Bridge Deck Condition Presentation Using 3D Visualization of Multiple Nondestructive Evaluation Data

Jinyoung KIM 1, Nenad GUCUNSKI 2, Trung H. DOUNG 3, Kien DINH 4

1 Center for Advanced Infrastructure and Transportation (CAIT), Rutgers, 100 Brett Rd., Piscataway, NJ, US; Phone: +1 512 689 1048, Fax +1 732 445 3325; e-mail: jk1325@rci.rutgers.edu

2 Department of Civil and Environmental Engineering, Rutgers, 96 Frelinghuysen Rd., Piscataway, NJ, US; e-mail: gucunski@rci.rutgers.edu

3 Center for Advanced Infrastructure and Transportation (CAIT), Rutgers, 100 Brett Rd., Piscataway, NJ, US; e-mail: duonghuytrung@gmail.com

4 Center for Advanced Infrastructure and Transportation (CAIT), Rutgers, 100 Brett Rd., Piscataway, NJ, US; e-mail: kien.dinh@rutgers.edu

Abstract A novel method is developed for presentation and visualization of a bridge deck condition in a three-dimensional space that presents data from multiple nondestructive evaluation (NDE) technologies: (1) delamination assessment using impact-echo, (2) concrete quality description using ultrasonic surface wave, (3) corrosion rate of reinforcement using electrical resistivity, and (4) high-resolution imaging of a bridge deck surface for documenting signs of deterioration and previous repairs. The developed visualization platform, NDEFuse, integrates and visualizes NDE data in a 3D space in an intuitive manner, owing to a number of interactive functions. Some of the functions include controlling the zoom level and view angle to review a region of interest, slicing 3D space into 2D images displaying the B-, C-, and D-scan views, cutting a surface image to expose internal defects and to establish correlations between internal and external deteriorations, and identifying areas where overlapping defects are detected by multiple NDE technologies.

Keywords: Nondestructive evaluation (NDE), bridge deck inspection, data analysis, visualization, concrete, impact echo (IE), ultrasonic surface wave (USW), electrical resistivity (ER)

1. Introduction

Due to the complex nature of material and deterioration processes, evaluation of concrete bridge decks often requires utilization of multiple nondestructive evaluation (NDE) technologies. Currently, two-dimensional contour maps are used to present the survey results from the individual NDE method. However, establishing correlations between multi-NDE results is not easy nor intuitive based on individual 2D condition maps. Efforts were made to develop a 3D visualization platform, NDEFuse, which presents a concrete bridge deck condition from multiple NDE data. The program integrates four types of NDE results: impact echo (IE), ultrasonic surface wave (USW), electrical resistivity (ER), and high-resolution surface image. The program delivers enhanced means of visualization of the NDE data in a 3D space through several interactive functions, and facilitates more comprehensive understanding of the overall condition of a bridge deck.

2. Bridge Inspection and Data Presentation

Conventional method of data presentation of multi NDE technologies in 2D contour maps is shown in Figure 1 for the deck of Madison Highway over I-66 Bridge in Virginia. The deck was surveyed in 2014 utilizing several NDE technologies, including IE for delamination assessment, USW for concrete quality (elastic modulus) evaluation, and ER for description of corrosive environment and corrosion rate estimate. The surveys were conducted on a 0.6 m by 0.6 m test grid. The overall condition of the bridge deck is poor, and the location and severity of deterioration and defects identified by IE, USW, and ER exhibit strong correlations.

International Symposium Non-Destructive Testing in Civil Engineering (NDT-CE)

September 15 - 17, 2015, Berlin, Germany

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(MPa)15,000 20,000 25,000 40,00030,000 35,000

Electrical Resistivity

(kΩ·cm)

Decreasing corrosion rate indicationHigh Med. Low

Figure 1. Two-dimensional condition maps of the bridge deck: delamination severity by impact echo (top), concrete modulus by ultrasonic surface wave (meddle), and corrosion rate by electrical resistivity (bottom)

The data presentation for different NDE technologies is described as follows. IE can be also described as the method that identifies the position of the wave reflectors [1]. The position (depth) of wave reflectors can be calculated from

Depth of concrete-air interface peak

p

f

C

2 (1)

where β is the correction factor ranging 0.945-0.957 for normal concrete [2], Cp is the compression wave velocity of concrete, and fpeak is a peak frequency. For shallow delamination with very low dominant peak frequency, in which the calculated depth is deeper than the full deck thickness, the depth corresponding to the secondary peak was obtained [3]. Using the relationship between peak frequency and depth, 2D IE map can be extended into a 3D space, where both the severity and depth of delamination can be visualized, as shown in Figure 2. In the figure, shallow delamination, deep delamination, and full thickness of the deck are identified as zones in red, yellow, and green, respectively. The z-axis (depth) has been exaggerated to visualize more effectively by separating delamination and reflection from the deck bottom. The presentation of modulus variability with depth is approximated by the information from the USW obtained dispersion curve, the relationship between the wavelength and phase velocity (or elastic modulus). Unlike the elastic modulus variation with depth is averaged at each point to create the 2D concrete modulus map, the program presents the modulus with depth from each of the dispersion curves. The correct information about the variation of modulus with depth can only be obtained through the process of back calculation or inversion [4]. For ER, the corrosion rate is displayed through coloring of the top rebar layer.

