An extensive instrumentation plan was devised to monitor large-span culvert behavior, soil behavior and culvert-soil interaction during backfilling and during live load testing. The goals of the instrumentation plan were to help control construction deformations, including insuring safe working conditions, and to gather sufficient data to advance the state of the art in the design and construction of large-span culverts. The instrumentation plan and sample results are discussed.
A 9.1 m (30 ft) span reinforced concrete arch and a 9.5 m (31 ft) span structural plate corrugated steel arch large-span culvert were tested. Both had shallow cover and live loads. Two tests were conducted, one with dense backfill and one with loose backfill.
Measurements were made of culvert shape, culvert strains, culvert-soil interface pressures, soil density, soil stresses, soil strains, foundation movements, temperature, cracking of the concrete culvert and shear movements between precast concrete segments. The most unique measurement was made by a custom built laser device for measuring movements of specific points on the culvert wall. The accuracy of this device was verified by level survey and tape measurements.
The instrumentation performed well and measured results were within the range expected. Culvert deformations were efficiently measured without impeding construction operations. Culvert-soil interaction effects during backfilling and during live load testing were reasonably defined with the instruments selected.