Knowledge map of week 1

Our team chose an approximate rectangular shape which we

thought can best fit the shape of the object given by tutor, has

the least space wasted and costs the least amount of materials

(MDF). Plus, as our base was the smallest among three groups, it

actually saved our time so that more time could be spent on wall

rising.

Studio 1 – Compression (hollow tower constructing)

When building the walls of the tower, we chose stretcher bond, which is most

frequently used in real building constructing because it has the longest load

path – with a longer pathway, the load is more separated (the shadow shows

the areas in which loads are separated) and therefore the structure becomes

more stable and can hold more load (ref: studio 1).

A technical problem showed up when we created the opening – in

order to make it wide enough to let the object get through, we

need to tie up at least three bricks horizontally with rubber band,

but it would become very unstable when more bricks are loaded

onto it because the three bricks are not strongly compressed

together and they would break up easily from the crevices

between them. Thus we did not build an enclosed structure but

left it semi-closed.

The final collapse happened when we tried to remove some of the

bricks from the middle part, which eventually caused a shift of the

gravity center and thus the whole body biased to one side and fell

down.

During the deconstruction

process, we found that the most

easily-removed bricks are either

on the open edges of the walls,

or at the turning corners where

the walls change direction. The

latter is because the plane walls

are the main support of the

whole structure and thus the

corner bricks are the weakest

parts which do not bear much

load as the plane walls do. The

marginal bricks are even easier

to remove because they are only

compressed at one end.

At first we were just making holes within the structure, but after an

accidental crush, the structure then became shuttle-shaped with a wide

body and a relatively narrow base. This is probably due to the strong

bending stress (ref: 2.14 Ching, ‘Beams’) created by the stretcher bond,

and also because the base is wide and firm enough to hold up the entire

structure.

Comparison with the other teams:

This team’s structure is not very high but must be the strongest among the three

groups. It has a base shape between circle and square, which behaves as a

two-way system (ref: 2.19 Ching, ‘Structural Units’) that spread the load equally

in four directions. Additionally, they thickened the base by adding several more

layers of bricks both vertically and horizontally, thus the load path is even longer

and the base is even stronger.

This team made a circular base for their tower, which uniformly

spreads the load in all directions to make the foundation stable.

It is also a large base which can bear more loads and thus

theoretically the tower can be built higher. However, the

grandness of the base also causes some problems, including a

waste of space and materials, and a much longer constructing

period, which actually limited the final height of their tower.

Their walls are also based on stretcher bond. And they created

an opening which we did not have. Yet they did not upload

many bricks onto the opening either, probably because they

met the similar problem as we did.

Their walls are also built in a

different way, laying bricks facing

two directions alternately, to

make it more efficient to build the

tower higher. However, as the

contact area between two brick

layers becomes smaller, the

stability of the whole structure is

also declined.

Knowledge map of week 2

This time the three groups coincidently chose the same

equilateral-triangle instead of square base, because triangle is

relatively rigid and stable. Also, among all polygons, triangle has the

least sides so it can help reduce material usage (ref: 2.17 Ching,

‘Frames & Walls’).

Studio 2 – Frame (balsa wood tower constructing)

Our team decided to build a triangular prism. To increase its stability,

in each storey, we joined every top vertex with the mid-points of its

corresponding side, so that three truss frames (ref: 2.16 Ching, ‘Truss’)

can be created within one single storey.

In this case, the load pressed on each vertex (except for the ones on the ground or at the top-end of the tower) can

be separated into four different pathways. In addition, we joined the three spatial sticks together to further

separate the load, and in the meantime, when one of the three sticks is overloading and tends to bend, the tension

provided by the other two can help prevent it from deforming.

To prevent the three vertical legs from

moving and strengthen the base, we

added a small piece to each base corner,

perpendicular to the bisector of that

angle, and then glue the four pieces all

together to create a strong joint.

Due to the lack of super glue, we had to try another two ways to join the sticks, using pins and tape

respectively.

Pin connection is not suitable in this case because the materials are thin balsa wood sticks, which are very

crisp and can be easily broken when drilling holes on them.

Super glue is the best choice as it can realize butt joint which is ideal for light materials like balsa wood (ref:

2.30 Ching, ‘Joints & Connections’).

Tape doesn’t fit this structure either because we were building a three-dimensional structure but tape can

only work well on a plane.

