There are several stone arch bridges in South Canterbury built between 1865 and 1880 that are still in use today, one of the best examples being the gorgeous Coonoor Rd - Fairview Rd bridge over Saltwater Creek. This one in particular is a great example of early engineering design and shows a high level of craftsmanship. The bridge was designed by the Levels Road Board at the time, engineered by one William Williamson and built by R B Sibley, there is still a marking stone on the side of the bridge, featuring the builders name and the date of construction; 1870?....the last digit being a little unreadable.
They were originally constructed by building a wooden framework which supported the weight of the prepared stones as they were laid in place. Cement was used only as foundations and in between the stones after the gaps had been filled with chips. Stones cut at angles to give an arch, were packed as tightly as possible. Those last to be placed in position were the wedge shaped key-stones which locked the whole structure and gave it strength. Once they were placed, the wooden framework was removed and the bridge was ready to take the weight of traffic. The years have proven their durability but it’s interesting to note that originally they were constructed over waterways and streams which only flowed in wetter periods and this has been a factor in their survival.
The bridges were made of local Timaru Bluestone, basalt, which was quarried from Kingsdown, large quantities of stone also came from quarries at Wai-iti and Washdyke. Often these bridges were built as single span structures which, of course, needed widening and strengthening to cope with modern usage. This particular bridge was beautifully restored by Mr Kurt Kempf in the 1980’s-90’s and is an outstanding focal feature along the Otipua Creek walkway.
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