How L&T built the Statue of Unity

The 182 m tall statue is made up of a 25 m high base and 157 m tall statue. The base has high roofs with steel trusses and RCC slabs. The statue is divided into 5 parts – the lower & upper legs, lower & upper body and the shoulder & head.

Salient Features
The design life of the project is 100 years.

Construction time
13 months for designing
33 months for construction

Vital statistics
182 m (597 feet) tall
The Sardar in a walking pose facing the Sardar Sarovar Dam (that was his vision)

Material used for construction
6,500 tons of structural steel
18,500 tons of reinforcement steel
210,000 cum of concrete

Bronze cladding
1,700 tons of bronze cladding
8 mm thick
550 macro-panels & 6,300 bronze micro-panels

Engineering Features
2 tuned mass dampers each weighing 200 MT to help the statue withstand strong winds & seismic activity. The steel inside is zinc-coated using hot gip galvanization to enhance its life and withstand corrosion. A viewing gallery at 135 m level that visitors can reach in 34 seconds from the base level

Unique Features of the Statue
At 182 m, it is 100 times bigger that a normal human being
It is twice the height of the Statue of Liberty
At 70 feet, the Sardar’s face is taller than the faces of US Presidents cut out on Mount Rushmore
The next tallest statue in the world is the Spring Temple, Buddha in China that is reported to have taken over a decade to construct
The statue has been engineered to withstand wind velocities of up to 180 kms/hour
The architect is Ram V Sutar, a Padma Bhushan award winner

Structural Specifications
The 182 m tall statue is made up of a 25 m high base and 157 m tall statue. The base has high roofs with steel trusses and RCC slabs. The statue is divided into 5 parts – the lower & upper legs, lower & upper body and the shoulder & head.

The steel in the statue is in 3 layers: Primary, Secondary and Tertiary. The Primary frames are vertical trusses that interconnected with infill steel members and in turn connected to the RCC cores. These transfer all the load from the statue skin onto the RCC cores. The Secondary steel, that is part of the primary layer, are trusses that carry the load from the bronze cladding connected through the tertiary steel frames. These two layers form the basic skeleton of Statue.

The Tertiary layer is set of steel trusses connected between secondary steel and bronze cladding that bridges the gap between the skin and the skeleton of the statue. Each tertiary steel frame is unique as each bronze panel is unique.

Every joint is unique and that makes the structure extremely complex in terms of design. As it involved Hot Dip Galvanisation, identifying the size of assembly is crucial based on bath size and high accuracy was required to match the profile of statue.

Steel Sections and Erection Technique
Steel section used in the project are basically UB and UC profiles along with plates. The grade of steel used is E350. Two tower cranes each having 8T capacity (at the tip) are used to erect the structure

Overcoming Challenges
For a project of this magnitude and complexity, there were several challenges that the project team faced. Here is one of them.

Due to space constraint, external cranes could not be positioned hence only tower cranes were planned for the entire erection. Till Dec 2018, the entire tower crane hours were used for completing the 2 RCC cores and hardly any steel was erected for the statue by that time.

From Jan 2019, both steel and bronze works were planned simultaneously. As the contractors for both these works were different, sharing of crane hours was very crucial. The cranes were used on all days including Sundays and holidays in 3 shifts for erection and unutilized crane hours for scheduled maintenance.

Ensuring Safety
To construct the world’s tallest statue, one of the biggest safety concerns was of people falling off the edges, falling to the ground through openings, tripping into excavation pits or loose material falling on people working below. Here are three safety measures that went a long way to deliver the project without LTI (Loss of Time due to Injury).

Co-ordination of multi-level activities through a common permit:
With work proceeding simultaneously across multiple work fronts, at various levels, special care was taken to ensure that while people working at lower levels were well-protected from falling objects, those working above were safe and steady on their platforms. 2nd & 3rd levels of PERI (formwork) core wall platforms were given complete fall protection through an all-inclusive permit.

Manpower Requirement
At peak times, the work force had 250+ engineers and 4,000+ workmen. A total of 2 million-man hours was consumed for the entire project.