Page 54 - Built Expressions - Online Construction Magazine - November 2014 Issue

Cover Feature The operation during the foating pass should be slow and uniform. This is then followed by the second pass to remove any marks due to disc movement. Skilled and trained operators are blades or foating disc at the time of needed to operate these machines. Floating, which is the frst pass. The operation during the foating pass 12. Power Floats should be slow and uniform. This is then A power trowel, also known as a followed by the second pass to remove ‘power foat’, ‘helicopter’ or ‘trowel any marks due to disc movement. machine’, is used to obtain a smooth, Once the surface has been 'foated', uniform, fat surface doing away with the blades of the trowel are changed to manual inaccuracies. Power trowels fnishing blades. The fnish pass should Pile Driving Equipment can be generally classifed based on be started when the surface has dried the way they are controlled. off, and walking on the surface leaves • Ride-on power trowels are operated no appreciable indentations. by an operator seated on the For the fnishing pass the blades are come in a variety of shapes and sizes. machinery and controlling power angled to suit the concrete, increasing They can be driven into the ground trowel movement. the angle after each pass - an angle of vertically or at an angle. The material, • Walk-behind power trowels are used around 5-10º is usual, the steeper the size, and angle of the piles used on by an operator walking behind the angle the harder the fnish. Several a Project are determined during the machine. passes with the fnish blades may be design phase. These characteristics It is mandatory to level and required to achieve the specifed fnish. will impact the type of pile driving compact the concrete surface prior equipment that the Contractor uses. to the use of Power Trowel. It is also 13. Pile Driving Equipment The ground material the piles are essential to trowel at the correct time. A pile is a structural member that driven into also impacts the choice of The operator must wait until the soft is driven into the ground to provide pile driving equipment. Piles can be concrete hardens suffciently to take support for a structure. Piles are made driven through gravel, sand, or fne- the weight of the machine and the from timber, concrete, or steel, and grained soils with a range of moisture operator. contents. During driving, friction will The trowel is ftted with either foat build up between the ground material and the pile. The amount of friction expected, as well as the material present, will play a role in determining the best type of pile driving equipment. Power Float A kind of ground treatment for strengthening the ground soil and makes it capable of supporting the load of building is called piling. It involves img.directindustry.com concreteconstruction.net the ground level. Generally, concrete the driving of pile into ground below piles, timber piles, steel piles and bored piles are used to make the soil stronger for holding the weight of a building. On the other hand, sheet piles act as supporting wall due to ability of sustaining the lateral load. Specially designed piling equipment can be used for driving piles into the ground. Bar Bending Machines PG 54 Built Expressions Vol: 3 Issue: 11 November 2014