Construction of The Shard and Jeddah Tower

Water ingress mitigation in The Shard’s large three-storey basement

Question 1

The Shard, London

1a). Weighting – 15% of total question grade.

Water ingress into any size of basement can be problematic. Explain how this issue was mitigated during the construction of The Shard’s large three-storey basement.

1b).  A concrete raft and Piles support the tower. The initial plan was to cast the raft in a number of sections. However, there were practical difficulties in doing this due to the densely packed 40mm rebar. The solution was to construct the raft monolithically with a 5,500m³ single pour of concrete.
• What were the advantages of using a single pour?
• What logistical issues needed to be overcome?
• How were the logistical issues solved?
• How was cracking and shrinkage in the raft alleviated?

1c). The ‘Top down Construction’ technique was adopted.
• Describe how this technique is carried out.
• Explain why this was the preferred choice for building the tower.

1d)Above ground, the building is a hybrid of different frame and floor designs. As the Shard tapers, the floors also vary in thickness.
• Describe the two designs that have been used.
• Explain why the floor thicknesses and designs are different in relation to space usage and internal services.

1e).What ingenious solution was used to speed up the transportation of contractors and materials up and down the unfinished Shard, 24 hours per day regardless of the weather?

Question 2
The Jeddah Tower, Jeddah, Saudi Arabia

2a). According to the architects, the Kingdom Tower is: “…an analogy of new growth fused with technology”.
The design was influenced by more than its economic and cultural significance; its footprint, shape and cladding are also of technological
importance – discuss why this is so
2b). Steel frame construction, freed buildings from their dependence on compressive structures, allowing them to go higher still. The invention of the elevator was spurned by this innovation; Elisha Otis created the safety elevator making it possible for passengers to travel to the top floor of buildings. Yet single elevators can no longer take passengers to the top floors of todays ‘Skyscrapers’.

Explain what problems are presented in tall buildings relating to their need for long reaching elevators. Also discuss how these issues will be mitigated in the Kingdom tower?

2c).Above we established that pointed loaded steel frames freed buildings from compressive structures yet only the final 44 metres of the tower are planned to be made of steel.

Explain why this is the case and the problems envisaged with constructing the higher levels of the core and floors of the tower. How will these technical problems be alleviated?

2d). The shape of the tower was designed to be functional and aerodynamic because of the phenomenon known as the ‘stack effect’ or ‘overturning moment’, yet the initial design was reduced in height from one-mile-high (1.6 km) to 1 km.

Briefly explain why was the height of the tower was reduced. In more detail, explain how the ‘Stack effect’ is being negated and why monitoring the ground below the tower with sensors has been so important.

2e). Since 911 the designs of tall buildings have incorporated different security and safety features to minimise risk.
Based upon your understanding of different systems that have been utilised in other ‘skyscrapers’, bullet point four features that you would like to be incorporated in the Kingdom Tower that will help to designout security and disaster risks.