Construction World December 2018

Consulting Engineers

DOUBLING OF THE TUGELA FERRY RIVER BRIDGE FOR THE KWAZULU-NATAL DEPARTMENT OF TRANSPORT

T he primary concerns were: safety (strength, stability, and robustness), serviceability, economy, constructability, durability and sustainability (i.e. job creation, skills transfer, etc.). The design complied with TMH7 Parts 1, 2 and 3, KZN DOT’s Standards Details and SANRAL’s Code of Procedure for the Planning and Design of Highway and Road Structures in South Africa. One of the challenging demands was that a modern two-way traffic solution with provision for pedestrians had to be provided without impacting on the aesthetics of the existing heritage steel bridge. The existing Tugela Ferry Steel Bridge has monument status and is an icon in the area. Another challenge was to design a foundation solution that would not clash with the existing foundations in spite of the fact that the two bridges are very close to one another. The last challenge was to design a bridge that could be constructed over the fast-flowing Tugela River. Due to the might of the Tugela River, any crossing would be considered unique. The first crossing at this very point was a ferry system consisting of boats being pulled over the river with cables operated from either side of the river bank. The second crossing was in the form of a single lane steel bridge, 5,4 m wide with a total length of 166 m. The current project would then be the third attempt at crossing the mighty Tugela River. Building Information Modelling (BIM) was used The design of the doubling of the Tugela Ferry River Bridge was a complex multi-disciplinary project involving communities, traditional leaders, structural engineers, geotechnical engineers, heritage consultants, environmental consultants as well as occupational health and safety consultants.

PROJECT INFORMATION

• Company entering: Royal HaskoningDHV • Client: KwaZulu-Natal Department of Transport • Project value: R97-million • Main Contractor: Group Five Coastal • Consulting Engineer: Royal HaskoningDHV

for the design and drafting of the bridge. The benefit of using AutoCAD 3D was increased accuracy and efficiency while reducing the risk of errors. The bridge was to consist of six 27,733 m spans with a post tensioned beam and slab deck. Considering the site conditions and the iconic properties of the existing bridge, a post-tensioned beam and slab deck was deemed to be the most suitable structural solution. The bridge project was also used to employ SMME subcontractors and additionally provide direct employment of local labour, providing income for the duration of the contract as well as providing skill transfer. The project is a good example of team work of all concerned; from the local community to the client, team of consulting engineers and the main contractor. The project aptly reflects the ‘Enhancing Society’ philosophy of RHDHV and all involved can be proud of the end product. 

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