Evolution of Cambridge

Cambridge, like so many towns and cities in the UK has evolved around water. The River Cam has been the spine of the city for over 1000 years.

 Red area indicates University Library and my neighbouring site.I learnt that my site is within the heritage/protected area of Cambridge (green areas, below) so my design would need to meet a number of criteria before it could be built... the legislation mainly listed materiality. Locally sourced, vernacular materials are important to new buildings in Cambridge. Modern buildings have the same material palette as buildings 100 years old but are buit in a much more contemporary way.

The material palette of Cambridge is mainly brick (various/red & dutch), stone (mainly limestone), timber (I noticed oak, birch and cedar when I was walking around Cambridge) and concrete (internal and external).

I found the nearest brick quarry, in Barrington, about 10 miles from the site:

... and the nearest timber merchants, which use timber from sustainably sourced forests just west of London. They specialise in Beech, Holly, Hornbeam and Oak.

Section and Volumetric Models

In section, the depository is 2800mm below ground, which ties in with the 1400mm grid. On the far left is the public building. The floor plates are small, 9.8m x 9.8m, so I propose one purpose per floor. 

Public Building (left):

Fourth Floor - Plant Room/Rainwater Recycling

Third Floor - Computer Area/Printing

Second Floor - Exhibition/Gallery

First Floor - Exhibition/Gallery

Ground floor - Reception, small shop and WCs.

Private/Staff Building (right):

Fourth Floor - Plant Room/Rainwater Recycling

Third Floor - Staff/Seminar Room

Second Floor - Digitalisation

First Floor - Workshop

Ground floor - Deliveries

The structures in between are the light wells and the ventilation towers. The larger towers are those above the underground reading rooms. 

I have shown the above ground structures on my 1:250 wooden model. I wanted to push the public building right up against the edge of the pavement, to maximise the number of people walking past it.

The building turns its back on the primary school to the south and the college to the west. However I want it to open up onto the new public space I am creating above the labyrinth:

I have shown below how people can inhabit this space. The 1.4 x 1.4 x 4.2m horizontal blocks are the same proportions as the neighbouring wind catchers; they aren't too tall to climb on. It would be interesting having the primary school using the space as a playground, and ultimately an interesting walk to work for the staff in the east building.

Labyrinth Development

Once I had divided the site up into 1400 squares I used AutoCAD and Photoshop to experiment with quick circulation patterns through the underground depository. Each 1400mm square would contain an A0 map storage unit, containing perhaps 1000 maps. I worked out I would need 550 square metres of map storage (not including circulation), which I feel my single subterranean level would accommodate for, being just over 1000 sq.m. 

I didn't want any wasted space underground, and I wanted the site boundaries to be as simple as possible, i.e. a rectangular containing wall. I decided the pathways should be 2800mm wide, so two map storage units could be wheeled past one another, and people could pass each other even if the A0 drawers are opened. The voids in the labyrinth are reading/work rooms and a supervised reading room for photocopying/tracing precious maps. The largest room is an atlas room, for books on shelves rather than in drawers:

The more I used parameters in the design of the labyrinth, the more it started to look like a viable floor plan. The obvious parameter between the three designs below and the design above is that the labyrinth is narrower due to the tall buildings above ground overshadowing any light pipes to the north. This meant that all the corners of the labyrinth, i.e. all the places that needed light pipes/ventilation, had to be placed between the two buildings above ground. This had the added structural bonus that the foundation structure of the buildings either side didn't interfere with the labyrinth structure - the two elements are now separate.

As these designs developed, I realised I would need to move the underground rooms further south in the site, to receive the most solar gain. The diagram below indicates the area of most solar gain in orange, the ideal location from light pipes:

The AutoCAD image above shows the 1400mm grid carved out to form the route through the site, and the subterranean reading rooms. The circulation is more clear when the image is inverted, below:

I have shown the quickest route through the site in red. What I felt important was that the route between the two buildings was not a straight line. I wanted people to discover the spaces, to be confused and intrigued by them, much like cartographers and explorers have dealt with maps in the past. 

My sketch below (from a couple of weeks ago) shows that I plan to organise the labyrinth into different types of maps, for instance: Ordnance Surveys, Historical Cartography, Modern Maps and Atlases. 

I like the idea of requiring a map to find your way around a map library, and I look forward to producing a map to guide visitors/external examiners through the building.

