Durban - There were three points of weakness close to each other in the partly built Tongaat mall which collapsed last November, with one of the beams being the “weakest link,” an independent engineering expert testified yesterday.
Ed Weakley, who was called in after the tragedy by the insurers, also told the commission of inquiry into last November's collapse Ä when two workers were killed and 29 others were injured Ä that the foundations of one of the columns that supported the beam in question was inadequate as there was only one pile.
One was not sufficient to carry the required load and, in his opinion, there should have been three piles, he said.
The department of labour-run commission of inquiry is to prepare a report on its findings and formulate recommendations to the labour minister and the director of public prosecutions for their consideration.
Presiding officer Phumudzo Maphaha, the department’s occupational health and safety manager, who visited the construction site on Wednesday, said yesterday that the aim was also to ensure that such incidents never happened again.
Weakley, who visited the site of the tragedy several times, said that the various engineers involved in the inquiry had reached agreement that the “triggers” for the collapse involved beam number seven and columns 243 and 319.
The beam had not been cast in a single pouring, he said. It had a join and, in his opinion, it could break at this point of weakness.
There were also seven reinforcing rods in the beam instead of the required 19, although only six were cast in concrete.
Column 243, a critical column required to support of lot of work, was close to its load-carrying capacity, he said.
In his opinion, the “column 243 could have failed along with beam seven,” he said, adding there were other general construction defects. Some of the columns were not being perfectly vertical which would have made them weak and meant their capacity to support was reduced.
Asked by advocate Saleem Khan, for Gralio Precast, the contractor, what he would have done if he knew that column 243 was close to its load capacity, he said he would have made the column bigger.
Asked again what he would have done in the event of an inadequate foundation in column 319, he said he would have taken measures to compensate and carried out underpinning.
Weakley was also asked by Khan if the engineer Andre Ballack had been negligent and he replied that there was negligence in relation to the design load of column 243, although he stressed he did not interrogate Ballack’s calculations.
Lawyer Richard Hoal, for the engineers, said any suggestion of negligence depended on whether the structure was braced or not. He said in an interview after the hearing that this suggested negligence was not the cause of the collapse of the mall.
The hearing continues on Friday, when an independent engineer called in by the eThekwini Municipality is to be quizzed on his report.