LOGBOOK WEEK 1 INTRODUCTION TO CONSTRUCTION

According to the image, the only ratio that we could roughly measure is the ratio of length to width, which is around 3:2. In order to draw the block in an accurate scale, I need to measure the blocks in real life. Then change the length of each side under the same ratio. This task was like working with masonry, which required complement and support from each brick (wood block in this case).

We decided to put these blocks in this order A.

Load path diagram Order B made the contact area

between each block bigger but we didn’t have enough wood to make the tower high enough. So we only created a base with order B.

Order B made the contact area between each block bigger but we didn’t have enough wood to make the tower high enough. So we only created a base with order B.

Base view from above

The base was built in Older B so that it has more contact area with the ground and the blocks on top.

Tension and Compression

Another group formed a tower with Order C. However, under the same static load, order c has more pressure with a smaller contact area than Order A.

load path diagram

The load path at the beginning was very uniform.

As we look at the ground, blocks exerting forces onto the ground and the ground push back with force with same magnitude but in opposite direction. Reaction force occurs.

As we were trying to close the tower, we built a triangle base with two beams (four blocks each) that we made with two rubber bands.

Rubber band was under a plastic behavior, so it always wanted to go back to its original form and this will produce forces acting towards blocks. This is the compression force that pushes on the beam. Compression force is now between each brick. Later on when we start to put blocks on top, beams are now under tension.

Or i put a rubber band around it. This would also form the opposite of compression: tension.

Load Path

The load will always try to find the closest way to the ground. After the first block was taken away, the load path wasn’t uniform anymore but it still managed to find its new path down to the ground. The load path then scape the original block, which has already been removed. We used the same rubber band

beam technic to form a door (gate) for the tower.

After closing the tower, we tried to take off as many blocks as possible, the tower collapsed. I didn’t manage to take the last picture before it fell. However, the other group that did the

As the sketch shows, the load path go through the supporting two columns.

tower with another block arrangement also tried to take blocks off.

When there is too much load going through one point, the structure will fall down due to too much load. This is also called point load.

Just like paper, if we enhance the base and

Last second before it fell

Trying to put loads onto another group’s tower base. This group’s tower is a great represent on how load is transferred onto the ground.

let the load easily transfer onto the ground through the strong beam, it might be able to pass the load into the ground easily. Load may not be point load like this case on the right. It just won’t be too concentrating on one point.

Material For a tower with MDF blocks only, even a very small dynamic load could ruin the whole structure. However, this material has it’s own advantages in practice as well, such as the large amount of production in Australia, which offers an inexpensive price of MDF.

KNOWLEDGE MAP

strong strength

Vector: weak

stiffness

material

shape

material behaviour

economy

sustainability

Stiff

Flexible

Stretchy

floppy

linear: mono- dimensional

planar: bi- dimensional

volumetric: tri- dimensional

isotropic

anisotropic

Tension Compression stretch push elongation shorten

Load Path-Point

Load Path

Magnitude Direction +

sense

Force

Scale

Knowledge Map

Static Load

Dynamic Load

Load

LOGBOOK WEEK 2 STRUCTURAL LOADS AND FORCES

This triangle base started up with three columns. Fixed joints on the ground are stable to start with, since it doesn’t allow any movement in horizontal or vertical direction. Apart from vertical This is a kind of soft material and

also very brittle, which means it breaks immediately after its elastic point. This property of balsa wood made the tower construction very difficult. Because balsa wood are not able to take heavy loads, especially when we cut them into stripes. However, using balsa wood in construction could be quite sustainable, because of the recyclability and accessibility in this country.

Sketching out our ideas brought out this question about what type of joint shall we use. We used a triangle base at first, they looked like that they are formed with three pin joints, however since we glued them in order to have a high stability. They become fixed joint, because they can’t rotate anymore. (No moment)

and horizontal reactions, it also provides another restraint, which is called fixed end moment (associated with the support from the fixed end).

WEEK TWO LOGBOOK CONSTRUCTING ENVIRONMENT

Structural System Framing a tower like this is just like building a structural system without the substructure (underlying structure forming the foundation of the building). Stability without a foundation became one of the biggest problems. As the tower got higher, we kept adding fixed joint triangle bases to brace the three columns and we kept on bracing for each level. In the lecture, we used pins to make pin joints with straws. However, framing tower with balsa wood, when it has open grain and very brittle. Once pins go d st k an

Load Path

Load path was very uniform at the beginning. Up to this point, the load path has already shifted slightly.

If we put an extra load, we could easily make the balsa wood tower collapse. Because apart of the load will pass through the balsa wood in the middle. As a vector, this extra load will add up with other load in that straight direction to form the collinear force. Since the balsa wood stripe is not so strong, it could easily break even with a small magnitude force.

