Site Visit

Week 7 Site Visit During this studio we got to go and visit construction sites. This was a really interesting experience as we were able to apply our knowledge that we have gained over the pervious 6 weeks to a real life example.

The first site we visited was in the process of excavating down to be able to build the basement levels and foundations for the proposed apartment building. To be able to continue excavating down the construction teams had to build retaining walls the prevented the sides of the hole from collapsing. This was done by getting a 14m drill to drill down into the ground at the sides of the site before digging commenced, in situ concrete was then poured down these holes to create columns that would help support the construction of walls as the excavating took place. The builder who took us on the tour explained that they could only dig down 1.5m at a time before they were required to shock-crete the walls, (this was a material we learnt about in the eLearning on concrete) which is applied through a pipe pumping out concrete which is then smoothed onto the walls manually.

These walls were also reinforced with wire mesh spanning between the columns, which enabled the shock-crete to stick to the walls and not collapse whilst drying.

The Machinery used to excavate the site

The in-situ concrete columns and wire mesh waiting to be shock-creted before further excavating can continue

The drill used to create the holes, which formed the in-situ concrete columns

The second site we visited was next to the previous site but was much more advance in it’s building stage. The building is a 6-story retirement home (two basement car park levels), with a special focus on elderly people with dementia. This therefore means that special consideration is given throughout the design process in contrast to a normal build and results in the building have a hospital-esque design and special technology being integrated throughout the building.

The building mainly consists of pre-fab concrete, which has then been craned into place by the crane situated in the main lift shaft of the building. The flooring however is slab concrete flooring and has pre tension concrete. We were able to get a close up look of how the pre-tension concrete works when we visited the roof slab, which had only been poured a few days prior. The pre-tension concrete works by having metal rods that span across the slab, the concrete is initially poured and these rods are then pulled into tension and secured as the concrete dries. Pre-tensioning the slab flooring give the building extra strength against lateral forces and in particular earthquakes as it allows the flooring to cope with higher tension forces. This building needs to have higher standards, in regards to events such as earthquakes because it is an elderly home and it is to hard to evacuate them all from the building in a short time frame and therefore it needs to provide extra protection for it’s vulnerable residents.

Exposed Pre-tension rods, used in the roof slab, these are later grouted over and therefore become invisible to the roofs appearance.

Another interesting aspect of the building was it outside panel and window design, which had been drawn by the architect. The outside panelling of the building was meant to be coloured poured concrete with the desired outcome being consistent black concrete panels. The construction manager

however explained that this had been a source of great trouble as the colour of the panels was not distributed evenly through the panels providing a more marbled look which did not meet the clients approved standards, this meant that more money is needed to be spent recoating the outside of each concrete panel to the desired panel which could have been an easier and more efficient cost decision to begin with. The building also has may windows in order to saturate it with natural lighting, this has however provided an issue in terms of venting as no vents are allowed to be placed within 6m of a window as it means that the air that is trying to be expelled from a building would just flow back in. This has resulted in venting pipes running from each floor to the plant room on the roof where it can be expelled. This means that there are pipes that then push the fumes and air from the basement car parks up through the centre of the building all the way to the roof (up 8 levels).

Example of a lintel found on the construction site.

One of the most exciting parts of the site visit was just being able to start to recognise features of the construction without guidance, drawing on my knowledge gained throughout the semester thus far. For example I was able to recognise lintels and bracing.

Overall visiting construction sites first hand was an invaluable experience in terms of being able to see what we have been learning in action, the second more developed site in particular acted like a 3D textbook in which you could identify all the different stages and reasoning behind the constructing process. The site visit also helped me to gain a deeper appreciation of the thought and organisation that is put in by the architects, structural engineers and builders themselves who all work to plan every stage of a building and ensuring it is of high standard, there is simply so much detail that goes into a building that the users never notice or realise.

Cabling and pipes (services) that were placed in the ceiling soon to be covered

Services Lift shaft being in the basement car park

Columns used in basement car park to support upper levels, temporary props can also be seen in the background, these were being used to help support the weight and load of the crane currently situated on top of the building until it is removed.

Exposed column foundation located on the lower basement -made from insitu concrete that will be covered for aesthetic purposes in later stages of the construction.

The Crane currently situated on top of the building being supported by the lift-shaft. This was due to be removed a few days after our visit to enable the construction of the plant room on the roof to begin. In order to remove the crane it must be disassembled and lifted off by another temporary crane that is brought onto the site. When the crane is lifted out of the lift shaft there is no room for error and the process will take place floor by floor to ensure that it doesn’t sway and destroy the walls of the lift shaft or other structural elements. The process of removing the crane depends strongly on weather conditions as any wind can make it impossible to remove the crane without creating damage.