Storm Sewer Pipeline Laser Profiling - Rinker Materials

TECHNOLOGY AVAILABILITY & COSTInitially, laser profiling was only available for specialized projects or for researchapplications. However, now that it is becoming more commonly specified, anincreasing number of contractors are equipped to perform the work. Manycontractors that are equipped to perform video inspection have enhanced theircapabilities simply by adding laser profiling equipment. There are currently severalmanufacturers of laser profiling equipment and associated software systems.Equipment is readily available nationally, and new systems continue to come ontothe market.Not surprisingly, pricing will vary. When performed in conjunction with traditionalvideo inspection, laser profiling can be performed for a relatively small incrementalcost. Compared to traditional mandrel testing and video inspection, laser profilingis very competitively priced, especially considering the wealth of information that isavailable by utilizing this technology.BENEFIT TO OWNER & ENGINEERProof of design and proper installation are critical for buried flexible pipeperformance. Inadequate design considerations and improper installation lead toover deflected flexible pipe which severely reduces performance and lifeexpectancy. Consequently, the owner of a project can justify the modest cost oflaser profiling to ensure that a pipeline was designed and installed according tospecification. This results in a relatively small investment to ensure theperformance of the project infrastructure.Flexible pipe design should be performed, though the process is cumbersome andonly a small handful of engineers are familiar with it. The process includescalculating theoretical deflection, buckling, bending strain, bending stress, and wallthrust. Most designers, however, prefer to forgo the full array of necessarycalculations and instead simply require a 5% maximum post installation deflectiontest as an indicator of the performance potential of the completed installation.IS 40304/09 Page 2 of 4

Once designed, flexible pipe installation is difficult if done properly because itrequires more stringent backfill and compaction levels. In many cases, contractorsdon’t take all the steps to properly install flexible pipe. Considering the complicateddesign and difficult installation associated with flexible pipe, comprehensive postinstallation inspection for deflection is critical.Laser profiling is now providing many owners this Proof of Design / Installation.BENEFIT TO CONTRACTORLaser profiling can be advantageous to the pipeline contractor as well. Traditionalmandrel testing can typically only identify the first point in the line where excessivedeflection has occurred, since an appropriately sized mandrel cannot be pulled anyfurther through the line. Subsequent testing is required after the first repair iscompleted. If another problem is identified, the process must continue. However,if equipped with the comprehensive information from laser profiling, the pipelinecontractor can pinpoint the exact location of all problem areas and complete therepairs in an efficient manner.USE IN ACADEMIAThe technology is also being employed for research work. For example, theUniversity of Texas – Arlington is in the process of conducting a multi-stateinvestigation of performance of buried high density polyethylene (HDPE) culvert andstorm sewer pipe 10 . Without the use of a laser profiling equipment and software,the necessary data collection would be virtually impossible to obtain.IS 40304/09 Page 3 of 4