2014_Interim Logbook

LogbooK Week1 Xiaodi Zhang 657695

Science & engineering principles

Materials Structural principles

Labor types

Construction System

•Strength •Stiffness •Shape •Material behavior •Economy & sustainabil ity

Language of construction

Construction term

Site processes

Construction drawings

•Tension---steel •Compression---steal, concrete, stone, brick

•Aim: To build a tower with exit by using MDF as soon as possible.

•Our group’s method: Built a rectangular tower firstly, and then made the exit by “destroying” part of the tower.

Step1: Build the base

Loan path of the wall The structure is firm because the load from top bricks is transferred to the bricks underneath and the load from all the bricks is transferred to the ground. The ground has the reaction to the base which is the same magnitude and the opposite direction as the load from bricks.

Step2: Transfer the shape into pyramid ďƒ˜In order to make the tower taller and faster, we decided to make a pyramidal structure at the top of the tower. Because of the time limit, we did not make a spire for the tower.

Step3: Make the exit by destroying the wall

The structure is still firm after the “destruction” because the bricks at the edges of the exit transfer their load to the bricks beneath, and the load from those bricks is gradually transferred to the ground. However, the structure will collapse if the gaps between bricks are too big as the contact surface is too small to let the enough load transfer efficiently.

Step4: Examine the size of the exit

Cameron, R. 2014, Introduction to Construction Materials, The University of Melbourne, Melbourne, Australia.

Cameron, R. 2014, Construction Overview, The University of Melbourne, Melbourne, Australia.

Cameron, R. 2014, Basic Structural Forces, The University of Melbourne, Melbourne, Australia.

LogbooK Week2 Xiaodi Zhang 657695

Explored how firm a structure was by making models by straws

• The surface of straws attached to the table is so little that could be estimated as points.

When a vertical force is pushed on the model, there is too much pressure on the base points. Additionally, straws are flexible so that, generally, they are not firm enough to withhold forces. These three structures are all attached to the table by points and there are no extra structure to improve the stiffness of straws, therefore the straws are either together or separated under the pressure.

• The attaching surface is changed from a point to a short straw, but the straws are only bonded at the top. So when a vertical force is added on the model, it will be separated.

• Load path • An example of rebuilding the model •By adding triangle structure into the model, the base is firmer than before. And the “beams” can help to reduce the flexibility of the straws.

Structural Connection Structural Systems& Form (Structural Symbol (Structural Connection 2014) systems and forms 2014) Roller Joints • Solid System (Compression is the main Load path • Load path transmits structural action) Reaction vertically Ex. Pyramid • Allow the horizontal • Surface System movement Ex. Shell Structure--- Opera House • Skeletal System (the most common system in construction) Pin Joints Ex. The bird nest in Beijing • Load path transmits vertically & • Membrane System horizontally Load path • Hybrid System (ETFE) • Allow rotation movement Ex. The swimming cube in Beijing Reaction Construction System (Ching 2008) Fixed Joints • Structural System Ex. Columns, beams, loadbearing walls… • Load transmits vertically, horizontally & rotationally •Restrict any form of movements • Enclosure System Ex. Roof, exterior walls, doors, windows.

Load path •Mechanical System Ex. Ventilating systems, the sewage disposal system…

Reaction

Aim: To build a tower as high as possible.

Step1: Make the base of the tower Step2: Build the upper structure

Load path of the tower • Triangle is the basic shape used in the tower as it has firm structure and it needs less pieces of MDF to build.

Prediction about the tower:

• It will stand firmly.

• It will twist under the vertical force.

• The interaction and beams are made to reduce the flexibility of the MDF material.

When pieces are bonded together, it is less possible to move around.

Vertical Force

Vertical Force

Result2: The whole structure twisted badly.

Result1: The base of the tower twisted badly while the upper structure had no obvious change.

Reason: • The centre of gravity of the triangle structures were not precisely on a vertical line, which results in unequal and unbalanced load transmitting to the ground. When the three pieces of the base were under different magnitude of force, the structure would twist.

• In the 2nd situation, a triangle structure was broken, which makes the upper structure more flexible than before.

Therefore the whole structure twisted.

Cameron, R. 2014, Structural Connection, The University of Melbourne, Melbourne, Australia.

Cameron, R. 2014, Structural systems and forms, The University of Melbourne, Melbourne, Australia.

Ching, F. 2008, Building Construction Illustrated, 4th edn, John Wiley&Sons, INC., Hoboken, New Jersey.