Bridge Construction with Atmospheric Corrosion Resisting Steel

Abstract

The Department of Rural Roads (DRR) has built two bridges on Rayong 4060 Road, in Rayong and Chanthaburi Province. The bridges are 630 meters and 420 meters long, respectively. This project has been collaborated with the Ministry of Natural Resources and Environment, to protect wild elephants from car accidents on the road between Khao Ang Rue Nai Wildlife Sanctuary and Khao Chamao - Khao Wong Natural Park.

Steel was used for making 30-meter-long I-shaped plate girders, so that bridge dead load can be reduced. Reinforced concrete substructure becomes smaller, and the number of bored piles can be decreased, causing the least required right of way. Furthermore, the application of steel can accelerate the project duration and mitigate the environmental impact on people and wildlife living nearby. Nevertheless, corrosion is still a major drawback of steel structure. Periodic inspection and maintenance are necessary. So, to cut down the future burden, especially for bridges in distant area, DRR has introduced the  atmospheric corrosion resisting steel, or so-called weathering steel, according to TIS 2982-2562. This alternative construction material is rather new for construction in Thailand.

In this paper, the use of weathering steel will be described. Comparison with conventional steel will be also mentioned.  It has been found that material cost for the application of weathering steel is about 18% higher than that of conventional steel. However, usage of weathering steel can curtail cost and time for corrosion protection. In long term, the maintenance burden can be taken away as well. So, it can be said that weathering steel is worth as a sustainable building material, especially in remote area.