Construction is one of the significant sectors of the Indian economy and is an integral part of the development. Today India’s urban population is the second-largest in the world and its future development leads to increased demand for housing to cope with this problem India should desperately need to plan for acquisition of land and rapid creation of dwelling units. One of the most important factors in determining the success of a construction project in terms of speed, quality cost and safety of workers is the formwork used in the project as it accounts for about 35 to 40 percent of the total project cost of the structure. When considering a construction project both the client and contractor want to finish the job early as the client wants to use the building for the intended purpose as soon as possible. The contractor wants to finish the construction as soon as possible to gain a higher profit. The most efficient way to speed up the work in mass housing construction is by achieving a very short floor cycle. The floor cycle of a building mainly depends on the formwork type, as it is the main time factor of a building project.
According to the Federation of Indian Chamber of Commerce and Industries (FICCI), keeping in view the existing housing crisis, the country shall need the addition of more 2.5 million new dwelling units annually. The recent years voiced the active participation of private sectors in finding the solution over the prevailing situation on the housing front. Keeping in view the gigantic task of providing affordable shelter to masses, the adoption of a cost-effective technology assumes greater significance. The present strain on the Indian economy and the overgrowing demands for housing calls for adoptions of appropriate building technology which could lead to economy and speed in construction. As a result of experimentation of innovating construction techniques and modern construction management, it is now possible to achieve an overall saving to the extent of 10 percent in the total cost of housing construction compared to the cost of traditional housing. There is growing realization today that the speed of construction needs to be given greater importance, especially for large housing projects. This is not only essential for the faster turnover of equipment and investment also leading possibly to the reduction in the housing cost – but also for achieving the national objective of creating a large stock to overcome the shortest possible time.
The disparity between the supply and demand for affordable housing is tremendous. Rapid urbanization has resulted in a geometric increase in the housing demand, which cannot be fulfilled using conventional materials and methods of construction. The traditional or conventional method of construction for mass housing is comparatively, a slow process and has limited quality control, particularly when a large size project is involved. It is, therefore, obligatory to work out a method or a scheme where the speed and quality of construction are controlled automatically by a systematic approach. Therefore Formwork System identified to be suitable for Indian conditions for mass housing construction where quality and speed can be maintained at a reasonably high level. It is adaptable for any design of a building and establishes a kind of assembly-line production.
Formwork technology is one the best choice for mass housing owing to its flexible design nature and cost. Formwork is a die or a mould including all supporting structures, used to shape and support the concrete until it attains sufficient strength to carry its own weight. It should be capable of carrying all imposed dead and live loads apart from its own weight. Formwork has been in use since the beginning of concrete construction. New materials such as steel, plastics, fiber glass and Aluminium are used in formwork. Greater attention is being given to the design, fabrication, erection and dismantling of formwork as a temporary structure. Form work includes the surface in contact with the concrete and all necessary supporting structure.
Formwork technology vs traditional method
In typical floor construction, around 20 percent of cost saving is possible in box type structure over framed structure. Almost 40 percent savings in project duration in Box type structure over framed structure. Construction cost escalation, Labor rates increases every year at the percent of 2 to 5.Cement and steel price increases every year at the percent of 10 to 15.Around 5 to 8 percent Savings in project cost is possible on reducing overheads by early completion of projects. High return on investment is possible.
Housing built with formwork technology are positively discriminated against other building systems in our country, which is face to face with the reality of earthquakes, with their durability, high technology and superior earthquake performance. This technology also allows for the opportunity to provide very special comfort conditions to the users and producing buildings with maximum energy performance by means of its flexible design criteria provided in the architecture. Efficiency and productivity is increased by eliminating unnecessary material usage. It is built 3 times faster than traditional building systems. On the other hand, high quality and low cost products are offered to the users.These housings, built with 90% recycled steel, are environment-friendly and examples of sustainable architecture by their nature. The system stands out with its advantages in fire and insulation with A-1 class incombustible and eco-friendly fiber cement used in the coating of all steel carcasses. Therefore, designs created within the frame of green building/ecological building are realized in maximum productivity with this technology.
Popular formwork construction for mass housing
There are several types of formwork construction but perhaps alumunium, tunnel and climb formwork are the most preferred ones for mas housing.
