Review of Saddledome's roof reveals concerns, mysteries

An engineering assessment on the condition of the roof of the Scotiabank Saddledome concludes there are issues with the aging structure, but also numerous unknown matters which require further exploration.

Despite that, the City of Calgary, which owns the building, dismisses the idea that any of the problems identified in the report as "critical" are truly serious or require immediate action.

It said no major expenditures on the building will be included in the city's upcoming four year budget.

CBC News obtained the assessment report by filing a request under the province's Freedom of Information legislation.

The report was done by engineering firm Entuitive, in January 2019. The City of Calgary confirmed it is the most recent such assessment.

The roof of the arena, which opened in 1983, is an interconnected system which gives the building its distinctive saddle shape.

It's made up of a series of cables which were attached to its perimeter roof ring. Concrete panels were then suspended on those cables and sealed in.

Further investigation needed

The company's review did not reveal any evidence that the Saddledome's roof has deteriorated so much that it presents a structural or safety concern. 

However, it did have numerous concerns with what it found.

Entuitive noted that:

• "...there is no information available regarding the condition of the cable system (cable net and anchorages) which, over a period of years, is likely to have deteriorated but the extent of which is unknown. It is critical that a testing agency be commissioned to establish a level of confidence regarding the current condition of the structure."
• "...a review of the condition of the bonded cable system must be undertaken and an ongoing deterioration mitigation plan must be followed per our recommendations. It is also critical that loading applied to the roof system remain within the allowances noted in this report."
• "Given the history of the roof membrane discontinuities and probability of moisture contact within the unbonded strands, corrosion of the strands is occurring. There is also the potential of corrosion of the cables." 
• "Unfortunately, conditions of the cable anchors are concealed at this time. Further investigation is required." 

Entuitive found roof cables that were exposed and showed signs of rust. It said it's possible that four cables have experienced breaks over an 18 year period.

It noted that the cable anchorage at high points of the Saddledome's roof are at risk of deteriorating due to corrosion, based on observation of the building's ring beam.

An acoustic monitoring system was established in 1998 to detect when strands break.

Netting installed

While the city owns the building, it is leased to the Calgary Sports and Entertainment Corporation (CSEC) which has several of its teams using the arena, including the NHL's Calgary Flames.

In January 2022, CSEC hired a contractor to install netting along much of the roof's ring beam to prevent concrete from falling free and posing any risk to areas or people walking below it.

The unknown condition of the support cables inside the roof structure appear to be a concern for Entuitive.

In the report, it noted that there is no redundancy between cables.

"Therefore, should failure of a cable occur, it could be sudden, and both the cable and adjacent sections of precast panel may collapse. It is critical, that a method(s) to inspect the cables and cable anchorage, enough to provide confidence in the condition, be determined and implemented." 

City not worried

The City of Calgary refused requests to do an interview on the condition of the Saddledome.

However a senior official with the city, who was authorized to speak on a background basis, said that after reviewing the report, the city has no major concerns.

The official likened the report to a list of things a homeowner might need to do to keep their house in top shape, but there isn't a critical time crunch to fix them. 

A separate report on the entire Saddledome done by Entuitive recommended the building needs tens of millions of dollars in work by the middle of this decade.

The city official said that the Saddledome is maintained as needed and it's currently listed as being in good to fair condition.

If any major expenditures were planned, funding would have to be approved by city council.

Roof limits operations

The limitations of the Saddledome's roof have been well documented.

The facility has been limited in terms of what kinds of events it can book because the roof cannot support certain stage and equipment setups which have been growing in weight. 

This has resulted in some performing artists skipping Calgary for other cities that have buildings which can accommodate their shows.

The city reached a deal in 2019 with CSEC to jointly fund a new $600 million event centre to replace the Saddledome, a short distance from the current arena's site.

However, the Flames' ownership group walked away from the agreement in December 2021 due to rising costs so the deal was terminated.

CSEC has 11 years remaining on its current lease for the Saddledome.

City council remains committed to pursuing a new arena.

It is currently looking for interested partners, including again possibly exploring CSEC's interest, to see if a new agreement can be reached.