The Johannesburg Roads Agency (JRS) decided it was time for one of its major bridges to be rehabilitated. The M1 ‘double decker’ is a highway bridge in the city of Johannesburg, between Newton and Fordsburg, which was posing a safety threat to motorists.
No small task
This 15 million Rand rehabilitation project, with a bridge-span of 1.02 km, was no small task and required the expertise of many specialists. Khato Civils were appointed as the main contractor for the project and was assisted by 17 small, medium and micro enterprises. A phenomenal number of 164 people were employed on this rehabilitation process. Sika was Khato Civils’ brand of choice due to its reliable and long-lasting products.
On site training by Sika
The bridge consists of two reinforced concrete deck superstructures, one directly above the other, that are supported on trestle-like piers. A variety of Sika products were specified for structural repairs, structural strengthening and coatings. SikaTop Armatec-110 EpoCem was used as a rebar protective coating in the structural repairs, as it is highly effective for corrosion prevention in concrete reinforcing. Also used in the repair process were the user-friendly Sika Monotop-615 HB which is designed for thick layer concrete repairs, especially for overhead and vertical applications; as well as the SikaGrout-212. For structural strengthening of reinforced concrete structures, and to increase sheer load capacity, SikaWrap-300 C was used. The concrete surface area was treated with the Sikaguard-705 L silane water repellent and SikaTop Seal-107, a polymer modified cement waterproof and chloride and Carbonation resistant, liquid applied membrane coating for concrete. To ensure that all product applications were executed correctly at every stage, all those involved in the project were provided with training and on site support by the Sika team. This included training in processes such as surface preparation, product mixing and product application.
Safety of motorists
A major challenge to all involved was that the motorway was under daily use by traffic. As disruption to traffic had to remain limited, it was anticipated that it would be difficult to complete the task within the allotted 22-month time frame. However, with the use of superior, tailor-made products and the appointment of a committed contractor, the project was completed, three months ahead of time. Mayor Herman Mashaba, who had stated his main concern and priority was the safety of motorists, visited the site and was pleased with the progress.
Roads and bridges form a critical part of the transport infrastructure, especially in a growing city, so their maintenance and rehabilitation are important. Now complete, the mayor and all his citizens of Johannesburg can rest assured that the best products have been used for the project and that this double-decker has a firm foundation.