Commercial Structures

ISPAT PG Medical Institute and Super Specialty Hospital, Rourkela

The proposed hospital will have 156 beds accommodating super-specialties like Cardiology, Cardiac surgery, Neurology and Nephrology. The new super-specialty block and 500-seater Auditorium and the medical Institute will spread across 3 lakh sqm space.

As per the architectural intent and the project requirements of client, we conceived appropriate structural framing for the hospital building as a steel-composite structure. This system resulted in faster construction with ease of working on parallel fronts, optimized cost and reduced beam depths to get better clear heights. It’s been possible with encased-steel columns laid out on the desired rectangular grid abiding by the architectural constraints yet maximizing carpet area and floor spaces

Hariom Gera
Director, Constructure Designs Pvt Ltd

Client Brief
Steel Authority of India Ltd (SAIL is building their expansion project for ‘ISPAT PG Medical Institute and Super Specialty Hospital at Rourkela, Sundergarh District, Odisha at a cost of Rs 260 crore, which comprises of mainly following three buildings with stated areas:

  • Hospital block (Basement+G+4 floors)- 31909.69 sqm
  • Service block (G+ 4 floors) – 4417.96 sqm
  • Academic cum Auditorium block (G+1 floor)-4653.30 sqm
  • Design Briefing
  • The proposed hospital will have 156 beds accommodating super-specialties like Cardiology, Cardiac surgery, Neurology and Nephrology. The new super-specialty block and 500-seater Auditorium and the Medical Institute will be spread across 3 lakh sqm space.

The design of the building had been conceived as a ‘Steel Intensive’ structure deploying energy efficient and green-building technologies, such as LED light fittings and occupancy sensors, optimum use of natural light an internal courtyard &atrium, solar water heaters & PV system, rain water harvesting and provision of STP & re-use of waste water, use of permanent, durable and local materials, Passive Architecture, Low Flow fixtures/faucets, Heat Resistant Tiles on Terrace, Double Glazed Units, Low VOC Paints etc.

As per the stated objective, the Main Hospital, Service Blk & Auditorium were all conceived as a steel-composite structure by CDPL. However, the Roof Truss System for the Auditorium was primarily a 3d-truss frames planned as per architectural intent of Arch-En Design, being executed by URC Construction Pvt Ltd. The total project completion time is 18 months, and the buildings are now nearing completion. The total structural steel quantity was about 1110 MT.

Structural System
The floor plan layout of the building is such that it is unsymmetrical with respect to vertical axis and as well as horizontal axis. A composite steel frame structural system has been adopted with sufficient stiffness by providing vertical bracing or shear wall to control lateral displacements within limits. Steel–concrete composite columns have been chosen to reduce the column sizes. Further, composite floor system has been introduced using corrugated steel deck sheeting for economy and fast construction purpose. The lateral resistance system shall be OMRF + R.C.C ductile shear walls to control lateral forces/displacement.

Steel-concrete composite systems have become quite popular in recent times because of their advantages against conventional construction. Composite construction has the biggest advantage of combined action of steel and concrete in structural design as well as construction. This system results in speedy construction with a possibility of working on parallel front. Encased-steel columns laid out in a rectangular grid according to architectural and structural needs.

The floor system consists of primary and secondary steel beams supporting an overlaid deck slab. All beams both primary & secondary are designed as composite beams connected to deck slab with shear studs. Deck slab is 150mm deep, with 1mm thick TR 60 sheet designed to with stand 2 hr. fire rating. Column to column beams are moment resisting beam and all secondary beams are moment released beams which are suitably modeled in ETABS. Web of Column at joints is strengthened to accommodate moment connection. In RCC walls & composite columns, steel members can be erected up to 3-4 floor including the steel column itself and concrete encasing of the steel columns shall be done thereafter.

