New Zealand's Bridges: Chaney's Overpass in Christchurch (3)

March 2011 (-43.430 Degrees, 172.646 Degrees) Chaney's Overpass

One last photo of Chaney's Overpass. Its odd that the precast girders extend beyond the sides of the pier wall. However, the bridge deck is haunched downward to sit on the pier wall, so its actually a solid cap sitting on the wall. 

It seems like it would have been easier to have set the ends of the girder segments on the wall, but maybe it's easier to design it with the ends near the inflection points of the spans. The wall looks kind of thin to be supporting this big superstructure. Even though it is well-seated at the abutments we could see cracks in the soil where the pier foundation had moved back and forth during the earthquake.

New Zealand's Bridges: Chaney's Overpass in Christchurch (3) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.

New Zealand's Bridges: Chaney's Overpass in Christchurch (2)

March 2011 (-43.430 Degrees, 172.646 Degrees) Chaney's Overpass

Another look at Chaney's Overpass. There are cracks, holes, and ejected material on the ground from February's earthquake. My friend Kawashima-san (in the yellow vest) is so well-known in Japan that he brings his own film crew on earthquake investigations to record his thoughts. 

The bridge barrier rail is bolted to the underside of the deck overhang. I wonder how effective it is at deflecting vehicles? They painted the bottom half of the pier walls for some reason. Maybe it makes them less reflective to oncoming traffic at night? The barrier rails are pretty close to the pier walls. I wonder if they have rules on how close the piers can be to traffic? 

It looks like the slope paving on the far embankment has slid downward. Also, it appears that the wingwall goes straight out instead of running parallel to the roadway.

New Zealand's Bridges: Chaney's Overpass in Christchurch (2) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.

New Zealand's Bridges: Chaney's Overpass in Christchurch (1)

March 2011 (-43.430 Degrees, 172.646 Degrees) Chaney's Overpass

There are just a few highway bridges around Christchurch. Chaney's Overpass is a three span precast box girder bridge that carries southbound Route 1 over the new road that connects northbound Route 1 to the Main North Road. 

This bridge site has some nice sand boils and other signs of liquefaction from the series of earthquakes that started in September of 2010 and has continued sporadically ever since.

New Zealand has made an art and science of building precast girder bridges that are continuous for several spans. This bridge is supported on big pier walls. If you look closely, you can see a construction joint at the top of the walls, but with the wall reinforcement continuing up into the superstructure.The girders are cantilevered over the pier walls and made continuous with drop-in spans over the road and at the abutments.

We'll take another look at this interesting bridge tomorrow.

New Zealand's Bridges: Chaney's Overpass in Christchurch (1) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.