Another group built a tower like this. This shape provides more possible paths for loads. However, the top doesn’t look like a part of the tower structure system but a straight antenna. The clever lightweight top does no harm to the supporting base.

Comparing with our project, this tower has a bigger base and more possible paths for the load to transfer. This increases the stability of the tower. Although this tower goes up really high, once we put some load on top of it, point load will easily destroy the tower bracing. Thinking We started with the smallest base in comparison to other group’s tower. This didn’t give us a perfect beginning. A bigger base could provide a lot more space for extra balsa wood strips that could share the load to go into. Maybe somet work better as I made to repr is also shown

KNOWLEDGE MAP

Local Aesthetic

quality

Construction Regulatory practice quality

Construction

System Requirement

Environmental Economic impact quality

material

Water harvesting

Insulation

Environmentally Sustainable

Design

Smart sun design

Cross ventilation

Wind energy

Material efficiency

Thermal mass

Night ait purging

Solar energy

KNOWLEDGE MAP Structural

Construction

Structural Connection

System

System

LOGBOOK WEEK 3 FOOTING & FOUNDATIONS

Activity: site visit around campus

The load will then be passed down to the ground

The underground car park is full of these columns. They are all curved up around the top and then go straight into the ground. The first question is how did builders build these columns ?

What they did is that they put the steel reinforcement first – steel columns and then pour and cure the concrete in situ after the columns are in place. You can see the edge of each circle of concrete being poured

An over hang is shown in the photo

A point load is transferred from the steel structure to stone then to the ground. This stone can be considered as in a equilibrium position, since it is stable. This means the stone is experiencing two equal forces from opposite directions. One force is the force from from the steel frame and the weight of the stone itself, then the other one is the supporting force offered by the ground. Equal but opposite to the one acting downwards. The moment of the stone is zero, since it is not moving (no distance), so we get zero moment.

These structural tie is designed to resist tension. It is opposite to a strut or column, which is designed to resist compression. Tie structure can be made by any material, the most common one, which is also the one you see here, its called galvanized steel. This steel ties are coated with zinc so that they don’t rust that badly.

This is the membrane structure outside union house. The reason why it is not formed with any masonry material is because material like stone or bricks are simply too heavy for a structure like this.

The structure is like this because when the wind is blowing, we let the window flow in and out instead of fluctuate the structure and potentially causing failure.

A gap between two bricks are left there. It is called a mortar joint. This kind of joint is built for any structural movement from thermal or moisture reasons. This is very important and it can prevent bricks from cracking on the surface.

You can see from the picture, the foundation underneath the building. It is timber strip footing. The reason why it is timber is because the building on top it is also made with timber, so it is not too heavy.

Wind will vibrate

Brick work detail

A flat membrane will fluctuate in wind-not stable

A load path diagram is shown in the photo

Steel and timber appear together. Although this timber is really clean finished but there are still weak points spotted. If a load go through the timber, the weak will be the potential first point for a crack to occur. Also at this point, crack is easier to go though and causing a failure in the structure. However, in the structure, the timber itself isn’t take such heavy load.

Different opening strategies are used in this building. However they are not load bearing windows. They don’t take heavy load from the whole building. They are just windows.

load path diagram

KNOWLEDGE MAP Structural concepts •  Structural elements •  Geometry &

Equilibrium

Construction systems •  Footings and

foundations

Material •  Mass and

masonry material 1.  Concrete blocks 2.  Stone 3.  Bricks

Strut: a slender element design to carry load parallel to its long axis

Tie: a slender element design to carry load parallel to its long axis. The load produces tension

Beam: generally a horizontal element designed to carry vertical load using its being resistance

Panel: a deep vertical element designed to carry vertical or horizontal load.

STRUCTURAL ELEMENTS

Slab/plate : a wide horizontal element designed to carry vertical load in bending usually supported by beams.

GEOMETRY & EQUILIBRIUM The center of mass : the point about which an object is balanced Depends on the shape of the geometry – center of gravity Equilibrium: is a state of balance or rest resulting from the equal action of opposing forces Reaction force

Moment＝ Force x distance

GEOMETRY & EQUILIBRIUM

FOUNDATION /FOOTING

Foundations are part of the substructure that are built under the ground in order to support the superstructure

settlement: over time, buildings compress the earth beneath them and the buildings tend to sink a little into the earth

Cracking in a building often occurs with deferential settlement

Shallow or deep foundation

Footing and foundations should be designed to ensure that this settlement occurs evenly and that the bearing capacity of the soil is not exceeded

Types of shallow footing

BRICKS Hand made – machined pressed –extruded and wire cut Different color-Clay is a natural material Users: walls arches paving Joints are usually 10 mm wide Vertical joints are called perpends and horizontal joints are called bed joints Hardness: medium high Fragility: medium Ductility: very low Conductivity: poor Durability: very durable Reusability: high Sustainability: tends to be locally produced Consideration: Non water proof Advantage: joint with water based mortar If adequately ventilated so that any wetness can escape, they will not deteriorate expansion joints Disadvantage: absorb moisture and expand overtime Efflorescence problem Expansion joint are required

LOGBOOK WEEK 4 FLOOR SYSTEMS & HORIZONTAL ELEMENTS

Drawing number Consultant Client Scale Date Project Director Drawing title Names of architecture/ director

so you know you are getting the right drawing you need and the direction/scale you are looking is right.