Aluminium Formwork System
Aluminium Formwork System is a construction system for forming cast in place concrete structure of a building. It is also a system for scheduling and controlling the work of other construction trades such as steel reinforcement, concrete placement and mechanical and electrical conduits.
The System is fast, simple, adaptable and very cost effective. It is unique because it forms all of the concrete in a building including walls, floor slabs, columns, beams, stairs, window hoods, balconies and various decorative features in exact accordance with the architects’ design. The dimensional accuracy of the concreted work also results in consistent fittings of doors and windows. The smooth–off form finish of the concrete eliminates the need for costly plastering.
Aluminium Formwork System provides Aluminium Formwork for RCC load bearing or RCC framed multi-storied buildings and enables the walls and slabs to be poured in the same operation. These increases efficiency and also produces an extraordinarily strong structure with excellent concrete finish. Due to the fine tolerance achieved in the machined metal formwork components, consistent concrete shapes and finishes are obtained floor after floor. This allows plumbing and electrical fittings to be prefabricated with the certain knowledge that there will be an exact fit when assembled.
Unlike other construction systems, Formwork Systems of aluminium forms can be erected by unskilled labour and without the need for hoisting cranes. The largest panel weighs not more than 25 kgs which means it can be handled by a single worker.
It can be used repeatedly with low average use-cost: Aluminum alloy formwork system adopts the integral extrusion forming as raw materials (6061-T6). With a normative construction, a set of formwork can be used more than 300 times in a low average use-cost.
The assembly of aluminum alloy formwork is simple and convenient; the average weight is 23-24kg/m2. It can complete assembly by manual without any machines assistance. (Normally, the construction workers only need a spanner or a small hammer to assemble or remove). A skilled installation worker can install 20-30 square meters per day (compared with the wooden formworks, aluminum formworks do not require the technicians but a simple training to the construction workers before the installation).
Aluminum alloy formwork system is a fast assembles and removal system that shorten the construction period and save the administration cost. A set of formwork can build one storey in every four days under a normative construction. Aluminum alloy construction formwork came with different standard sizes and is flexible to assemble according to the requirement of the respective projects. Only 10-15% of non standard board needs to be replaced when the formwork is reused for another new project and reduced the cost. All parts of Aluminum alloy formwork is assembled by Aluminum Alloy Plate. Once the system is assembled, it will be formed a complete framework with very good stability and Bearing capacity of up to 60 k per square meter.
Tunnel Formwork System
Tunnel form is a formwork system that allows the contractor to cast walls and slabs in one operation on a daily cycle. It combines the speed, quality and accuracy with the flexibility and economy of in-situ construction. Construction durations are reduced significantly by this rapid system when compared to conventional methods. Tunnel Form System brings speed, quality and accuracy to concrete construction and provides big savings in finishing and M&E works. Hi-tech technologies for steel formwork production make tunnel forms strong & durable. The system creates efficient load-bearing structures which are known as the most earthquake resistant structures. The result is a cellular reinforced structure, the surfaces of which are sufficiently high quality to require only minimal finishing for direct decoration, while the end walls and facades are easily completed with thermally insulated units that can be clad as required. The system creates an efficient load-bearing structure for use in a wide variety of applications. It is particularly effective in projects suited to repetitive cellular construction such as residential blocks, hotels, student accommodation and barracks. Tunnel form is a formwork system that allows the contractor to cast walls and slabs in one operation in a daily cycle. It combines the speed, quality and accuracy of factory/off-site production with the flexibility and economy of in-situ construction and is recognised as a modern method of construction (MMC).
The result is a cellular reinforced structure, the surfaces of which are sufficiently high quality to require only minimal finishing for direct decoration, while the end walls and facades are easily completed with thermally insulated units that can be clad as required.
Tunnel form systems are used to construct repetitive cellular structures (such as hotels and apartment blocks) and enable the construction of horizontal and vertical elements (floors and walls) together. Each unit is in the form of an inverted L, the vertical leg being the formwork for one face of a wall and the horizontal leg being soffit formwork. Several units are erected together to create the formwork for a number of ‘tunnels’ consisting of walls and ceiling slab. The normal dimensions of tunnel form units are 8 to 11m long and 2.4 to 6.8m wide, but individual units can be joined to give tunnels of greater length. The forms are positioned, reinforcement is fixed and the concrete poured and cured. When the concrete has achieved sufficient strength the forms are lowered and moved to the next location.
