ABSTRACT
Mamin H. Sarker Deputy Executive Director, CEGIS, Dhaka, Bangladesh
ABSTRACT: Recently a review was made of the performance of the Jamuna Bridge River Training Works, (RTW) crossing the braided Brahmaputra River in Bangladesh. The RTW are functioning since 1997. The review was carried out to identify any improvements which could possibly be made both in the design proper and in the supporting studies for forthcoming bridge projects. In the review period of 13 years, the RTW were not fully tested, as during none of the years was the design discharge approached or was the upstream channel pattern characterized by extreme outflanking. Although the yearly maintenance required until 2009 is on the average only 0.13% of the capital costs of the RTW, still some unexpected phenomena were observed. The design scour depths were exceeded substantially, and scour holes of almost 45 m below average flood levels were observed. The scour occurs during outflanking and additional studies are needed to understand the cause and possible remedies. Locally substantial shifting of the rock of the slope protection is observed, leaving the underlying geotextile exposed. Regular inspection and maintenance as specified is needed to keep the RTW in optimal condition.