Methodology
The design of Composite Columns & beam is being done using AISC 360-10, IS456-2000 and SP-16. Limit state method was followed as per IS 800-2007 for design of steel structures. The steel building structure with basement being designed using ETAB software. Composite beam is designed with AISC 360-10 and pre-camber shall be given to compensate deflection of at construction stage. The composite column design was be done as per AISC 360-10. Other important aspects like Stability of the structure as per codal requirements were taken care of. Serviceability requirements like Vertical deflections (Total load deflections) =Span/240 and Lateral displacement of Structure=Height/ 500, were suitably observed. All composite beams were coated with fire resistance coating for two hours fire rating.

The foundation for the proposed building is optimally conceived as isolated footing/combined footing. The foundations have been designed in SAFE software and spreadsheets by considering an SBC value of 35T/sqm at a depth of about 2m below NGL as per soil investigation report.

Fact File
Client: Steel Authority of India
Architect: ARCH-EN DESIGN
Structural Consultant: Constructure Designs Pvt Ltd
Contractor: URC Construction Pvt Ltd
Steel Supplier: Steel Authority of India
Steel Tonnage : 1110 MT

Aviary, Vadodara

This special section covers the out-of-the-box design having steel as an essential element of the design. The main aim of this section is to showcase how steel can be innovatively used in today’s world of architecture.

Here Er. Jigar Rana, Director, Safe Consultants helped converting out-of-the-box design concept of Ar. Babar Yahya & Ar. Hiten Chavda, Architect,
MAY Architects that ought to turn the tables in the future…

Vadodara Mahanagar Seva Sadan has come up with a refurbishment of Sayajibaug Zoo at Vadodara with the concept of “Unzoo the Zoo”. Under this project, there is bird Aviary which will be one of the largest in India in terms of volume. The exciting part about this Aviary is its architectural design, introducing thrill in design by having a skywalk with a trendy shape and elevation.

Structural Details
The overall confining mesh of Aviary is supported on 8 Columns which has a height 15m to 24m forming two quadrangles and giving an exciting visual. These columns and overall meshing will be supported by guyed ropes making it sleek and elegant, yet stable.

The key structural aspect of this project is as below:

  • Civil Foundation design of Skywalk steel structure and Main supporting columns
  • Civil structure design of Guyed Ropes
  • Performing structure design and detailing to ensure no tress gets damaged during foundation or super structure stage.

Steel the Ideal Choice
The challenges faced during the project were few but unique. There was one portion from where trees were passing through a line of RCC beams. The RCC beams and wall were having stone cladding. As per Architect’s requirement, there was no possibility of breaking the language or pattern, but they also wanted to ensure that there is enough tolerance for trees to sway during high winds. To counter this problem steel was chosen.

The span was fabricated in steel structure and later was covered with plates and camouflaged with concrete layer and stone cladding. Visually, the beam has void creating curiosity that there is a void in concrete structure, but which is not the case. Although, the problem was small, but the overall process and its relevance was awesome and required lots of efforts. For ensuring correct execution of solution, a 3D BIM model in Autodesk Revit was prepared which made life simple for executers to understand and execute accordingly.

The skywalk fabrication and its orientation were also very interesting aspect in this project. A 3D BIM model in Autodesk Revit was prepared simulating overall skywalk and its Architectural requirement. Once Structure design was done, the calibration in sizes to suit Architect’s vision was investigated using BIM model. The main columns supporting overall mesh were designed in such manner that they can stand freely at around 60-degree angle until, it was capped with dish.

The primary frame of this Aviary structure are 8 columns at around 60-degree angle from horizontal of 800 mm dia tubular pipe structure. The other structure i.e. skywalk has primary column members as Hollow circular pipe section of 200 mm diameter and frame forming above as deck with 150 mm pipe and other hollow sections as secondary members.

Unique Features
The Aviary structure itself is a unique structure which has ferrule mesh supported on 8 columns which are inclined to form shape of Octagon. Further, the skywalk travelling through the Aviary structure which forms the shape of number “8” when seen in plan makes a very exciting travel for visitors. The overall design and detailing also includes ensuring that no tress was cut in overall planning, foundations or while erections. These aspect makes the project more valuable by having good amalgamation of nature, Aviary, birds, and structure.

