If it begins to drift sideways, the hydraulic jacks are adjusted to steer it back on center. Keeping the box level and on-target is key during the move, so a total station set up at one end monitors prisms mounted to the box. "We have some really experienced guys who know how behaves in all kinds of soils." "For this kind of job, we are talking about millimeters of accuracy," he says. Properly surveying soil characteristics and planning around the environment is critical to the success of the box-jacking method, according to Diego Rodriguez, project manager for Petrucco USA. site, the box's final position was entirely on natural soil. site, the box's final position will be half on the slab and half on soil. The box is pushed off of a concrete launching slab, but that slab does not extend the full distance it will travel. At the Covert Ave. While Petrucco’s method normally calls for sliding the box underneath existing rails, limited site access meant the rail had to be installed on the top of the box. Prep work included excavating the underpass and installing sheet piles to shore up the sides. The 2,000-metric-ton concrete box was cast on site, and then slid 58 ft into its final place. ![]() The Covert Avenue box consists of a 112-ft by 40-ft reinforced concrete slab, with 24-ft side walls and two spans on top bearing rail and a roadway. ![]() and Covert Ave., we will have cars flowing underneath the railroad in six months." But this, it's just ingenious."įor comparison, Tufano says LIRR did a grade-crossing elimination further down the line several years ago that took almost three years to complete. "If we had done it with a conventional method, we would have had to build abutments while the tracks were there, taken a lot more outages to put those abutments in place, and we would have had to fly a bridge in or roll a bridge in, like when we do a bridge replacement. According to Tufano, it's a huge leap forward from how LIRR traditionally does grade-crossing eliminations. "So we profiled our tracks beforehand and we excavate, push this bridge in, put the soil back and build a railroad," he says.
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