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Should wide or narrow sheetpiles be adopted in temporary work?

In general, wide and deep sheetpiles tend to be more cost-effective than narrow sections because they provide the same bending strength with a lower weight per square foot. As such, with increasing width of sheetpiles sections, fewer sheetpiles are required to cover a certain length of piling operation. Hence, the cost of installation can be reduced accordingly.


What is the vibration mechanism caused by driving sheetpiles?

There are generally three main vibration mechanisms caused by driving

(a) When the sheetpiles are impacted by a hammer, a compressive wave would be formed and it travels down to the toe of sheetpiles. A large amount of energy would be used to cause downward movement of sheetpiles while some of the energy would be reflected back up to the sheetpiles. The remaining energy would be transmitted to soils which expand outward as a spherical wavefront called “P” waves.


Why does square hollow section become more popular than circular hollow section in steelworks?

Circular hollow section was available for many years until in 1960s for the approval of square hollows section and rectangular hollow section.


How can heating assist in rebending of steel reinforcement?

It is not uncommon that starter bars are bent up within the formwork as a measure of temporary protection. Later, after the concrete is placed and formwork is removed, the steel bar reinforcement would be pulled out and straightened.


Is fatigue more serious in large-diameter reinforcing steel?

Indeed past research showed that large-diameter reinforcing steel appeared to be weaker under fatigue loading conditions. Therefore, in some standards the stress range for testing fatigue of steel bars are reduced for increasing bar size for the same reason.