The project involved the replacement of the Route 18 bridge over the MBTA Railroad. Sixteen (16) drilled shafts with diameters of 48 and 78 inches were installed to support the abutments and piers, respectively. The project was carried out in 2 phases to allow for continued traffic flow over this busy corridor during construction.
HUB foundation engaged GTR to perform Cross-hole Sonic Logging (CSL) on the sixteen (16) drilled shafts. The CSL results for a few of the drilled shafts indicated anomalies. Most anomalies observed were minor and by implementing Cross-hole Tomography, estimated strength evaluations and rebound hammer testing, GTR provided a means for the shafts to be accepted. A couple anomalies where more significant and considered defects. GTR provided remediation procedures, such as drilling a micropile through the defect zone to repair the shaft. This was a quick and effective solution for the shaft.
