Deputy Transport Minister Mkhuleko Hlengwa calls for patience as SANRAL aims for Mbokodweni River Bridge reopening by mid-December

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08-11-2024
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Deputy Transport Minister Mkhuleko Hlengwa calls for patience as SANRAL aims for Mbokodweni River Bridge reopening by mid-December

Durban, 7 November 2024 – Deputy Transport Minister Mkhuleko Hlengwa has called for patience from road users as the South African National Roads Agency SOC Limited (SANRAL) undertakes emergency measures to repair the damaged Mbokodweni River Bridge on the N2 in KwaZulu-Natal.

Addressing members of the media, Hlengwa said, “We are calling for public patience as we respond to this crisis on the N2 south bound. SANRAL is doing preliminary work to assess the extent of the damage and a briefing will be given to the Minister in due course.”

“From the briefing I received from SANRAL, there will be two sets of interventions, that will be urgently undertaken, to lift the bridge up. The assurance we want to give is that there is no structural damage to the bridge. These are ‘wear and tear’ elements which have broken down and will require replacement. SANRAL’s technical team is currently assessing how quickly this can be done.”
“It is the intention of SANRAL to ensure that traffic flow resumes on this road within a period of three to four weeks, in time for December. In January SANRAL will undertake comprehensive repairs of the damage to the bridge. This carriageway is due for an upgrade by SANRAL during which further improvements will be made on this road.”

Deputy Minister Hlengwa was accompanied by a delegation from SANRAL that included the Board Chairperson, Themba Mhambi, CEO, Reginald Demana, Chief Construction Operations and Maintenance Engineer, Dumisani Nkabinde, and Acting Regional Manager for the Eastern Region, Dudley Mbambo, to assess the damage at the Mbokodweni River Bridge along the N2 in Durban on Thursday, 7 November, following damage sustained to the bridge on Monday, 4 November.

On that day, SANRAL promptly conducted an emergency inspection and recommended that the bridge be immediately closed to traffic until it is restored to meet safety standards.

According to SANRAL’s preliminary findings, the damage to the bridge resulted from the failure of span four of the bridge caused by the malfunctioning of its bearings, particularly the concrete rocker bearing on the east side, and the central bearings. These bearings, which support the bridge deck, are susceptible to excessive vibrations, such as seismic or earthquake loads, which can induce cracking and splitting.

Built over 64 years ago in the early 1960s, the Mbokodweni Bridge consists of six spans, with a total length of 137.16 meters. It carries the N2 southbound carriageway over the Mbokodweni River from Durban to Port Shepstone.

Over the bridge’s 64-year lifespan, the vibrations, along with potential age-related deterioration, likely caused spalling and cracking of the concrete. The deterioration would have exacerbated the corrosion of the reinforcement within the bearings, weakening them and ultimately leading to their failure.

A full inspection of the remaining bearings is being undertaken as all bearings on the bridge may need to be replaced due to their age and vulnerability. Challenges to the repair work include high-water levels and the ongoing wet season, which will impact access to the site. To manage this, SANRAL will do the work in two phases.

Phase one will involve temporary support for span four, lifting the bridge deck, installing temporary supports with rubber padding, and lowering the new temporary deck to the required road level to allow it to reopen by 13 December 2024, before the holiday season.

Phase two, expected to begin in January 2025, will entail the replacement of all bearings to prevent future failures and to ensure the continued functionality of the bridge. This phase will also address critical repairs, including the restrained cracking. Work will be planned to align with SANRAL’s long-term bridge upgrade plans and will be executed with temporary short-term traffic closures, either at night or on weekends.

Responding to questions around the safety of bridges across the country, SANRAL’s Acting Regional Manager for the Eastern Region, Dudley Mbambo, said, “We conduct regular inspections of all our structures, including bridges, as part of our bridge management system. The most recent assessments were completed in February this year for the entire country.” He added that the Mbokodweni River Bridge received 98% in its last assessment in February and that the bridge failure was due to wear and tear.
Mbambo explained that the technology for bridge construction has advanced since the 60s when concrete bearings with corroding steel bars were used, and that the steel bearings being currently used do not corrode.

SANRAL’s emergency procurement policy is being followed to appoint a competent contractor to attend to the works immediately. This section of the N2 forms part of SANRAL’s major upgrades, with the tender for Package 2 – upgrading of the N2 from Moss Kolnik Drive to Isipingo – due to be published soon.

The southbound carriageway of the N2 is currently closed and traffic accommodation has been established at the Joyner Road Interchange (Exit 146). Metro police and

Road Traffic Inspectorate (RTI) officers are deployed at key intersections to direct traffic. SANRAL and the traffic law enforcement authorities are investigating other traffic management options.

“We recognise the inconvenience caused to road users and the public, especially as traffic has been rerouted through a residential area. We want to reassure everyone that this is a temporary inconvenience and that SANRAL will move with the necessary speed,” said Mbambo.