Gauge Newsletter January 2020 | Page 54

The wind around the top of the Shanghai tower has a speed of more than 6m/s which is very good for generating wind power. Therefore, there are 270 wind turbines located on the top of the building which are capable of generating about 1.19 million kWh of electricity every year and it provides electricity for exterior lighting and public spaces. The building was designed to collect rainwater and it is used to flush the toilets of office areas, supplement the outdoor landscape, irrigate plants and wash the floors. To conserve the water resources effectively, the water treatment system is optimized to recycle the bath wastewater from hotel areas and toilet flushing wastewater from office areas. These design concepts reduce the tower’s water consumption by a considerable amount. The shape of the outer façade of the building was designed using a wind tunnel test where the results showed that twisting the shape of the outer façade by different degrees can affect the wind load on the building. By rotating the building 120° compared to a rectangular-shaped building with the same height, 24% of wind load can be reduced, which is quite a considerable amount in a city that suffers from typhoons every year. This iconic twist was able to save a considerable amount of material cost for construction and also it increases its aesthetic value. To stand against the external forces, skyscrapers need an extra helping hand sometimes. Installing dampers is one way. There are several types of dampers like active mass dampers, tuned mass dampers, viscous dampers, etc. On the top of the Shanghai tower, there is a Tuned Mass Damper (TMD) to hold the tower still. The TMDs are essentially pendulums in tall buildings tuned to the natural frequency of the building. When the building starts to sway because of the applied load on the building, damper also sways in the same frequency offering a counteracting force that stops the oscillation in a short period and stabilizes faster. Besides, the Shanghai tower’s damper was designed artistically for attraction too. Exterior twist and Glass facade Top view of Shanghai tower showing Mechanism of a TMD TMD of Shanghai Tower Page 52 University of Peradeniya GAUGE Magazine