Basic floor layout, sign and scale, accessibility, type of windows and doors, dimensions, material

Social room: 86.8m2 Unit: meter – square meter

There is a grid. It provided reference to the basic foundation system.

It provides meaning od the labels in the drawing. / identify materials, functions – doors/walls.

ACTIVITY : DRAWING QUESTION SHEET

To expand further details, to explain further details. Clarify what is going on with some important parts.

View directions and how they are linked to another drawing.

Stairs Reduced lever (RL) Stairs into plan of building Ramps

The revision clouds are there to make the job easier to identify where the change in the plans has occurred.

It shows the height, the physical features in the building. It is 3D rather than 2D

Yes they are shown, elevator is on vertical dimension, horizontal dimension shows the plan.

Finished floor level (FFL) Finished ceiling lever (FFL) Reduced level (RL)

No grid, but there are certain vertical columns that indicated the walls.

Types of mass Some further detailed descriptions

W01 windows EL numbers

B.21-02 - elevator

Different views All levels includes basement Different angles Rooms Cut views

Where the building are cut is represented with dotted lines

Bricks Soil cross hatched

A21-01

Wall detail canopy detail Link details

KNOWLEDGE MAP Structural concept •  Beam and cantilevers •  Span & Spacing

Construction systems •  Floor & framing

system 1.  Concrete 2.  Timber 3.  Steel

Materials •  Concrete 1.  In situ 2.  Pre cast

SPACING AND SPAN Span: distance measured between two structural supports

Can be measured between vertical support and horizontal support

span is not always the same length of a member

Spacing: repeating distance between a series of like or similar element

Is often associated with supporting elements both horizontal/vertical

Spacing: measured from center lines

SPACING ( supporting elements) - SPANNING capabilities (supported elements)

FLOOR SYSTEM Concrete Timber

Steel

Stronger when span are longer

Concrete system: slabs one way or two way

Steel system: steel framing system take various forms, with some heavy structural steel members and others using light gauge steel framing

Gauge: main beams

Combination of structural and steel

Larger building : steel system – cope with fire longer

Timbe system :

Bearing (primary beam)-joists (secondary beam)

Not span too long : keep cross- sectional area small- -bearings in between to cut down the size of the material

CONCRETE Concrete mix: 1 part cement(lime portland) 2 parts fine aggregate (sand) 4 parts coarse aggregate(crushed rock) 0.4-0.5 part water

Too much water: week

Too little water: unworkable – stiff

Fluid and shapeless – liquid concrete- form work-removed

In situ or precast

Different finishes:

Sand-blasted

Exposed aggregate

Raked finish

Bush hammered

Board-marked

Board and batten

Reinforced concrete

Strong in compression and week in tension; reinforcement- mesh or bars

But steels are strong in tension

hardness: hard Not so fragile Low ductility Low flexibility Low –medium porosity-water proof Low ductility Low flexibility Medium density Poor conductivity very durable Medium low reusable Cost : labor and how is is cast Not completely water proof Steel bars to close to the surface they will not be protected from moisture and oxidation Poor vibration of concrete – to get rid of air bubbles – compromise the structural performance

LOGBOOK WEEK 5 COLUMNS, GRIDS & WALL SYSTEMS

ACTIVITY: MODELING OVAL PAVILION

When we come to choose a material for modeling the kitchen of the oval pavilion. We needed this material to be cost effective. Also we need this material to be easy to carry around – light weight. Balsa wood seem to be perfect for this. Also the structure element needs to be considered as well. For example, in the site the kitchen is constructed on top of pad footing. Then there is con

The structure on top of the foundations is the flooring system and wall system. The picture above shows a load bearing wall. The retaining wall take the load from above to the foundation. Then the foundation transfer the load in into the ground (soil)

Glued-surface joint

Point joint-connected with nails

As you can see the elements that formed the foundation is joined together with glue. The finishing is therefore not so clean. In real building construction, if we decide to use timber to be the material, we will at least try to have the finishing edge clear.

Glue surface joint

This type of connector is called surface connector. we used this type of connector, because this resist rotation and we don’t want the base to rotate at all.

Connection joint – bolt point joint-however this might lead to rotation

Same joint are made- point joint but this time it goes from the top of the timber. However, this will create a weak point through the whole timber column. When it actually come to the point of load taking, the timber will crack really easily.

