The Fourth Avenue Bridge Is Falling Down
The Fourth Avenue Bridge has been a major thoroughfare in Moose Jaw since its first wooden iteration in 1911.
It has always been a major traffic bridge over top of the operations of the Canadian Pacific Railway (CPR) today’s forerunner of Canadian Pacific Kansas City Railway (CPKC)
The present day cement Fourth Avenue Bridge was constructed in 1929 and is in dire need of major structural and other repairs.
According to documents submitted by the City to the Canadian Transportation Agency “the Viaduct is well past any legitimate service life expectations.”
Repairs will potentially cost into the tens of millions of dollars and take the main traffic artery out of service for months during reconstruction.
With the design work on the lastest rebuilding proposal for the Fourth Avenue Bridge almost complete the big question is where will the money come from?
The City of Moose Jaw is hoping CPKC will shoulder part of the cost of the multi-million dollar re-build. The railway has responded negatively to the City’s request.
The entire matter is now before arbitration with the Canadian Transportation Agency for a decision.
At the present time neither side is commenting publicly while arbitration is on-going.
The Canadian Transportation Agency is yet to render a decision in the case.
Today we look at true condition of the Fourth Avenue Bridge and how the rough roadway is the least of its problems.
Third in a series.
By Robert Thomas
“The Assessment concluded that the structure will require demolition and replacement within the next 15 years as the continuing deterioration would make a major rehab impossible”
It is not an understatement the Fourth Avenue Bridge is in need of extensive repairs.
It has been in need of repair for some time.
Almost a decade ago a reporter in his weekly column at the now defunct Moose Jaw Times-Herald described the bridge as being “carpet bombed.”
It’s something the City has recognized in condition and engineering reports on the structure.
The City’s 2023 arbitration application to the Canadian Transportation Agency (CTA) contains no less than five engineering reports numbering into the hundreds of pages.
A February 2021 preliminary design report by Associated Engineering lists the costs of rehabilitating the bridge at $12,638,500 (+/- 25 percent).
The major cost estimate in the 2021 preliminary design report is $3,521,500 for structural items.
It also needs to noted these costs are 2021 construction costs and construction costs - just like groceries - have been hit with some major inflationary price increases.
For example concrete prices - a major input to the bridge rehabilitation project - has risen 27 percent since 2020 according to some building trades organizations.
The 2021 calls for 14 major repairs.
The listed repairs are:
Removal of ACP and waterproofing on the deck.
Replacement of deck drains and expansion joints.
Repairs to damaged barriers and sidewalk.
Removal of top 100 mm of concrete deck on 1929 structure.
Removal of top 127 mm of concrete deck on 1965 structure, infill of half of deck voids.
Removal of half joint on 1965 structure and making the deck continuous over the joint.
Partial depth concrete repairs to abutments.
Placement of a reinforced HPC overlay on the deck complete with 2 mats of corrosion resistant reinforcing.
Installation of separation barrier between driving lane and shared use path.
Application of protective concrete sealers.
Replacement of steel barriers with cast-in-place concrete barriers on the 1965 spans.
Installing retaining wall at south abutment and reinstate earth fill.
Repair and replacement of decorative barrier terra cotta bollards and light fixtures.
Redisgn of approach roads to account for elevation change due to overlay.
Photo of the 2020 inspection of the Fourth Avenue Bridge - MJ Independent file photo
It’s obvious that the Fourth Avenue Bridge needs much more than the minor milling and repavement that was done this summer to what many local motorists are now referring to as “goat trails.”
SEE RELATED - Update Given On Future of Fourth Avenue Bridge
A major concern with the Fourth Avenue Bridge has to deal with its ability to carry heavy loads.
A load capacity review found the current structure did not have the capacity to carry the evaluation buses and fire trucks provided by the City.
In layman’s terms if a heavier vehicle were to use the Fourth Avenue Bridge in its present state the odds are sections of the bridge would be severely damaged or even collapse.
The 2021 report stated a “major strengthening rehabilitation of the structure would be required.”
The report calls for a reinforced overlay rehabilitation would allow City buses and fire trucks to use the bridge.
The 2021 report also stated the minimum construction period to rehabilitate and upgrade the structure is 12 months.
The report also included what turned out to be a highly optimistic construction schedule with work beginning in October 2021 with substantial completion in October 2022.
The City did not proceed with the recommended construction schedule due to the lack of funding and the desire to get the Canadian Pacific Kansas City Railroad (CPKC) to contribute to the costs.
The City’s reasons are based upon original the original cost sharing agreement with the CPR and a 1910 order for the original 1911 bridge.
Bridge Chloride Profiling
A major concern with the Fourth Avenue Bridge is the concrete decking and the effects chloride - cement deterioration - has had upon it.
Although covered with a surface layer of asphalt the decking is subject to cracking allowing road salt (sodium chloride) to penetrate causing the cement to weaken or corrode.
As part of the testing eleven locations were tested by coring on the 1929 structure.
The tests on the exposed concrete sidewalk indicated corrosion may have already occurred in multiple locations.
A December 2020 Condition Survey Report by Associated Engineering “found that chloride levels in the bridge deck are above the testing threshold limit corrosion at depths up to 100 mm.”
The report sounded an alarm about the risks of reinforcing within the depths at risk of corrosion “if they have not already started.”
It’s not just corrosion of the cement but also the re-enforcing steel (commonly known as re-bar). The bridges structure is literally in varying stages of corrosion.
The 1965 and 1989 structures chloride corrosion was not as high as the original 1929 structure.
The recommended repair is the removal of 100 mm of the concrete deck on the 1929 structure and removal of 127 mm of the 1965 structure and infill of half the deck voids.
A recent photo of the Fourth Avenue Bridge showing the minor repairs the City conducted this summer - MJ Independent file photo
The Catcher Beam
Structural integrity saw the City close the Fourth Avenue and install a catcher beam.
The catcher beam was installed due to corrosion of the critical half joint.
A December 2020 Condition Survey Report made the recommendation to install a support system below or a catcher beam in case of a sudden collapse. If the half joint area collapsed the support system or catcher beam would catch it from collapsing further.
The catcher beam can be likened to a back up system to stop a total collapse at the half joint.
The recommendation came after an August 27, 2020 visual inspection and sounding of the half joint.
A drawing of the catcher beam installation - City of Moose Jaw engineering report
The visual inspection indicated rebar corrosion was occurring and that “structural capacity can occur with little warning due to a lack of structural redundancy.”
The catcher beam was installed in January 2022.
With the condition of the Fourth Avenue Bridge not improving and many Moose Jaw residents noticing the most recent repairs being superficial it’s a fact not lost to CPKC as well.
The “carpet bombed” observation of a reporter from days gone by is not lost in the on-going disagreement between the City and CPKC.
If you go back to Part One of this series the 1910 order and 1929 agreement called for as one of condition the City to maintain the flooring of the bridge.
The question to be asked did the City live up to its side of the agreement?
It’s something CPKC points out in its position and as such the Railroad claims the repair costs are the City’s alone. Documents the City and CPKC have never released publicly. It’s the topic of Part Four in this series.
Next: Legal Filings
A copy of the front page of the legal response from CPKC