Convert PDF to SKP

Unfortunately it appears that PDF documents cannot be imported to Sketchup to produce .skp drawings, except in the Mac version that can import PDF files as raster images. You will need some CAD drawings like DXF or DWG for Sketchup. Perhaps you could convert the graphics from PDF document to some vector graphics like SVG or DXF, which you ou can do that in programs like Inkscape, and then import that to SketchUp.