LogBook Week 5: Knowledge Map:
E-Learning: There are mainly three types of wall system in the building construction, which are structural frames, load bearing walls and the stud walls. Structural Frames: 1. Concrete Frame structures are very commonly used in modern buildings. As the name suggests, this type of structure is formed of a frame or a skeleton of concrete. With the help of combination of slabs, beams and columns, the building is kept stable.
It can be easier to understand this structure by knowing the load path.
(Diagram of load path diagram) According to the above load path diagram, the load path starts at the highest point to the lowest point to the ground, where the ground dissipates the loads. Loads are transferred between structural members at the joints depending on different types of connections. In most of the concrete frames,
rigid joints are applied. 2.
Steel Frame: Steel Frame is typically use a Grid of steel columns connected to steel girders and beams. In Melbourne school of architecture, the steel frame is consisting of series of girders and joists, as well as the diagonal of bracing.
Those members take the load back to the main building, and transfer the load all the way to the ground.
(Diagram of Load Path)
(Diagram of UC, CHS, RHS)
Steel Column: There are three types of steel column, which are universal column, circular hollow section and rectangular hollow section. Universal columns look like letter I, and both sides of the columns are relatively equal because this design reduce the probability of being buckled when one side is smaller and weaker.
Circular columns are always efficient, while sometimes rectangular hollow sections are used as steel members. 3.
Timer frame (Post and Beam) Timber frame typically uses a grid of timber posts and poles connected to timber beams.
bearing panels may also provide support for spandrel panels over and link into other structural elements such as floor slabs and roof structure.
In the above picture, we can see that in order to keep the stability of this structure, corner braces are sometimes added, and rigid joints might be used again in the timber frame.
1.
5.
Stud framing
3.
(Diagram of Load Bearing Wall) 2.
Load Bearing Walls: Concrete load bearing walls Concrete load bearing walls can be achieved using ether in situ or precast elements. It is commonly used in the construction of apartment or units. The load
4.
(Diagram of concrete blocks) Solid masonry load bearing wall can be created with single or multiple skins of concrete mansonry units or clay bricks. Cavity masonry walls are typically formed from two skins of masonry. This type of wall has better thermal performance and opportunities for insulation within the cavity, better waterproofing.
Reinforced mansonry load bearing walls can be constructed from core filled hollow concrete blocks or grout filled cavity mansonry. To maintain the strength of the wall, reinforcement might be used to cross through the concrete blocks.
Metal and timber stud framed
walls use smaller sections of framing timber of light gauge framing steel to meet the structural demands of the construction. The studs were quite close to each other; more studs are present in order to prevent some individual stud buckling, so it is very efficient. Brick veneer construction: Brick veneer construction is the combination of 1 skin of non-structural masonry and 1 skin of structural frame wall; it is quite widely used in the construction industry.
Early wood: It is produced in a rapid growth at beginning of growing season; the appearance might be thin, large cells and relatively lighter colour.
Obviously, brickwork is just the exterior wall of the building sitting on the girders and joists, so it cannot be regarded as a structural masonry skin. WOOD AND TIMBER: Provenance: From the outer to inner shell of the tree, the timber type can be seen as outer bark, inner bark, cambium cell layer, sapwood and heard wood.
Late wood: It is produced with a slower growth, and often limited by lack of water, the appearance of late wood is the opposite of early wood, and it has thick small cells and darker colour. It would have an extra ring within one extra year.
Grain direction: Timber will be relatively strong when pulled in parallel rather than being pulled in perpendicular direction. How is the moisture removed? 1. Air seasoning (drying) It is the cheapest way but also the slowest way of drying, because the presence of moisture in the air will slightly limit the drying process. In the way, it would take about 6 months to 2 years per 50mm thickness to dry the timber. 2. Kiln seasoning (drying) Typically 20 40 hours to dry to 12% Products produced from timber:
3.
Solar kiln seasoning (drying) Less expensive to run
Some properties of timbers:
Conductivity (Poor) Durability (Very durable) Reusability (Reusable) Sustainability (Yes) Cost effective (Yes) Size (max.6m) Grade (strong) Moisture content (seasoned<15%) Species of wood Availability (quite available in forest)
Hardness (Medium low) Fragility (Medium Low) Ductility (Low) Flexibility (High) Porosity (High) Density (Depend on type of timber)
Laminated veneer timber: It is an engineered wood produced that uses multiple layers of thin wood assembled with adhesives. This material is now available in structural members.