Yet tape can be very useful for two-dimensional joining, especially

when joining three sticks together to make a right angle, because it

actually creates a triangular shape at the corner to make it a rigid

frame. The following shows how to make the best use of tape joint

(based on experiments in studio 2):

Turn over Repeat

Comparison with the other teams (1):

This team made a complex structure with four

different bracing patterns to reinforce the tower,

namely K-brace, cross bracing, Knee bracing and the

simplest one-member brace (ref: 2.22 Ching, ‘Lateral

Stability’). All of them are based on triangular frames

to spread out loads and make them rigid.

They cut the materials into very thin pieces, which

actually lightened the dead loads provided by the

self-weight of the structure (ref: 2.08 Ching, ‘Loads on

Buildings’). The final structure is bamboo-shoot-shaped, with the

storeys becoming narrower as the tower grows up.

Unlike prism ones, this structure has bevel sides in some

storeys. Because those bevels have the same length,

they need to have very similar inclination angles to make

the top plane even. Obviously this requirement is hard

to achieve manually, and that’s why their tower biased

to one side for several times. However, since the

materials are very light, the slight shift of the gravity

center didn’t matter a lot. Thus their tower finally grew

very high and reached the ceiling.

This team’s structure is a combination of a few separate triangular

prisms, and each of them is a completed frame without any shared

side with others. This means those sections can be built separately

at the same time and thus the constructing process can be much

more efficient.

Comparison with the other teams (2):

Similarly, they also chose a K-brace-like

frame to strengthen the tower walls. But

they made a difference by inserting a

right-trapezoid-shaped frame to each side

plane, which meant there were three

triangular frames within one side plane and

this structure should be the most stable one

among the three groups (ref: 2.22 Ching,

‘Lateral Stability’).

The challenge is to make

sure the base and top of

two adjacent storeys have

the common mid-point or

center of gravity, so that the

whole structure can stay

steady with a gravity center

right in the middle as it

grows up.

Knowledge map of week 3

This building is a typical concrete

structure, which is qualified as rigid and

non-combustible construction. The

reinforced concrete columns are laid out

along a regular grid, because the

structure is nearly square and thus

two-way system of beam-and-slab

forming would be the most effective and

economic one. (ref: 2.19 Ching,

‘Structural Units’)

Similarly, the concrete columns supporting this

underground car park are also laid out regularly in grids.

Particularly, as the car park requires massive span for

cars to move and park, all concrete columns are

thickened at the top to make a funnel shape. Those

thickened parts act as a transition between the top plate

and the columns, transferring loads from top to ground

in a more smooth way. (ref: 2.20 Ching, ‘Structural

Spans’)

The photo in the bottom right corner shows the

resealing paint on the top plate. Due to

potential deformation of concrete elements, it

is common to see tiny gaps between concrete

slabs which would allow moisture to get in.

This structure is a steel trapezoid-shaped ladder. Nearly all of the

structure’s weight is bear by the side wall and the two supporting beams in

the bottom. Thus the two hanged beams at the top are not actually

load-bearing but for visual purpose only.

The main structure is formed with ‘C’ beams

and the supporting elements are wide-flange

‘I’ beams. Those steel beam types are

supposed to be light-weight and

material-efficient, and also show good quality

in resisting bending forces and shearing

forces. (ref: 4.16 Ching, ‘Steel Beams’)

This is a membrane structure,

using thin, flexible surface to carry

loads through the development of

tensile stresses.

Each membrane edge is connected

to a pole using steel cables,

transferring loads to the ground.

(ref: 2.29 Ching, ‘ Membrane

Structures’)

In the middle of the membrane there is a waterhole,

through which rainwater can be transmitted

downwards to the ground.

The steel cables here are actually loose and are not

providing much tensile stress, because the

self-weight of the structure is already providing the

downward force for equilibrium. Yet those steel

cables are still useful in fixing the gravity center and

preventing the structure from being unstable under

lateral forces.

This structure is a decorating steel beam, with truss

frames inside. It is a simple beam supported only at

both ends, as it is a light-weight structure and only

needs to bear its self-weight.

This indoor swimming pool

is a simple structure built

with steel rigid frames and

two concrete walls on both

sides.

The steel rigid frames are

left exposed. The two side

walls are shearing walls,

bracing the whole structure

and protecting it from lateral

forces like wind.

