Engineering Commons^™

Bridge Deck Overhang Design: Effective Vehicle Impact Loads, Ultimate Strength, And Implications On Bridge Rail Performance, Andrew Eric Loken

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

When an errant vehicle strikes a bridge railing on a typical girder bridge, impact loads are transmitted downward through the railing and inward through the deck overhang to the primary superstructure elements. In this research effort, design demands for deck overhangs supporting concrete railings were characterized using physical testing and complementary modeling in LS-DYNA. Physical test and modeling results were also used to better characterize the ultimate strength of overhangs supporting post-and-beam railings. Ultimately, a novel design methodology for deck overhangs was developed and proposed for adoption to the AASHTO LRFD Bridge Design Specifications (BDS).

For overhangs with solid concrete …

Bridge Deck Delamination Segmentation Based On Aerial Thermography Through Regularized Grayscale Morphological Reconstruction And Gradient Statistics, Chongsheng Cheng, Zhexiong Shang, Zhigang Shen

Department of Construction Engineering and Management: Faculty Publications

Environmental and surface texture-induced temperature variation across the bridge deck is a major source of errors in delamination detection through thermography. This type of external noise poises a significant challenge for conventional quantitative methods such as global thresholding and k-means clustering. An iterative top-down approach is proposed for delamination segmentation based on grayscale morphological reconstruction. A weight-decay function was used to regularize the reconstruction for regional maxima extraction. The mean and coefficient of variation of temperature gradient estimated from delamination boundaries were used for discrimination. The proposed approach was tested on a lab experiment and an in-service bridge deck. The …