We tried to as quick as possible to build the other part of the foundation. So we changed pad footing into strip footing however, if we keep on building on top of it, this balsa strip may not be at stable as pad footing.

A really unstable structure is shown in the picture and also. Because framing are pretty much all connected with tapes.

Steel bracing with little load

Compressed bracing, especially when it’s made of timber and tape, they would easily crack under heavy load

KNOWLEDGE MAP – WEEK OF COLUMNS, GRIDS & WALL SYSTEM

Structural concepts •  Columns •  Frame •  Grids

Construction systems •  Walls •  Grid •  Columns

Material •  timber

KNOWLEDGE MAP – CONSTRUCTION SYSTEM WALL, GRIDS AND COLUMNS Structural frames Concrete Use GRID of columns Steel Steel columns to connect girders and beams Bracing – stabilize the frame Timber timber posts and poles connected Load bearing walls Concrete Masonry 1)  Reinforced masonry

reinforced with steel columns

2)  Solid masonry 3)  Cavity masonry Stub wall Light gauge steel framing Timber framing

FRAMES

LOGBOOK WEEK 6 SPANNING & ENCLOSING SPACE

SITE A

Site A

Wall system

Cost saving

Structural framing

Foundation system

FOUNDATION SYSTEM

Slab footing on top of the water proofing membrane.

Raft foundation is under the steel columns. However, between that dynabolts are used to connect them.

WALL SYSTEM/COST ISSUES

There is a expansion joint between every 6 meters brick work. These joints are there to prevent bricks from cracking.

The material they used in between the gap as water proofing is VPS.

A gap is left between the internal and external wall.

STRUCTURAL FRAMING

Styrofoam is used, because of the lower cost of spray concrete.

SITE B

Site B

truss

Drainage system

Framing

Brick work /

Insulation

BRICK / INSULATION

Facing north, so the sunshine could come in. this is also a very sustainable arrangement, because we can save energy for heating.

Insulation foil sheet that can thermal issues

TRUSS/FRAMING/DRAINAGE

Pipe are already inserted. These are left there for the the toilet.

Pipes are already set up for water/electricity/heating. Bulkhead are already on site for the future kitchen usage. Green lines is for drainage. (you can see from outside)

Steel beams and timber framing are all used in this site.

KNOWLEDGE MAP-SPANNING & ENCLOSING SPACE

Structural Concepts •  trusses •  Plates •  grids

Construction System •  Roofing strategies

and system

Material •  Metal

TRUSSES

KNOWLEDGE MAP- ROOFING SYSTEM

Flat roofs Not 100% flat – drainage problems/leaking Different types of supporting system 1)  Trust 2)  Large beams and decking

with concrete form work 3)  Litter weight joist with roof

sheeting

Pitched and sloping roof 1)Rafters 2)Beams and purlins 3)Trusses

Concrete roof – a a frame – for load transfer Water proofing and membrane layers

Structural steel framed roofs – 1)  Flat 2)  Sloping 3)  Portal frame – rigid joint –

connected between beams and columns

Truss roofs

Space frames

Light framed roof: 1)  gable roofs : a ridge beam 2)  2) hip roof -

LOGBOOK WEEK 7 DETAILING STRATEGIES 1

NO ACTIVITY WEEK=CONSTRUCTION WORKSHOP Maximum point load

Deflection at the beginning

Deflection at the end

340kg 128 196

Week points have been cut off from the pine wood. This bit of timber is the week point, because once you try to break the timber. The crack will go through the grain really easily.

we didn’t want to use the plywood, because the not so strong under

screws give superior holding ability compared to nails, especially when panels are under the stress of bending. Nails in this situation lack the leverage inherent in screws to maintain this tension if a glue joint lets go for some reason.

A point load will be added in the middle

Problem occurs when the screw goes to deep, you it actually create a weak point by going thought he timber grain

When a crack goes through the grain of timber

The timber will be much more brittle when it already has a natural grain

Crack occurs in the red direction

If we have plywood, the crack will be harder to occur in the direction

Maximum point load

Deflection at the beginning

Deflection at the end

180 120 153

Load path diagram

Maximum point load Deflection at the beginning

Deflection at the end

370kg 154 192

Section of this structure, however the nail go through the entire structure. The plywood attachment has a lot a deflection when the point load is applied

When timber goes deeper or shorter, this increase strength

Maximum point load

Deflection at the beginning

Deflection at the end

480kg 196 266

Plywood is attached to the timber from the top, also the two parallel timber will not increase the compression strength but weaken it

KNOWLEDGE MAP Structural concepts •  Arches •  Domes •  Shells

Construction systems •  Detailing for heat &

moisture

Metal •  Rubber •  Plastics •  paint

ARCHES DOMES SHELLS

Arch barrel vault dome

shell

LOGBOOK WEEK 8 OPENINGS

ACTIVITY: 1:1 DRAWING

From drawing one

Finding where it is on site plan

My section on the drawing plan. All the sections are connected to each other’s. the point it for us to understand how it work as a whole and why are we using that particular material for each element.

