City mayor shuts main stadium after consultant’s report highlights roof problems.
Rio de Janeiro’s main athletics stadium for the 2016 Olympics has been closed because of fears about the roof’s ability to resist strong winds.
It will remain closed until engineers find a “definitive solution” to make it safe.
Sited 13km from downtown Rio, the six year-old João Havelange stadium in Rio de Janeiro was shut last month on the orders of the city’s mayor Eduardo Paes.
He was reacting to a report by German consultant Schlaich Bergermann & Partner that warned the structure could collapse if exposed to wind speeds above 18m/s.
“There is a structural problem with the stadium’s roof and we are going to find a definitive solution,” said Paes.
“The [construction] consortium has shown me what the problems are but at this stage there is still no proposal for a solution.
“If they tell me the stadium needs to be closed for a month, it will be closed for a month. If it needs to stay closed for a year, it will be closed for a year,” Paes added.
Known locally as the Engenhao stadium, the 46,000 seat venue is Brazil’s equivalent of Wembley stadium.
Measuring 284m by 232m the main structure is flanked on each side by huge 2m diameter tubular steel, 2m diameter arches that are between 64m and 73m tall.
Coming off the arches are ties that support a 34,250m2 metal roof that covers all seating.
Investigations will now decide whether the problems are due to fabrication and construction faults or down to more fundamental design flaws in the roof structure.
Its closure just as Brazil gears up for the 2014 World Cup and the 2016 Olympic Games is a major embarrassment, not least because on its website project engineer Andrade Rezende acknowledges one of the major challenges was down to the site being “constantly exposed to coastal winds”.
Infrastructure facilities ,including the roof were contracted to OAS, CVS and the Norberto Odebrecht consortium, with TAL Project as lead consultant.
Standing Committee on Structural Safety chairman Gordon Masterton warned repairs to the tubular steel supports carrying the roof would be complex.
“[Repairs] are more difficult than during construction as the steel tube is carrying the full load of the roof,” he said.
In addition, access will also be a problem. Engineers would have to erect a platform to gain access to the weak points on the steel tube.
Alterations would have been much easier during construction as the original welds connecting its various components would have been made at ground level before the roof was installed.
Brazilian television has shown footage of large rusty fractures in at least one of the main steels.
Buro Happold chief executive Paul Westbury told NCE that while expansion and contraction of steelwork caused by Rio’s extreme temperature range could “rip a building apart”, he said it was extremely unlikely to be the cause of the stadium roof’s failure because: ‘…roofs like that just do not flex that much.’
Instead Westbury, who described the failure as “terrifying”, said that while he could only speculate, a failure to protect the steel around key welds was likley:
“From the images I have seen it is probably a protection problem. It is a question of getting the [protective] coating right and not damaging it during construction, particularly around the weld points.”
Masterton said that the relatively low speed of wind that could threaten the stadium roof suggested there was a lack of robustness in the structure.
“There can’t be huge reserves [in the capacity of the roof tube],” he said. “That makes it all the more concerning.”
Concerns about the stadium were first raised in 2009, when, only two years after its opening, Portuguese consultant TAL Project questioned whether it would cope in winds over 32m/s.
Under plans for the 2016 Olympic Games the $192M (£127M) stadium’s seating capacity will be boosted by another 15,000 to around 60,000; but until an engineering solution is found, it will remain shut: “We can’t play around with something like this,” said Paes. “According to this report we can’t open the stadium until we can say the situation has been safely resolved.”
Construction of the stadium was hit by scandal last year, when main contractor Delta was implicated in a massive bribery case involving the head of an illegal gambling cartel, Carlinhos Cachoeira.