Miller Consulting Engineers provided structural engineering services for this 200,000 square foot, four-level parking garage that serves residents of the American Plaza Condominium Towers in downtown Portland, Oregon. The garage was originally constructed in the early 1970s, and consists of a reinforced concrete waffle slab for the elevated levels of the structure. MCE was contacted to provide an assessment of the condition of the structure, as cracks were observed throughout many areas of the waffle slab and deterioration/corrosion was present in numerous areas of the slab.
The initial phase of MCE’s scope of services consisted of providing a visual observation of the garage, a preliminary review of the loading capacity of the structure, and a report outlining a recommended course of action to repair the structurally deficient areas.
The second phase of work consisted of MCE preparing a finite element analysis of the entire garage structure in order to more exactly identify areas that were overstressed. The finite element analysis allowed a precise measure of the structure’s load carrying capabilities, and thereby reduced the overall scope of structural upgrades. MCE also worked closely with a testing agency to outline areas of the building where non-destructive and destructive tests were needed in order to verify both the reinforcing steel in the slab and the compressive strength of the concrete. Additionally, MCE prepared an Engineer’s Opinion of Probable Construction Costs for the client to use in planning out the repair phases.
The third and final phase consisted of preparing construction drawings for the structural upgrades, and providing construction administration services. Various upgrade and repair methods will be utilized to strengthen the structural elements, including the use of fiber reinforced polymers (FRP), conventional reinforcing steel, and repair mortars. This phase of the project is currently ongoing.