Page 37 - Built Expressions - Online Construction Magazine - November 2014 Issue

Cover Feature silovesaiwan.fles.wordpress.com The project manager, who may be usually a civil engineer and the plant engineer at the project site, will need to have a continuous dialogue during all stages of planning and execution. Similarly, in respect of concrete, batching plant, truck mixers, concrete pump and tower crane may be involved. In all such cases, the capacities of various linked up items of equipment should be properly matched in order to obtain the projected output. method selection, sequencing operations be lower than the projections given Recently, at one of the project sites, and coordinating specialty trades, as well in the manufacturer’s catalogue. To it was noted that a hydraulic excavator as selection and management of proper cite an example, the concrete batching was being utilised at less than half of construction equipment for specifc plant rated as 30 m³/hr by the its rated capacity. On investigation, construction tasks and monitoring its manufacturers may at best give 20-25 it was realised that the excavator was production can help effect cost savings. m³/hr in actual practice. Similarly, idling for substantial time as there Some of the advantages of building using the concrete pump at the rated were not enough dumpers to clear construction mechanisation can be capacity of 50m³/hr, the feld engineer the excavated material. In yet another listed as under. may be able to pump not more than case, concrete was being produced • Higher Speed of Construction 35m³/hr. Considering these factors, in the batching plant, transported by • Timely Project Completion the ratings given the catalogue will truck mixers and placed in position • Quality Maintenance have to be multiplied by a utilisation using crawler crane and skip buckets. • Cost Effectiveness factor which may vary between 60% Ever though the capacities of the • Higher Productivity and 80% in general, depending on batching plant, truck mixers and crane • Reduced Manpower the quality of equipment, normal were matching the requirements of • Worker Safety working conditions at site, etc. This is the job, the output was found to be an important factor to be taken into only half of what was planned. On Equipment Productivity account while deciding on the capacity investigation, it was realised that the The manufacturers generally provide and the number of equipment to be concrete bucket was of a much smaller the productivity ratings for equipment deployed for each operation. capacity compared with that of the under different operating conditions. Having decided pragmatic crane and in consequence because However, it has been realised that the values for productivity, these can of the lack of advance planning ratings given in the manufacturer’s be ensured only if the equipment concerning a small item, the output catalogues represent optimum fgures operation is managed effectively. For of major items of equipment suffered. under ideal conditions which can performing many of the functions, In the absence of proper planning rarely be realised at site. As such one needs a series of matching items for the access roads, including their it is prudent to use one’s own past of equipment. For instance, a typical quality for movement of construction experience and judgment and arrive earth moving operation may involve equipment, it is a common experience at the probable outputs that can be the use of dozers, loaders, scrapers, to fnd low productivity due to bogging realised. Such outputs will invariably dumpers and vibrating rollers. down in transit. Vol: 3 Issue: 11 November 2014 Built Expressions PG 37