week 1 Constructing Environments India McKenzie 639 234
Mass Construction
WK 1_JOURNAL
tutorial 1
To begin with, we decided to spend some unstructured time getting to know the properties of the materials by feel. From here we brainstormed and brought our individual ideas together to decide on the most logical formation for the base of our structure. Working within the requirements of the brief, we identified two key targets: 1. Material efficiency 2. Stability In order to achieve the most stable base with the least amount of blocks we established that we would begin with a triangular base, of double thickness, to provide maxiumum stability at the base of the tower. At present time, efficiency of materials was not our main priority as a sturdy base was essential.
The next step was to establish a pattern of laying the bricks in a manner that was strategic and careful but was not time consuming. From observing the teams around us and in neighbouring tutorials, the construction process had to be swift yet precise, the latter of which we somewhat failed to adhere to. Our base began to take shape and as our structure emerged from the sketches into reality, we identified the need for stabilisers in the form of buttresses on each of the three corners of the triangle. With three people in our group and three sides, our production rate was matched throughout the group.
Whilst our buttresses provided sufficient stability for the corners, the hypotenuse of the triange (as seen in the above image) became a slight worry. We realised our issue when one team member began to taper the blocks more severely than another, resulting in a Leaning Tower of Pisa-esque structure. Whilst the corners were bolstered by the buttresses, we identified the face shown as the weakest point. After we formed a suitably sized gap to fit the toy dog, we changed tact and the target of material efficiency took over stability as our main priority. From here we began a steep vertical incline in a tight circle formation with offset bricks for maximum efficiency.
When evaluating our own structure, it was useful to observe other students’ work not only from our own tutorial but of those in the next room. The most successful towers were those with a wide, circular and regular base that operated on the repetition of a simple rule and precise placement of the blocks. This image is of another group in our tutorial. I included this image to illustrate how rigid the structure becomes when the force of compression is in operation which makes such dramatic gaping holes possible in the structure. Whilst this gap may have compromised the integrity of the structure as it teetered higher and higher towards the ceiling, it showed how strategic placement and construction can render some of the structure unnecessary in maintaining its form.
The final part of the tutorial raised the issue of load and weight distribution. After we had exhausted our supply of materials, we began to add objects on top of our structures. Although somewhat precarious, the structure was able to withstand the addition of more weight on top of the structure due to the distribution of load through the compression systems. The circular based structures, with their symetrical and balanced base were more successful than our triangular based structure as it eventually succumbed to pressure and buckled sideways. This task was rather revealing when we analysed the concepts of load distribution, material efficiency, construction sequences and stability in relation to the compression buidling systems.
week 2 Constructing Environments India McKenzie 639 234
Construction Method
WK 2_JOURNAL
As opposed to the mass construction used in last weeks studio task, the materials we were given this week required us to create a post and beam style structure using the thin balsa wood beams and super glue. We began by sketching geometries for the base, deciding on a square base due to its symettry and stability. In retrospect, the use of a triangle base would have been a more effecient use of materials by removing the fourth component as well as being a more rigid structure against lateral forces. After we established the base formation, we then wish to confront our construction method. Learning from the failures of last weeks’ haphazard formation, it was imperative that we plan the stages of construction to be effective with our time and our materials both of which acted as constraints to the brief. We opted for a modular sectioned method whereby each group member was given a task in creating a number of individual modules that could simply be connected together to form the vertical structure. This division of labour mimiced the specialised members of a construction team as we assigned responsibilities to each member. It also made efficient use of limited time and operated on sound principles that if executed correctly, have been found to yield effective results in large scale building constructions. The difficulty we had was with the imprecise nature of the materials and the error or margin being small. The use of superglue also complicated the matter as it required compression and time in order to set properly. Slight differences between each module became apparent when we began to construct the model and the posts didn’t align as they should theoretically have done.
Joints + Structure
WK 2_JOURNAL
As we experimented with the properties of the materials, we experimented with a couple of different joint styles in order to evaluate the rigidity and appropriateness of the different types. One suggestion was the ‘Moulded or Shaped’ joint that would have been structurally sound with the balsa connections yet the time constraint ruled this option out as it was labour and time intensive. Instead we opted for a stacked ‘butt joint’. This can be seen in the sketch design below. The decision to inset the posts within the horizontal beam structure was discounted due to the potential for vertical slippage once the dead load above became too much. We were unsure if the adhesive could cope with the downward pressure and thus opted to create a point & load system by aligning the posts directly above one another.
