Monday, February 11, 2013

London Bridge is Falling Down.....

You get used to something happening that you might not expect when you are the caretaker of a spectacular spot such as Swallow Tail peninsula but loosing a substantial chunk of concrete from under the end of the concrete steps and the beginning of the bridge was not one that we wanted to see.

The concrete steps replaced wooden ones in the late 1960s.  Built by the keeper at the time, Grimmer Ingersoll, and a crew of other able-bodied men, they were designed to be durable and functional, with a ramp on one side to slide items down and hand rails on both sides to protect the user from extreme wind gusts and guide them up or down, day or night.
Morrill and Laurel Ingersoll on the wooden footbridge in 1966.  The former wooden stairs can be seen in the background.  The gate was to keep their rabbits on the peninsula.  Photo from the collection of Hilda and the late Grimmer Ingersoll.
Current concrete stairs with ramp on one side.
The wooden foot bridge spans a gully called the Sawpit which is a mafic dike, a lava flow of iron rich rocks that filled a gap 200 MYA between much older rock of probably 500 MYA.  The foot bridge allowed access at all times to the peninsula and was used by the keepers and visitors since the lighthouse was built in 1860.
Old wooden foot bridge prior to 1922. This was the first of two footbridges at the top of the hill.  This spanned a gully that was filled in 1966, eliminating the need for this bridge. This area is now a parking area and has picnic tables and a bench.  The lower bridge at the foot of the stairs is not in this photo. From a postcard.
The deck of the bridge was replaced in 1996 by the Village of North Head, reusing the existing metal support legs, and has seen its share of weather.  The concrete block kept the rocks in place, provided support for the end of the concrete stairs and for the bridge.  Through many years of freezing and thawing and rocks eroding away, the massive block let go sometime at the end of January and slid down the slope, lodging against one of the metal support legs.
Footbridge with concrete block in place, October 2012

Footbridge with concrete block fallen and lodged against the metal support  leg, February 2013
We are now consulting with structural engineers, trying to figure out how to move the block off the support leg and how to reconstruct crib work or something similar to replace the previous function of the block and repair any damage caused by the collision of the concrete with the support leg.  While this is happening, we unfortunately must restrict access to Swallow Tail as a safety precaution.  We hope this will not be for a long time and apologize to anyone who is inconvenienced by this.

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