Project Highlights

Pavilion Damansara Heights (Phase 1)

Scope of Works: foundation, retaining wall and basement works

The project site is located within Damansara Heights between 2 MRT stations - Semantan and Pusat Damansara. Phase 1 footprint alone is 9.573 acre. The contract entails the removal of existing foundation of demolished buildings as well as the construction of bored pile foundation, retaining wall system and 8- level basement.

The basement is one of the largest and deepest ever constructed in the region with a massive floor plate area of approximately 300,000m2. The total depth from existing ground level to lowest slab is approximately 31m excluding the deepest lift core construction which required another 10m depth of temporary shoring works.

Approximately 900 points of bored piles with diameters ranging from 750mm to 3,000mm were constructed in Kuala Lumpur Kenny Hill formation.

Existing surrounding dense environment and Sprint Highway had precluded the construction of deep basement using conventional open cut method and tie back system using soil nail/ground anchor due to encroachment issue by site boundary.

Top-down construction and semi top-down construction methods where floor slabs are utilised to strut against the deep basement wall while excavating downwards are adopted. The top-down work sequence adopted alternate basement permanent floor (B3, B5 & B7) as strutting slabs against the contiguous bored pile (CBP) basement wall.

Sequence took into consideration of basement slab (including temporary openings to facilitate earth removal and concreting works of lower floors) and CBP wall in modelling, design, logistic and construction work aspects.

Naga 3 Integrated Entertainment Complex, Phnom Penh, Cambodia

Scope of Works: Piling, Pile cap, Diaphragm Wall, Basement & Associated Works

The project sits on Sangkat Tonle Bassac within the heart of Phnom Penh City and shall consist of 3 towers rest atop a lower podium when completed. The foundation and substructure package entails construction of bored pile foundation, retaining wall system and 4-level of basement.

The project site is divided into three main sections, i.e. Tower 1 (Section 2), Tower 2 (Section 3) and Tower 3 (Section 1).

The site measures 4.62 acre and is located within congested urban environment which comes with inherent construction challenges. 36 borehole investigations were carried out in 2019 to determine the nature and location of different soil or rock layers; followed by construction of 2 preliminary test piles in 2020 to verify design calculations.

Drilling rigs and supporting machinery were mobilised from Malaysia to Cambodia in early 2021 and site works have since commenced.

With weak ground conditions, deep soil method was used to improve soil in-situ and thus minimising soil settlement along the western boundary adjacent to existing buildings. A total of 1,154 soil mixed columns were installed to a depth of up to 24m covering an area of 1,273m2 in mid-2021.

A 778m long diaphragm wall comprising 120 cast in-situ panels with varying sizes and wall thickness between 0.8m to 1.0m were completed in early 2022 to support the soils at the sides prior to deep excavation.

First quarter of 2023 saw the completion of piling works in all three sections, with the installation of close to 800 bored piles, ranged from 1.0m to 2.0m diameter with length up to 64.5m. The scope was a challenging feat as not only did we have to manoeuvre drilling in a congested urban environment, but also socketing the piles into some very hard rock.

The top soil profile of the project site consists of silt and sand followed by very stiff clay. This is underlain by weathered sandstone. The rigs started encountered rock layer from 30m to 40m below grade and the rock strength gets higher as the rigs advanced deeper. Some of the rock strength encountered was more than 100MPa. Core barrel, drilling bucket, cross cutter were the primary drilling tools used.

Coring through hard rock was not only hard on the rigs, but also the tooling. The experienced piling team had to make frequent adjustments and switched out drilling tools to overcome the challenging subsurface conditions. Comprehensive instrumentation was planned and implemented i.e. bi-directional static load test, sonic logging test, point load test and pile integrity test to ensure the quality of the piles installed as well as to make sure the piles meet their designed capacity.

As at end of October 2023, basement construction works are ongoing with the structure works for Tower 1 and Tower 3 completed. A semi top-down sequence is adopted to minimise cost and risk. Ground floor slabs across three sections were firstly cast to provide structural rigidity to the retaining wall before excavation proceeded in a top-down order from B1 level to B4 level.

With earthquake resistant design, a massive concrete raft foundation is required. The project has accomplished a record-breaking largest concrete pour in Phnom Penh in April 2023. The continuous concrete pour was to form part of the 4m thickness raft slab for Tower 1. It started at around 9am on 9 April 2023, running through to 4am the following day. The continuous pour saw 6,000 cubic metres of concrete laid below ground at Level B4 across an area of around 1,600 square metres. 9 concrete pump trucks were used and over 700 loads of concrete were delivered to site. The complexities that come with a single concrete pour of this magnitude requires rigorous inspection and planning to ensure success. Over 200 professionals and workers from different groups came together and worked in shifts throughout the 19 hours on the historic pour.

Immigration, Customs and Quarantine Complex (ICQC) for Rapid Transit System Link (RTS Link) between Johor Bahru and Singapore

Scope of Works: Bored piling works

The project entails the construction of over 250 bored piles with diameter and length ranging from 0.75m to 2.5m and 40m to 100m respectively. Of these, over half are large piles measuring 1.8m in diameter onwards and up to the length of 100m. The piles were installed in sandy soil conditions without embedment into support rock.

This completion of this project reinforces the Group’s ability to construct large-diameter deep depth piles in stringent quality control environment.

This project successfully showcases not only the capability of our fleet of large-capacity drilling rigs (Bauer BG50, BG40 and BG39), but also the competence of our team in providing peak efficiency whilst upholding the highest quality, health and safety standards throughout the project execution.

Sungai Besi-Ulu Kelang Elevated Expressway (SUKE) Package CA3

Scope of Works: foundation, substructure and ancillary works

The contract entails the construction of over 1,000 bored piles and 50 caisson piles for package CA3 starts from CH. 4200 to CH. 7800 with total length of approximately 5.2 km in Alam Damai, southeast of Kuala Lumpur.

This project is of particular engineering importance as it showcases the pioneering expertise in large diameter hard rock drilling using down-the-hole (DTH) hammer in challenging rock formations. With percussion boring, the DTH technique, compared to conventional rotary drilling, has been proven to be significantly more efficient in hard rock areas. DTH hammer was used to drill 200 points of large-diameter bore holes for the project (with 1,200mm∅ and 1,500mm∅ casings through hard granite strata).

MAS Building Annex Redevelopment

Scope of Works: foundation, retaining wall and basement works

A 37m deep excavation was carried out to construct a 6-level underground basement at Jalan Sultan Ismail in downtown Kuala Lumpur. On top of being situated very close to the Raja Chulan monorail track, the site is located next to a busy road with heavy traffic, high-rise buildings and the existing MAS Building. The project demanded control of minimum lateral wall movement, minimum soil settlement, and timely completion in a very limited site area of about 2,400m2.

Major works for phase one included demolition of the front podium and removal of existing 450mm∅ CBPs. Second phase involved installation of new CBPs ranging from 600mm∅ to 1,350mm∅, of an average depth of 45m and 3,000mm∅ foundation bored piles of an average depth of 70m. The semi top-down construction method with kingposts was adopted, in place of installation of temporary steel struts and walers to support deep excavation. 6 basement slabs were constructed and the volume of earthwork was approximately 82,000m3.