Dimetix laser distance sensors, manufactured by Dimetix AG, are rugged, accurate, cost effective, and long range, easy to set up sensors that are an unconventional substitute to traditional techniques of measuring structural movement.
Title: Structural monitoring of New Orleans Bridge Lift
Description: Laser-View Technologies 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.
Title: Structural Monitoring of Building Near Excavation Site
Description: Laser-View Technologies 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.
Title: Structural Monitoring System of Bridge Movement in 3 Axis
Description: 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.
Title: Bridge Deflection Testing Using Non-Contact Laser Sensors in Place of LVDT Gauges
Description: Bridges that are suspected to be structurally deficient require technical analysis for deflection and strain under loading conditions to determine acceptable load limits and general structural worthiness. Traditionally, this type of analysis requires combinations of non-contact and contact measurement techniques.
Laser-View Technologies recently had the opportunity to work with AECOM on a bridge deflection test over rail tracks in New England. The bridge in question handles traffic over a set of commuter rail lines. The bridge load limit had been lowered as a measure of caution since the structural members of the bridge had deteriorated. The structural test had been ordered to determine the actual load capacity of the aging bridge under the existing conditions.