REFLECTIVE JOURNAL WEEK 6 This week’s focus was on columns, grids and wall systems. I found it particularly interesting because of the readings. A lot of thinking needs to be put into constructing any type of building regardless of its purpose, the inclusion of factors such as light, air movement, heat, sound and moisture are essential in choosing the materials. Different materials are come across which are used for framing such as concrete, steel, timber and masonry. It is interesting how an opening is created at the top of the structure when masonry is in use as to transfer all the loads to the load bearing walls which in turn transfer them to the earth. Understanding the use of different materials, I noticed that Melbourne uses brick veneering in most of its buildings. Another interesting concept I came across is where the wind loads and earthquake loads act on the building. So as I am slowly proceeding with the chapters, I have begun to understand that materials and the formwork of the building are very vital in the role of constructing an efficient and sustainable building. A presentation was supposed to be made in class this week but because we had a tight schedule, we decided to send our presentations to one another to have a look at one another’s construction site. The site provided to my group and I was the MSLE. We had studied the basic layouts of the MSLE plans in week four and were given a more elaborate and detailed case study of the building in week 5 therefore told to construct the structural system of the MSLE building which focused on the primary and secondary structures of the site. After about an hour’s discussion, we sort out to tracing over the maps and highlighting the dimensions of the structure and making sure we were using the correct scale as it had to be converted to another scale to obtain a large sized model of the MSLE building. After getting the dimensions correct, everybody had divided responsibilities and so the next step was to convert these numeric figures onto the card board sheet, cut them and put them into place on the floor created according to the plan layout of the building. The pictures of the model are displayed below:
This week, our class had the timber workshop and I was pretty excited about it because I have never used the hammer or any other such tool before. We were divided into groups and given the task of constructing a beam of our choice as long as it spans over a meter. Some factors we had to consider before continuing with the project was: 1. 2. 3. 4. 5.
We required a simple design Efficient planning Time constraint Materials provided Using the right connecting structures (bolts/screws/nails)
We received three thick timber planks which measured about 1.2 meters and two thin wooden planks which measured out to be the same and was figuratively a little thicker than paper. And
so, we decided on making an I-beam which is a rectangular hollow section usually made of steel. We used screws to join the structures to create an I-beam and used the thin wood provided as supporting structures at the sides of the I-beam which required nails as they are fragile and if cracked/broken will lose their tensile strength.
BEFORE:
AFTER:
The above diagrams are the design thought of when creating the I-beam and the result of the beam respectively at the end of the task. The initial reading ranges from 330 and drops continuously till about a 50, having a deflection of 75 miles. The reason why the structure had a low deflection was because a crack was created when trying to put in a nail through the plywood grain and it went through the timber creating a crack thus reducing the tensile strength in the structure and making the supports of the I-beam weaker. Another issue could have been the spacing of the nails/screws. An improvement that could be made to the structure is shown below:
Having the plywood grain spread out, distributes the load throughout the structure thus resulting in a more stable and withstanding structure when subjected to forces.
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AFTER:
The above diagrams display the model created by another group before placing it in the machine to study the deflection of the model created. This model created above read about 330 on the scale and then dropped to 195, having risen again to 365 and dropped back to 195, having a deflection of 35 miles. I reckon it is the fixings used in this structure that wasn’t compatible to hold the structure together. The plywood grain is generally a weak element and is used to hold the timber which is placed in the center. The shear forces are coming up as the plywood grain begins to deflect because no blocks are placed at the bottom. Having a stronger support rather than the plywood grain would have resulted in a less deflection of the structure as there would have been less sheer forces acting upon the beam.
BEFORE:
AFTER:
This model has an initial reading of 240 on the scale and increases up to 290 indicating that the deflection of this structure is 50 miles. There was a knot present which is the impression on the wood making it weak at that point and when force was applied, it broke down exactly at that
point, being the point of impact. The structure is stable and well supported but it is necessary to assess the wood used in constructing a model. BEFORE:
AFTER:
This model was a quite stable model because this group had the timber planks layered over one another making it strong in compression and the plywood grain were spread on the sites but cut at the bottom as to sit on the machine properly. This model had an initial reading of 320 all the way up till 590 where cracking was heard at 570 resulting in a higher deflection as compared to the previous beams designed. I also learnt that when steel deflects, it remains in its deflected state but when using wood, if you remove the nails, the wood will come back right up in its original form. An improvement to this model would be cutting out the plywood grain accurately as to not be an obstruction when the load is placed on it because it deflects more easily otherwise.
Here are a few pictures of the completed model of the MSLE building as displayed below:
This week’s tutorial was interesting because it was a different experience and I am definitely looking forward to the next timber workshop!