Geotechnical Requirements Needed Because Public Safety Is Involved

Source : The Business Times, 28 September 2007

I REFER to the report, 'More accountability, stricter regulation with building bill' (BT, Sept 21).

The statement, 'it is understood that despite a PE and a geotechnical specialist being involved with the construction work on the Nicoll Highway, it still collapsed', is misleading and requires clarifications.

There are several new requirements in the Building Control (Amendment) Bill on the design, construction and supervision of temporary earth retaining structures (Ters, in short).

The Bill mandates that the geotechnical aspects of the design of Ters have to be carried out by a geotechnical engineer and independently checked by a geotechnical accredited checker. The geotechnical engineer for the design also has to monitor and supervise the Ters during construction and ensure that it is suitably modified to meet any unforeseen circumstances or changed ground conditions.

Furthermore, Ters are now to be treated like permanent works and the plans are to be submitted to the Commissioner of Building Control for approval. These elements were not in place prior to the Nicoll Highway incident. These geotechnical requirements in the Bill are necessary since public safety is involved.

The report also mentioned that some members of the Institution of Engineers Singapore (IES) questioned the need for a geotechnical engineer to undertake the geotechnical aspects of piling works for buildings exceeding 30 storeys. In our extensive consultations with members of the engineering profession, we found that the vast majority of engineers supported this requirement.

Tan Guan, who is chairman of the civil and structural practices committee of the Association of Consulting Engineers, Singapore (Aces), had expressedly supported the proposal during the industry consultations. In addition, this proposal is not unique to Singapore and is also practised elsewhere, like Hong Kong.

Nonetheless, we value the feedback from the engineering profession and we have accepted the suggestion for the detailed requirements on geotechnical inputs to be calibrated according to the complexity of the foundation designs.

For example, for simple piling systems, only basic geotechnical inputs like having the ground investigation report containing geotechnical design parameters would be required.

BCA will continue to work with the industry to finalise the provisions in the regulations.

We need to take a balanced approach towards ensuring construction safety and managing cost. While the new rule would add to construction cost, the increase is only marginal.

Ong See Ho,
Commissioner of Building Control,
Building and Construction Authority