This tongue-like three-storie

structure is an extended part of

the main building.

To hold the overhanging part, the

whole structure needs to be long

enough and have a reasonably

long part being placed on the

base, so that the gravity center

can stay within the main building.

The bracing structures underneath

the extended part are mainly cross

bracings, using trusses to increase

rigidity.

Knowledge map of week 4

Construction workshop – Beam spanning structure

The materials we got were three solid timber beams and a thin, hard

plywood board.

The beam structure made by our team is a continuous beam sitting on

a series of solid supports, with the plywood board pinned on one side.

(ref: 2.15 Ching, ‘Beam Spans’)

Compared with simple beams, continuous beams are

supposed to have greater rigidity and smaller moments,

and thus can bear more pressure. We place more studs in

the middle to bear more pressing force. The plywood

board on one side also helps spread the loads.

Nails are pinned in two directions to make the studs tight

within the wood frame, increasing the rigidity of the

structure. (ref: 2.15 Ching, ‘Beam Spans’)

The structure bends under the pressure in the middle. Its

deflection is not satisfying, around 15mm, because the

continuous beam structure is weaker in bending moment.

The tendency of the studs’ rotation

results from bending stress – tension

in the bottom and compression on

the top. When the pin joints can no

longer hold the bending stress, the

studs would fall off. (ref: 2.14 Ching,

‘Beams’)

The natural knots and the points

where nails are pinned in are the

weakest points, which would break

more easily.

Thus instead of slowly transforming in shape before the collapse, this structure almost stays straight all the time

until it suddenly breaks. Yet due to its rigidity, the maximum load goes up to 168kg. (ref: 2.14 Ching, ‘Beams’)

The first crack happens in the plywood board because it is thinnest and holds the least load in the whole

structure.

Compared with other teams (1):

This team’s structure is formed by two thin

plywood boards with a series of short wood

studs in between. Yet some studs in the middle

are not well fixed to the plywood and thus

most of them fall off later, which means they

do not bear much load in this case. Their main

function then changes into linking the two

plywood boards at both ends.

Thanks to the accidental loss of some studs in the middle, the plywood boards become very

flexible and can be rotated easily. Thus it can have an incredibly strong bending moment and

high deflecting level – the maximum deflection goes to over 100mm! (ref: 2.14 Ching, ‘Beams’)

Yet due to the great flexibility, this structure easily reaches its maximum deflection and then

cracks. Therefore it shows very poor quality in load bearing – only 45 kg maximum.

Compared with other teams (2):

This team’s beam structure is an open-web timber joist, using

trusses to reinforce the structure. (ref: 4.20-4.21 Ching,

‘Open-web Joist Framing’)

A thin plywood board is added on one side of the structure,

but in fact it does not bear any load in the beginning because

it is only attached to the bottom timber panel. Yet when the

top plywood board is bended under pressure, this side board

becomes useful as it is flexible enough to be twisted, which

actually helps buffer the compressive force. An obvious twist can be seen in both top and side boards.

Similar to the previous team, this is because thin plywood

boards show good quality in flexibility and bending moment.

The following graph shows how the members at the two

ends, which are supposed to be zero-force members and

carry no direct load, can actually create a moment to resist

the bending moment and help maintain the shape of the

whole structure.

This structure combines the rigid framing of truss and the

flexibility of plywood boards. Thus it shows good

load-bearing quality and medium deflection– maximum

320kg and 65mm respectively.

Knowledge map of week 5

Our team’s structure is

two-storie, with a kitchen

on the first floor and a

public restroom on the

second.

The overall structure is

simple and direct, but

there is a slope on one

side of the roof.

The rooms in our structure are framed by

stud walls.

In those stud walls, each section is braced

with a nogging in the middle, and every

adjacent noggings are slightly different in

height, so that a better quality in bearing

shearing forces can be achieved.

Compared with other teams

This team’s structure is

one of the top parts of

the roof. It is a

complex, geometric

structure with lots of

trusses and cross

bracing to create a

rigid triangular roof

frame.

This team’s structure is the part located just

beneath the one of the previous team. It is a

single-skin open-web joist, braced with trusses

and cross bracings.

Knowledge map of week 6

Site 1: Box Hill North

In site 1, prefabricated roof trusses have been placed. Later a

series of tile joists will also be added to make a tile roof.

