How do old structures pose problems for present-day engineers?
What are the problems that arise when experts from different fields try to tackle the same problem?
What is the value of computer modelling for analysing structures?
How can structures respond to changes in their immediate environment?
What is the power of natural disasters to galvanise action?

How close were your ideas about dealing with problem (a) to the ideas actually considered or tried out in practice?

Activity 2: Experts Cannot Fail!

Piero Floriani, the Mayor of Pisa, says he has ‘no fears that the tower will fall ... the committee is staffed by international experts whose credibility hangs on this plan’.

From what you have seen in the programme, do you think his confidence is justified or misplaced?
If the tower were to fall, how might present-day architects and engineers tackle the problem of reconstructing the tower on the same site?

Activity 3: Alternative Suggestions

Reducing the lean of the bell tower of the cathedral in Pisa poses an ongoing engineering challenge. Throughout history, attempts have had at best no effect and at worst, made the tower tilt even more.

An alternative suggestion to the one used involved a slightly different three-stage approach.

1. Attaching steel support cables, 90 metres long and 9 centimetres thick, to the tower. The cables would be attached to a cement ring sunk into the ground 90 metres away from the tower, gently supporting it.

2. Using thin wires covered in chipped diamond as long, thin saws running parallel to each other under the base of the tower. The saws would carve out soil from beneath the north side of the tower. The silt would be slowly removed by bringing the wires out repeatedly, and drawing bits of soil with them. As the ground is taken from under the north side of the tower the cables will tighten, settling the tower upright.

3. Build a cement base under the tower, preventing it from shifting in the future.

What do you think of the suggestion?
What would your suggestion be?