The scale is 1:5 on an A3, there for we times it by two to get the A1 one to one size.

As a part of the roofing system, insulation and resistance to water are the main part to be considered

To prevent water from entering the building, a folded aluminum sheet is designed-waterproofing is very important for roofing.

However, we can’t really scale them, because the scale may be a little bit inaccurate. For example, the aluminum sheet on top is meant to be 275 but it is not even close to 275.

THE MATERIAL THEY USED

Aluminum surface is already reacted with oxygen in the air, which make the aluminum coated with another layer that can prevent aluminum from reaction with other element in the air. This is a rather sustainable choice for material. Because eventually, the surface will last longer.

Internal

External

Thermal insulation

Acoustic insulation

Non dressed Timber

Timber

Plasterboard-too thick, should be 9 mm, will change it in week 10’s refined drawing

Joint sealant with backing ROD

KNOWLEDGE MAP Structural concepts •  Deformation &

Geometry (of beams)

Construction systems •  Strategies for opening

Material •  glass

DEFORMATION-BEAMS

Deflection: perpendicular distance member deviates from a true course under transverse loading, increasing with load and span and decreasing with an increase in the moment o inertia of the section or the modulus of elasticity of the material Bending moment: is an external moment tending to cause part of a structure to rotate or bend, Resisting moment: internal moment equal and opposite to the bending moment Bending stress: combination of compressive and tension stress developed at a cross section of a structural member to resist a transverses force Transverse shear: occurs at a cross section of a beam or other member subject to bending Vertical shearing stress: resist transverse shear Horizontal shearing: prevent slippage along horizontal planes of a beam under transverse loading, equal at any point to the vertical shearing stress at that point

Efficiency of a beam is increased by configuring the cross section to provide the required moment of inertia or section modulus with the smallest possible area 1.  Making the section deeper 2.  Reduce the span

OPENING STRATEGIES

GLASS

Glass: formers(silica) fluxes(help the glass to melt at low temp)-soda ash/potash/carbonate stabilizer(more life of stable-from dissolving (limestone/alumina/magnesia) Property: porosity: water proof – non porous Density: medium high Conductivity: transmit heat and light but not electricity Hardness: high Fragility: high Ductility: very low Plasticity: a little bit elastic but low Durable Could be reused High embodied energy Cost : expensive

GLASS Flat glass: sheets of clear or tinted float, laminated, tempered Shaped glass: curved, blocks, channels, tubes, fibers Float glass: is now the most common glass production

Melted tin to flat it

Float glass: 1) clear float glass(annealed glass): low risk and low cost- break 2) Laminated glass: a tough plastic interlayer (PVB) is bonded together between two glass panes –adhere to plastic rather then fall apart 3)Tempered glass: toughened glass

LOGBOOK WEEK 9 DETAILING STRATEGIES 2

Concrete slabs are poured in situ. Considering how big the span of each slab is, it makes sense they are poured in situ. Because is they are pre casted, the transport fees will be a lot more.

Roof top is designed to be a roof garden for the residences. Protection around the roof is as important as it is now when builder are working on site. The steel frames will be removed once the roof top is finished. However, other types of protection system around the roof will be constructed.

Holes for pipes to go through the concrete slab.

The timber frames are there as a protection frame, it acted as a temporary stair handles to keep builders from falling.

The in situ concrete left evidence here

Load path from outside

Activity: site visit

Pipe going through the concrete

These holes are left here for pipes to come in. They are a part of the drainage system. This is very important in this sit because of the usage of the roof top garden.

A part of the water and heating system: is shown is the photo Black – cold water Red- hot water Yellow – gas tube By using these different color tubes, it will be easier for builders to identify which is which. Also if one of the system actually has some problems, it will be easy to find the problem and fix it.

The ceiling is unfinished as we can see, because it rained the night before. There are leaking problems right now on site. You can also see the joint mark of concrete slabs. However, as we can tell, this is just concrete so far. Membranes and insulation layers will be put on.

A detailed drawing of a roofing

Pipes section

Air conditioning place is hanged on the concrete slabs

steel framing is placed around a bathroom, they are a part of the structural system. Because they are carrying loads down into the ground.

You can see the black and red tubes are ready to be used as cold and hot water system in the shower. A draining tube hole also goes through the concrete. The other set of tubes is probably for a separate sink.

Expansion joint is seen in the basement between two concrete slabs. They are there in order to allow and structural movement, such as shrinking or expansion because of the thermal or moisture consideration.

