Tuesday, August 11, 2015

After reading this report, you’ll think twice about going over the Pattullo Bridge

A few weekends ago, I was walking on Columbia Street with some friends. We were walking from Downtown New Westminster to the Brewery District near Sapperton SkyTrain station. We walked underneath the Pattullo Bridge.

Now, it is generally known that the Pattullo Bridge is in rough shape, but what I saw was shocking. There was netting installing under the bridge to prevent chunks of the bridge from hitting people walking, cycling, or driving along Columbia. I wish I took a picture. Clearly TransLink has been monitoring the condition of the bridge because where there was sections of cracked concrete, or exposed rebar, there was orange spray paint. I am not exaggeration when I say that the section of bridge deck above Columbia Street was covered in spray paint. Beyond the cracks and sections of missing concrete, the bridge is also rusting away.

Sometimes when governments say something needs to be replaced due to age, there is an ulterior motive. For example, both the old Port Mann Bridge and the current Massey Tunnel were/are in a state of good repair, but one was replaced to build a massive toll highway and the other is being replaced to enable better access for Port Metro Vancouver.

The Pattullo Bridge needs to be replaced because it is falling into the Fraser River, but how bad is it in need of replacement?

I found a June 17, 2014 report on the bridge deep within TransLink’s website. The bridge has the following overall issues:

  • susceptibility to collapse from a moderate earthquake;
  • river scour threat to the stability of the bridge foundations;
  • a delaminating bridge deck [concrete and rebar seperating;
  • concrete and steel structural elements reaching the end of their functional life;
  • spalling concrete from the underside of the deck and from the piers creating a falling debris hazard;
  • narrow travel lanes;
  • no median barrier;
  • the bridge has not been designed to withstand a vessel impact;
  • poor pedestrian/cycling facilities, including an absence of suicide prevention measures.

Overall it is in rough shape, but some of the details really make you think twice about using the bridge. For example, the report states:

The inspected deck areas varied between fair and poor, with considerable areas of delamination (disconnection of the concrete from the steel), localized patching, and surface spalls. While deck patching and repaving have been undertaken in recent years, these repairs are considered viable in the short-term only. It is expected that the corrosion and its related damage will occur at an increasing rate, requiring bridge maintenance closures to occur at increasing frequency and for longer durations.

There have been several instances during the current and previous deck repair programs where removal of the deteriorated concrete from the top surface of the deck resulted in small holes through the deck, usually less than approximately 100 mm in diameter. The frequency and size of these full-thickness damage events should be expected to increase over time. At this time, the possibility of a localized full thickness deck failure (a small or large but deep pothole that could cause damage to vehicles) cannot be ruled out.

With this is mind, it is no surprise that TransLink is planning massive closures for the bridge to complete a $100 million repair job in 2016. Of course, there will still be fundamental issues with the bridge. Even with the repairs, the bridge’s life will only be extended by about decade. The repairs will only “reduce the magnitude of the prevailing risks” of having the Pattullo Bridge remain in service.

It is interesting that the provincial government is committed to replacing the safe Massey Tunnel, but expects local government to come up with the majority of the funds to replace the Pattullo Bridge which is crumbling into the Fraser River.

1 comment:

Adrian said...

This is scary stuff. Why isn't the province all over this?