Wirtgen has rolled out an upgraded "Max-Pass AVE" (Automatic Vertical Elevation) stringless paving package for its SP 15i offset slipform paver, targeting curb-and-gutter, median barrier, sidewalk, and parapet applications on highway reconstruction and urban streetscape projects. The SP 15i is a compact offset slipform machine capable of paving monolithic concrete profiles up to 1.3 meters in height and narrow slabs up to 2.1 meters in width. Traditional slipform paving depends on a physical stringline-typically nylon twine strung between steel stakes every 7.5 meters-that defines the reference plane the paver's elevation and steering sensors follow. Setting and surveying stringline for a 2-kilometer curb run typically consumes two surveyors for a full day, and the string is frequently disturbed by foot traffic, wildlife, or adjacent construction activities, producing deviations that translate directly into dimensional errors in the finished concrete.
The Max-Pass AVE system replaces the stringline with a "Leica 3D Machine Control Package" comprising a robotic total station mounted on a fixed survey tripod and a 360-degree prism array on the paver's sensor mast. The engineering breakthrough is the "Automated Vertical Mold Control." The total station tracks the paver's position at 10 hertz and compares its actual location to the 3D design model loaded into the onboard controller. As the paver travels along the design path, the system continuously calculates the required mold elevation and steering offset, then commands the "Offset Mold Hydraulic Lift and Tilt Cylinders" to dynamically position the slipform mold within ±3 millimeters of the design surface-without any physical reference line.
Furthermore, the system features "Profile-Adaptive Mold Logic." For variable-section pours such as monolithic curb-and-gutter that transitions to a median barrier with a taller profile, the system automatically commands the vertical mold's extension stroke to adjust the finished height while the machine continues traveling-eliminating the manual mold repositioning that previously required stopping the pour, re-surveying, and restarting. This continuous profile adaptation increases production rate by 25 percent on variable-section pours and eliminates the stringline disturbance errors that previously required manual hand-finishing of out-of-tolerance sections.