Ventilation and Lighting Studies

I want to incorporate the modern light pipe design into a traditional wind catcher aesthetic. The brick of the wind catchers ties in with the brick aesthetic of the surrounding buildings of Cambridge. Modern architecture in Cambridge uses a very small material palette - brick and masonry, but in contemporary ways. I hope to achieve this with the aesthetic of the wind towers. The towers fit neatly into the 1400mm grid of the site, and are proportioned as three 1400mm cubes stacked on top of each other; where the top cube contains the air vents.

In the centre of the tower will be a reflective tube so light will bounce back and forth before it illuminates the spaces below:

The stack effect will help draw fresh air in and expel warm air, due to the temperature differences between the  air outside and the air in the subterranean depository. The blue arrows show fresh air, red arrows the stale air from underground; and the yellow arrows show light bouncing down the light pipe:

Geology & Site Constraints

For this section of group work, we researched bore hole data from the east of the site, just behind the library, to learn about the geology of the site:

0-1.2m below the turf is just topsoil, man made, this layer soaks up drainage from the site. Beneath the layer of topsoil is 3m of sand and gravel, composed mainly of fine particles of flintstone, chalk and limestone. A 2m layer of clay lies below this, which is fairly soft so pile foundations would be required to pierce into the calcareous mudstone (the supporting ground). The borehole data stopped at -20m, but I presume the mudstone layer continued below this.

The most interesting we discovered was the large amount of fossils that have been found in Cambridge, in the layer of mudstone. These are all marine fossils, indicating that Cambridge and The Fens region of Eastern England was at one time in history (we think the cretaceous era) submerged under water.

 

 

We researched the feasibility of construction on site, which with such a large site was quite straightforward. Construction vehicles have good links to the site from Grange Road,  less than 2 miles from the motorway.

 

 The diagram below is to scale, and shows:

Red rectangle indicates size of maximum (single) portacabin.

Blue rectangle indicates maximum size of lorry on UK road.

Orange circle shows maximum turning circle for the lorry (vehicle must be able to drive inside the orange doughnut shape). 

Green shape is the access/servicing road to the University Library, and must not be obstructed in construction.

Wind and Water Analysis

The prevailing wind on the site comes in mainly from the south-west. The wind is channeled around Robinson College west of the site creating high wind speeds on Grange Road, between my site and the college. The south west is the windiest part of my site and the north west is the least windy.

 Turbulence and Pressure

Arrows show prevailing winds from the south west. Turbulence is located in areas where high and low pressure meet, in this case in areas of difference in height or temperature (i.e. next to buildings)

Wind is sucked down into the site after kings College School and the surrounding trees, and up again over the Solar Trees and the Real Tennis Club.

Since warm air is less dense and creates less air pressure, it will rise, whilst cold air is denser and creates greater air pressure, so it will sink. When warm air rises, cooler air will often move in to replace it, so wind often moves from areas where it's colder to areas where it's warmer. The greater the difference between the high and low pressure or the shorter the distance between the high and low pressure areas, the faster the wind will blow. This is shown by rotating arrows in my diagram above.

Water Analysis.

The image below shows the nearest body of water, a small stream 40m north of the site. The stream is shallow and even in a record 100-year flood (shown in light blue) its flooding does not affect my site. Cambridge's irrigation initiative has drastically reduced the flooding levels of the River Cam and all of its tributaries (like the one below). The direction of the stream (flowing east towards the main River Cam) is shown in my model.

 

 Tributary

River Cam Context

Lighting, Ventilation & Volumetric Experiments

Keeping the environmental conditions underground suitable is extremely important for the map depositary. I wanted to provide natural ventilation, by using traditional wind towers, similar to ones seen in Accordia housing, by FCB Architects.

I also wanted to create a consistent aesthetic by designing the two buildings either side of the wind catchers and light pipes. I built a simple volumetric model illustrating this. I located the exhibition space on the crossroads, to promote the gallery as best I could on site. The positioning also keeps the height of the building away from the solar panels to the north:

The large blocks are the two buildings - the public and private buildings. The intermediate sized blocks are light-wells above the underground reading rooms; and the smaller blocks are the wind catchers. 

I treated the site plan as a canvas, placing the sculptural towers in a way that created public spaces in between.

I then thought to rearrange the elements on their side to provide seating. These seats could incorporate light-wells to naturally light the corners of the labyrinth below:

The composition of elements makes more sense when overlaid onto one of my earlier labyrinth. The wind catchers and light-wells are strategically placed over certain places within the labyrinth. These models are purely volumetric, diagrammatic, but will help form an idea of organisation structure on the site: