State to 'assess health' of 3 crucial bridges in city
KOLKATA: Kolkata Metropolitan Development Authority (KMDA) issued a letter of intent (LOI) for health assessment of three old but crucial bridges in the city. The exercise will include structural conditional assessment, load tests and preparing of a detailed project report for repair and retrofitting.
All the three old bridges are located over Tolly Nullah-Dhana Dhanyo Setu at Alipore, Kidderpore steel Bridge and Doi Ghat Bridge, close to West Port police station. "All these bridges are old so their condition can be assessed only after proper test. After a thorough assessment, the agency will give recommendations for necessary corrective measures," a senior official of KMDA said.
According to KMDA sources, the Dhana Dhanye Setu dates back to 1836 while the Kidderpore Bridge dates to 1826. KMDA has already received financial approval from the state government for the engagement of agencies for the work. Once the work order is issued it will tentatively take 6 months time for the exercise.
The three bridges are all steel truss ones, whose load bearing superstructure is composed of a truss, a structure of connected elements, usually forming triangular units. Known for its strong load bearing capacity, the connected elements (typically straight) may be stressed from tension, compression, or sometimes both in response to dynamic loads. A truss bridge is economical to construct because it uses materials efficiently. In the 1800s, America was the leader in truss bridge design, though older constructions used wood.
KMDA has recently completed short term repair work of Kalighat Bridge situated on Tolly Nullah. Portions of concrete had worn-out and several cracks had developed weakening its structure. The corroded portion was properly treated and reinforcement was done in a thorough manner to strengthen the bridge. Grouting was done for repair of the cracks.
"However, the work was temporary and as per recommendation of the expert committee on bridges, we will now dismantle the bridge and a new bridge will be constructed," the official added.
KMDA has already submitted the Detailed Project Report (DPR) in this regard to the state Finance department for necessary financial sanction.