Barrow’s construction frenzy in Rosebank

By Eamonn Ryan

The team of Barrow Construction and Gauteng Piling have jointly undertaken a string of developments in the area alongside the corner of Oxford and Glenhove roads. The R250-million Oxglen Phase 2 site will ultimately consist of a new office complex, nestling in the heart of this ultra-modern Rosebank address. 

Piling equipment2


Drilling one of the 168 piles required on site.


Phase 2 of the Oxglen development is adjacent to the existing Oxford and Glenhove commercial building — a 21 000m² office development located on 114 and 116 Oxford Road, situated on one of the most prominent corners of Rosebank, Gauteng, also developed by Barrow Properties. The development will have Oxford Road exposure and is within walking distance from Rosebank Mall and the Gautrain Station.

It is a Barrow Construction site, involving as part of the earthworks the construction of 168 piles varying between 450mm and 1 500mm. Size will depend on the load on the piles and on whether it is founded on rock. In depth, they vary from a shallow foundation down to 11m. The site is about nine metres below road level. Approximately 85 000m3 of earth and waste were removed from the site, while 650m3 concrete and 50 tonnes of steel were used.

Where the tree occupies the site, that area could not be excavated. The site has lateral support consisting of 750mm-diameter piles, with gunite in-between.

The building was designed by LYT Architecture, which was also responsible for the design of the 26-storey PwC headquarters in Waterfall City, as well as the Katherine & West — recently voted ‘the coolest building in Jozi’. LYT’s portfolio of completed projects includes commercial, industrial, retail, educational, residential, hotel, and leisure projects, as well as numerous projects for the mining industry. While the majority of its work to date has been in South Africa, it is also currently active all over Africa and particularly West Africa, serviced through its branch office in Lagos.

Poised to drill2


The single biggest challenge in piling is understanding the ground conditions.


Challenges of shallow rock

Nico Haas is CEO of Gauteng’s second-largest piling company, Gauteng Piling, a firm which has 16 large auger piling machines. This positions it as one of the larger piling companies, with most regional companies having an average of four to five. The national companies typically have 25 to 30, explains Haas.

Having such a large variety of equipment at its disposal has allowed the company to embark on contracts ranging from underpinning for residential houses to massive housing projects in Angola. Haas says Gauteng Piling actively promotes the idea of partnering, which means working together with all the parties to a contract, as a team. Oxglen Phase 2 is a prime example of this approach.

The gunite for the site’s wall is placed while not quite dry, says Haas, though with as little water as possible mixed. The gunite is a mixture of cement, sand, and water applied through a pressure hose, producing a dense, hard layer of concrete also used in building for lining tunnels and structural repairs. As it is sprayed on, the water is added at the nozzle using the same technique as they do for swimming pools.

“The single biggest challenge in piling is having experienced people who understand the conditions and are able to interpret the soil report. However, based on current market conditions in South Africa, the biggest challenges today are getting work at the right price, and then getting paid.”

“It is a relatively straightforward job, but it had the challenge of some of the piles being founded on shallow rock. Extra holes had to be drilled to ensure piling was not on a ledge but on rock. However, this was expected and planned for,” says Haas. Gauteng Piling had undertaken piling on both the adjacent sites on behalf of Barrow, “so we had a fair idea of what was there,” he says.

The view of the neighbouring siteThe site is surrounded by established buildings such as Oxford and Glenhove – most of them developed by Barrow Properties.

Haas says it is a useful risk mitigation technique to get the same piling company and the same geotechnical company to work on adjoining sites. “It is very important to do a geotechnical investigation if you don’t know what is going on in that area. There are lots of jobs we tender on where there is not a proper geotechnical investigation — where guys just do back-holes or they do penotrometer tests, which can give you an indication but do not tell you where the rock is. The back-holes only go down three-and-a-half metres, and if the rock commences below that, it doesn’t tell you anything about the rock.”

The general challenge with piling is to have the right machine for the job. For this reason, Gauteng Piling owns all its own equipment. In fact, nationally, there are not many machines for hire, “and there are far too many piling companies in the country for the amount of work available at the moment”.

The siteThe site is about nine metres below ground.

Explaining his company’s growth, Haas says that piling is a capital-intensive business, thereby creating a significant barrier to entry. Barrow Construction owns 40% of Gauteng Piling. “When we were getting established in 1996, it was our original intention to overcome the heavy requirement for capital by selling shares to five separate construction companies — but Barrow (through John Barrow Snr) was willing to take all 40% in what was a strategic partnership. It has been a very good partnership for us. This deal enabled us to buy our initial three machines (at current value of R1.8-million each), for which Barrow assisted us with arranging bank finance.”

Nico Haas and supervisorNico Haas, CEO of Gauteng Piling, with supervisor Victor Mudau on the right.

The motivation for the strategic partnership, says Haas, is that while capital is essential in acquiring the costly piling equipment, so too is the need for deep knowledge and experience for each type of area to be piled. “This is possibly even harder to acquire than capital, and my contribution [to the partnership] was my experience in working on all types of difficult sites, including dolomitic sites and on bridges.” He gives the example of cross-border work in Africa, which is popular today but for which Gauteng Piling finds the risks too high. “One can lose a lot of money when working on sites with terrible ground conditions. Especially in the DRC, there are sites where the ground is volcanic ash, and on drilling down five metres it becomes like cotton wool. We worked on one such site, lost a lot of money, and will consequently not go cross-border today.”

“The single biggest challenge in piling is having experienced people who understand the conditions and are able to interpret the soil report. However, based on current market conditions in South Africa, the biggest challenges today are getting work at the right price, and then getting paid,” says Haas.

Professional team

Client: Barrow Properties
Main contractor: Barrow Construction
Architect: LYT Architecture
Civil engineer: Kantley & Templar
Quantity surveyor: Barrow Construction
Geotechnical: Gauteng Piling 

* Photos by Eamonn Ryan


 

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