Petty's Run - Capital Park

Petty's Run - Capital Park Project

Client
Hunter Research

Location
Trenton, New Jersey

Structure
Petty’s Run, located in Trenton, NJ, is an underground culvert. It no longer functions as an active waterway, but rather a conduit for storm water run-off. Its stone side walls date from 1814 and are from a different building episode than its brick vaulting, which was erected around 1876. In 1914 substantial cover material was laid atop the culvert, leading to the current excavation initiatives.

Challenge
The unearthing of Petty’s Run is part of a larger urban planning project, intended to highlight and celebrate some of Trenton’s hidden historic remnants. Our investigation of Petty’s Run was twofold. First, evaluate the existing structure to determine if unearthing the culvert might potentially jeopardize its historic fabric and then, if necessary, to design an appropriate bracing plan. Our second role was to oversee the general excavation and provide benching plans and shoring designs throughout the site to ensure safe working conditions.

Scope of Service

Investigate the existing structure of Petty’s Run and identify potential issues related to excavation. Design bracing as needed to protect the structure.
Provide a procedure and mapping for the excavation.
Oversee the excavation process, providing benching plans and shoring designs, as needed.

Solution

The culvert’s stone side walls and brick vaulting were found to be relatively sound. Large washouts at the base of the walls were of concern however, and we recommended infilling any of the voids within 12 inches from the base of the wall with a hydraulic grout.
We designed lateral shoring for a number of the deeper excavation trenches and provided bracing schematics for temporary retaining walls where deep cuts had been dug.
We called for the replacement of corroded railroad ties which were carrying a load of large stone slabs and beginning to fail.