Constructing Environments Week 1 There are 3 basic types of “shell” for a building 1. Masonry 2. Timber 3. Steel - UC = column, often square to resist loading from all directions - UB = I-beam which is particularly strong on one axes - PFC = U-Beam or Channel Types of structures: 1. Column and beam – forms a kind of skeleton around which a shell can be created 2. Mass construction - Small module (i.e. mud/clay bricks). Useful for creating shapes and curves in a structure - Large module (i.e. concrete slabs). Generally makes up large components of a building Small module structures rely on the formation of bricks to resist lateral loads. For example, an interlocking style of brick arrangement adds strength in multiple directions. Large module structures - Precast concrete is more time efficient as it allows for 1. Other tasks can be undertaken on site while it is under construction elsewhere 2. There is no period where you need to wait for the concrete to set where things can’t be put in place until it’s dry. - Pre-cast concrete also allows for better quality control as it is produced in isolated conditions. - ‘ Loads on Buildings - Static loads are assumed to be applied slowly to a structure without rapid fluctuation and don’t change the position of their load. (stationary structural elements are static loads) - Live loads are comprised of any force created by a moving thing or occupant. (Live loads may Load Paths: this diagram shows the projected load path a load (f) would take if it acted directly on top of the building as shown. Load forces take the most direct path to the ground
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Transcript
Constructing Environments
Week 1
There are 3 basic types of “shell” for a building
1. Masonry
2. Timber
3. Steel
- UC = column, often square to resist loading from all directions
- UB = I-beam which is particularly strong on one axes
- PFC = U-Beam or Channel
Types of structures:
1. Column and beam – forms a kind of skeleton around which a shell can be created
2. Mass construction
- Small module (i.e. mud/clay bricks). Useful for creating shapes and curves in a structure
- Large module (i.e. concrete slabs). Generally makes up large components of a building
Small module structures rely on the formation of bricks to resist lateral loads. For example, an
interlocking style of brick arrangement adds strength in
multiple directions.
Large module structures
- Precast concrete is more time efficient as it
allows for
1. Other tasks can be undertaken on site
while it is under construction elsewhere
2. There is no period where you need to wait
for the concrete to set where things can’t
be put in place until it’s dry.
- Pre-cast concrete also allows for better quality
control as it is produced in isolated conditions.
- ‘
Loads on Buildings
- Static loads are assumed to be applied slowly
to a structure without rapid fluctuation and
don’t change the position of their load.
(stationary structural elements are static loads)
- Live loads are comprised of any force created
by a moving thing or occupant. (Live loads may
Load Paths: this diagram shows the
projected load path a load (f) would
take if it acted directly on top of the
building as shown. Load forces take
the most direct path to the ground
have a vertical as well as a horizontal force component representative of their motion)
Elements of materials
Strength – how strong something is, whether it’s able to withstand forces without failing
Stiffness – the resistance of a material to deformation (plastic deformation)
Shape – a linear, bi-dimensional description of the appearance of an object
Material Behaviours
Materials can have both isotropic and anisotropic behaviours.
- Isotropic behavior is when a material is similarly strong under compression and tension,
whereas;
- Anisotropic is when a material is stronger under one force (compression or tension) than
the opposite force. Concrete is an anisotropic material as it’s much stronger under
compression than tension
Tension – when an external load pulls on a member, deforms by stretching
Compression – when an external load pushes in on a member, forming by shrinking or compressing
During the tutorial we created a compressive
tower to try and achieve a maximum height.
We chose a relatively dome shaped design to
achieve maximum compressive force.
Week 2
There are 4 basic types of structural systems:
1. Solid – compression is the main form of
support. Arches are very strong as they
work under compression as their main form
of support
2. Surface/shell- i.e. open house
3. Skeletal – efficient way of transferring loads,
using less material (i.e. trusses)
4. Membrane – useful for covering large areas
efficiently while staying strong under
tension
Construction System
Splits a structure into subsystems which allows ease of analysis, generally made up of 3 main
components:
1. Enclosure system – i.e. roof
2. Structural system – i.e. members, load bearing structure
3. Service system – i.e. heating and electricity supply
All 3 elements need to be taken into consideration when designing/analyzing a structure. Among
these main building considerations, it is also important to consider:
Performance requirements (i.e. comfort)
Aesthetic qualities (is it nice to live in?)
