A contract manager and engineer involved in the construction of the Grayston Drive pedestrian and cyclist bridge on Wednesday repeatedly declined to answer questions at the inquiry into its collapse in 2015, which killed two people.
Hein Pretorius was on leave on October 14, 2015 when the bridge caved in, also injuring 19 people.
He told the commission he was not in a position to know what had caused the collapse.
He declined to answer a question relating to the load the structure could carry, saying he risked incriminating himself and equally would not say who was responsible for inspections on site.
In reply to a question from the presiding officer in the inquiry, Phumudzo Maphaha, Pretorius said he was aware that the project required a mentor to be appointed for candidate engineer Oliver Aadnesgaard, but conceded that he did not know who the mentor was.
He said he was nonetheless satisfied that Aadnesgaard met the requirements of a competent person.
Pretorius added that he had regularly received health and safety reports from the construction site.
The drawings for the collapsed structure were supplied by FormScaff and Pretorius said his discussions with the company had mainly revolved around the ease with which the temporary bridge could be erected and disassembled.
He would not take a question as to why construction had proceeded without loadings assessments.
Aadnesgaard had similarly declined to answer questions put to him.
The inquiry resumed its work this week for the first time since late last year.
It was set up by the department of labour and is investigating contraventions of the Occupational Health and Safety Act 85 of 1993 which led to the fatal collapse of the structure.
The inquiry is due to continue on Thursday.
