Productivity Analysis Of Box Jacking

Trenchless Technology (TT) offers methods to install utilities through the ground without damaging the surface. Box Jacking is a trenchless method for installation of prefabricated box and drainage structures without digging a trench. The concept of box jacking is similar to pipe jacking operations by first excavating an entry shaft, building the thrust block and concrete base, and setting jacking equipment. The process starts with pushing boxes while excavating at face, however, the movement of each box is achieved each time excavation at the shield is completed. Additionally, a pilot tube might be required in advance of box jacking operations. Box jacking projects often face schedule delays or loss of productivity due to inherent uncertainties in identifying unmarked underlying structures, type of soil and subsurface conditions. Although there are uncertainties in each and every construction project, management factors have a key role in reducing loss of productivity due to lack of prior investigations and/or improper planning and preparations including means and methods. The main objective of this study is to analyze productivity of box jacking operations, and make recommendations for improvements. To achieve goals of this thesis, a box jacking project was observed. Productivity data was collected and analyzed by MicroCYCLONE simulation and Method Productivity Delay Model (MPDM). While conclusions of this study showed it is possible to improve box jacking productivity, the cost may become major a factor when additional crews and equipment are selected. It should be noted that contractors and field personnel make resource decisions based on their past experiences which allow considerations for safety, productivity and costs. These issues are considered in this thesis while describing features of the case study project.