Concrete blocks are used as load bearing wall as well as in in situ concrete slabs. Expansion joints can also be spotted between them.

Why is it steel framing but not timber? It depends on so many factors, such as cost, time consumption, supplier at that the time when framing was built.

Spraying/shot concrete is often seen in swimming pools and basement walls. Because the is easier to apply on top of the structure that are already there. However, comparing with precast or in situ, spraying concrete requires a harder labor work. The finish of the surface doesn’t look smooth as precast concrete but it is more efficient in a way that it doesn’t need any transport.

Why is the beam long like this ? Due to the basement’s purpose-car park, we want it to have as much space as possible. So we choose beam that span this way to have more space for cars to park here.

The basement is designed to be a two-floor car park. Columns load paths are shown in the photo.

KNOWLEDGE MAP

Structural concepts •  Stress and structural

members (behavior under stress-columns)

Construction systems •  Construction

detailing

Materials •  Composite

materials 1.  Fiber 2.  Fiber reinforced

cement 3.  Fiber glass 4.  Aluminum sheet

composites 5.  Timber

composites

BEHAVIOR UNDER STRESS-COLUMNS Short thick columns: 1.  Failure by crushing rather than

duckling 2.  Occurs when axial load

exceeds the compressive strength of the material available in the cross section

3.  Eccentric load produces uneven stress distribution in the section

4.  Kern area: central area of an horizontal section of a column or wall; compressive load beyond this area will cause tensile stresses to develop in the section

Long slender columns: 1.  Failure by duckling rather than

crushing 2.  Occurs when under duckling

load, a columns will begins to deflects laterally and can’t generate internal forces to restore the linear condition

3.  Additional load beyond duckling load will cause collapse in bending

4.  Slenderness ratio(L/R) is inversely proportional to the critical stress

L is the effective length R is the least ration of gyration

Buckling occurs in the weaker axis or in the direction of the least dimension

Effective length L : is the distance between inflection points in a columns subject to duckling, when this portion buckles, the entire column fails

Effective length factor L: coefficient for modifying the actual length of a column according to its end conditions

Radius of gyration R is the distance from an axis at which the mass of a body may be assumed to concentrate

JOINT & CONNECTION

Butt joint/overlapping joint/shaped joint

Point connector: bolt

Linear connector: weld

Surface connector: glue

MOVEMENT JOINTS

1.  Expansion joint: permitting thermal or moisture expansion to occur without damage to either part 2. Control joint: In concrete ground slabs or concrete masonry walls to form a plane of weakness and thus regulate the location and amount cracking resulting from drying, shrinking, thermal stresses, or structural movement 3. Insolation joint: divide a large or geometrically complex structure into sections so that different movement or settlement can occur between the parts

1.  A joint that creates a complete break through the structure, which is then usually filled with a compressible material

2.  A waterstop that may be in form of an elastic sealant, a flexible waterstop embedded within the construction, or flexible membrane over flat roof joints

Common structure

Types of joint

Water stop

JOINT SEALANTS/CONNECTIONS

Joint under compression

Sealants: 1.  Low range: oil-based or acrylic

compounds (little movement is expected)

2.  Medium range: butyl rubber, acrylic, or neoprene compounds (non working, mechanical joints)

3.  High range: polymercaptans, polysulfides, poyurethanes and silicones (significant amount of movement)

Substrate: 1.  must be clean, dry and compatible

with the sealant material 2.  A primer maybe used to improve

the adhesion between substrate and sealant

Joint filler: 1.  controls the depth of the sealant contact

with the joining parts 2.  Compressible but not adhere to the

sealant 3.  Rob, polyethylene foam, butyl rubber

Provide an effective seal against the passage of water and air, a joint sealant must be durable, resilient an have both cohesive and adhesive strength

Butt joint/overlapping joint/shaped joint

COMPOSITE MATERIALS Monolithic: •  Single element •  Metal alloys (in distinguishable)

Composite: •  Two or more materials are

distinguishable (metal/glass) •  Bonded together •  Remain their identities •  Act together Cleaning issues

WEEK 10

WHEN THINGS GO WRONG

ACTIVITY: SITE VISIT THE OVAL This is where my section is-on tope of the function room

Seeing what is really going on is rather difficult but the other half of the roof is very similar

AL-01: Aluminum Fascia AL-06: Aluminum flashing RFS-01: Metal deck roofing INS-03: Thermal insulation INS-08: Acoustic insulation roof WPS-02: in ground sheet membrane IL-03: impact and fine resistant plasterboard INS-01: Acoustic insulation walls