Glued laminated timber: It is a type of structural timber products comprising a number of layers of dimensioned timber bonded together with durable, moistureresistant structural adhesives.
Cross-laminated timber: This type of timber has different usage rather than the above two; it can be used on structural panels.
Lecture content: Materials and Construction of new ABP building
1. 2. 3. 4. 5.
Foundation and footing Slabs Columns and joints Cantilever structure Beams
Foundation is always set up after excavation of the basement of the new building. 47 excavators were working at the beginning of the construction.
During the process of setting up retaining walls, reinforcement was already there; sprayed concrete was then used until it was all cured in a certain period of time. Reinforced concrete has good ability of compression from concrete and excellent tension ability from steel, therefore generally this type of concrete guarantee the stability of retaining walls. Slabs were transported to the site by oversized trucks, it was made of pre-cast concrete from factories. With the help of tower crane, those slabs were successfully placed on the top of steel structures and combined with beams using rigid joints to prevent horizontal, vertical and rotation movement.
Another joint other than rigid joint is the bar connection between beams and walls, it is designed like the following sketch:
(Diagram of bar connection) This design increases the floor depth of the building, because normally beams are sitting on top of the walls and columns. However, if beams can be place aside, it might have significant changes on floor depth. Since this building may contain several big lecture theatres, columns would not be designed over there, which means more large slabs and more long beams are required in the construction. It can be achieved by using thick columns with greater cross section area. According to the compressive strength equation: P θ= A Where P represents the load, A stands for the cross section area. The load mass is inversely proportional to the cross section area. There is a giant steel cantilever structure in the north of the building. The length of the diagonal bracing is approximately 12m, it can be used to transfer the loads back to the main building along the slabs, beams and columns and all the way to the foundation.
（Diagram required for the cantilever）
Glossary: Concrete frame is a type of structure is formed of a frame or a skeleton of concrete. Steel Frame is typically use a Grid of steel columns connected to steel girders and beams. Timber frame typically uses a grid of timber posts and poles connected to timber beams. Concrete load bearing walls can be achieved using ether in situ or precast elements Reinforced mansonry load bearing walls can be constructed from core filled hollow concrete blocks or grout filled cavity mansonry. Solid masonry load bearing wall can be created with single or multiple skins of concrete mansonry units or clay bricks. Cavity masonry walls are typically formed from two skins of masonry. Brick veneer construction is the combination of 1 skin of non-structural masonry and 1 skin of structural frame wall. Early wood is produced in a rapid growth at beginning of growing season. Late wood is produced with a slower growth, and often limited by lack of water. Laminated veneer timber is an engineered wood produced that uses multiple layers of thin wood assembled with adhesives. Glued laminated timber is a type of structural timber products comprising a number of layers of dimensioned timber bonded together with durable, moisture-resistant structural adhesives.
Studio session:
Constructing Oval Pavilion Model: The completed model represents the structure on the right hand side of the building. The model is mainly focus the roof structure including rafter, ridge and eaves. First step is the measurement of the length of rafter and ridge, according to the scale 1:100 and the legend aside, the balsawood is cut into different length and thickness. After that, glue and sticky tape are required to fix the joints. (See below)
Some model members do not have enough length, so we have to cut another few pieces of balsawood and join them together. During this process, it was better to cut them with an angle because it can make it much stronger. It can be seen as below:
When the rafters and ridge are completed, we were going to finish the eaves structure.
When all the structure has been done, we then were trying to put a base underneath it, in order to make it sit on the paperboard nicely and stably.
Referencing Lists: 1. Concrete Frame Structure viewed 06.04.2014 http://www.understandconstruction.com/concrete-frame-structures.html 2. Hardwood and softwood (2006), Didgeridoo Design viewed 06.04.2014 http://www.copperman.co.uk/didgeridoo/how_to_make_a_wooden_didgeridoo/what_is_wood.php
3. Laminated Veneer Timber (2014) Wikipedia view 06.04.2014 http://en.wikipedia.org/wiki/Laminated_veneer_lumber 4. Glue Laminated Timber (2014) Wikipedia view 06.04.2014 http://en.wikipedia.org/wiki/Glulam