Your browser is no longer supported

For the best possible experience using our website we recommend you upgrade to a newer version or another browser.

Your browser appears to have cookies disabled. For the best experience of this website, please enable cookies in your browser

We'll assume we have your consent to use cookies, for example so you won't need to log in each time you visit our site.
Learn more

Errors and ignored cracks led to Injaka collapse, inquiry told

THE OFFICIAL inquiry into last year's Injaka bridge collapse in South Africa has heard of errors in the deck-launching procedures and that cracks in the deck were ignored.

Fourteen people died when the incrementally-launched second span of the seven span concrete box girder crossing collapsed last July. Shear failure of the lower flange over temporary bearings at the second pier has been blamed (NCE 21 January). Under questioning last week workers from main contractor Concor Construction admitted that Teflon pads were sometimes fed into the bearings the wrong way round because it was easier.

These 600mm by 350mm pads were meant to move with the deck over the 1m by 1m bearings and allow it to slide smoothly. The pads should have been inserted with the long side at right angles to the deck. However, workers said that on occasions the pads were rotated by 90degrees and fed in lengthways, halving the area of contact with the support and doubling the pressure on the underside of the deck.

The inquiry was also told this week that cracks in segment two of the deck, which was resting over an intermediate support at the time of the collapse, were ignored by designer VKE.

Concor contract manager Lesley Wardaugh said he had pointed out to VKE a series of 0.5mm wide cracks in the segment's internal diaphragm wall.

The inquiry heard that assistant resident engineer Marelize Gouws, who died in the collapse, told bridge designer Johan Bischoff about the cracks but was instructed over the telephone to carry on with the launch. She was then told to release four of the segment's 18 prestressing cables the next day to close up the cracks.

This week the South African Department of Labour's investigating expert Andries Oosthuizen will take to the stand. He is expected to agree with experts appointed by VKE and Concor that the trigger for the collapse was the failure of the deck's flange over the intermediate support. But sources claimed he was also likely to point out 'more fundamental errors'.

The inquiry, held at Council of Scientific & Industrial Research offices in Pretoria, is expected to continue until 19 February.

Have your say

You must sign in to make a comment

Please remember that the submission of any material is governed by our Terms and Conditions and by submitting material you confirm your agreement to these Terms and Conditions. Please note comments made online may also be published in the print edition of New Civil Engineer. Links may be included in your comments but HTML is not permitted.