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case of the 42nd Ave S Bridge, these primary load carrying components are the two longitudinal steel <br />trusses. <br />In-depth Inspection <br />To further ensure the safety of the load -posted 42nd Ave S Bridge, Tukwila requested that TranTech <br />provide an in-depth inspection to ensure its continued safe use. The attached inspection report tabulates <br />and locates the condition of each main span truss element. Below is a summary of the in-depth <br />inspection results provided by the bridge inspectors from Fickett Structural Solutions: <br />The structure has areas of painted over section loss in localized areas along the lower chord and gusset <br />plates. In some areas, the corrosion is becoming active again with minimal section loss at panel points. <br />There are large amounts of debris and guano in most lower panel points and some upper panel points. <br />Most diagonal compression members have pack rust along seams between rivet heads causing up to <br />1/8" deflection along the member. There is seam rust along most vertical members and along sway <br />bracing with areas of pack rust up to 1/4" and 1/16" section loss. Several sway bracing members have <br />high load impact damage which have caused upward deflection in flange angles. The paint system has <br />widespread areas of peeling paint with surface corrosion present. <br />Concluding Remarks <br />Based on this in-depth inspection, it is TranTech's opinion that the bridge can safely continue to serve at <br />a restricted level barring a large-scale seismic event. This continued use must be monitored by more <br />frequent inspections and adjusted as necessary while the process of funding and designing the <br />replacement bridge continues. <br />These results also confirm that the bridge is approaching the end of its service life. Without replacement <br />or major maintenance repairs, it will require more and more restrictions for its continued safe use in the <br />coming years. Maintenance projects have been investigated in the past and it has been determined that <br />the cost of repairing the bridge would not be justified as compared to the replacement cost. Especially <br />the cost to strengthen an old fracture critical bridge to allow unrestricted legal loads. <br />TranTech concurs with Tukwila's timely decision to begin the development of a replacement project. As <br />early as 2016, the City recognized the issues with this important bridge, the magnitude of required <br />rehabilitation, and the scope of a potential replacement project. Projects of this scale historically takes <br />years and sometimes decades to fund /develop and was correctly started well before the end of the <br />bridge's designed service life. <br />Should you have any questions, please call me at 425.453.5545 or email me at <br />knikzad@trantecheng. corn <br />Best regards, <br />Kash Nikzad, PhD, PE <br />Project Manager <br />TranTech Engineering, LLC <br />Attachments: Appendix A — In-depth Inspection Tabulated Results <br />Appendix B - Select Inspection Photos <br />TranTech Engineering, LLC <br />365 — 118th Ave SE, Suite 100, Bellevue, WA 98005 <br />425-453-5545. Fax: 425-453-6779 <br />12 <br />