Timber framing Joint sealant with backing ROD

The correct thickness of the plasterboard-9mm

timber

Refined drawing

Metal decking

Dressed timber/non dressed timber

How they fold the metal sheet

What happened when the joint sealant under compressed and tension

3D drawing in 15 minutes

KNOWLEDGE MAP

Structural concept Construction system Materials

Lateral forces Collapses & Failures Heroes & Culprits

week 10

Wind earthquake Case study Issue kinds

Example materials

Earthquake waves are both longitudinal and transverse

Wind causes movement

STRUCTURAL CONCEPT-LATERAL FORCES

CONSTRUCTION SYSTEM- COLLAPSES & FAILURES

Case study-beach house

Timber fascia-black on one

side-deflection

Plywood are not fixed to

stub-rib off the surface

Re-clad but may come off again-stability issues need to be considered

Flat steel sheeting on

plywood-thermal-glue

problem

MATERIALS-HEROES & CULPRITS

Issues to

consider

Energy use and

embodied energy

Waste/recycling

pollution Life cycle

Health and IEQ (indoor environment

quality)

materials

Health/IEQ

villains

Paint Glue carpets Chemical for cleaning

heroes

bamboo Surface spray

Embodied energy

villains

Light bulbs Aluminum

heroes

timber Australian made

Source &waste

villains

timbers stone

heroes

Recycled timber

Recycled fabric

pollution

villains

Cigarettes smoke PVC

heroes

More Natural material

Non PVC cables

MATERIALS-HEROES & CULPRITS

A LITTLE BIT EXTRA RESEARCH INTO ARCHES Bending moment for an arch means a lot, it determine whether is will bend and fall down or not. Moment or torque means the turning effect of a force around some point. This moment of a force is the product of force F and the perpendicular distance x from the turning point (T=Fx in newton-meter, Nm). For a parabolic arch, bending moment is zero but when it has a heavy load on it, it then will induce a bending moment. For understand the reactions, we can used the suspended cable equations.

Vertical reaction, Rav=Rcv=wL/2

Horizontal reaction, Rah=-Rcv=wL/8D

Maximum force in arch=(Rav^2+Rah^2)^0.5

In order to understand these formula better, I set up an example on how to prove an arch with uniform loading has no bending moment. Just like what people in 1800 B.C did when they first created the mode of corbelled arch.

Y= A+Bx^2

In the graph x=0,y=0

A=0

Therefore

At x=L/2, y=D

D=BxL^2/4

So B=4D/L^2

The final equation will then be y=4Dx^2/L^2

So the clockwise moments = wx^2/2+wL^2/8Dx4Dx^2/L^2

= wx^2/2+wx^2/2

= wx^2

Anticlockwise moments = wxxX=wx^2

The arch ring, with its voussirs, is very much like a curved wall. So when we talk about the thrust lines of a wall, what are we actually talking about and what is middle third cutting. Continuing the previous story, Hooke was the one who put this into words. First of all he made four assumptions about elasticity. The compression stresses are so small that crushing will not break material. Owing to the use of a mortar or cement, the fit between the joints is so good that the compressive forces will be transmitted over the whole area of the joint and not just at a few high spots. The friction in the joints is so high that failure will not happen because of bricks or stones sliding over each other. In fact no sliding movements at all will take place before the structure collapses. The joints have no useful tensile strength. Even if, by chance, the mortar does have some strength in tension, this cannot be relied upon and must be neglected. The person who put the masonry elasticity deformation into account is Thomas Young. He considered what would happen in a block of stone, if we put a vertical load onto it, like M. If the stone obey Hooke’s law, then Young suggested that the stress distribution graph would look like the graph below. (Fig.M) If the position so the load is displaced still further from the center-in fact to the edge of what id called the middle- third of the wall. If the load went over that middle-third, then the wall will immediately fall down. This is like what is happening to arches, apart from the fact that an arch won’t fall down immediately. A thrust line can also indicate the position of the compressive loads at each joints in the same way, in the arch case, the line just bend towards the curve. Because there is no point to going to deep of arch bridges, we can just simply treat the voussiors can’t slide over other and that joints can’t take tension. The joints between the voussoirs will behave in the same way as they do in stones in any walls. If the thrust line strays beyond the ‘middle third’ then a crack will appear. Also, if a thrust line moves to the joint edge, a hinge will then being developed. So as a crack or a hinge appear, then the wall will eventually fall down. But the arches won’t, their structure allow them to develop three joint points without any major damage (due to the middle third effect). If we have four joint points on a single arch, putting any loads on one joint point can easily damage the arch. No matter if it’s bridge or arcade. The reason why is shown in the diagram bellow (Fig. g). Another way to damage a arch or a arch bridge is to move their foundation. This is always because of some natural reasons (earthquake). This is the method architects still use to make sure the arch is not going to bend or fall down apart from using computer. Now by knowing the method about how to analyzed the basic structure and parts of a arch. We can move on to analyzing roman arch. One thing is really obvious about Roman arches is that their shape is not parabolic but round. It’s more like a half circle.

