b'HISTORIC CONSTRUCTIONMelan, in 1893, this construction method essentially entailsbuildinganarchedsteel-beamarmature that follows the general shape of the bridge, then buildingtheformsarounditandencasingthe structure in concrete. In1905,however,theCanadianbuilderswere notcompletelyfamiliarwiththepropertiesof reinforced concrete, so the Canal Lake Bridge arch ringandabutmentsweresignificantlyoverbuilt, probablyinanexcessofcaution.Thestructure has been modified over the years. In particular, it was rehabilitated in 1987. The deck was widened slightlybeyondtheoriginalarchway,andthe originalrailingswerereplacedbysolidconcrete parapetswithinsetrectangularpanelsonthe outside. THE INVENTOR OF THE MELAN SYSTEMIn 1988, the bridge was designated a NationalJoseph Melan was born in Austria in 1854 and lived until 1941. Duringhislifetime,hewasregardedasaleadingauthorityon Historic Site of Canada. The official plaque markingbridge construction. He studied civil engineering at the Technical thesitestatesthatthisstructureillustratestheUniversity of Vienna from 1869 to 1874 and went on to pursue a transitionfromstonetoconcrete,withmassivecareer in railway engineering and bridge-building. abutmentsandsurfacemarkingsimitativeofitsIn 1893, Melan published his highly regarded work on concrete-and-masonry predecessors. iron arches. His Melan Systemquicker and cheaper than other ParksCanadadescribesthisdistinctivefeaturemethodswas first adopted in Europe, but soon moved to North America and other parts of the world. In 1900 he was awarded a inmoredetail,notingthatatthetimeofitsgold medal at the World Exposition in Paris, and by 1924, some construction,thesurfaceofthebridgewas5,000 bridges in the U.S. alone employed the Melan System or a enhancedbymarkingsontheconcretesurface,closely similar method of construction.whichsimulatethevoussoirstonesofmasonry archesandthecoursedstoneworkofstone masonry bridge abutments.These faux-stonework markings would have made the bridge seem more familiar to members of the public at a time when poured concrete was still something of a novelty, and perhaps even increased the confidence of people driving over it. Not long afterwards, however, concrete almost entirely replaced stone as thefavouredmaterialforbridges,andsurfacetreatmentslike these were no longer used.RECENT REHABILITATIONOverthe30yearsfollowingitsrehabilitationandhistorical designation, the Canal Lake Bridge deteriorated further, and in 2018, GMP Contracting Ltd. was hired by the City of KawarthaWeigh ItLakestocarryoutfurtherrehabilitationworktoextenditsPile Itlifespan without sacrificing its historical integrity. The project entailed the construction of a cofferdam, excavating existing fillMonitor Itto expose the bridge arch, repairing damage and deterioration to the concrete, and backfilling using new granular fill at the interior face of the arch itself and the spandrel walls.In addition, the existing concrete curb and barrier wall were removed to facilitate the construction of a new concrete deckProduction Managementslab, new concrete curbs and new parapet walls. The surface of the concrete arch soffit and exterior bridge walls were completelyDowntime Reportingrefaced, and a new guide-rail system was installed. The projectEfficiency Analysiswas completed in March 2019. Inventory ControlThesurfaceoftheconcretewasinpoorcondition,says David Bonsall, manager of structural engineering for D.M. Wills Associates Limited, which worked on the project. He says that1-877-428-3573the rate of deterioration might be slower than you would seeequipfix@equipfix.ca | www.scalelink.comFALL 2021AVENUES 31'