Cape Town – The R130 million new Ashton Arch Bridge was officially opened at a ribbon-cutting ceremony on Sunday by Western Cape Premier Alan Winde together with Transport and Public Works MEC Daylin Mitchell.
The Ashton Arch, located in the small town of Ashton is South Africa's first concrete-tied arch bridge constructed using a transverse launching method.
It replaces an existing multiarch bridge that was built in the 1930s. It is an important tourist destination along the national road crossing the Cogmanskloof River.
The construction of this world-class infrastructure project that created more than 500 work opportunities for local residents commenced five years ago.
To minimise traffic disruption, the new bridge was constructed adjacent to the existing one thereby maintaining traffic over it.
After completion, the new bridge has been used as temporary bypass/river crossing while the existing bridge was demolished, and new abutments built.
The new tied-arch bridge was launched transversely into its final position in less than 24 hours on Saturday, August 14, a first of this kind of construction in Africa.
The modern state-of-the-art structural components were designed, manufactured and installed using complex techniques.
These included the concrete arch ribs, post-tensioned tie beams, stay anchors and cables as well as the transverse launching equipment which had to be specially imported.
Using a transverse launching method for a completed concrete tied-arch road bridge is a first in South Africa.
More than 8 000 tons of concrete and steel were moved over a distance of 24m in less than 24 hours after several years of meticulous planning, design and construction.
The new tied-arch bridge comprises a cable-supported concrete deck which spans 110m between supports with arching ribs rising 22m above the asphalt road surface.
The original earth-filled multiple-arch bridge was constructed in 1930 for single-lane traffic. In 1950, a substantial structural retro fitment that allowed two-way single carriageway vehicular and pedestrian traffic was undertaken.
The superstructure was modified to a cast in-situ beam and slab configuration that maintained portions of the old arch superstructure, including an arch-profile and related hydraulic opening configuration.
The 1950 upgrade was, however, retained at an elevation which still resulted in overtopping with enhanced flood risk to the road and adjacent residential properties.
The high river debris load combined with deep deck and wide solid wall piers, orientated at unfavourable skew angles relative to the flow direction, exacerbated the effects of flooding.
Mitchell said the objective of this project was to reconstruct parts of Trunk Road 31 Sections 2 and 3, from Ashton to Montagu (start of tourist Route 62) to a higher standard to improve traffic and pedestrian safety as well as improve flood capacity of bridges and resistance to overtopping of the road at several problem locations.
This included the Cogmanskloof River crossing in Ashton which has experienced substantial flood damage on several occasions.
“This is a massive contribution to the economy, to an industry under pressure and to the creation of work for our residents. This project created over 500 work opportunities.
“I am very proud of this achievement. My department will continue to upgrade, rehabilitate and maintain provincial roads as well as national roads located in the Western Cape and provide Expanded Public Works Programme (EPWP) work opportunities, develop emerging contractors, and contribute to economic empowerment in local communities where it undertakes projects,” said Mitchell.
“I cannot stress enough the importance of safer roads in this province and its benefits of attracting investors and tourists to boost our economy.
“My department will continue to dedicate resources to constructing, refurbishing, and maintaining roads that change the lives of many for the better,” Mitchell added.
Winde said: “For our economy to grow and create the jobs our province needs to recover from the pandemic, we need to invest in world-class infrastructure that improves access to markets.
“I therefore welcome the opening of the Ashton Bridge today which will improve road access and alleviate congestion along the N1, which is an important route for our regional economy.
“The development of this bridge would not be possible without the support of each and every stakeholder, from the workers and businesses to the broader community. I thank you for making this impressive bridge possible.”
Video: Ian Landsberg/African News Agency (ANA)