Author ORCID Identifier
Semester
Fall
Date of Graduation
2024
Document Type
Dissertation
Degree Type
PhD
College
Statler College of Engineering and Mineral Resources
Department
Civil and Environmental Engineering
Committee Chair
Yoojung Yoon
Committee Member
Hota GangaRao
Committee Member
Fei Daí
Committee Member
Udaya B. Halabe
Committee Member
Monique Head
Abstract
Concrete bridge decks are vital components of transportation infrastructure, yet their deterioration due to aging, environmental, and operational factors poses significant challenges to maintenance and safety. In the United States, approximately 9.1% of bridges require improvement, with millions of daily trips relying on structurally deficient bridges. Cracking is one of the most frequently observed defects on concrete bridge structures. Traditional bridge inspections evaluate cracks based on severity (crack width) and extent (crack area), combining these values with other performance indicators to assess overall bridge health. However, the effect of concentrated cracking in localized areas on bridge integrity remains largely unexplored. Therefore, it is hypothesized that a higher concentration of cracks in local areas may have a more detrimental effect on the structural integrity compared to evenly distributed cracks. This research aims to investigate the weighted effect of localized cracking on the structural integrity of concrete bridge decks.
The study utilizes ultrasound testing to collect pulse velocity data across various surface crack concentrations on concrete bridge deck samples. The dimension of each sample size is 10 feet by 10 feet. Three frequency sensors—54 kHz, 150 kHz, and 250 kHz—are employed to account for cracks of varying extents and severities. Additionally, each sample is photographed using a high-resolution camera, Nikon D3200, and the images are processed and analyzed using deep-learning algorithms, YOLOv11. Then, the Crack Concentration Index (CCI) is calculated for each sample, defined as the ratio of crack areas (length × width) to the boundary area of the cracks. Statistical analysis is conducted to identify the relationships between ultrasound pulse velocities (UPVs) and CCIs for the data points classified by National Bridge Inventory (NBI) condition ratings ranging from 7 to 5 and determine threshold values indicating shifts in UPV-CCI slope.
The research findings reveal several critical insights into the effects of crack concentrations on the structural integrity of concrete bridge decks. Multiple sensors applied to each bridge deck sample demonstrated sensitivity to varying crack extents and severities, highlighting the importance of advanced monitoring techniques. Samples with the same condition ratings exhibited diverse ranges of CCI, with CR-7 samples showing relatively low values, CR-5 samples displaying significantly higher values, and CR-6 samples falling in between. UPV measurements varied widely across samples, influenced by crack severity. While decks rated as CR-7 generally indicated better overall conditions, UPV data revealed poor localized conditions due to concentrated cracks. A similar pattern was observed in deck samples rated as CR-6 and CR-5, where localized crack concentrations also adversely impacted the UPV measurements. Statistical analysis confirmed significant relationships between UPVs and CCIs for each NBI condition rating, showing that UPVs decrease with increasing CCIs, which indicates that higher crack concentrations have a more adverse impact on structural integrity than evenly distributed cracks. Thresholds derived from UPV and CCI derivatives identified critical damage zones, serving as benchmarks for immediate maintenance actions. Additionally, CCI demonstrated a strong correlation with the compressive strength of concrete (f’c), emphasizing the weighted effects of cracks on structural performance. In essence, this research is pioneering a more nuanced approach to evaluating the structural integrity of bridges by combining the weighted effect of locally concentrated cracks along with conventional crack-related measures such as extent and severity. Additionally, this research contributes to the existing body of knowledge regarding the structural implications of cracks in complex patterns. In practice, this research is expected to enhance the accuracy of bridge condition assessment, which provides a more reliable basis for informed decision-making.
Recommended Citation
Uddin, Md Ala, "WEIGHTED EFFECT OF CONCENTRATED CRACKING ON THE STRUCTURAL INTEGRITY OF CONCRETE BRIDGE DECKS" (2024). Graduate Theses, Dissertations, and Problem Reports. 12700.
https://researchrepository.wvu.edu/etd/12700