The main objective of the overall two-year study is to evaluate the feasibility and accuracy of non-destructive evaluation and testing techniques, specifically ultrasonic testing, for the condi-tion assessment of timber and composite piles. Testing of in-situ piles will be performed and results will be verified through traditional laboratory testing in the Civil Engineering’s Infra-structure Laboratory.
Intermodal
Traditional laboratory testing of composite piles is intrusive since piles need to be extracted, shipped, and replaced and introduces some constraints with regards to the size and number of piles that can be tested. Alternatively, existing piles can be tested and monitored in-situ using nondestructive testing (NDT) techniques, specifically ultrasonic testing (UT). UT uses high fre-quency sound energy as a basis for making measurements including flaw detection, dimensional and material characterizations (i.e. moduli of elasticity and rigidity). The objective of this study is to investigate the use of ultrasonic testing in assessing the integrity of composite and timber piles. Results will be verified using conventional laboratory tests conducted at the Civil and En-vironmental Engineering (CVE) Department. An important contribution to this project will be made through collaboration with Dr. Miguel Pando at the University of Puerto Rico at Mayagüez (UPRM). Dr. Pando has published extensively on the behavior of composite piles. The investi-gators intend to use this project to strengthen exchange between URI and UPRM both at the fac-ulty and student level. Additionally, various aspects of this research will be incorporated into the junior-level Structural Engineering Laboratory (CVE 355) which emphasizes the use of sensors and instrumentation as applied to structural systems.
The proposed research project will consist of the following tasks:
Task 1: URITC Spring 2006 Symposium. The research team will participate and present the details of the proposed study at a 1-day kick-off symposium organized by URITC.
Task 2: Literature Review. A comprehensive literature review of relevant publications, testing practices, and experimental data will be performed. The search will include all related research done by the US Department of Agriculture, US Department of Transportation, Federal Highway Administration, Forest Service and Forest Products Laboratory.
Task 3: Development of an Experimental Program. Upon completion of the literature re-view, a detailed experimental program will be developed. The program will allow for in-situ field testing of installed timber and composite piles using non-destructive evaluation/testing techniques, specifically ultrasonic testing. Several ultrasonic testing equipments will be com-pared and the one most suitable for this application will be selected. The feasibility and accuracy of using ultrasonic testing as a nondestructive evaluation technique for the condition assessment and material characterization of timber and composite piles will be evaluated.
Task 4: Field Evaluation of Composite Pile Properties. The equipment, purchased as a result of Task 3, will be used to conduct multiple in-situ field tests of installed piles. The condition of the pile will be “mapped” using contour and color gradient plots overlaid on photographs of the piles. Visual observations on the condition of the pile will also be made.
Task 5: Laboratory Evaluation of Composite Pile Properties. A series of short composite piles will be fabricated by Pearson Pilings using various fiber architectures with and without known defects and tested in the laboratory to compliment UT field testing. Testing will be car-ried out at the Infrastructure Laboratory using an MTS 110 Kip Servo-Hydraulic Testing System, which includes a 5-ft strong base table. Coupon tests will also be performed to evaluate material characteristics. Special hydraulic grips will be used for the tension testing and three extensom-eters will be mounted on the coupons to measure strains.
Task 6: Final Report and URITC Fall 2007 Symposium. The final report will document the entire research effort, testing procedures, and all findings. The analysis and procedures devel-oped for the evaluation of various factors affecting the work will be presented in a complete form. The final report will be submitted in accordance with URITC specifications by September 1, 2007. The research team will also participate and present the outcome of this work at the Fall 2007 URITC Symposium.
It is anticipated that the study will last for two years. Project completion and presentation of findings of results are scheduled for the Fall 2007. The research team will actively participate in the URITC Spring 2006 and Fall 2007 Symposia. The project final report will be completed and submitted for publication to the URITC by September 2007.
Task 1, Jan-Feb 2006
Task 2, Jan-Apr 2006
Task 3, May-Aug 2006
Task 4, Sep 2006-Apr 2007
Task 5, Nov 2006-Jun 2007
Task 6, Jul 2007-Aug 2007
$213,697.68
This study will directly involve students at the graduate and undergraduate level. The project will support one graduate student and one undergraduate student during the summer of 2006 and the 2006-2007 academic school year. The students will be involved in performing field and laboratory tests and collecting and analyzing the data. Students will also be encouraged to con-tribute to technical papers for publication and presentation at professional conferences.
This project will build upon the results of a previous URITC study on the drivability and fender-ing capabilities of composite piles. That study showed that there may be advantages to using composite piles for fendering systems if the damping characteristics of the pile system are incor-porated in the design (Bradshaw et al. 2005). However, there is still a lack of information re-garding the integrity of these piles during driving and throughout the life of the piles (Iskander et al. 2001). Dr. Pando has also been involved in several studies focused on the analysis of the be-havior of composite piles under loading. Pando (2003; Pando et al. 2005) studied the feasibility of using composite piles for load bearing applications such as bridge substructures. The pro-posed research will help complement the ongoing work of the research team.
The results of this research will be compiled into a report that will be presented to the URITC at the end of the study. Findings will also be published in the composites and geotechnical litera-ture such as the TRB Journal and Conference Proceedings and the ASCE Journal of Geotechni-cal and Geoenvironmental Engineering. Details of the research and all findings will also be pre-sented at the URTIC symposia.
This research will provide developers and designers of marine facilities a new option of using corrosion-resistant composite piles. The advantages to intermodal port and waterfront facilities will be the economic savings due to an increased lifespan compared to traditional pile foundation systems. The results of a well-documented field and laboratory study will be applicable for fa-cilities throughout New England. Collaboration between URI faculty and local businesses (Pear-son Pilings) and other universities (University of Puerto Rico-Mayagüez) also serves to enhance the research by linking professionals with common research interests together.
GFRP, FRP composite piles, nondestructive testing, ultrasonic testing, integrity assessment