The new six-storey 2Ten Hotel is immediately noticeable by the slender and elegant vertical and horizontal lines that traverse the full length and width of the east, west and south walls of the structure.

Meanwhile, lean horizontal and vertical strips of pre-cast concrete coping on the perimeter of the north side seamlessly blend in with the exposed concrete columns and roof slabs, as well as other building materials, to complete the external aesthetics. The look is enhanced by the rounded chamfers, as well as smooth and silky finish of each pre-cast concrete panel and coping that makes up the external façade of the new hotel.

The façade of the structure was the most complex aspect of Corestruc’s large involvement in this project, which entailed the accurate installation of more than 800 square metres of pre-cast concrete wall panels and coping.

By August, the pre-cast concrete specialist was finalising minor aspects of its contract, while the various specialist trades had already commenced their operations.

Corestruc’s team started working on the façade earlier this year after completing the bulk of the super-structure, consisting of pre-cast concrete columns, beams and slabs. 

George Magwabeni, the developer of 2Ten Hotel and owner of EMM Convention Centre, was first introduced to the company’s modular construction system by structural engineer on this project, Paul Botha. Representing VBL Consulting Engineers, Botha worked with Corestruc and other CORE group companies on another successful project.

The professional team agreed that the system would help achieve the client’s requirements for a durable build that would continue to add value for many years, while providing a modern and sophisticated look.

Moreover, a modular approach to construction would also overcome many of the complexities associated with conventional in-situ construction techniques, especially on this extremely congested site. In addition to the EMM Convention Centre to the right, the site neighbours another building expansion programme to the north. They encroach on the site boundary with merely a few metres distancing the west wall of the new 2Ten Hotel from the existing EMM Convention Centre. 

Willie de Jager, managing director of Corestruc, says a pre-cast concrete system eliminated the need to install and erect scaffolding, while doing away with large shuttering and formwork teams on site, as well as the complex co-ordination of building material deliveries.

“Right from the outset, we were well aware that the success of the project relied on close co-ordination between our teams and CoreSlab, the manufacturer of the system. During the early design phases of the structure, we also worked closely with our sister company to determine the most optimal construction sequence, which relied on timely supply of the pre-cast concrete items,” says De Jager.

Meticulous attention was also paid to the connection system that was designed and manufactured especially for this project to avoid unnecessary handling of the panels and coping, while striking a balance between cost and site conditions.

A template to guide the installation teams was also finalised, and work commenced with the bolting and grouting of the coping into the hollow-core slabs at each floor level of the structure which, in turn, support the large wall panels to complete the external pre-cast concrete shell.

Despite a slow start, up to nine wall panels were delivered to site and installed in a day, while accuracies of between two millimetres (mm) and three millimetres were achieved by Corestruc’s installation team.

They were dispatched by CoreSlab on a just-in-time basis due to the severely constrained working conditions. There was just enough space for the tower crane laydown area behind the structure, while deliveries also had to be co-ordinated via the main entrance to the EMM Convention Centre. Once on site, trailers had to be separated to allow the truck to manoeuvre around the tower crane.

Jaco de Bruin, managing director of CoreSlab, says that a special self-compacting concrete mix was designed especially for this project to ensure swift turnaround times at the batching plant, and has since been introduced to all of the company’s other projects.

Precision in the casting process was also facilitated by the specialised forms that were imported from Australia.

As is the case on all of the company’s projects, a system of pre-checks and post-checks are undertaken throughout the production cycle, while sensors inside the sophisticated plant constantly monitor the temperature and moisture content of the concrete mix.

Only washed aggregates and sand from reputable suppliers enter the production cycle and silica fume supplements a portion of the cement content to create a denser micro-structure of the concrete.

A separate steel-fixing yard also ensures a high quality reinforcing in the concrete casing.

The skills of Corehire, another member of the CORE group that specialises in heavy lifting, was appointed to erect the tower crane once the foundations had been cast.

Positioned in the middle of the site, it provided adequate reach to help Corestruc’s small team, comprising seven people, including the crane operator, commence erecting the pre-cast concrete structure.

Extending all the way from ground level to the roof of the hotel, the internal continuous columns vary between 60 MPa and 80 Mpa, with one of these bearing about 400 tons, including structural steel, as well as the pre-cast concrete floor slabs and beams.

The latter span between 5,5 m and eight metres between the centre columns, optimising the use of floor space. They are connected to the perfectly aligned columns that were installed according to a template that was placed on top of the foundations in the very early stages of installation.

De Jager says that, as is the case on all of the company’s projects, nothing was left to chance.
A total station was used to align the columns to achieve the desired levels, demonstrated by the small tolerances at height that were achieved by the installation teams at this stage of the build.

Once the beams were in place, the floor slabs were laid and then filled using a non-stitching self-compacting concrete designed by Corestruc to provide high weather proofing properties. This is in addition to the good curing traits of the grouting.

Corestruc took ownership of the site when the foundations of the structure had already been completed by another contractor. Their limitations meant that they had to be demolished and rebuilt by Corestruc.

This added additional time pressures to the works programme, while the professional team also had to contend with unpredictable and heavy rainfalls in Limpopo. The notorious clay ground conditions in the area, when wet, make it impossible to operate heavy equipment bringing deliveries to a grinding halt.

2Ten Hotel will open its doors in June 2018, by which Magwabeni will have almost doubled available room capacity at the very popular EMM Convention Centre in Sibasa.

Magwabeni is looking forward to opening the new hotel, which will also feature the same high quality facilities its visitors, including government dignitaries, have come to enjoy over the years. They will enter the hotel via a wooden bridge spanning a swimming pool before enjoying amenities, such as a bar, restaurant and gymnasium on the top floor that provides spectaculars views of Sibasa’s rolling green topography.