Tilt-up Concrete Construction - Coursework Example

Name: Professor: Institution: Course: Date: Tilt up Concrete Construction Tilt-up construction involves a ready mixed concrete that is placed in horizontal forms at the site of construction where it is then tilted up to form walls. The concrete floor slab of the building is most preferred casting base in the building structure. This involves preparation of wood or steel edge forms that are positioned in the casting base. Positioning of reinforcing steel, insulation, door and window frames, and electrical conduit is then carried out. A tilt up construction starts with the preparation of the job site which includes pouring of the slab. It is at this stage that the workers install the main footings around the slab in readiness for the panels. The workers then assemble the panel forms on the slab. Under normal circumstances, the panel form is made using wooden pieces that are joined together. These forms form the basis for the panel mold. They do this by providing the required sizes and shapes for the doorways and window openings and also by making sure that the panels meet the basic standard requirements for the design specifications. The workers then tie in the steel grid for the purpose of reinforcing bars into the form. Inserts and embeds are also installed in order to lift the panels and attach them to the footing, and to the roofing system. The slab below the forms is later cleaned to get rid of any debris or stagnant water. Workers then pour concrete into the forms for the creation of the panels. After the panels solidify and upon the removal of the forms, the first panel is connected to a huge crane which has cables that are hooked into the inserts. The weight and height of the panels determines the size of the crane, but ordinarily it is two to three times as the size of the biggest panel. Braces are also attached to the panel. The panel is guided into its position by workers and is also set into its place by the crane. The braces from the tilt-up panel are then connected to the slab as the panel’s embeds are also attached to the footing. At this point the cables are also disconnected from the crane. This process is repeated as the workers move to the next panel. A mobile crane tilts –up a panel from the ground and eventually sets it in its place, and can handle huge panels that weigh thousands of tones that dangle at the crane’s lines. The workers perform their duties as a team in setting the braces and in guiding the panel in its right position. A tilt-up crew that is experienced can set up to 35 panels in a day. Once the panels have been erected, the workers perform the finishing on the walls by either sandblasting or by painting. In the finishing they also fill- up any joints and fix any imperfection on the walls. The crew then proceeds to install the roofing system. Uses of Tilt-up Construction This type of construction is mostly used for one storey commercial houses that include warehouses, office buildings, and stores. With advancement in technology, buildings that are considered to be tall have been erected by this method. It can also be used for buildings that have windows, doors and other architectural features. During the construction, recycled materials such as fly ash, slag cement, and recycled aggregates can be incorporated into concrete and this reduces the chances of using new materials and hence cuts down on cost. Wall panel are normally constructed with locally available materials. Tilt-up constructed is attributed to thermal maintenance in buildings when concrete is combined with insulated tilt-up walls. Concrete acts as an air barrier that reduces infiltration of air and eventually saves energy. This construction method is mostly preferred because it is relatively economical with most of the materials being locally available. Modification of lengths and heights of the panels is applicable for the purpose of making sure that the required standards are achieved. Tilt-up concrete can be textured and colored to fit any architectural design or technique as dictated by market demand. This can be achieved using pigments, brick facing, and curved surfaces. Surface Condition of steel Reinforcement Steel is commonly used in the construction industry either in making of slabs or in the roofing system. Hot-rolled bars delivered from the mill have a layer of mill-scale on the surface which can be used to preserve the steel if it’s stored under cover. During handling of the steel the mill-scale on rods and bars may be loosened and at times rust forms on them. Under different climatic conditions especially where the atmosphere is hot and humid black rust forms on bundled steel bars. When the bars are exposed to some dry conditions the corrosion dries and turns to red rust that is powdery. The above clip shows a crane lifting wall panels in position during a tilt-up construction. This is an illustration a tilt-up construction of windows. In this type of construction doors and windows are fixed in the vertical walls according to architectural specifications. There are many types of roofs that can be used in the tilt up construction depending on the cost requirement and durability. Local materials can be utilized in constructing a wide range of economical roofs. Tiles can also be used as well as steel roofs but this might be expensive in the long