Fact File
Client: Vadodara Municipal Corporation
Architect: MAY Architects
Structural Consultants: SAFE Consultants
Developer & Steel Fabricator:
Shiwalay Infra Projects Pvt Limited
PMC: Adroit Project Management & Consultants

CESTA

This special section covers the out-of-the-box design having steel as an essential element of the design. The main aim of this section is to showcase how steel can be innovatively used in today’s world of architecture.

Here Ar. Shashirekha, Chief Architect, Space Studio unveil their out-of-the-box design concept that ought to turn the tables in the future…

Cesta in Sanskrit means movement. The theme represents the ocean in built form. The sculptural steel facade expresses the form of an ocean wave, corrugated steel / containers form part of the fabrication of exterior walls, an overstated anchor symbolism in steel embellishes the rear side facing the backwater; together the design elements capture the spirit of the ocean in a steel structural form. The colour scheme is predominantly grey with accents of primary colours green, red and blue.

Almost all great ideas begin with a why. When questioning a normative idea, a designer usually finds his path to inspiration and creative solutions. This is how great designs; engineering feet and massive structural wonders are built across ages.

This is how we came about building cars, airplanes and monumental habitable structures in steel and concrete. The answers never appear before the question does.

At Space Studio Chennai, a Chennai based architecture firm, the design process begins with a why closely followed by how. This is how their architects arrive at appropriate design aesthetics for buildings, especially for this steel building purported to be a warehouse and office space for a shipping company.

Why should warehouses be boring, dull, uninspiring? They asked.

How can we make it interesting and even inspiring? They sought to wonder.

How far can we stretch our imagination in building something with steel? They seem to have questioned themselves.

The answer is a corrugated steel enclosure with a facade that is free flowing, fluid and seemingly as whimsical as waves can be. It started out as a boring box building and transitioned into an interesting form.

As they say, the answer usually appears after the questioning begins.

Concept Note
The design brief from client is to create a warehouse and office building for a shipping office. The spatial planning brief is to include warehouse/storage space in the basement ,ground level and first floor level, office space in floor two and top management in floor 3 three, with an active terrace space to house conferencing facility, canteen and a terrace garden.

Prefabrication & Structural system
The architects have ideated a prefabricated steel structure that can be built to specifications and brought to site for building and assembly. The substructure, staircase and lift walls are in reinforced cement concrete. The rest of the super structure including the supporting structural framework is prefabricated steel.

Architect’s Interpretation

Façade systems are a form finding process that can often thrill and surprise both the designer and the onlooker. The design decision of Ar. Peter Zumthor led to thin, elongated bricks at Thermavale and led to Ar. Frank Gehry using titanium as an exterior material. It is possible to take an existing material and stretch it to form a whole new shape or to find an unusual usage for a usual material. As architects when we attempt to stretch the limits of a specific material, we end up finding a whole new form as seen in Cesta where steel is given a sense of free-flowing form. Apart from the design aesthetics the functionality of a façade system is crucial. The louvered steel form here acts as a shade blocking about 70 per cent of direct sunlight on the east side while also providing an interesting visual aesthetics.
Shashirekha
Chief Architect, Space Studio Chennai

Steel as a material
Steel as a material, much like concrete, can be surprisingly fluid or flexible despite the superior strength it offers. Steel can be bent, beaten to a specific shape, hot rolled, moulded, modified and fabricated in almost any shape, size and strength. The immense strength of steel is an advantage to buildings in use as structural support system. Steel structures perform better under seismic pressure as they bend but do not break so easily. However, at high temperatures the material can lose its strength too soon which makes an appropriate fire protection treatment necessary for the specific material. Another concern with steel is to adequately address the corrosive properties of the material. Heat retention could be higher in steel and requires adequate coolant treatment prior to using steel as an enclosure wall material.

Innovation in steel
The façade massing is disruptive in parts while also following an order in chaos, much like the waves of an ocean. The louver like design permits adequate lighting and ventilation to the interior spaces. The façade form creates an interplay of light and shade that constantly moves with the direction of sunlight, rendering a sense of movement. The façade is wrapped in free-flowing steel members that twist, turn, and are sculpted in a parametric pattern of striations.

