Constructing Environments

Logbook

louis Wyatt

W EE K1Lecture notes

http://techstudies.myblog.arts.ac.uk/!les/2013/02/IPE-AA-Beam.jpg

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Steel beams are considered a stronger material than planksof wood, especially when constructing framework.

Qualities of Di!erent Materials:

Strength: How strong the material is, and how well the material acts under di#erent forces. For example, steel is far stronger than timber, with steel working su$ciently under both compression and tension forces.

Sti!ness: Sti#ness relates to how "exible the material is, and how it responds when stretched. For example, rubber is a highly "exible material, whereas concrete represents a far sti#er material.

Shape: Building materials can come in a variety of shapes; they can be mono-dimensional (linear), bi-dimensional (planar), or tridimensional (volumetric). A clay brick would represent a volumetric material, with volumetric materials useful in mass construction.

Material behaviours: Materials can be equally strong under both compression and tension forces, with these materials de!ned as isotropic. If a material works well under only one type of force, eg tension, it is de!ned as anisotropic.

Economy: The economy of a material is based on a number of factors, including the price for purchasing the raw goods, the cost of having the goods transported to site, as well as the cost of having the material installed.

Sustainability: A material is considered sustainable if it is produced in an environmentally friendly way, such as originating from a renewable source. Many economic factors are can be considered along side sustainable factors, such as the distance the material needs to travel during its lifetime, as well as if a use can be found beyond your current project.

W EE K1block construction

A

C

B

All photos taken by myslef during classAll photos taken by myslef during class

Comments on Construction:

As a foundation for our design, we began by examining a variety of di!erent building techniques, consideringhow we could maximise the height of the design with the limited number of blocks, while simultaneously ensuring it was structurally sound. It was a requirement that the design either house, or support a plastic dog, with weight tests carried out on preliminary designs (as seen in "gure B).

It was decided that a semi-circular design would besu#cient (as seen in the adjoining diagram,) as it would allow for a sturdy continuous shape, while still requiringless bricks than the traditional, full circle option. Whilebricks laid horizontally, yet along their thinner side would allow for a greater height (Figure A), it was evident that this would result in a design less structurally sound. Thus bricks laid along their thickest side (Figure C) were chosen. While a small second tower was considered, such a tower to hold the dog, with the main tower achieving the soul purpose of gaining great height, the semi-circle nature of the design meant that the dog could just beplaced within its central void.

W EE K1key terms

Load Paths: A load path is the trail taken by the force through the structural frame, delivering the live loads and dead loads from the building, through the foundations, and inevitably into the soil.

Reaction Forces: Because all forces require an equal, opposite reaction, as the load of the structure enters the soil, it requires the soil to place equal force back onto the frame, this is known as the Reaction Force.

Masonry: Masonry is the system of construction whereby bricks made from a variety of materials are joined with mortar to create a structural or aesthetic element. Masonry walls can be constructed from bricks, concrete, marble, granite, glass, tiles etc.

Point Load: A point load, is a load which is placed on one speci!csection of the frame. This can be a live of dead load, yet di"ers in that it isn’t part of the inherent loads within the frame itself.

Compression: Compression is the application of an inward “pushing” force, which aims to decrease the mass of the structural element. This contrasts tension, where the element is “pulled”, the layers of the material being pulled from one another.

Beam: Beams are one of the fundamental elements of a structural system, which, designed to withstand bending can be made from concrete, steel, wood, marble, as well as other materials. Beams can be constructed in a variety of systems; trussed, cantilever, !xed, continuous etc.

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Masonry Wall

Steel Beam

W EE K1block construction

Photo taken by myslef during class

Comments on Final Design:

Inevitably, we were forced to alter our original concept, thus attempting to enhance both the stability and height of the design.

To enhance the stability, it became evident, that a straight wall connecting the ends of the semi-circle would be required. This connection, as seen in the neighbouring diagram, enhanced the strength of the circular form, the tower loosing its tendency to tilt inwards as it increased its height.

Likewise, it became clear, that while laying the bricks along their thickest face was creating a seemingly strong structure, the tower was not gaining height quickly. Thus, having deduced that a strong foundation and base had been constructed, the bricks were rotated onto their sides for increased height (see attached diagram).

Once blocks were slowly removed from the tower, it quickly became clear that the joints that had beenformed between the ends of the semi-circle and the connecting line, were physically the strongestaspect of the design, (see attached photo). Thus the tower remained upright, despite the largehole within its main circular form. With only two columns, connected by a spanning bridge, it was shown that the compression forces at play were strong enough to support the entire block structure.

W EE K 2Lecture notes

The Ei!el Tower in Paris is an example of a "x joint constructon system.

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Structural Joints:

Roller Joint: Within a roller joint, loads are only transferred in one direction, with the roller moving when the load is pushed horizontally. Thus roller joints can only support vertical loads, with suchjoints not often used in small residential projects, but rather, when contraction and expansion of components is required.

Pin Joint: Pin joints are common in the construction industry, as they allow for movement within the components of the project. Pin joints are used commonly within truss systems, for while they allow rotation, they resist translation within the construction.

