Constructing Environments

Week 06: MSLE BuildingStructural Concepts (Part Two)

1:50 Model

Following close examination of the structure of the Melbourne School of Land and Environment Extension we began our own construction of a model displaying the structural systems used. In an attempt to simplify the models construction process we chose to omit the basement as it did not hinder our ability to illustrate the strutural systems used in the extension.

Roof ConditionsLooking at the roof structure in the plans we can see two main roof conditions:

– Firstly, the steel members cantilevering from the central column– Secondly, these steel members are all connected to a steel I beam which

spans the length of the the interior ceiling. It is then hung off this steel structure using pin joints – thereby creating a tension based structure.

– The pre-existing brick-wall is then used to fix this steel structure in order to provide lateral stability

PurlinsFigure 1

BracingLooking at figure 1, we can see that the T frame structures have been fixed together through the use of purlins. In this way, the single frames are made into one single structure

– By placing the purlins between the main steel frame members increases the lateral stability of the structure through rigidity.

– This makes it more resistant to lateral loads including wind and earthquakes.

Wood-shopIn the second part of the week 6 tutorial, we visited the wood shop in the basement of 757. There, we were told we were to created a 1200mm span that could hold the most weight possible.

Materials:

• Two pieces of 1200mm Timber • 1 length of plywood • Hammer • Saw • Nails, screws (of varying sizes)

Design

We decided to do a very basic compression design to maximize strength in our span. To do so, we place the three planks of timber on top of each other, hammering them together using nails one at a time. Nails were placed at equal distances apart along the piece of timber, this was to ensure force was spread equally along the span.

Plywood ProblemUnfortunately, the addition of the plywood to our structure only acted to weaken it. We could not find a way to use it with great efficiency. If given the option it would have been left out. We chose to place it on one side of the span and used screws to attach it. For greater strength we minimized the amount of screws used towards the outside of the span and focused them in the middle. This was suggested by the workshop assistant as it had a great strength against shear forces.

Result

Despite our greatest efforts we could not stop the span from splitting. However, due to our boring but powerful design we were able to create a span able to withstand 800kg.

Conclusion

Compression has great strength against decentralized lateral and vertical force. However, it is not strong in tension and when pressure is centralised simply cannot cope. We found that using a minimal number of materials was beneficial as this resulted in a smaller number of weak points at which the structure was most vulnerable. The fewer of these points you could have, the stronger your structure.