Civil & Structural Engineering highlights

The use of secant bored piles

The secant bored piles (SBP) serve two functions – as the earth retaining wall structure and as deep foundation elements.

The dual function of the SBP helped to eliminate the need for additional structures and reduce the overall cost of the deep foundation elements and earth retaining wall structures.

Innovative Observational Method for the deep basement excavation work

During the construction of the main tower basement for IOI Central Boulevard Towers, excavation depths of up to 8.5 m were required for the general areas and 11.5 m, locally, at the lift pit area.

The design took into consideration two scenarios, the Characteristic Scenario and the Probable Scenario, with different soil design parameters.

Instruments were installed for close monitoring, throughout, of the excavation process.

During the Decision Stage, the readings of various instruments were observed to be below the Observational Method Implementation Level (OMIL) for the Probable Scenario, as shown in Figure 2. Consequently, it was decided to omit the third level of struts, result- ing in a single-stage completion of the basement pilecap.

This decision led to significant timeand cost-savings for the basement construction work.

Installation of a long span steel transfer structure

A long span steel transfer structure was installed to overcome the ‘no pile zone’ created by the presence of the Common Services Tunnel (CST) and the PUB Collector Drain.

This inter-storey transfer steel truss is integrated into the building from Level 3 to Level 5 (the carpark levels), enabling minimal headspace occupation for such a deep transfer structure and maximising the spatial efficiency.