wall and floor slab 6 300mm reinforced concrete load bearing external walls finished with an anti dust sealant 75mm mineral board insulation with vapour barrier 25mm board insulation between wall and window mullion mitigates any cold bridging rubber gasket to prevent moisture ingress anodised aluminium window mullion fixed to wall with M10 x 100mm concrete anchor bolts isolator connecting glazing and mullion glazing, 10.3mm Security laminate inner pane 11.5mm Anti-Bandit laminate outer pane insulation to prevent cold bridging aluminium flashing to protect insulation
Facade buildup
7 20mm Magnesite screed, polished and sealed compression strip 300mm reinforced concrete floor 75mm board insulation 50mm screed to level site Magnesite will be used on the floor for its likeness to concrete and its minimal slip value the comprssion strip spans the full depth of the screed and is used at the perimeter to strengthen the floor and prevent cracking
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50mm flagstone paving damp proof membrane 100mm concrete screed infill 300mm reinforced concrete strip foundation
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Section through facade 1:50
Ground/Floor Detail 1:10
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