CRC building in Rivonia a monument to engineering innovation

CRC
building in Rivonia a monument to engineering innovation

The new Christian Revival
Church (CRC) on
the corner of Witkoppen and Riverbend Roads in Fourways is an architectural and structural-engineering feat
that showcases excellence in the design and application of steel and concrete
technologies.

It also bears testament to
the skills and capabilities of DBM Architects and Fortem Consulting Engineers,
as well as the principal contractor, Mike Buyskes Construction, which executed
the technically complex design with meticulous precision.

Among the many stand-out
features of the building is the spiral ramp in the entrance hall. Starting at
the lower parking basement, it provides the about 6 000 congregants with safe
and convenient access to all four levels of the building.

It is suspended from the
roof via a circular reinforced concrete beam-and-slab system that is supported
by a central reinforced concrete column.

The slab-and-beam system is
braced by perimeter
columns and beams which also support the building’s glass façade. Suspended
from the slab-and-beam system, slender steel hangers with adjustable couplers
support the inner steel stringer channels. The latter are connected to the
outer steel stringer channels, braced at various points to the columns
surrounding the ramp, with I-beams. A reinforced concrete slab that forms the
floor of the ramp is supported between the two stringers and intermediate
I-beams for the length of the spiral ramp.

Another
engineering highlight is the steel ring that supports
the concrete staircase leading from the one side of the triple-volume entrance
atrium. It fulfils a critical aesthetic function by eliminating the need for
reinforced concrete columns extending from the first to the second landing.

The base of the structure
is supported on either side by a reinforced concrete column located beneath the
landing of the first flight. It circumvents the first flight’s staircase landing
and connects with the base of the second staircase at the apex of the circle.
The structure is fixed to the base of the second flight staircase landing and
at either side of the landing of the first flight to provide stability.

Another highlight of the
church is the auditorium’s 14 m cantilevered balcony. An in-situ-cast raking beam, which was pre-cambered to minimise
long-term deflection, supports precast-concrete seating slabs. This upper
gallery seating area has no columns below that would obscure views of
the stage.

Both the entire lower and upper auditorium area for
the 4 500 congregants is enclosed by a curved structural steel roof that
is supported by seven 1,9m-deep
and 2,4m-wide triangular-shaped roof
trusses.

These “Toblerone” trusses
were fabricated from
a variety of circular hollow sections with two top chords and one bottom chord
connected with diagonal members along the span.

The
top chords are braced together with horizontal circular members, while
intermediate support is provided by a curved ring beam located at different
points along the length of the trusses and which form the rear perimeter of the
auditorium.

In
order to reduce load on the 8000m² elevated parking structure
to provide cost savings in the foundations and columns, Fortem Consulting
Engineers’ Director, Hans Koorn, recommended the use of SCP 327 as a
waterproofing agent.

This is opposed to the
traditional approach of waterproofing parking decks by first applying a thin
impermeable membrane and then constructing a sacrificial asphalt overlay or
paving blocks that increase the overall weight of the slab.

SCP 327 is known for its ability to enhance and improve concrete performance throughout
its service life.

The product penetrates into the capillaries and
pores of reinforced concrete structures to protect the embedded reinforcing
steel. Once it has reacted with the free alkali, it forms a Calcium Silicate
Hydrate gel within the concrete capillary and pore structure to reduce water
migration to levels acceptable for most adhesives, coatings and coverings.

International
tests have shown that concrete treated with SCP 327 is able to withstand 100m
of head pressure, while the full range of Spray-Lock Concrete Protection
products continue to undergo extensive testing worldwide, including in South Africa
by the University of Cape Town’s Department of Civil Engineering.

Notably,
Spray-Lock Concrete Protection products are also known for increasing concrete
durability to provide longer lasting and less maintenance-intensive concrete
structures.   

Koorn
and his team were first introduced to SCP 327 by Leonard Scott-Turner, Managing
Director of Concrete Junction, and Carl White, Managing Director of Creative
Engineering.

Creative
Engineering is the South African agent for the full range of Spray-Lock
Concrete Protection products and Concrete Junction, the approved applicator.

“The
product has been used on many large international projects, including bridges,
ports and wastewater treatment plants considering its ability to also improve
the compressive and flexural strength, as well as the density of the concrete.
These were also other notable advantages of SCP 327, although the quality of
the concrete on this project already was of an exceptionally high standard
before being treated with SCP327,” Koorn says.

Importantly,
SCP 327 also acts as a curing compound for new concrete and, therefore,
eliminates the need for water curing/ponding. Due to design strengths being
reached earlier, formwork stripping times can be reduced. This was a major additional
benefit for Mike Buyskes Construction, which was working to
extremely tight deadlines.

Concrete Junction applied the treatment
within two to three hours after the concrete had been power floated, with a
litre of SCP 327 covering a surface area of about five square metres. The
treatment proved to be successful in drastically reducing shrinkage, in
addition to acting as a curing compound and moisture barrier.

As
advised by Concrete Junction and the Creative Engineering, critical areas, such
as construction and expansion joints, were treated separately. Hydrophilic
water stops were placed at the construction joints and Polyurea then applied
over both the construction and expansion joints.

As
a leader in the field of waterproofing, expansion-joint sealing, as well as
concrete repairs and rehabilitation, Concrete Junction assisted Fortem
Consulting Engineers with the design of the treatment of these critical areas.

Both White and Scott-Tuner conclude by noting that they are proud to be associated with a prestigious project that has already received so much acclaim for innovation by the South African built-environment profession, and look forward to continuing their long working relationship with Fortem Consulting Engineers.

For more information please
contact:

David Poggiolini

David@thecontentengine.co.za

Debbie Poggiolini

debbie@thecontentengine.co.za