Engineering & Construction
DIMETIX USA helped make history in 2010 by collaborating with Applied Geomechanics, Inc. to develop a system to monitor the lift and placement of steel bridge truss sections on the Huey P. Long Bridge over the Mississippi River in New Orleans. The project involved transportation by river barge, lifting, and placement of the pre-assembled bridge truss spans to reduce stress on the bridge and minimize interruption of traffic. Ten DLS-C15 laser distance sensors were lifted aboard the 2,700 ton trusses and were used in conjunction with specially fabricated targets and software developed to monitor beam deflection during the day long lift.
DIMETIX USA also partnered with Civionic Engineering & Consulting Inc. to develop a new multi-axis, multi-sensor structural health monitoring system to measure sub-millimeter displacements in 3 axis of freedom. New tower development in the heart of a busy sports complex required excavation only a few feet away from three existing bridge piers. The developer needed to ensure no shift of the existing bridge structure occurred during the excavation and construction periods for a new 320’ high mixed commercial/residential development.
A structural health monitoring (SHM) system utilizing Dimetix laser distance
sensors was implemented during a long‐term study of two of the piers on a Western PA
bridge monitored on three axes for movement under load. For context, a common criticism
of SHM systems is the inability of the system to translate raw sensor measurements
into actionable information that can be used for management decision making. Reasons for this shortcoming include poor anticipation of the ultimate use of the SHM system, measurement complexity, and the lack of a comprehensive input‐output characterization of the SHM system. For this case study, allowable thresholds were computed based upon superstructure load strength and substructure serviceability limits, as
well as a limit associated with expansion joint allowable movement as measured by the non‐contact laser distance sensor SHM arrays.