Historical McLauthlin Elevator Building: Part 2
In our previous blog post we talked about restoring the iconic iron-clad façade of the McLauthlin Elevator Building, however we have been working at this building for a number of years. 12 years ago, this building, over 100 years old and supported on timber piles, was experiencing noticeable settlement. At that time, the McLaughlin Building was constructed on what appeared to be a location removed from the Boston shoreline, but in reality was straddling some of the old timber dock structures on the prefill harbor shoreline. Groundwater withdrawal that attended the construction and operation of the Callahan Tunnel, along with tidal flow effects through the now backfilled land, caused timber piles to deteriorate. The phenomenon of ground water depletion is well known in the Boston area, most notably in the Back Bay.
12 years ago, CBI engaged in an extensive underpinning replacement of failed timber piles at the McLauthlin Building. Survey points were placed to monitor building grades in the early 1980’s and monitored through today. The information gathered suggested that additional settlements were still taking place. Test pits at several remaining timber supported granite pile caps revealed that deterioration had continued to the point where additional measures would be necessary to preserve the vertical support system of the structure.
Underpinning repair to the piles were done in two ways. Replacement of rotted timber sections with steel pipes and concrete columns in one location and in other locations through the use of rammed piled placed by the Helical Pile Company and overseen by BC Construction, completed this phase of the project.