Economic Efficiency (budget, longevity of material)
Environmental impacts (generally try to reduce these)
Residential areas make up a large portion of
building areas and therefore play a key part in
environmental issues as they consume a lot of
energy.
Reduce – Reuse – Recycle
It’s important to consider the emissions both in
terms of direct emissions as well as embodied
emissions (i.e. those emissions created by the
production of a product or structure)
ESD strategies can be used to reduce emissions and
environmental impacts of a structure.
Types of Structural Systems
This is an example of how structural considerations
were taken into account in order to be more
environmentally sound
Some environmental strategies are:
- Solar energy use
- Frontal ventilation
- Water harvesting
- Night air purging
Structural Joints are of 3 types:
1. Pin joint (resists vertical and horizontal loads)
2. Roller joints (resists vertical loads)
3. Fixed joints (resists vertical loads, horizontal loads and moments about the joint)
sourcing manufacturing
Distribution & use
recovery
DESIGN
Week 3
Footings and Foundations
Foundations are the substructure of a building that
transfers loads from the footings to the ground
There are 3 types of footings:
1. Pad Footings – help to spread the load over a
wide area of ground to reduce any sinking and
add to the stability of the building
2. Raft foundation – also called a raft slab,
increasing stability by joining the individual
strips together
3. Strip footings – used when loads from a wall or
a spread of columns are spread linearly (along a
line)
Deep Foundations
Deep foundations can be used on heavy buildings or
where there are softer foundations in order to provide
more stable footing. When a building is very high it needs
to be counteracted by extending far underground to aid
in resisting lateral loading.
Retaining/Foundation Walls
Retaining and foundation walls are used when sites are excavated to create basements etc. the
pressure exerted on the wall by the earth behind needs to be considered to prevent the wall from
failing inwards.
Some sketches of the different types
of footing
Bricks
Advantages:
- Bricks can be joined by mortar
- If adequately ventilated they won’t deteriorate
- Forms a naturally compressive structure that is
good at holding high loads
Disadvantages:
- Absorbs moisture and expands over time which
requires expansion joints
- Salts and lime from the ground can be absorbed
up through the bricks
Concrete Blocks
Advantages:
- Holes in concrete blocks allow for
reinforcement to be placed and
increase the insulation that they
provide.
- Reinforcement allows the blocks to be
strong under tension as well as under
compression.
Disadvantages:
- Concrete blocks tend to shrink
overtime, whereas clay bricks expand
- Clay bricks absorb moisture from the atmosphere,
whereas cement in concrete loses
- water to the atmosphere
Above the windows you can see a
series of weep holes that were
created where a concrete slab is
placed for the second level. These
weepholes allow excess moisture to
exit the structure.
Pictured is a brick wall where you
can see marks left from the
absorbtion of salts and lime from
the ground, leaving white marks on
the walls.
Stone
3 types of stone used for construction purposes:
1. Igneous – formed when lava cools, extremely dense
2. Sedimentary – created from accumulated sediments,
not very structurally sound.
3. Metamorphic – formed when igneous or sedimentary
stone changes when subjected to pressure.
Pictured are the bluestone footings of a
building in the university of Melbourne
campus. Bluestone is an igneous rock
and is extremely strong.
Week 4
Floor Systems
Both dead and live loads are carried from the slab through the supports
- Concrete
- Timber
- Steel
Larger spacing leads to a larger span which
requires the material to be thicker in the
direction of loading or stronger.
Concrete systems; slabs are used to span
between structural supports
Steel Systems; steel is occasionally
combined with concrete slab systems to
utilize advantages from both
Timber Systems; the most common type of
system in residential construction.
Concrete
4 major elements:
Cement + Fine Aggregates + Coarse aggregates + Water
In Situ Concrete
Formwork is the material and structure used to keep fresh
concrete in its intended shape until dried.