International Symposium Non-Destructive Testing in Civil Engineering (NDT-CE)

September 15 - 17, 2015, Berlin, Germany

Figure 2. Delamination severity and depth shown in a 3D space

Figure 3 shows as an example 3D visualization of a small section of the bridge deck. The NDE data and the surface image are integrated in a 3D space, where internal deterioration and defects detected by IE, USW, and ER are exposed through the "window" cutting in the surface image. The program was set to display only the areas with defects and deterioration: delamination in purple, areas with low concrete modulus (< 20 GPa) are shown green, and the top rebar layer is colored red in the high corrosion rate regions (< 20 kΩ·cm). Areas with no considerable deterioration detected from the either of the NDE technologies (black zone) can be easily observed, and more importantly, those where all NDE technologies detected deterioration (colors are overlapped). It can also be observed that delamination and areas with high corrosion rates are mostly overlapping, indicating that delamination is likely induced by corrosion. This is also supported by the depth of delamination matching the level of the top rebar.

Surface Image Cut

DelaminationConcrete Modulus

Lower than 20,000 MPa

ER Lower than

20 kΩ·cmSound Area

Deterioration

Overlapped Area

Figure 3. 3D visualization of four NDE technologies integrated in a 3D space

The user can define threshold levels for optimum presentation of results for each NDE technology. In addition, the program is equipped with a number of interactive and user-friendly functions to help users better understand the complex relationship of multiple NDE results in a 3D space. Those include, for example: controlling the zoom level and view angle to review a region of interest, slicing 3D space into 2D images displaying the B-, C-, and D-scan plane

International Symposium Non-Destructive Testing in Civil Engineering (NDT-CE)

September 15 - 17, 2015, Berlin, Germany

views, and cutting a surface image to expose internal defects and to establish correlations between internal and external deteriorations and defects. An example of a good correlation between internal and external defects is shown in Figure 4, in which delamination and area with a very high corrosion rate are overlapped underneath the damaged concrete deck surface.

Figure 4. Damaged deck surface (left) and exposed internal defects, where delamination and area with high corrosion rate are overlapped

3. Conclusions

An interactive three-dimensional visualization platform for multiple nondestructive evaluation (NDE) data, NDEFuse, is developed to present a concrete bridge deck condition. The program integrates and presents four types of NDE data: delamination from impact echo, concrete quality from ultrasonic surface waves, corrosion rate from electrical resistivity, and the deck surface image to identify surface damage and previous repair. Merging of multiple NDE data and visualizing together in a 3D space using the developed program provides an enhanced means of NDE data visualization for more intuitive and comprehensive understanding of the complexity of a bridge deck deterioration. Moreover, the relationship between visible damage (cracks and concrete spalling) and internal defects (corrosion, delamination, and low concrete quality) could be visually identified using the program. The developed 3D visualization platform is also expected to assist in decision making prior to bridge deck repairs or rehabilitation.

Acknowledgements

The authors gratefully acknowledge the help from Mr. Reinhold Fragner of Industrial Motion Art, Vienna, Austria, in the NDEFuse program development.

References

1. M. Sansalone, and N.J. Carino, 'Impact-Echo: A Method for Flaw Detection in Concrete Using Transient Stress Waves,' National Bureau of Standards, Washington, DC, 1986.

2. A. Gibson, and J.S. Popovics, 'Lamb Wave Basis for Impact-Echo Method Analysis,' Journal of Engineering Mechanics, Vol 131, No 4, pp 438-443, 2005.

3. N. Gucunski, M. Yan, Z. Wang, T. Fang, and A. Maher, 'Rapid Bridge Deck Condition Assessment Using Three-Dimensional Visualization of Impact Echo Data,' Journal of Infrastructure Systems, Vol 18, No 1, pp 12-24, 2012.

4. J. Uzan, R.L. Lytton, and F.P. Germann, 'General Procedure for Backcalculating Layer Moduli,' First International Symposium on Nondestructive Testing of Pavements and Backcalculation of Moduli, Baltimore, MA, 1988.

International Symposium Non-Destructive Testing in Civil Engineering (NDT-CE)

September 15 - 17, 2015, Berlin, Germany