51
CONSTRUCTION WORLD
JUNE
2014
ROADS AND BRIDGES
The contract necessitated the widening of the existing bridges,
which includes the Jan du Toit River bridge. The bridge consists
of three 9,8 m spans and required widening of about three
metres on either side of the deck.
Since the carrying capacity of the original bridge does not comply
with the TMH7 Bridge Loading code requirements, structural strength-
ening of the original deck was required for code compliance. Design
engineers from Aurecon originally specified steel plates, 150 mmwide
and 5 mm thick, with a bolt and epoxy fastening method, as additional
reinforcement to the existing deck soffit.
It was soon realised however, since the bridge is spanning water,
the heavy steel plating system becomes cumbersome and difficult to
handle and install. It would require rust-removing maintenance and
monitoring of the system in the long term. A further problem was
that the steel would be prone to possible theft for sale as scrap metal.
Specialised civil contracting company, DSC-Zendon suggested
the use of carbon fibre plates instead of steel. In liaison with the client
(Western Cape Provincial Government), the designers specified the
used of an approved carbon fibre strengthening system. The contractor
decided to use internationally approved Sika CarboDur S512 Plates
(50 mm x 1,2 mm thick) for the bridge strengthening.
These pultruded carbon fibre reinforced polymer (CFRP) laminates
are designed for structural strengthening of concrete, timber and
masonry and were bonded to the bridge structure using Sikadur-30, a
thixotropic, structural, two-part adhesive, based on a combination of
epoxy resins and special filler.
Sika CarboDur Plates are exceptionally strong and provide excellent
durability and fatigue resistance. Importantly, for this project, these
non-corrosive plates are easy to install, especially overhead. Supplied
in rolls, they are lightweight and easy to transport while their unlimited
lengths eliminate the need for joints. This versatile product is suitable
for use in a wide variety of strengthening and reinforcing applications.
High strength Sikadur-30 (46 kits used), is easy to mix and apply,
hardens without shrinkage and provides high initial and ultimate
mechanical resistance.
Due to the extreme ease of installing 513 metres of the innovative
Sika CarboDur system, DSC-Zendon was able to complete the project in
just one month. This drastic reduction of the installation period enabled
substantial timesaving, which contributed to the project costing the
same as a steel plating installation. With Sika CarboDur Plates being
used worldwide to rectify earthquake-damaged structures, the R43
Bridge is guaranteed to stand the test of time.
BRIDGE WIDENING
Sika’s carbon fibre plates became a feasible
option when the R43 route between Worcester
and Wolseley, in the Western Cape, was recently
upgraded and widened.
Preparation of the Carbodur-Colma cleaner.
Application SikaDur 30.
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