10.3. SR 05-07-2018 - Laserfiche WebLink

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City of Elk River Jackson Street Water Tower Condition Assessment August 3, 2015 CDG Project # 15010.00 EXECUTIVE SUMMARY From a structural standpoint, all components of the Water Tower appear to be performing well. Besides some more superficial issues, such as the presence of chipped paint, rust, and lichen, all steel components are in average condition, especially for their age. The legs are securely bolted to the concrete footings. There are no noticeable problems with any of the tie rods, horizontal girders, or lattice work on the legs. Two issues were observed, both located on the legs, which will need further maintenance beyond the obvious painting. The first issue relates to some corrosion of the steel at the base of the legs. This condition is hidden by the concrete that was installed to drain water from the legs. It would be important to investigate the condition of the steel behind the concrete further during the painting project by removing a portion of the concrete infill and inspecting the steel. If the corrosion is worse than what is observed presently, some remedial action may need to be done to strengthen the base, such as the addition of steel plates to replace the loss of cross sectional area due to corrosion. The second potential concern involves the steel splice plates connecting the leg sections. Some of the plates are bowing as result of rust jacking, which occurs when the backside of the metal rusts and expands, causing the front of the panel to move outward. Further investigation and testing is recommended to confirm the severity of the corrosion and determine the proper remedial action. Paint is chipping on the Water Tower's legs, tie rods, and horizontal girders; the surface of much of the exposed steel is covered in rust. The condition of the underside of the tank and its surrounding walkway platform was observed to be similar to that of the legs, tie rods, and girders, with a significant amount of weathered paint and rust. The sides of the tank appeared to be in good condition relative to the rest of the Tower, but the roof and cap are weathered with rust stains present from seams in the roof panels. Considering that the Water Tower structure is no longer supporting the weight of water in a full tank, maintenance and periodic observation will be all that is required in the future, and no major structural modifications will be necessary. Some minor modifications may be necessary as identified above. All of the Tower's surfaces should be painted, including areas that may not be easily visible from the ground, such as any exposed areas of steel angles, the inside of legs, and the walkway platform. A new coat of paint will not only return it to its original appearance, but it will also protect the steel from further rusting and deterioration. The two potential structural issues should be further investigated with a more in depth study of the areas in question. We recommend that a portion of concrete from one of the leg bases be removed to get a better understanding of the condition of the steel. The bowing steel splice panels should also be closely observed and tested to determine the extent of damage. Co COLLABORATIVE DesignGroup,,nc.