What is Mivan Technology?
Mivan is an aluminium formwork system developed by a European construction company. A Malaysian construction company by name Mivan started manufacturing these formwork systems in 1990. The Mivan technology has been used extensively in Europe, Gulf Countries, Asia and other parts of the world. Today, more than 30,000 sqm of formwork from Mivan Co. Ltd. is used across the world. Aluminium Formwork system is a comparatively a new technology in India. It saves cost ,time and improves the quality of construction. It was used by L&T for the first time in India in its projects in Mumbai, Delhi & South India (South city, Bangalore) in 2003 for the construction of both low and high rises apartments and buildings.
Can I know more?
The system of aluminium forms (MIVAN) has been used widely in the construction of residential units and mass housing projects..Aluminium formwork is very cost effective for repetitive buildings layouts and for above the plinth work. The aluminium formwork panels can be designed for any condition/components of buildings such as bay windows, stairs , balconies and special architectural features. This system is very unique as all the components in a buildings including slabs, beams, walls, columns, staircases, balconies and special window hood are of concrete and there is no need for block works or brick works. It produces total quality work which requires minimum maintenance and when durability is the prime consideration. High quality Mivan Formwork panels ensure consistency of dimensions. On the removal of the formwork mould, a high quality concrete finish is produced to accurate tolerances and verticality. The high tolerance of the finish means that, no further plastering is required. Column and beam construction are eliminated. Walls and slabs are cast in one operation specially designed, easy to handle light weight pre-engineered aluminium forms. Fitting and erecting the portion of shuttering, carrying out concreting of the walls and slabs together.
Mivan technology is suitable for constructing large number of houses in a short span of time using room size forms to construct walls and slabs in one continuous pour on concrete ensuring High Quality Column. In this system of formwork construction, cast–in–situ concrete wall and floor slabs cast monolithic provides the structural system in one continuous pour. To facilitate fast construction.Early removal of forms can be achieved by hot air curing / curing compounds. Large room sized forms for walls and floor slabs are erected at site. These strong and sturdy forms are fabricated with accuracy and are easy to handle.They afford large number of repetitions (around 250). The concrete is produced in RMC batching plants under strict quality control and convey it to site with transit mixers. The frames for windows, doors and ducts for services are placed in the form before concreting. Staircase flights, façade panels, chajjas and jails etc. and other pre-fabricated items are also integrated into the structure. This proves to be a major advantage as compared to other modern construction techniques.Precisely-engineered system fabricated in aluminium. The modular nature of the formwork system allows easy fixing and removal of formwork and the construction can proceed speedily with very little deviation in dimensional tolerances. System is quite flexible and can be easily adapted for any variations in the layout. The availability of concrete from ready mix concrete facility has augured well for the use of this work system. In India, the willingness to use mechanized means of transport and placing of concrete, the use of aluminium formwork system has received a boost. The formwork system can be used for construction for all types of concrete systems, that is, for a framed structure involving column beam –slab elements or for box-type structure involving slab-walls combination.
How does this work?
On leaving the MIVAN factory all panels are clearly labelled to ensure that they are easily identifiable on site and can be smoothly fitted together using the formwork modulation drawings. All formwork begins at a corner and proceeds from there. The panels are held in position by a simple pin and wedge system that passes through holes in the outside rib of each panel. The panels fit precisely, simply and securely and require no bracing.Buildings can be constructed quickly and easily by unskilled labour with hammer being the only tool required. Once the panels have been numbered, measuring is not necessary. As the erection process is manually, tower cranes are not required. The result is a typical 4 to 5 day cycle for floor–to–floor construction. EFFICIENT — QUICK STRIP PROP HEAD One of the principal technical features which enables this aped to be attained using a single set of formwork panel is the unique V shaped a prop head which allows the ‘quick strip’ to take place whilst leaving the propping undisturbed. The deck panels can therefore be resumed immediately.The formwork is designed using the most economical assortment of panel sizes with the help of the state-of-the art design software. The use of the software along with the experience and skill of the designers ensures an efficient construction process by incorporating the optimum assembly procedures, economical panel selection and ultimately minimizing capital and operational costs. The combination of bespoke software and the experience of MIVAN designer’s guarantees :- Most efficient construction process incorporating the optimum assembly procedures. Economical panel section. Ultimately minimizing capital and operational cost.