run. (Source: http://www.builderbill-diy-help.com/roofing-materials-residential.html#toc2) This is an example of a designer roof that can be used in tilt- up although it is not cost effective. Different types of roofing material that can be used in tilt-up construction include; corrugated galvanized iron which is very costly, steel roofing, copper roofing, aluminium roofing, cement tile roofing, and clay roofing. This is an example of thatch roof used in a residential building. It is made of palm fronds and is relatively cheap. Within the tilt-up construction, there is a structure comprised of a cladding system that is designed to put together the cladding material panel when constructing a building structure. It includes upper and lower bracket members that engage the adjacent cladding material panels. This is an example of a tilt-up construction. In the foreground it shows a finished panel and at the behind there is a stack of panels that are ready for erection, while four panels have already been fixed. Wide span buildings Portal frame type Construction Portal frames can be used in commercial and industrial buildings that are timber based. They give enough height clearance and can be used in the construction of factories, churches, sports centers, and warehouses. Timber Portal frames are generally cost effective and can be erected relatively fast. Their outer shell is aesthetically satisfying. Timber portal frames are most suitable for high visual impact buildings such as churches and halls or in corrosive environments such as swimming pools enclosures. Source: http://www.timber.org.au/NTEP/menu.asp?id=75#Portal_frames These diagrams show different portal frames Portal frames can be made from natural timber from a sawmill or from plywood webbed beams. The connections should be strong and stiff to be considered effective. Timber portal buildings can be clad with fibre, metal, timber, or cement. Source: http://www.timber.org.au/NTEP/menu.asp?id=75#Portal_frames The above are diagrams of portal frames construction Arch and Dome Systems They are slender structural systems which are essentially two dimensional with the strength based in the plane of the arch. (Source: http://www.timber.org.au/NTEP/menu.asp?id=75#Portal_frames) Arch shaped structures Domes are very efficient in carrying heavy vertical loads. Trusses Timber trusses are used in many building construction. It gives designers a chance to have floor layouts without interior supports. They provide versatility in construction designs and ease in erecting them. The roof can either be flat or pitched . In buildings that are used to demonstrate a particular theme may, different types of trusses may be used. The themes may be strength or an impression oof spaciousness. Trusses can be painted, oiled, decorated, or even left in their natural status. Designers may have a variety of truss shape that they can construct. Different types of truss connections Trusses may be joined using plywood gussets where nails are used. Very large truss elements are at times joined using fin-plate connections. Bolted gluham timber trusses may be used as an archtectural feature in buildings. Pole Construction This construction uses poles sometimes whole tree trunks for provision of gravity loads support. The poles are used for both structural and aesthetic purposes. It can be used in the construction of restaurants, churches, tourist resorts, hotels, and industrial buildings. (Source: http://www.timber.org.au/NTEP/menu.asp?id=75#Portal_frames) Poles are very appropriate for steep sites and they also give buildings flexibility for earthquake and strong winds. Pole construction is in two types. There is pole platform construction where poles act as platform only above floor level. In the pole frame construction poles act as columns for a building from the foundation to the roof. Poles are ether embedded into the ground or supported on concrete base. Demolition plans Any demolition of a building is done with permission from environmental authority. This is to ensure that demolitions are done as per the regulations set by environmental organizations. Any demolition is supposed to have minimum impact on the surroundings. Methods used in the demolition should not be hazardous to the people carrying out the demolition and extra should be taken to protect the health of the people involved. To oversee the demolition the project, oversight team headed by Operations Superintendent and the Site Safety and Health Manager (SSHO) should be present. Decontamination & Demolition team that includes the laborers and foremen should also be present. It is of great significance to have a Hazard Mitigation Team with a supervisor and laborers. Within the region of demolition, only authorized individuals have permission to access. This is to avoid injuries that might be caused by debris. Professionals Consulted Relevant industry professionals should be consulted to give advice on the design process of the two construction types that have been covered. These professionals include land surveyors to check the authenticity of the land where the building is being erected. Engineers also provide advice on the structure and the best material to use. Others include environmentalists and contractors. References Amorin Construction. Retrieved on 28th February 2011, from http://www.amorin.com.au/whatis.html Read More