Repair cost assessment of longitudinal continuous ballastless track structure on high-speed railway bridge with spatially distributed interlayer area damage

In the context of the performance-based earthquake engineering, a scalar engineering demand parameter (EDP) is commonly utilized for a performance group of components with sheared demand quantity to further assess seismic damage and repair cost (RC). However, a longitudinally continuous ballastless track structure on a high-speed railway bridge (HSRB) may suffer from spatially distributed interlayer area damage (IAD) subjected to earthquake, which hinders the conventional demand evaluation by scalar EDP. Our work leverages a vector-based EDP, LD with variable dimensionality, to quantify all IAD through the track structure. Correspondingly, a vectorized damage measure (DM) is derived with uncertainty quantification. A piecewise linear repair cost model is proposed to map and aggregate the DM entries pertaining to different damage states to RC. In case study, the RC of the track structure is assessed in a three-span simply-supported HSRB. The result shows that greater accuracy in RC is gained by LD with a higher ratio rγ of the cost per meter of repair to replacement and a greater critical replacement length LDS,1 in the RC model. With high LDS,1 and rγ, an alluring finding is that repairing several slightly damaged regions may be more expensive than replacing a few seriously damaged regions.