The system creates an efficient load-bearing structure for use in a wide variety of applications. It is particularly effective in projects suited to repetitive cellular construction. The large bays constructed using tunnel form provide exceptional flexibility in the design and layout of the building and allow a high degree of freedom in the final appearance.
Tunnel form has integral working platforms and edge protection systems. In addition, the repetitive, predictable nature of the tasks involved encourages familiarity with operations, and, once training is complete, productivity improves as construction progresses. The minimal requirement for tools and equipment when moving the tunnel form further reduces the risk of accidents on site.
Climbing formwork system
Climbing formwork is a special type of formwork for vertical concrete structures that rises with the building process. While relatively complicated and costly, it can be an effective solution for buildings that are either very repetitive in form (such as towers or skyscrapers) or that require a seamless wall structure (using gliding formwork, a special type of climbing formwork).
Best known in the construction of towers, skyscrapers and other tall vertical structures, it allows the reuse of the same formwork over and over and over for identical (or very similar) sections / stories further up the structure. It can also enable very large concrete structures to be constructed in one single pour (which may take days or weeks as the formwork rises with the process), thus creating seamless structures with enhanced strength and visual appearance, as well as reducing construction times and material costs (at the joints which would otherwise require extra reinforcement / connectors) An advantage of guided climbing systems is that they remain connected to the building during the lifting process.The climbing formwork structure normally does not only contain the formwork itself, but also usually provides working space / scaffolds for construction crews. It may also provide areas for machinery and screens for weather protection, up to being fully enclosed while yet staying modular around a changing building structure
Normally, this type of formwork is constructed from steel members. Concrete form panels are attached to this frame; some of them supported on rollers. After the concrete walls are poured, it is released and moved away from the wall. Then, if self-climbing formwork is being used, jacks lift the frame up to the next level or to the next area where it will be used. This is normally a relatively fast procedure.
Once the climbing formwork is in position, the panels are closed, and the next concrete wall is poured. The cycle continues, which is normally three to five days. Faster times can be achieved but you will need a really specialized and trained crew. However, the limiting factor to faster times is usually the construction of the floor slabs, which are poured as a separate process.
New age technologies adopted Housing for All by 2022
The construction industry is rapidly changing and new materials, construction technologies are being introduced on a regular basis. Execution of construction projects and their delivery in a timely manner has become a prime concern for developers in view of the buyer’s agitation on delay in construction. Especially after RERA, which emphasizes the need of timely completion of projects, adoption of modern technologies has become the need of the hour for a developer to survive in the market.
Around 2 million homes need to be built by 2022 to achieve the ambitious goal of the Modi government’s ‘Housing for All’. As per Colliers Research, to achieve such a huge objective, it is imperative to adopt newer technologies at a much faster pace. Adoption of such technologies will not only reduce the turnaround time but also improve the quality and durability of construction and help in generating more interest in affordable housing projects among buyers.
Private developers are continuously exploring new technologies that improve the quality, strength and safety of the buildings. In metro cities, few developers have started using technologies such as self-climbing formwork and aluminum shuttering. These technologies are not only cost-effective, but offer advantages such as minimal labour force, higher earthquake resistance, more durability than conventional building techniques, higher carpet area, smooth finish on walls and lower on maintenance.
There’s no doubt that construction has formed the basis of modern civilization. Whether it be buildings, houses, roads, tunnels or bridges, construction has enabled humans to evolve by providing the means necessary to make our lives easier and more comfortable. Since its inception, modern technology has played a crucial role in the construction industry. Having the ability to design and construct entire structures digitally has significantly increased speed and efficiency and considerably reduced costs at the same time. Formwork has developed into an ancillary construction, where temporary or permanent moulds are used into which fresh concrete is poured that subsequently hardens. Forms or shutters are the terms used for made up sections that touch the concrete while it is hardening.
Source – iaeme.com, iitk.ac.in, prefabrikyapi.com, smartnet.niua.org, bslscaffolding.com, financialexpress.com, goomaxalu.com, ulmaconstruction.com, doka.com, winntus.com, goldapple-alu.com