The future of steel
The ductility and tensile strength of steel makes it a more manageable material. Steel could be a great material for 3-D printing parts or whole of a built structure soon. This offers greater freedom to architect in imagining various design possibilities with steel. The possibility of building with steel only gets limitless as we move towards finer aesthetics in steel structures.

Devaiah’s Commercial Building, Bengaluru

For a commercial complex locate at Kalyan Nagar in Bangalore, we decided to do away with the conventional column and beam structure in favor of a lattice structural system, which was used as the architectural feature. The idea stemmed from the want to ‘celebrate steel’ and to celebrate the structure instead of concealing it behind the facade.

Ideation
In a typical beam column steel system, the vertical members are under compression and the horizontal members are under tension. To move away from this conventional system, we conceptualized a triangular framework that forms a veritable ‘exo-skeleton’ for the building. In the steel support used in the building, the web-like exoskeleton withstands both compression and tension.

The triangle is one of the most stable forms and provides the required flexural stability for the structure. Therefore, we were able to avoid ties and braces, which are typically found in steel buildings. The genesis of this idea was from an attempt at a bit of biomimicry. It is inspired by arthropods – or insects that possess an exo-skeleton. The exo-skeleton gives them better muscle leverage, enabling them to carry weight many times their body weight.

Similarly, the lattice structure we used transfers the slab loads to a web-like structural system built in steel. Not only does this provide great structural ability, but we wanted to leverage the aesthetic appeal as well. Our intent was to use the structural system as the architectural highlight by making it a key design element. In addition, the structure is also amazingly earthquake resistant. The design is a great example of balancing aesthetic appeal with structural stability.

The say that ‘God is in the details!
Here too we have had to painstakingly detail out the joints or ‘Nodes’ as we called them, to actually erect the building. The Nodes are the interface between the horizontal beams and the lattice. Their precision of alignment and design both were very crucial, while execution, even if one of the nodes was out of alignment by say 5mm at the ground level, it would lead to an error of about 100 mm at the top, perfectly drawing up the marking and achieving the same at site was critical. The detail of all the joints of the members have been dealt with, with as much aesthetic detailing as structural sufficiency.

Construction methodology
Once the design concept was frozen, it was then a matter of building the structure that we had never built! I had to come up with a Construction methodology that would help us bring the design to reality, the complex “Tapestry in Steel” had to be simplified! The solution had to be simple, repetitive, and cost effective. After all this was to be built by an ordinary fabricator without the use of CNCs or robotics…!

Simplicity was achieved by breaking down the Lattice into smaller elements that could be easily understood by the workers, better understanding gave them more confidence at site, after we had erected the ground floor one of the fabricator told me he had an ‘easy-feel’ about the rest of the build. It was our ‘Lego’ approach that seem to work…!

We had to work out an algorithm of geometry, alignment and assembly that had to be taught to the people at site so that they knew what to do. This was a set of rules of what came first, what factors were given importance than the others, a logic statement of how to adjust slight misalignments to not cause a deformity.

The Lattice comprised mainly of two elements, the ‘nodes’ and ‘struts. A typical node had 6 struts meeting into it. Almost all struts were the same size, except the ones at the vertical edges of the building. Using the Lego assembly approach, these parts were factory made and brought to site to be assembled, but here there was a challenge…! The entire lattice was to appear like a “tapestry in steel” which meant that we could have gussets, cleats and flange plates usually associated with any steel junction.

But now we had another problem, since we had 6 tubes that met at a node, it was impossible to have all of them slide into a node, since all the nodes were prepositioned at specific locations on the elevation. So how do you slide a tube with sleeves on both ends between two nodes…?

It took some creative, out of the box thinking to crack this! If the pipes could not slide, could the sleeve slide instead? That was it….! A ‘Sliding Sleeve’. This simple idea of sliding the sleeve inside the tubes after they have been positioned perfectly between the nodes was the only way this could have been done.

Contributed by Sujay Gorpadkar,
Principal Architect, Opus Architects