2014-3 Log Book

Week 1

Forces defined by direction, sense and magnitude

Knowledge Map

• Tension o external load pulls on a structural member o particles move apart and undergo tension o stretch and elongate the material • Compression o opposite effect of a tension force o external load pushes on a structural member o particles of the material compact together o result in the shortening of the material

Materials • Melbourne – bluestone (basalt) Victoria volcanoes Dark colouring • Sydney - sandstone • Perth - clay for brick, limestone

Tutorial Activity

Bricks are acting as dead loads (CHING: 02 The Building 2.08), vertically downward on a structure.

Our pyramid shape tower allows the load on the top to be dispersed in the next lower level. We place the bricks vertically as a column supporting each level. However, our wall is at the same width from the bottom to the top.

When the tower is built higher, it becomes less stiff.

Materials Materials we used are MDF (stands for Medium Density Fibreboard).

They are made from wood fibre under heat and pressure. They are cheap and easy to manufacture.

Photographer: Jiayi Gong 7/3/2014

Load path The load path is simply the direction in which each consecutive load will pass through connected members. The sequence commences at the highest point of the structure working all the way down to the footing system, ultimately transferring the total load of the structure to the foundation.

Construction system The lowest level is the foundation. As it goes higher, Vertical bricks’ (footing) load path flows down through to the foundation. The first floor load path flows down to the footing then the foundation. Then another layer of vertical bricks’ load path flows to the first floor then to the footing then the foundation.

Comparison with other groups

Load Path This group’s tower’s bottom is narrower than ours. The bricks are piled up tightly like a standing cuboid; therefore it is more stable than our tower’s thin wall.

Photographer: Jiayi Gong 7/3/2014

Since the upper part of this tower is at a same width, the loads are directly transferred to the lower part then split into two directions then to the ground.

Compared to our pyramid shape tower, this group’s tower is more likely to be built higher. However, when its ratio between width and height approaches a certain level, it collapses.

Week 2 Knowledge map

Theatre session Strategies to increase the load capacity (Water tank, straws)

Studio session Cut the balsa wood provided into fine strips and build a tower We started building our tower with a triangular shape as a foundation because triangulation is stable.

We used sticky tapes to as joints. Therefore the joint becomes a fixed joint which restricts vertical movement, horizontal movement, or rotation of balsa strips.

We used three single strips as footings to transfer upper loads directly to the foundation.

In order to increase the load capacity we tried to build a bracing between posts.

Considering that building another triangle wastes material, our bracing was built as shown in the photo on the right hand side.

Photographer: Jiayi Gong 14/3/2014

The top load splits into three directions then straight down through footings to the ground.

(Shown as blue arrows in the right)

Photographer: Jiayi Gong 14/3/2014

Our tower is not stable because 1. A few footings to transfer loads.

If added another vertical strip to support the red point, it can share some loads.

2. All joints are fixed joints.

Bending and deflection occur. To improve we can put pin joints in the 4 green spots shown on the right. As it’s a triangular structure, rotation is not happening anyway, at least pin joints somehow will decrease the risk of bending and deflection.

3. Small surface area contacts with the ground. Easy to fall down. To improve we can make the foundation triangle larger and add some bracings between posts.

4. Materials used are balsa woods which are very light.

Also we cut them too thin so they became more fragile.

Comparison with other group’s tower This group’s tower is stable and high enough to reach the ceiling.

For the lower part, the triangulation and the bracing between strips help with the stability. Footings are not too long therefore decrease the danger of swaying.

Strips and sticky tapes form fixed joints. As there are many bracings, there are many fixed joints so deflection or bending is not likely to happen.

For the upper part there’s a smaller triangle shape to support a single long stick on the top.

The load flows from the top point to the three footings of a small triangle, then to another three footings of a larger triangle, then to the triangular prism which has many bracings allowing the load to be splitted and transferred to the foundation.

Photographer: Jiayi Gong 14/3/2014

Fixed joints

Bracings between posts

Short footings

Triangulation

Glossary Compression

A force that occurs when the ends of an object are being pushed towards each other.

Tension

A force that occurs when the ends of an object are pulled away from its center

Parapet

Walls that go past the roof

Load path

The direction in which each consecutive load will pass through connected members

Reaction force

Equal and opposite to the load path

Stiffness

The physical property of being inflexible and hard to bend

Masonry construction

A form of construction in which structures from individual units are laid in and bound together by mortar

Point load

A point where a bearing or structural weight is intense and transferred to the foundation

Beam

A structural member which spans horizontally between supports and carries loads which act at right angles to the length of the beam

Reference List D.K Ching, F. (2008). Building Construction Illustrated (4th ed.). Hoboken, New Jersey: Wiley.

Grose, M. [ENVS10003]. (2014, March 6). Melbourne’s Bluestone. Retrieved March 11, 2014, from http://www.youtube.com/watch?v=CGMA71_3H6o&feature=youtu.be Newton, C. [ENVS10003]. (2014, March 5). W01 s1 Load Path Diagrams. Retrieved March 8, 2014, from http://www.youtube.com/watch?v=y__V15j3IX4&feature=youtu.be Newton, C. [ENVS10003]. (2014, March 5). W01 m1 Introduction to Materials. Retrieved March 8, 2014, from http://www.youtube.com/watch?v=s4CJ8o_lJbg&feature=youtu.be Newton, C. [ENVS10003]. (2014, March 5). W01 c1 Construction Overview. Retrieved March 8, 2014, from http://www.youtube.com/watch?v=lHqr-PyAphw&feature=youtu.be Newton, C. [ENVS10003]. (2014, March 9). W02 c1 Construction Systems. Retrieved March 11, 2014, from http://www.youtube.com/watch?v=8zTarEeGXOo&feature=youtu.be Newton, C. [ENVS10003]. (2014, March 9). ESD and Selecting Materials. Retrieved March 11, 2014, from http://www.youtube.com/watch?v=luxirHHxjIY&feature=youtu.be Selenitsch, A. [ENVS10003]. (2014, March 9). Framework for Analysing Form. Retrieved March 11, 2014, from http://www.youtube.com/watch?v=KJ97Whk1kGU&feature=youtu.be