Fixed Joint: While considered to be the most complicated joint to calculate, a "xed joint maintainsthe angular relationship between the forms and joined elements. Providing moment and force resistance, the "xed joint ensures a rigid structure withno movement amongst the separate components.

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W EE K 2Lecture notes

Denver International Airport uses a membrane structure for its roof system.

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Structural Systems:

Solid: Often found in older structures, such as the Pyramids in Egypt, or Ancient Roman structures, solid systems were often built out of stone, mud or bricks. Within solid systems, compression is the only structural force, as there is no frame that would create tension.

Surface: Surface systems are created by using a shell-like structure to form the main structural element, with the Sydney Opera House acting as a prime example of such building techniques. This structural system is not regular practice within tradition residential projects.

Skeletal: The most commonly found structural system is a skeletal system, which is based around a central frame. The use of a frame within the design is considered an e!cient means of transferring the load of the building down to the ground.

Membrane: Membrane systems are considered the least common of the four system detailed above, however their uses can create interesting results. Membrane structures (refer to attached photo) are useful when a large, open space needs to be spanned cheaply, such as a sports stadium.

Hybrid: Conjoining two of the above systems within the one construction project would create a hybrid system, with many hybrid systems consisting of a skeletal frame, covered in a surface cladding.

W EE K 2frame construction

Photo taken by myslef during class

Comments on Construction:

For this construction task, we were required to construct a tower using the wood obtained from one piece of balsa wood. By cutting the wood into long, thin strips, an optimum number of small wooden pieces were obtained.

As opposed to the block construction, a semi-circular form was impractical, as all the wooden segments were straight, thus, a square based tower was considered the most desirable.

In order to ensure that the frame would remain sturdy, unable to bend or twist as further levels were added, a series of diagonal braces were conceived to hold the form together. This was enhanced through the use of horizontal braces that would hold the four external faces together. Once the tower reached a substantial height, the design was such that it would have a slanted roof, with a central beam rising vertically (see diagram) acting as an architectural feature.

In order to make construction easier, each of the walls were constructed separately then attached once their glue joints had set (see photo).

W EE K 2frame construction

Photo taken by myslef during class

Comments on Final Design:

Once construction began, it quickly became apparent that the glue we had chosen to act as an adhesive within the joints was not drying su!ciently quickly. Persevering for a short while in the hope that the glue would work, we inevitably were forced to use masking tape as a means of creating the joints (this can be seen in the attached photos).

Likewise, the lack of time, meant that the design was altered, so that the height of the tower took priority over its structural stability, this decision inevitably proving a fatal one. It was decided that one tall would be constructed, instead of the original box, with two supporting triangular walls running perpendicularly of this main frame. (see attached diagram)

Between the combination however, of the highly unstable frame, and the use of masking tape as a means of constructing a suitable joint, the tower did not remain upright, the centre of balance being unevenly positioned (this also clear within the photo). In the future, a box frame would be far more suitable for constructing frame towers.

W EE K3knowledge maps

olympic constructs

largest new parkin london in

100 year

over 30 new bridges

the constructionof the power station

was permanent

every elementwas bolted

back tosubstructure

prevent shrapnelin explosion

buildigns builtfor athletes now

and citizins in the future

materials were oftenchosen so that they

could be broughtalong the canal system

landscaping

had to be transformable

swimming poolbuilt then

dissemabled

rebuilt in schools

stadium built to accommodate 80,000

would inevitably hold only 25,000

buildings not weldedso it was easier

to dissemble

W EE K3online learning

Structural Elements:

The design of a structural element is based on the loads to be carried, the material used and the form and shape chosen for the element.

Sturts, such as columns, work in compression, while in contrast, a tie, such as a brace, works in tension. Ties are often seen used in suspension bridges. Beams, with a load placed in the middle, work in both tension and compression, when supported at each end. Beams are the fundamental structural elements in many buildings.

A slab or plate will transfer loads in two directions, unless the slab has been thickened in just one direction, in which case the load will be transferred either horizontally or vertically.

Panels such as walls transfer the loads of the build-ing, through to the footings and/or foundations of the structure. Likewise, walls can act as a shear diaphragm to prevent the building from over turning.

The Golden Gate Bridge is an example of a suspension bridge which uses ties within its main struscture

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W EE K3online learning

Footings and Foundations: The main purpose of a building is to remain in place, its foundations vital for achieving such a purpose.

Foundations are found at the bottom of buildings where the building meets the ground. The foundations are the substructure of the building and their function is to safely transfer the loads acting on the building to the ground.

Footings and foundations are designed to all settlement to occur evenly across the structure, while ensuring the bear-ing capacity of the soil is not exceeded. Cracking in a build-ing will occur if there is di!erential settlement.

Shallow footings are used when soil conditions are stable and where the required soil bearing cap city is adequate close to the surface. In contrast, when building high-rise buildings, or where soil is of a poor quality, deep founda-tions are required. Most houses have shallow footing systems.

Shallow footings include pad footings, strip footings or raft footings. Deep foundations include, end bear piles and friction piles which both evolve the foundations reaching the bedrock. Piles and piers used in deep foundations can also be used when creating retaining walls for use in base-ments.

Machines used during the installationof pile foundations

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A retaining wall within a basement

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