Steel as Building Material

1.        What are the major advantages of using steel vis-à-vis conventional materials?

To begin with, from the stand point of buildings, steel really cannot be qualified as a “non conventional material”. Not just globally, but in India as well, steel has been used as a building material for a long time. The iconic Howrah bridge is an example, as are so many other buildings, structures and building elements across the country. In fact, to add a “feel” of technology and contemporary imagery, architects turn to steel.

All of the development around aviation, has also seen steel as a major component of buildings ,whether it is for terminals or for logistics support centers. Terminal building design especially, has added a slew of interesting results using steel tubular structures, lighting and acoustic finishes.

Compared to the usage of masonry and concrete, steel will have several advantages.

A. It can (and rather needs to be) completely pre-planned and pre-designed/engineered. As a material, it is not forgiving of errors and careless work, and by its very nature, increases the care, professionalism and foresight that buildings and structures need. This is certainly an aspect of our industry that we often neglect to discuss; but is obvious in the way our buildings and cities look. Here, I am making a case for robust, detailed and thorough pre-construction intervention in buildings. Not just the idea of steel as a stand alone entity in the building material palette, but also its interface with foundations, flooring, various types of infill and walling material, its use in interior design and the interface of the structure, with building services.

B. It lends itself to engineered, geometric solutions and therefore, optimization of material. The physical planning and geometry of the buildings has largely been adapted to the design of form-work, and ease of pouring concrete. Steel allows of the usage of structural material in complex bio-mimicry, and therefore, potentially a large drop in the material consumption itself. In the long term, if manufacturers can invest in the technical skills and machining technology for welding and fabricating natural forms, we can see a substantial drop in steel consumption, reduction in not just the overall monetary cost, but also environmental cost, and an increase in value chain.

C. This also extends as an overall project saving, from the stand point of foundation costs. Since the overall superstructure is lighter, the reactions on the foundation are reduced ,and, will provide a consequent reduction in foundation/ piling costs.

D. Since steel can be formed/fabricated as space frames and trusses, the space between beams can be used for accommodating building services, therefore, optimizing floor to floor heights. It has a collateral saving of energy by using less of it for movement from floor to floor. Vierendeel girders can be another important contributor to creating more flexibility in multi-storey buildings.

E. Components of a building can be pre-fabricated in a controlled, industrial environment, and assembled at site using simple tools. There is less chance of error and misalignment on the site. Not only bespoke elements, but of typical loading and grid patterns, all building elements including columns, struts, beams, junctions and details can be available as standard sections and numbers parts. Projects such as mass housing, commercial and retail projects and village redevelopment will benefit from it. In fact, since the PEB industry is now quite matured, a project can be launched to create BIS and other approvals for standardization of details. These “building components” can then be manufactured and sold through hardware and building material stores. Not only is it a long term business, but it can galvanize the overall improvement and safety of buildings across the country.

F. A building designed in steel, will also allow for other engineering services to be pre-fabricated, since tolerances will be known. In high service buildings, often attic or plenum spaces are left in the entire volume of the building, in order to cater to services, being installed “later”. The truth is, building services and their general location and approximate sizing is known at an early time during the design process. By taking into account the actual attic or plenum spaces required, the building services can be neatly tucked away, much like the inside of the bonnet of a car.  And overall, save spatial volume of the building, provide more usable real estate in the same built up area, and, reduce the sizing of building services through optimization. It has a huge ability to be salvaged and re-used after its active life in the building.

2. How structural steel can be innovatively used in construction to provide design aesthetics and at the same time offer economical solution?

Aesthetics and Economy:

I believe steel has a very defined and universal language of design. It allows for very thin members and the quality of making a building feel weightless.

When steel is used in the form of space frames, and the structure is analyzed as a 3 dimensional form, it results in incredibly light and spectacular forms.

The use of steel as space frames, trusses and Vierendeel girders allow a designer to create unique languages for buildings and, the structural properties of steel, allow for it to be economical.

3.        What is your take on the variety of sections/grades provided by our steel producers for various demands of creativity?

Availability of Sections:

In India, we seem to have a bit of chicken and egg situation on the proliferation of steel as a structural member.

There is no doubt, that designers and the industry will benefit from the availability of a larger range of tubes and sections, I do feel that there is also a lack of Eco-system for their widespread usage.

On the top of the pile, in terms of the need for change/ innovation are:

A. Standardization and wide spread training for welders and building fitters.

B. Domestically produced and economical intumescent/ fire safe coatings.

C. Updating the IS Codes for industrial production of buildings, beyond rolled steel sections.

4.        What trend are we going to witness in next 5-7 years, as far as designing structures with steel is concerned?

Medium Term Outlook:

I believe there will be three large sections of development that will emerge and take centre stage so far as steel buildings are concerned:

A. The proliferation of steel as a structural member and commodity in medium size and medium rise buildings. This will probably be the single largest “revolution” in terms of the breadth of usage as well as overall improvement in the stock/ quality of our buildings. The way RCC is being used ( largely un-designed) in the smaller markets is a disaster waiting to happen, especially from the standpoint of seismic safety. Steel structural elements as a commodity offer a cheap, industrial and quickly proliferating alternative. It will provide a massive impetus not just to small and medium steel fabrication industries but also associated industries such as bolts/ fastener manufacturing and engineered panels for walls/ roofing etc.

B. In the urban infrastructure segment, especially for light rail and mass transit applications.

C. In industry, for high performance buildings, as production and technology matures, and the need is felt for “building performance” rather than sheds.

5.        What should be the strategy of industry in promoting structural steel construction in India?

Industry Strategy:

Before we look at a strategy for wider acceptance of steel, let’s look at what “works” for RCC/ Brick today:

1.    Its conspired a “solid” material;  robust and long lasting.

1.    Its “easy” and “low skill” workmen can use it.

2.     Mistakes are easy to rectify.

I believe a strong narrative needs to be created along the following lines:

A. Performance / efficiency and strength/longevity of steel in architecture, especially from the standpoint of seismic performance, speed and economy.

B. Pride in high performance/ skilled work. It will need the design and implementation of skill development and certification courses, and, up-skilling of workforce. The unfortunate migration of labour force doe to the COVID lockdown has exposed the risk and dependence of the construction industry on “unskilled manpower”. It is a vicious cycle, and, we cannot go back to it. Getting people skilled and efficient is the only way forward.

C. Indian engineering and detailing tools that allow a largely “plug and play” model of drafting and detailing for steel members. It will take away the “steel detailing phobia” from the design industry and allow design teams to adopt this material more easily.

D. Steel is a viable alternative, when offered as a part of a holistic solution. So long as we have people trying to make a steel frame, with brick infill, we will not move forward. The steel industry needs to join hands with building component and panel based solutions providers, as well as integrate elements such as commoditised hollow cored slabs etc. When the solution is offered as a complete set (structure-slabs-walls-doors and windows) it will make much more sense for people to switch, and also, bring down the overall cost of building construction.