Glossary

Load path: the direction in which each consecutive load will pass through connected members.

Reaction force: every force on one object is accompanied by a ‘reaction ’. Equal magnitude but opposite direction.

Masonry: is the building of structures from individual units laid in and bound together by mortar; the term masonry can also refer to the units themselves

Point Load : s a load which is localized to a specific location on a structure

Tension: is the pulling force exerted by a string, cable, chain, or similar solid object on another object.

Compression: is the pushing force.

Beam: is a structural element that is capable of withstanding load primarily by resisting bending.

Framing: in construction is the fitting together of pieces to give a structure support and shape

and sometimes is used as a noun such as "the framing" or "framing members”.

Bracing: a reinforcement used in architecture, such as in timber framing---is a general term for building with heavy timbers rather than "dimension lumber"

Column: is a structural element that transmits, through compression, the weight of the structure above to other structural elements below. In other words, a column is a compression member.

Moment: Force x distance moved in that directio

Retaining wall: is structures designed to restrain soil to unnatural slopes. Load taking

Substructure: foundation of buildings that support supersturcture

Joist: Any of the wood, steel, or concrete beams set parallel from wall to wall or across or abutting girders to support a floor or ceiling. Steel decking: deck is a flat surface capable of supporting weight, similar to a floor, but typically constructed outdoors, often elevated from the ground, and usually connected to a building.

girder: girder is a support beam used in construction.[1] Girders often have an I-beam cross section for strength, but may also have a box shape, Z shape or other forms.

Concrete plank: a long, thin, flat piece of concrete, used especially in building and flooring.

Stub: A wall stud is a vertical framing member in a building's wall of smaller cross section than a post. They are a fundamental element in building framing.

Nogging: Bracing in-between the studs to make the wall structurally stronger in the middle of the partition wall. Lintel: A lintel can be a load-bearing building component, a decorative architectural element, or a combined ornamented structural item. Buckling: resisting any sudden movement, may also cause a crack

Seasoned timber: moisture removed timber

Rafter: a beam forming part of the internal framework of a roof.

Purlin: a horizontal beam along the length of a roof, resting on principals and supporting the common rafters or boards. Cantilever: over hang

Portal frame: a rigid structural frame consisting essentially of two uprights connected at the top by a third member. Eave: the part of a roof that meets or overhangs the walls of a building.

Alloy: a metal made by combining two or more metallic elements, especially to give greater strength or resistance to corrosion. Soffit: the underside of an architectural structure such as an arch, a balcony, or overhanging eaves. Drip: a projection on a moulding, channelled to prevent rain from running down the wall below.

Vapour barrier: A vapor barrier (or vapour barrier) is any material used for damp proofing, typically a plastic or foil sheet, that resists diffusion of moisture through wall, ceiling and floor assemblies of buildings and of packaging.

Gutter: a shallow trough fixed beneath the edge of a roof for carrying off rainwater.

Parapet: a low protective wall along the edge of a roof, bridge, or balcony

Down pipe: a pipe to carry rainwater from a roof to a drain or to ground level.

Flashing: a strip of metal used to stop water penetrating the junction of a roof with another surface.

Window sash: sash: a framework that holds the panes of a window in the window frame

Deflection: deflection is the degree to which a structural element is displaced under a load. It may refer to an angle or a distance. Stress: Force per area

Shear force: Shearing forces are unaligned forces pushing one part of a body in one direction, and another part of the body in the opposite direction.

Sandwich panel: Aluminium Composite Panel also Aluminium Composite Material, is a type of flat panel that consists of two thin aluminium sheets bonded to a non-aluminium core. Skirting: a wooden board running along the base of an interior wall.

Shear wall:In structural engineering, a shear wall is a wall composed of braced panels to counter the effects of lateral load acting on a structure. Soft storey: A soft story building is a multi-storey building in which one or more floors have windows, wide doors, large unobstructed commercial spaces, or other openings in places where a shear wall would normally be required for stability as a matter of earthquake engineering design.

Braced frame: A Braced Frame is a structural system which is designed primarily to resist wind and earthquake forces. Fascia:is an architectural term for a frieze or band running horizontally and situated vertically under a roof edge, or which forms the outer surface of a cornice, visible to an observer.

Reference

Francis D. K. Ching, 2008. Building Construction Illustrated. 4 Edition. Wiley.

E-learning

Walter T. Grondzik, 2009. Mechanical and Electrical Equipment for Buildings. 11 Edition. Wiley.

Edward Allen, 2013. Fundamentals of Building Construction: Materials and Methods. 6 Edition. Wiley.

Christopher Gorse, David Johnston, Martin Pritchard, Martin Pritchard (BEng (Hons), PhD.) (2012) A Dictionary of Construction, Surveying, and Civil Engineering, : Oxford University Press.