Constructing environment log book

download Constructing environment log book

of 58

  • date post

    23-Mar-2016
  • Category

    Documents

  • view

    220
  • download

    3

Embed Size (px)

description

 

Transcript of Constructing environment log book

  • Constructing Environment Log Book

    Chan Cheung Fung Ian 692233

  • Week 3 E-learnings

    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. The elements from which a structure is made or assembled have, in engineering or building terms, specific names which are used for convenience

    Strut Tie

    Beam Slap/Plate

    Panel

    a slender element design to carry load parallel to its long axis. The load produces compression

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

    Generally a horizontal element designed to carry vertical load using its bending resistance

    a wide horizontal element designed to carry vertical load in bending usually supported by beams

    a deep vertical element designed to carry vertical or horizontal load

  • Week 3 E-learnings

    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 all loads acting on the building structure to the ground. Where parts of the substructure are located below the ground, the foundations must also be able to resist the force of the soil which is pressing against the foundation walls, or retaining walls.

    Footings and Foundations

    Settlements

    Shallow Footings

    Deep Foundations Pad Footings

    Strip Footings

    Raft Foundations

    End Bearing Piles

    Friction Piles

    Buildings compress the earth beneath them and the buildings tend to sink a little into the ground overtime. Also, footings and foundations should be designed to ensure that this settlement occurs evenly and that bearing capacity of the soil isnt exceeded. Cracking in a building often occurs with differential settlement which means settlement that is uneven

    rely on the resistance of the surrounding earth to support the structure

    are used where soil conditions are stable and where the required soil bearing capacity is adequate close to the surface. The load is transferred vertically from the foundation are used where soil conditions are

    unstable or where the soil bearing capacity is inadequate. The load is transferred from the foundations, by the unsuitable soil and all the ways down to levels where bed rock, stiff clay, dense sand or gravel is located

    It is also named isolated footings. This type of footing helps to spread a point load over a wider area of ground used when loads from a wall or series of columns is

    spread in a linear manner

    sometimes also called a raft slab, this type of foundation provides increased stability by joining the individual strips together as a single mat

    extend the foundations down to rock or soil that will provide support for the building loads

  • Week 3 E-learnings

    Different Materials used in construction

    Bricks Concrete Block

    Stone

    Types

    Extruded and wire-cut

    Machine pressed

    Handmade

    A standard concrete block is standard size masonry unit made out of concrete. There is a large range of sizes and proportions available in orider to suit different purposes. They are manufactured from cement, sand, gravel and water. The manufacture process involves mixing, moulding and curling. They are mainly used in the construction of walls both load bearing and non-load bearing, to provide greater structural resistance to lateral loads, concrete masonry units are often strengthened with steel reinforcing bars and then filled with grout

    Igneous stone

    It is formed when molten rock cools down

    Sedimentary

    limestone, sandstone. It is formed when accumulated particles are subjected to moderate pressure

    Metamorphic

    marble, state. It is formed when the structure of igneous or sedimentary stone changes when subjected to pressure, high temperatures or Chemical process

  • Week 3 Class Activities

    In this week we went for a tour around the school looking at different buildings and their structures

    In the pictures we can see the beams there which are black in color. However these are pretty special beams. As beams are suppose to have vertical load coming from above. As

    indicated in the sketch below

    The picture below is showing the one of the support in the underground car park below South Lawn

    The design of this support is pretty interesting as there is a tree inside it

    There are quit a lot of these supports in the car park, which they can act as drains for the South Lawn and the support of the car park at the same time

    Another design that can act as a drain as well outside of Union House

  • Week 4 E-learnings

    Span

    the distance measured between two structural supports

    Can be measured between vertical supports (for a horizontal member) or between horizontal supports (for a vertical member)

    is not necessarily the same as the length of a member

    Spacing of the supporting elements depends on the Spanning capabilities of the supported elements

  • Week 4 E-learnings

    Different Systems

    Framing Systems Timber Systems

    Concrete Systems Steel Systems

    sometimes combine with concrete slab systems to where the particular benefits of steel framing and shallow depth floor slab systems are desired. The spanning capabilities of the particular materials help to determine the spacing requirements of the supports In many instances a combination of member types and materials are combined (e.g. heavy and light members) depending on their structural function

    Traditional Timer Floor Framing systems use a combination of Bearers (Primary Beams) and Joists (secondary beams) The span of the bearers determines the spacing of the piers or stumps and the spacing of the bearers equals the span of the joists

    Slabs of various types are used to span between structural supports. These can be one-way or two-way spans

    Steel Framing systems take various forms, with some utilizing heavy gauge Structural Steel members and others using Light Gauge steel framing. Steel Framing systems sometimes combine with concrete slab systems to where the particular benefits of steel framing and shallow depth floor slab systems are desired. The spanning capabilities of the particular materials help to determine the spacing requirements of the supports In many instances a combination of member types and materials are combined (e.g. heavy and light members) depending on their structural function

  • Week 4 E-learnings

    Concrete components

    Provenance Process Formwork Process

    Reinforcement

    When the cement powder and water are mixed, a chemical reaction takes place and heat is released. This process is called hydration. During this process crystals are formed that interlock and bind the sand, crushed rock and cement/water paste together. If too much water is added, the concrete mixture will be too stiff and it will be very difficult to work with (unworkable)

    One of the great advantages of concrete is that it is fluid and shapeless before it hardens. It can be formed into any shape we desire

    is the term used for the temporary support or moulds used to hold the liquid concrete in place until it becomes hard Formwork can be built at the building site IN SITU or in a factory PRE CAST out of a range of different materials timber, metal, plastic, formply etc.

    During the curing process the formwork needs to be supported as the weight of the wet concrete is very heavy. This is achieved by using props and bracings of various types Concrete generally reaches 75% of its compressive strength in approximately 7 days with testing for the required strength occurring at 28 days Once the concrete is hardened and strong enough, the formwork is carefully removed. Formwork is often removed, stored and reused or it may stay in place forever (sacrificial formwork)

    Concrete is also known as artificial stone. This suggests that the properties of concrete and stone are similar. Concrete is very strong in compression but is weak in tension. To improve its structural performance, steel (very strong in tension) reinforcement in the form of Mesh or Bars is added. The result material is what we know as reinforced concrete.

  • Week 4 E-learnings

    Properties of Concrete Hardness

    Fragility

    Ductility Flexibility/plasticity Porosity/permeability

    Density

    Durability/Life span

    Reusability

    Sustainability & Carbon Footprint

    Cost- generally cost effective, Labor

    High . Can be scratched with a metallic object

    low. Can be Chipped with a hammer

    typically very durable

    very low ductility low flexibility and plasticity

    medium low, depending on proportions and components (aerated or high water ratio concrete has a high porosity vs waterproof concrete that is created when permeability reducing admixtures are included in the concrete mix

    Medium High. Approximately 2.5 More dense than water

    Conductivity Poor conductor of heat and electricity

    Medium-Low. Can be partially re0-used when crushed to be used as aggregate for new concrete elements

    high embodied energy, Non-renewable. Long lasting

    generally cost effective. Labor dependent for formwork & Pouring

  • Week 4 E-learnings

    Concrete- considerations 1. Concrete is permeable (not completely waterproof). This is one of the main sources of problems in concrete. If the steel bars are too close to the surface they will not be protected from moisture and oxidation. This will cause both