Civil Geometrics has been engaged by J.F. White Contracting to provide geometric and survey support services on the new Chelsea Creek Bridge between Chelsea and East Boston, Massachusetts.  This project involves the replacement of the old bascule bridge on Chelsea Street with a new longer (420′) lift span that will acommodate larger tankers and allow access to vital oil import facilities that serve much of New England.  Among the challenges that it offers are the high precision surveys that are required to position the scores of 2″ anchor bolts for the structure’s towers and the delicate alignment challenges that its machinery requires.  We look forward to moving forward with this interesting new project.

In the process of developing our software, we have been using Autodesk’s Civil 3D to check our results.  When some comparisons showed deviations, we were surprised to find that the errors lay not with our work, but with the venerable Civil 3D.  Lengthy correspondence with Autodesk’s developers and a recent (June 2, 2009) meeting at their office confirmed our conclusions.  Autodesk has been working hard to fix their problems and should be caught up soon.  Meanwhile, if you are doing high-speed rail design, use caution with compound spirals!