Shell Structures

R. Sundaram, B.E.SM (MIT.USA) B.L., FIE. M.ASCE, M.ACI. M.IASS.
Chairman & Managing Director, Sundaram Architects Pvt. Ltd., Bangalore, India.
President, Structural Engineers World Congress Inc. [SEWC Inc.] Worldwide.

Environmental issues are drawing worldwide attention. Manufacturing of cement results in emission of carbon dioxide gas into atmosphere and that is most polluting. Therefore we must use less of cement. Concrete thin shell roofs require minimum concrete and steel when compared to other concrete structural systems. Consequently minimum of cement is used and so in this way concrete shells are environmental friendly. The shells have other features like they can span large areas efficiently and they are aesthetically pleasing. Of course cost of form work has to be controlled by intelligent reuse of form work. Moldability of concrete to any shape has resulted in immense variety of structural forms which are extremely aesthetically pleasing. Concrete shell roofs are of different kinds and for many uses. Cylindrical, hyperbolic paraboloid and folded plates have been used. The roofs cover convention centres, food courts, industrial buildings, sports halls, wedding reception halls, multipurpose halls and the like. Shells built as early as in 1963 are behaving extremely well. This paper includes photographs and drawings of the shells built in India from 1963 until the present.

Many outstanding concrete shell structures have been designed and built in different parts of the world. Of late, there is a great demand for large span buildings due to various functional requirements like sports stadia, convention centres, theatres, exhibition halls etc. An analytical and rational approach is needed to select an appropriate span keeping the future needs into consideration.

Concrete shell roofs are one of the best alternatives to cover large spans.

The analysis and design of large span concrete roofs is indeed a challenging and interesting job compared to conventional roofs. In addition to a careful consideration of all critical load combination on the structure, analysis of the structural behaviour, during different stages of construction and final design are all essential steps for the successful realization of concrete shell structures.

As far as choice of the material is concerned, in recent times, the material is not just limited to structural steel. In this context, it is worth mentioning that concrete is a very versatile construction material which can take any desired shape and form for the structure. With the growing need for large span concrete roofs, precast, prestressed concrete structures can be adopted in order to minimise the dead weight of the structure and also to reduce the material consumption and shorten the construction time.

Different Geometrical Patterns
Different geometrical patterns

Large span concrete shell roofs are an ideal solution and is a result of a unique synthesis between architecture and structural engineering.

The unique combination of concrete and steel can be used in innumerable number situations resulting in awesome structures and it is a source of inspiration for many designers who have created innovative shapes and forms spanning large areas in different parts of the world. Such structures are immensely pleasing to the eye while satisfying functional requirements.

No structural form perhaps does greater justice to the special attributes of concrete than thin shell construction. They derive strength through form rather than through mass.

The transition from pure sculpture to utilitarian architecture includes a great spectrum of variations.

Thin shells are probably the best morphological structures to express this range through their inherent plasticity of form which lends them to diverse expressions. Thin shells come in an immense variety of structural forms.

The paper presents details of several concrete shell roofs designed and built by the author's office. The details contain important features like construction methods and design issues.
This is a premium article available exclusively for our subscribers.
If you are already a subscriber, please Login
If not, subscribe now and get access to well researched articles & reports on infrastructure construction, equipment & machinery, innovations & technology, project reports, case studies, and more. All this by simply paying just ₹200/- for a month of complete portal access, or a discounted rate of ₹1000/- for a full year of access.
Concrete Rheology - Unveiling the Secrets of Concrete
Concrete is a heterogeneous composite complex material, and its hardened property is influenced by its fresh property. Concrete today has transformed into an advanced type with new and innovative ingredients added - either singly or in

Read more ...

ICRETE: Making Concrete Economical
ICRETE offers many benefits apart from reducing cement content and giving high grades saving to ready-mix concrete companies; it helps reduce shrinkage and permeability in concrete slabs, increases the durability of concrete, and also works

Read more ...

UltraTech Cement to implement Coolbrook’s RotoDynamic HeaterTM revolutionary technology for industrial electrification
UltraTech Cement Limited, India’s largest cement and ready-mix concrete (RMC) company, and Coolbrook, a transformational technology and engineering company, will jointly develop a project to implement Coolbrook’s RotoDynamic HeaterTM (RDH)

Read more ...

Plastic Shrinkage and Cracks in Concrete
Plastic shrinkage cracking occurs when fresh concrete is subjected to a very rapid loss of moisture. It is caused by a combination of factors such as air and concrete temperature, relative humidity, and wind velocity at the surface of concrete. These can cause

Read more ...