The curing process of the concrete requires supports and
bracing
Concrete reaches 75% of its maximum compressive
strength within 7 days
Finishes:
- Sand blasted
- Caked finish
- Exposed aggregate
Here is a section of concrete that
has clearly been created in situ as
can be seen from the marks left by
the formwork
An example of some of the common elements in a
timber beam system
Reinforcements:
- Concrete is weak in tension, so steel is added to give tensile strength in the form of
mesh or bars depending on the conditions of the concrete
In Situ Concrete: when concrete is poured on site within some formwork
- Short amount of time where the concrete is considered workable
- Concrete can be placed by spraying it on a surface (shot-crete) and is held in place by a
mesh. This is useful for concreting vertical surfaces
Joints:
1. Construction joints – divide construction into smaller sections
2. Control joints – useful to ensure the concrete doesn’t crack over time during the shrinking
process.
Pre-cast concrete
Pre-cast concrete is created under more controlled conditions which allow for greater quality
control
After being cured to a sufficient strength they are taken to the site and lifted into place
The size of a pre-cast concrete slab is limited due to transport requirements both to the site and
once the slab is on site it is important to be able to move it into position without too much hassle.
Joints:
1. Contruction joints – naturally occur when one precast element meets another
2. Structural joints – the type and performance of structural connections is integral in the
buildings stability.
Week 5
Floor plan with measurements for workshop activity -
These measurements were taken from the architectural
floor plans in the reader.
Week 6
This week we brought material (cardboard and balsa) and cut it into shape throughout the tutorial in
an effort to create a skeletal model of the primary structural elements of the new sports pavilion.
It’s difficult to see in this photo, but the model consisted of two levels of structure. The
measurements our group had taken for the model appeared to be slightly skewed as we may have
taken them from a resized plan, but we managed to recreate the upper level still with some
accuracy.
Week 7
Detailing for Heat & Moisture
Basement
Require full tanking if subject to a wet environment. Tanking is when a waterproof membrane is
placed around the construction.
In dry ground it’s possible to put an agricultural drain where water is carried away from the building
and into a storm water pipe.
Walls
Attempt to put an impervious surface on the outside
Double skin wall (i.e. brick cavity)
Roofing
Water hitting roofing needs to be carried away from the building perhaps over the eaves or through
gutters and to downpipes
Detailing for Moisture
For water to penetrate into a building there must be:
1. An opening
2. Water present at the opening
3. A force to move water through the opening
Openings
Can be planned elements such as windows, doors, skylights etc.
Can be unplanned due to poor construction workmanship or deterioration of materials
Common techniques used to remove openings to prevent water penetration include:
- sealants (i.e. silicone)
- gaskets
Keeping water from openings is a commonly used strategy in construction detailing. This can be
done by grading roofs so that the water is collected in gutters and transferred to downpipes into
stormwater systems. Overlapping cladding around roof elements ensures water cannot enter.
Sloping window and door sills encourages any moisture to runoff. Sloping the ground surface away
from the walls at the base of buildings allows water to run away from the building.
During this week’s tutorial we drew detailed section of
different parts of the building and set them up to be
connected. This detail pictures an insulated wall as well as
part of the roof system where you can see a z-purlin hanging
from which a ceiling can be supported.
Here is another detail of a roof
section on the right with an
insulated wall and a z-purlin.
Week 8
Glass
Changes in glass technology have allowed for ever larger sheet sizes at a lesser cost. The changes
that enabled buildings like the RWE tower are cultural as well as technological.
Glass occurs naturally when sand is exposed to intense heat. Soda is added to reduce the melting
point and stabilized with lime when creating manmade glass.
In the 19th century architectural glass was primarily hand blown and very limited by a number of
technological factors. After a series of revolutions in glass making from the 1920s to 1950s glass
could now be mass produced in computer controlled factories.
A window frame was necessary in the Wainwright building to secure the glass, but this framing
system has been reduced to a set of point supports.
Components:
- Formers: the basic ingredient, any chemical compound that can be melted and cooled into a
glass is a former (i.e. silica)
- Fluxes: help formers to melt at lower temperatures (i.e. soda)
- Stabilizers: combine with fluxes and formers to keep the glasses integrity
Properties:
- Non permeable
- More dense than water
- Conductivity: transmits heat and light but
not electricity
- Relatively Hard
- Low ductility
- High flexibility when heated, low flexibility
when cooled
- Durable
- Highly recyclable
- High embodied energy & expensive
Glazing
Glazing reduces the heat transfer of the glass which acts as an insulator and moderates the exterior