Mosquito Road Bridge - Temporary Access Trestle Design and Construction-PPT Presentation

PPT Presentation

Pdf Summary

The Mosquito Road Bridge Replacement Project involves a 1,200-foot cast-in-place balanced-cantilever bridge over the American River, east of Sacramento, California. The $74 million project is led by Eldorado County DOT, with Shimmick Construction as prime contractor and GeoEngineers designing the temporary works.<br /><br />The presentation focuses on temporary access needed to build the bridge in steep, challenging terrain. The work included access roads and county road improvements, a temporary soil nail wall, and two crane trestles providing more than 12,000 square feet of working space. One trestle reached over 60 feet in height and supported equipment such as concrete boom pumps and 275-ton cranes.<br /><br />Design and construction required coordination of road alignments, pile-installation access, geotechnical conditions, drainage, structural loads, and impacts on the permanent structure. The team used LiDAR and modeling, owner-provided geotechnical exploration, test pits, and field adjustments as conditions became clearer. Design goals included reusing available equipment and steel sections, maximizing prefabrication, accommodating field tolerances and variable ground conditions, and enabling end-over-end construction.<br /><br />Trestle foundations used 36-inch drilled shafts and 24-inch steel pipe piles. Construction on the south side was especially challenging because of steep terrain, variable conditions, and down-the-hole hammer requirements; work was sequenced using bench access and progressed across bent rows. The completed temporary works enabled safe access for foundation, superstructure, concrete-delivery, crane-hoisting, and material-staging activities.

Keywords

Mosquito Road Bridge

bridge replacement

temporary works

balanced cantilever

crane trestle

drilled shafts

steel pipe piles

geotechnical conditions

access roads

American River