WK 2_JOURNAL
“lateral and torsonial instability” The post and beam system is effective in acheiving height however the balsa wood proved to be a particularly flexible post option thus creating this “lateral and torsonial instability” throughout the structure. In order to counteract this instability we sought an element that would add rigidity to our design. Our first attempt to stabilise the structure came from our readings of Chapter 2 of Ching. At first, we consulted the chapter to assess the most suitable spanning and bracing options. Given the square formation of the base, Ching suggested that we use a two-way span rather than a one-way which is better suited to rectangular objects. Yet we quickly establish that cross spans would be relatively ineffectual and an ineffective use of materials. We then explored the concepts of bracing which proved a more efficient use of materials. Whilst the cross-bracing was noted to be more stable, the regular length of the rods meant this option was impossible without reducing the width of the structure. It also would have consumed a significant amount of our finite supply of balsa. We opted for the simple knee joint to counteract these restrictions and provide extra support to “resist lateral forces”.
Rigidity
WK 2_JOURNAL
As we began to put our modular sections together we began to have issues with the adhesive in that the glue required compression and time to set in place. This meant thtat our point and beam system was placed under extensive stress as the downward pressure required for the glue drying process, meant that the weaknesses in the structure were exaggerated. As illustrated in the diagram below, the concentrated load ran directly through the vertical posts and caused a deformation of alignment particularly at the bottom. This can be seen in the image as the posts on the base are seen to buckle inwards despite the knee bracing. The sketch identifies the weaknesses and illustrates how the imprecise construction process resulted in the development and exacerbation of weak points as the tower grew in height.
Weaknesses
Reflection
WK 2_JOURNAL
R:
Once we had exhausted our supply of materials, and acknowledged our structure was neither the tallest, nor the most rigid in the group, we decide to first analyse and detect the elements that made the other groups’ structures more successful. We identified the geometry of the triangle to be a much more logical form for the base which lends well to the structural rigidity of the truss system which draws upon the linear members and a webing system to create rigidity between the chords. Our next step was to analyse the destruction of our structure and thus we then applied a force to one corner. This highlighted the weakness of the point and beam system as the concentration of load on a single point lead to the buckling of the ‘long slender’ columns and the structure folded in on itself. This was partly due to the incompetency of the the adhesive to perform its function and the innaccurate construction methods.
week 3 Constructing Environments India McKenzie 639 234
WK 3_JOURNAL
Site 1: Eastern Precint Student Centre
The exposed aggregate concrete material here is reminiscent of the time frame in which is was designed- most likely the 1970’s. This image also illustrates the way the steel beams extrude from the existing building. The use of a cantilever system to overhanf the joining space emphasises the properties of steel. Combination of mass and lightweight construction methods. The pre-existing buiildings use predominantly mass construction as seen with the building on the left here. The exterior of the buidling shows how the framework structure of the bridging covered area is supported by the mass constructed buildings it joins.
Louvre windows provide excellent cross-ventilation systems. The extensive use of glazing on the east and west ends of the structure in the form of wall to ceiling glass curtain walls capitalises on the natural elements to provide natural light and ventilation to the space.
Materials_ - concrete with unrendered exposed aggregate - polished concrete slab with steel ribbings - steel (framework) - glass - timber/plywood - steel (decorative) This image of the interior space is included to illustrate the cantilever system as there are no internal columns supporting the bridging roof structure. The use of very large steel beams across the space is made possible by the lightweight beam structure. The use of glazing over half of the roof also floods the area with natural lighting which creates an interesting atmosphere for the space.
Site 2: MSLE Building
WK 3_JOURNAL FEATURES: - Rubber skirting - Plaster board used to cover brick masonry. - Wooden door architraves using frame joinery - Infill glazing membrane= natural light. - Veneer: 1 side plaster, 1 side brick. - Cantilevered beams span across the void and support the stairs. - Original texture of brick masonry retained for aesthetic appeal
Potential construction constraints_ - science lab facilities - classroom use throughout construction - university construction guidelines - existing amenities ie. ventilation ducts, heating and cooling.
The space that joins the two building uses a lightweight steel structure to merge the two masonry buildings creating the foyer space inbetween, The image on the right shows the mass construction of the western end of the foyer space where mass construction can be seen in the form of the in-situ concrete staircase. Conversely, the two photos above show the steel membrane structure. The use of welding to forge two perpendicular elements together has been used in the cantilevered midlevel that is supported by a steel plate bolted to the wall in a semi-rigid joint. The horizontal level is stabilised from the perpendicular brick wall.
