Traylor and its sister company, Ballard Marine Construction, are working as a joint venture to perform rehabilitation on the 94-year-old dam that spans Lake Vermilion in Danville, IL. The lake provides drinking water to the county of Vermilion and the surrounding area. The scope of work consists of replacing ten tainter gates and their trunnion brackets, as well as their actuator/hoist components. There is also a high-level vertical sluice gate to be replaced and a new bulkhead and gate slot assembly to be installed upstream. The gates are covered by a 252-foot-long concrete deck that will be cut out and replaced with prefabricated steel bridge deck pans.
The scope of work has been split into two phases, with the first phase consisting of replacing and commissioning the first six tainter gates and bridge decks, and the second phase focusing on the replacement of tainter gates 7-10, as well as the vertical sluice gate and the bridge decks on top of them. During the second phase of work, Traylor SRG will perform a post-tensioned anchoring campaign to anchor the dam to the bedrock that lies beneath it. A winter work hold from December of 2019 to March of 2020 has been scheduled between the phases.
Prior to working on the tainter gates, the joint venture constructed a permanent sheet pile bulkhead to use as a work platform for the yard crane. The bulkhead will be utilized by Aqua in the future for conducting regular dam and lake maintenance. The joint venture also had to place 20 ballast blocks for the 10 tainter gate bays. The ballast blocks weigh roughly 20 tons each and act as counterweight during demolition of the existing bridge deck and tainter gates to prevent any uplift, since the dam is not currently anchored to the bedrock.
All work is being done from two barge spreads – one upstream and one downstream. The upstream barge spread is where Traylor’s 200-ton Manitowoc 888 sits and the downstream barge has two manlifts that aid in the demolition and installation of the tainter gates.