The foundation uses ‘waffle pod footing’. The pods are hollow

and are about to be filled with grout to create concrete

footing columns.

Around the bottom of the building, there is a temporary slope

to transfer rainwater away from the foundation. Additionally,

a permanent guttering system is also set around the building.

As a part of service system, some unfinished PVC sewage

pipes can also be seen.

The main bracings in this building are ply bracing, cross

bracing and hoop bracing.

- Ply bracing is made of thick ply wood, but still not strong

enough for load bearing, thus always used as wall

connections.

- Cross bracing uses truss function to make a rigid form.

- Hoop bracing is similar to cross bracing, but is adjustable

in tension.

Site 2: Footscray

In site 2, the building is a townhouse and is attached to it

neighbours. Thus fire-check walls and insulation foil (blue

board) is used for safety issue.

Also for fire purpose, many materials have fire rating signs on

them, showing the fire resistance level of the material.

Stud-framing walls are widely used in this building.

Fosil joists can be seen in this site, using keyed strutting

instead of other joints.

5 stages for constructing:

- Slab stage

- Framing stage

- Fixing stage

- Lock up stage

- Occupying stage

Knowledge map of week 7

Knowledge map of week 8

Knowledge map of week 9 & 10

General built form & materials

The main material of this building is structural reinforced concrete, with a few steel framing

and glass cladding. Recycled concrete is used, which creates less carbon footprint, but takes

more time.

The building is curve-shaped, not only for aesthetic purposes, but to create more space

between itself and the surrounding buildings (shadowed area in the top right diagram).

In response to the curved shape of the

building, all individual bedrooms are

slightly different in shape and direction

Besides, the interior view along the

corridor also changes according to the

curved shape, which creates a visual

effect of ‘endlessness’.

Interior construction

The side walls of the

entrance hall are

formed with steel

framing, and are

ready to be filled

with glass to make a

good view of the

surroundings

The bottoms of the main windows are double framed, not only to hide the wiring and concrete

beams, but also to achieve better finishes with a thicker bottom.

There is also flushing in the window frames to prevent water from moving in. (ref: 7.18 Ching,

‘Flushing’)

The hollow spaces in the floor are left for

air-conditioning piping and probably

electricity wiring as well

Some height differences can be seen on the floor.

Those gaps are prepared for the ongoing timber

frames to fit in.

Interior construction

Two shearing walls are already built up in

cross directions on the third floor. They are

constructed to bear lateral shearing forces

like wind or earthquake

Light-weight steel frames are widely

used for interior framing

Between every two bedrooms,

double studs are used for both fire

resistance and noise separation.

Service system

The two photos on right hand side show the heating

and ventilation system in the bedrooms:

- Black pipes for the heater

- Rectangular metal tubes for air freshening

The two photos above show the service systems in public spaces. Electricity systems, gas system, heating

systems, water supply and sewage systems are mostly set up in site:

- White pipes for water supply and sewage disposal

- Red wires for electricity

- Black and red metal tubes for gas or heating

Functions & Finishes

For both public and private spaces,

concrete celling is to be exposed.

Therefore, neat cutting and clean

finishing are needed for aesthetic

purpose.

Those rectangular frames are for bathrooms – using timber to create the shape, in which liquid

concrete is to be poured and tiles are to be set up to make a base for water collection.

The roof is built of concrete and is prepared for another floor to be

added. From the photo above, the lift, columns and stairs are all set up

and are ready to go.

Flushing – preventing moisture form moving in

Insulation – waterproof and heat separation.

Gap between surface and insulation – for further insulation

Wall ties – tying the surface walls and the internal walls

Weepholes – for water to get out of the building

Vapour barriers – for moisture proofing

Steel strip and plastic/glass – forming a lighting tube.

Some layers of brick work are set

a few centimeters in from the

surface, probably for aesthetic

purpose.

The walls are formed with a

combination of soldier course

and stretcher course.

Weepholes provide an exit for

the moisture to get out. Downpipes transfer the

collected rainwater to the

ground.

The white stripe is a lighting

tube.

The gutter system for this building is eaves gutter. It

is exposed at the edge of the roof but is well

integrated in the roof structure.

Another gutter type is box gutter. It is hidden

within the walls and so has a better finish and is

more commonly used. But there is one main thing

to be considered: rainwater may directly come into

the house when there is a crevice in box gutters.