Is it any better?
Buildings are compared as: 1). Conventional RC columns, beams, and slab construction (RC moment resisting framed structure) 2). RC load-bearing walls and slabs. In the case of RC moment-resisting framed structures, the horizontal forces due to wind or earthquake are resisted by the frames resulting in the bending moments in columns to resist bending moment and vertical loads would be more than that required to resist vertical loads without bending moment. Similarly, additional reinforcement will be required in beams at supports. In the case of RC load-bearing walls, monolithic casting of slab along with RC walls results in a box type structure, which is very strong in resisting horizontal forces due to wind or earthquake. In view of large depth of shear walls, the resulting stresses due to bending moment and vertical loads are smaller and in many cases, concrete alone is capable of resisting these forces.
On evaluating above alternatives, it is seen that the beam column frame system in the following. 1) Performs poorly against earthquake forces compared to RCC wall and slab construction. Recent changes in the IS Codes, as well as recommended good practice demand provision of additional reinforcement comply with ductility requirements. 2). The sizing and detailing of columns needed to be –that they are 20% stronger than beams they support.
What are its advantages?
The MIVAN formwork is specifically designed to allow rapid construction of all types of architectural layouts. Total system forms the complete concrete structure. Custom designed to suit project requirements. Unsurpassed construction speed. It provides High quality finish. Cost effective. Panels can be reused up to 250 times. Erected using unskilled labor..Easy to handle.
AluminIum does not rust like steel; therefore, the aluminium formwork can be reused hundreds of times. Formwork is made with an aluminium alloy, which has high tensile strength and is also very hard. Saving on overhead expenses due to speedy construction. Monolithic crack free structures. Doesn’t require timber or plywood for construction activities so, it saves the environment.Casting of walls and slabs possible simultaneously. Doesn’t require skilled labour. For the marking purpose there is no need of starter. Floor slabs forms removed without moving props. Earthquake resistance of resulting structures increases manifold. Less debris generation. Higher scrap value.
Carpet area will increase.
Collect the best premium from the customer, because of 100% RCC buildings.
What about disdvantages?
Even though there are so many advantages of MIVAN formwork the limitations cannot be ignored. However the limitations do not pose any serious problems. Some of them include
a)Because of small sizes finishing lines are seen on the concrete surfaces.
b) Concealed services become difficult due to small thickness of components.
c) It requires uniform planning as well as uniform elevations to be cost effective.
d) Modifications are not possible as all members are caste in RCC.
e) Large volume of work is necessary to be cost effective i.e. at least 200 repetitions of the forms should be possible at work.
f) Architectural changes not possible on the structure (but some walls can be of brick work or openings can be entertained).
g) The reinforcement will be congested in the lower floors up to 4th floor thus max. slump (200mm) is required, so cement content will be increased.
h) Due to tremendous speed of construction, working capital finance needs to be planned in advance.
i) Number of holes will be more in the vertical wall, outer wall which is in direct contact with the rain, hole should be grouted by Non Shrink compound.
j) The formwork requires number of spacer, wall ties etc. which are placed @ 2 feet c/c; these create problems such as seepage, leakages during monsoon.
k) Due to box-type construction shrinkage cracks are likely to appear.
l) Heat of Hydration is high due to shear walls. Remedial Measures In external walls, ties used in shutter connection create holes in wall after deshuttering. These may become a source of leakage if care is not taken to grout the holes.
How to fix?
Due to box-type construction shrinkage cracks are likely to appear around door and window openings in the walls. It is possible to minimize these cracks by providing control strips in the structure which could be concreted after a delay of about 3 to 7 days after major concreting. The problem of cracking can be avoided by minimizing the heat of hydration by using flash.