Newburyport/Rockport line Abutment
Services Applied by VCS Engineering
Project Introduction
The MBTA Newburyport/Rockport line Manchester Harbor crossing fender system plays a critical role in safeguarding the bridge abutments against boat and debris strikes. Comprising 48 timber piles and 11 steel sheet piles, this system has been a key protective measure. However, the absence of detailed as-built plans concerning the depths of these piles posed a significant challenge. The need arose to install a new communication line along the MBTA rail line, but without clarity on the pile lengths, determining how deep to run the lines became a formidable task. In response, NDT Corporation (NDT Corp.) was contracted by Smith Marine, Inc. to conduct pulse-echo pile integrity testing (ASTM D5882) to ascertain the lengths of both the timber and steel piles.
Project Scope
The scope of the project encompassed employing NDT Corp.'s pulse-echo two-sensor setup, coupled with a hammer serving as the excitation energy source, to conduct the pile integrity testing. This method involved placing sensors on the piles and striking near them to generate a wave propagating down the pile to the end, where it reflected back up to the surface. By measuring the time taken for this reflection, the length of the pile could be accurately calculated. Given the unique location of the fender system, situated over water, accessing the piles required innovative solutions. Thus, the testing was executed using a boat to access the face of the timber piles from the water, while the steel sheet piles could be reached from shore during low tide.
Project Solution
NDT Division's comprehensive testing provided crucial insights into the lengths of the timber and steel piles, resolving the ambiguity surrounding their depths. The obtained data, indicating timber piles of approximately 50 feet in length and sheet piles of around 40 feet, proved instrumental in guiding the directional boring for the communication line crossing. Moreover, the inspection results furnished pile lengths and assessed the condition of the timber and steel piles. Visual observations, complemented by pulse-echo testing, highlighted instances of damaged or cracked timber piles and severe deterioration and reduction in thicknesses of the steel sheet piles. With these findings, the project engineers could proceed confidently, ensuring the successful installation of the communication line while taking necessary precautions to address any structural concerns identified during the testing process.
