Seismic action and structural safety of urban landscape sculptures

The seismic action of urban landscape sculptures is very closely related to structural safety. According to seismic data records, about 5 million recordable earthquakes occur worldwide every year, among which 50,000 are felt earthquakes and nearly 1,000 cause damage. Moreover, on average, more than ten strong earthquakes of magnitude 7 or above, which are capable of causing severe damage, occur every year in the analysis of the dynamic characteristics of the statue's structure.

The impact of seismic action on structural safety is significant. High - rise buildings are particularly sensitive to earthquakes because as the height of the building continuously increases, the influence of horizontal loads on the structure also becomes greater and greater.

For example, the bronze colossus of Apollo, built in 282 BC, was located at the entrance of the port on the Greek island of Rhodes. The white marble base of the colossus was hollow, and the statue body was made of bronze, standing 3m tall. A strong earthquake in 225 BC severely damaged the statue. The weaker parts were shattered and never repaired again. Earthquakes are closely related to the dynamic characteristics of the structure itself. Changes in the mass and stiffness of the structure will directly affect the intensity of seismic action.

Therefore, the code requires that the plane and elevation of the building be reasonably arranged during the design. However, for large - scale statue structures, since the irregular shape cannot be artificially changed, the center of mass often seriously deviates, and the height - to - width ratio is much larger than that of ordinary high - rise buildings. Therefore, its dynamic characteristics are also very different from those of high - rise buildings. For this reason, this chapter, taking the project of the Thousand - Hand Bodhisattva statue in Changsha as an example, introduces how to calculate and analyze the dynamic performance of large - scale statue structures with an extremely large height - to - width ratio according to the code requirements using the mode - superposition response spectrum method and the time - history analysis method.