These two images illustrate how masonry and mass construction functions in wall systems. The compression of the bricks on top of each other create the stability that enables gaps to be formed for doors and arches. The left image shows how a pre-existing gap in the wall has been filled with the red bricks. The right image shoes the structural element of a lintel that distributes the compressive load of the wall above to the outer edges of the archway so the load is transferred around the archway to alleviate pressure on the missing parts of the wal..
Site 3: Queens College
WK 3_JOURNAL
Materials - concrete slabs - steel columns - timber framework - screed to expose aggregate (sand, stone + lime stone)
Here we can see the external oining of the old and the new. While the two buidling do not directly come into contact, their proximity encourages an aesthetic comparison which emphasises the contrast of the cream pre-existing building to the contemporary concrete structure that is being formed on site. The introduction of new buidlings onto a site with buidlings of cultural and historical significance means that external materials play a large role in either integrating the new buidling into the style of the existing buidlings or emphasisng the develep ment as seen in this site.
This photo shows the use of a box gutter system ie. the rectangular prism on the right side of the buidling. This differentiates from the eve gutter system used in the pre-existing buidlings. Could be speculated that the concrete is yet to be rendered potentilaly in the same colour as the neighbouring buidling to assimilate it into the site.
The merging of the two structures can be seen here with the use of a stacked box window infill. Althought not yet sealed at the top this marks the point where the two gutter systems will meet. Also shows an effective way of creating light in the internal space witthout creating a weakness within the wall itself. This choice of material allows for light infiltration without compromising the privacy of the internal space.
The timber framework seen here illustrates how both mass construction and framework construction methods can work in conjunction to create the most effective design solution. It is also likely that the framework assists in supporting the exterior cladding. It also facilitates the internal cladding most likely with plaster board. This also enables insulation.
Site 4
WK 3_JOURNAL
Suspension system use as part of the concrete structure. Creates dyamism in the form as the solidarity of the material is made to seem paradoxically lightweight. This image of the exterior shows the integration of mass and lightweight structures. The solidity of the concrete beams is contrasted with the vertical posts of steel and the etched panelling. It also shows the use of suspension systems with the horizontal spans of the membrane structure.
The atrium space lacks environmental efficiency with full wall glass windows which acts like a green house. The permanent timber shield introduced postconstruction provide some degree of sun protection from westerly sun. However high-vaulted ceilings permit hot air to rise and thereby create an ineffficient heating system in winter. The entrance of the building is also the hub of the amenities and services and provides direct access to the fire systems etc.
Cantilevered overhanging eves with steel beam framework and ornately patterened steel detailing Materials_ - Thick stacked glass window blocking. - Plywood glulam window framing boxes - Plywood roofing and wall cladding - Wire (suspension systems) - Tiled flooring - concrete with pattern wood texture
Potential construction constraints - proximity to college - neighbouring heritage building - budget and timeline limits from college
Pavillion Site Visit
WK 3_JOURNAL
1. We began our inspection of the site on the northerly side which allowed us to inspect the foundation layers and water-proofing structures. The order of construction focuses on a north-south approach as the northern side is used as the structural base of the structure. The above view showed the layers of the reinforcement process. First the concrete slab then the solid brick wall layered on top. The site manager discussed with us the processes of drainage and water-proofing as the site flows from the highest to the lowest point to pool on the westerly side of the building. This is to avoid flooding of the northern/rear part of the buidlding which may compromise the integrity of the foundations.
2. This image is taken from the northwesterly corner with the existing rotunda just out of view in the right hand side of the photo. The use of the crank/L/starter bars here show how the walls and floor are joined together and fixed. It also shows the render of zypex additive that has been use in the concrete slab here for waterproofing purposes.
3. The preservation of the existing club house pays homage to its culture and heritage past. Whilst the buidiling is slightly decrepit and derelict in parts, the essential structure and the charm of the original buidling is kept intact. We can also see here in the right side of the vision, the integration of the new structure with the old. The refurbishment of the existing rotunda will include replace the roof incorporating plywood over the rafters for sound insulation in consideration for the neighbouring buildings and their occupants.
4. This image, taken from the southerly side of the construction site, facing north west, provides a good impression of the stage of progress of construction. Whilst the foundations have been layed and the form of the building is beginning to take some shape, the multiple framework grids, scaffolding and supports would suggest that this stage of the process may be continuing for quite some time. The site manager placed great emphasis on the foundation system being appropriate to the natural clay soil of the site.
Pavillion Site Visit
WK 3_JOURNAL
1 2
3 4