Mechanised way of plastering with spray Plaster Machine
This paper covers the research work carried out on cement plastering process for internal and external building wall by using spray plastering machine. Objective of study is to experiment and compare the plastering activity by conventional way and

Read more ...

Construction Defects Investigation & Remedies
In recent years, the speed of construction has increased very fast; buildings which used to take 3-5 years are now getting completed in 1-2 years. There is a race to complete projects faster, but due to this speedy construction, the quality of construction is often

Read more ...

Challenges in usage of Hydrogen in Cement Industry
With its zero-emission characteristics, hydrogen has become a promising decarbonization path for the cement industry. While there are several issues that need to be resolved in the use of hydrogen, there are also many advantages, so much so that the growth

Read more ...

Enhancing Corrosion Resistance of Steel Bars in Reinforced Concrete Structures
Reinforced concrete is a composite material which is made using concrete and steel bars. Concrete takes the compressive forces and steel bar takes tensile forces. Concrete around the steel bar protects it from corrosion by providing an alkaline environment

Read more ...

Moving toward workability retention to rheology retention with low viscosity concrete technology
Amol Patil, Sr. Specialist - General Manager (Admixture and Specialty Products), Master Builders Solutions (India), and Nilotpol KAR, Managing Director, Master Builders Solutions (South Asia), present a paper on the concept of low viscosity concrete in

Read more ...

Cement industry innovating eco-friendly packaging
Cement companies are constantly innovating to meet global sustainability standards and improve logistics, shelf life, and utility of cement, while reducing wastage. Thei aim is to reduce their environmental impact without compromising their product

Read more ...

IIT Madras uses Solar Thermal Energy to Recycle Waste concrete
Researchers at the Indian Institute of Technology Madras have developed a treatment process using solar thermal energy to recycle construction and demolition debris. Waste concrete from demolition was heated using solar radiation to produce recycled concrete

Read more ...

Textile Reinforced Concrete - A Novel Construction Material of the Future
As a new-age innovative building material, TRC is especially suited for maintenance of existing structures, for manufacturing new lightweight precast members, or as a secondary building material to aid the main building material. Textile Reinforced Concrete

Read more ...

Technological Innovation for Use of Bottom Ash by-product of Thermal Power Plants in the Production of Concrete
The day is not far for the adoption of this innovative, eco-friendly, and cost-effective bottom ash – concrete process technology by construction agencies undertaking road/infrastructure project works, real estate developers, ready mix concrete (RMC) operators

Read more ...

Headed Bars in Concrete Construction
Using headed bars instead of hooked bars offer several advantages like requirement of reduced development length, less congestion, ease of transport and fixing at site, better concrete consolidation, and better performance under seismic loads.

Read more ...

Sustainability of Cement Concrete - Research Experience at CRRI on Sustainability of Concrete from Materials Perspective
It can be said that ever since the publication of the document of World Commission on Environment and Development [1], the focus of the world has diverted towards sustainability. Gro Harlem Bruntland [1] defined sustainable development as “development

Read more ...

Shrinkage, Creep, Crack-Width, Deflection in Concrete
The effects of shrinkage, creep, crack-width, and deflection in concrete are often ignored by designers while designing structural members. These effects, if not considered in some special cases such as long span slabs or long cantilevers, may become very

Read more ...

Concrete Relief Shelve Walls - An Innovative Method of Earth Retention
Relief shelve walls are a unique concept that use only conventional construction materials like PCC / RCC / steel reinforcements, and work on a completely different fundamental to resist the lateral load caused due to soil. Information on the various dimensions

Read more ...

Carbon Neutrality in Cement Industry A Global Perspective
Increasing energy costs, overcapacity, and environmental pollution are the top concerns of the cement industry, which is one of the major contributors to CO2 emissions. Dr S B Hegde, Professor, Department of Civil Engineering, Jain College of Engineering

Read more ...

Finnish company Betolar expands to Indian concrete markets with a cement-free concrete solution
Betolar, a Finnish start-up, and innovator of geopolymer concrete solution Geoprime®, has expanded its operations to Europe and Asian markets including India, Vietnam and Indonesia. Betolar’s innovation Geoprime® is the next-generation, low carbon

Read more ...

Why Fly Ash Bricks Are Better Than Clay/Red Bricks
It is estimated that in India each million clay bricks consume about 200 tons of coal and emit around 270 tons of CO2; on the other hand, with fly ash bricks production in an energy-free route, there are no emissions. Dr. N. Subramanian, Consulting

Read more ...