SHELL STRUCTURESLOTUS TEMPLE

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INTRODUCTION

Shell structure, is a thin, curved plate structure shaped to transmit applied forces by compressive, tensile, and shear stresses that act in the plane of the surface. They are usually constructed of concrete reinforced with steel mesh

It functions both as structure and covering

Types of shell structure :

Single curvature shell: are curved on one linear axis and are a part of a cylinder or cone in the form of barrel vaults and conoid shells.

Double curvature shell: are either part of a sphere, or a hyperboloid of revolution.

Advantages:

1. Very light form of construction

2. Dead load can be reduced economizing foundation and supporting system

3. They further take advantage of the fact that arch shapes can span longer

4. Flat shapes by choosing certain arched shapes

5. Aesthetically it looks good over other forms of construction

Dis-advantages:

1. Shuttering problem

2. Greater accuracy in formwork is required

3. Good labour and supervision necessary

4. Rise of roof may be a disadvantage

INTRODUCTION

LOTUS TEMPLE

• Architect : Fariborz SahbaLocation : New Delhi , IndiaProject Year : 1976-1986

• The building has a height of 34.27m and diameter of 70m .

The shell structure resembles the petal structure of a LOTUS, hence called “Lotus Temple”. The first two ranks curve points towards inward, embracing the inner dome; the third layer curves outwards to form canopies over the nine entrances. Nine arches are provided to support the superstructure ring of the central hall.

LOTUS TEMPLE

Sequence of constructionThe basement and the inner podium were constructed first. The structure was divided into convenient parts .The structure was divided as follows:Arch• The inner leaf, comprising a

cusp (ridge) and a re-entrant (valley).

• The inner leaves rise to an elevation of 34.3m above the inner podium.

• At the lowest level each shell has a maximum width of 14m.

• It is uniformly 200mm thick.Inner leaf• The inner leaf, comprising a

cusp (ridge) and a re-entrant (valley).

• The inner leaves rise to an elevation of 34.3m above the inner podium.

• At the lowest level each shell has a maximum width of 14m.

• It is uniformly 200mm thick.

Interior dome

•Three ribs spring from the crown of each arch. •While the central one (the dome rib) rises radically towards the central hub, the other two (the base ribs) move away from the central rib and intersect with similar base ribs of adjacent arches, thus forming an intricate pattern. •Other radial ribs rise from each of these intersections and all meet at the centre of the dome. •Up to a certain height, the space between the ribs is covered by two layers of 6Omm-thick shells.

LOTUS TEMPLE

LOTUS TEMPLE

Entrance and outer leaves.• There is one set of spheres

for the entrance leaves. • The diameters of the

spheres have been fixed to satisfy the structural consideration of varying shell thickness.

• For outer leaves, another set of spheres defines the inner and outer surfaces of the shells.

• The shell is uniformly 133 mm thick towards the bottom, and increases to 255 mm up to the tip, beyond the glazing line.

• The entrance leaf is 18.2m wide at the entrance and rises 7.8m above the podium level.

• The outer leaf is 15.4m wide and rises up to 22.5m above the podium

LOTUS TEMPLE

Material Used :Concrete:

• All the ribs and shells up to radial beam level are in white concrete.

• To avoid crazing and shrinkage cracks, a mix of M 30 grade white concrete was designed.

Reinforcement:

• The reinforcement used in the white concrete shells as well as the binding wires was entirely galvanized so as to prevent the long-term effect of rusting of reinforcement on the white concrete.

• Sandblasting was carried out to reduce pickling time

Marble cladding :

• The outer surface of the shells, as also the inner surface of the arches, are cladded with white marble panels fixed to the concrete surface

• After waterproofing of the top surface of each shell, timber templates of the same size as the marble panels were used to define the location of the bottom-most rows of marble panels first.

LOTUS TEMPLE

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