This paper discusses the design, construction and performance of a 30 inch thickdiaphragm wall recently constructed in Baltimore, Maryland at Inner Harbor East.The project site is an established marina and waterfront property. The geologicprofile consists of fill, alluvial silt and clay, Potomac sand and clay, decomposedrock, and weathered rock on top of gneiss bedrock. The approximately 1,300 ftlong perimeter diaphragm wall serves as a water cut-off, perimeter basementwall and support of excavation for the high rise project’s five levels of below-groundparking. Due to the fast track construction and the tight schedule, theinitial design of the diaphragm wall was based on a limited amount ofgeotechnical information. Supplemental borings were then performed along thealignment of the wall to verify the design assumptions and wall depths.Additionally, the design criteria required that the wall be keyed into a competentstratum with low permeability. The Engineer of Record for the diaphragm wall,Mueser Rutledge Consulting Engineers (MRCE) completed the design andproduced accelerated construction documents allowing the developer to releasethe drawings early for bid. This paper describes the theoretical soil parametersused to develop the loads, moments, and shears for the design of the diaphragmwall and the temporary tieback anchors. It also discusses the refinement ofthese soil parameters using the observed wall displacements and tieback pre-stressingforces as a baseline. This paper compares the calibrated parameters tothe values used in the design of the wall. It explains how the soil structureinteraction model was developed and the soil parameters calibrated usingPLAXIS 2D non-linear finite element software. The paper also discusses the useof the proprietary CWS joint by Soletanche/Inquip JV as end stop betweenconsecutive wall panels and the unique top-down construction utilized to supportthe diaphragm wall at the Southeast double re-entrant corner.
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