Application of Mobile Mapping System to a Cable-Stayed Bridge in Thailand

Abstract

Infrastructures must be inspected regularly to ensure serviceability and public safety. In the case of the Thailand expressway, 200 km of an elevated structure must be inspected once a year. Thailand expressway is an elevated reinforced concrete structure. Visual inspection for defects and structural movements such as excessive deflections, transverse movements, or settlements is a cumbersome process. Therefore, a mobile mapping 3D laser scanning (MLS) which is a high-resolution 3D laser scanner (Trimble MX-8) equipped on a vehicle, was introduced. Scanning was performed on live traffic on the expressway. From MLS, both the structure geometry and pavement point cloud data were obtained. A good agreement between elevations of the Rama XI bridge in Bangkok measured by point cloud data using MLS and by a real-time kinematic survey was obtained. The effect of mesh size on the output by MLS was investigated. It was found that a mesh size of 10 cm reduced the computational effort by 75% when compared to a mesh size of 5 cm. However, the International Roughness Index was reduced by 5%. International Roughness Index (IRI) estimated by MLS was close to the IRI values measured by the profilometer. However, a significant overestimation in the case of rutting depth was observed.

Applications of Terrestrial Laser Scanner in Detecting Pavement Surface Defects

“…Feng et al [19] used TLS point clouds to determine five pavement distresses. In similar studies, El Issaoui et al [20] and De Blasiis et al [24], and Lueangvilai [25] investigated the feasibility of using mobile laser scanning (MLS) system for measuring rut-ting depth and road slope for pavements system. The authors used the TLS measurements as a reference for MLS.…”