While permanent work or Finished product is final deliverable to the client / customer, temporary works or enabling works are required to enable the contractor performing main works with due safety, quality and within stipulated time. A good contractor always keeps consistent focus in planning and design of temporary facilities for success of their project.
Examples of these enabling work are; proving safe access to work place, Entry / Exit points, supporting arrangement or Falsework for main works, temporary facilities for labour, staff, equipment, production of concrete, storage of raw materials, formwork, deep excavation and dewatering, temporary bunds / cofferdams, working platforms, Pre-casting facilities, Erection schemes etc.
Planning and design of Temporary Structures / Enabling works play a key role in a successful construction project. Enabling works design is a specialized subject and these designers should be able to foresee risks associated while installation, during use and during removal of any temporary works once construction work is complete. They should also coordinate with permanent structure designers and principal contractors to discuss the effects of any temporary work loading and possible disturbances during the construction of the permanent structure.
Major aspects covered in Temporary works planning / design are:
Site Logistic Plan and Temporary facilities: Good Site Logistic Plan helps safe and smooth movement of traffic, avoids congestions during peak periods, and provides access to desired work locations during work. Foremost physical activities to carry out at project site are; setting up temporary facilities like labour accommodation, site office, Stores, Canteen, Laboratory, Workshop, Batching plant, Fabrication and material Storage Sheds, Yards, water supply, power supply and illumination, site Barricading/ Boundary wall, Drainage, Temporary roads to enable smooth movement of construction traffic etc. Size of these facilities is designed considering peak manpower / staff requirement, duration and type / quantum of various activities to be carried out during various phases of the project. Provision shall also be kept augmenting these facilities time to time to avoid disruption to main works and complete project in time.
Logistic Plan also includes location of various stationery equipment like batching plant, Ice plant, Tower Cranes, Jib Cranes, Gantries, Fabrication Sheds etc. Logistic plan shall be finalized in consultation with all concerned stakeholders / Function heads in order to ensure its effectiveness / adequacy and avoid any risk later.
Sequence of Structures / execution and Technology selection: includes sequencing various structures according to the project plan to avoid creating unnecessary peaks of resources. Size and number of pours, location and number of construction joints etc.
Methodology of construction include factor like type of moulds, Selection of formwork system based on Speed, quality, handling and type of finish required, size of erection modules based on crane capacity etc. Selection of right Technology and Equipment is the key to complete a project on time, with desired quality, utmost safety and within budget. E.g. For a building project with more than 25 stories and modular room sizes, Aluminium Formwork may work out economical if multiple towers to be constructed and enough time available to achieve higher than 50 repetitions. However, if project design or duration is such that repetitions are low, other system like Flex, Table etc. may work out economical for the same duration.
Contractor must evaluate cost-benefit analysis for various technology/method options in order to choose right technology considering various aspects like Cost, Schedule, engineering and mobilization time etc. Good contractors maintain capital assets like Equipment, Formwork/ Shuttering, scaffolding etc. and possess internal competency / design partner to provide designs / schemes ensuring minimum lead time for mobilization and Engineering of enabling works. They also inspection / support during implementation of designs/ schemes.
Most crucial aspect of Temporary works design is to ensure Safety of manpower, equipment and surroundings at site. We often come across incidents like collapse of Falsework, Shoring, scaffolding, slabs under construction, toppling of cranes during erection / handling, fall of bridge element under construction, collapse of trench / excavation sides, cracks in buildings/ structures near an excavated pit and other various examples of failures of temporary structures. Generally temporary works are not given due importance being temporary in nature and contractor want them at the lowest cost possible.
Design competency is a critical factor in temporary design being a specialized subject which require different approach than the permanent design. Small contractors do not have enough technical manpower at site and mainly depend on prior experience of frontline Engineers/Foreman. This often leads to improper planning and wrong selection of technology which ends up resulting in delays, failures and cost overrun.
In an un-organized construction market with cut-throat margins, it is also not commercially viable for all contractors to maintain a pool of temporary designers and detailers and hence contractors need to take support from external agencies to provide temporary designs.
A professional Temporary Design agency shall partner with contractor from bidding stage to provide initial data on design and cost for bids and support project execution on award of job. In today’s world of fast-track projects, agency must be resourceful and prompt for quick response to avoid waiting time for their customers and their projects.
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