Precast and Cast-in-Situ Combined Construction Technique for Concrete Edge Parapets of Padma Bridge in Bangladesh
Measured 18 km in total length and 1.8 m in depth,the reinforced concrete edge parapets of the roadway deck of the Padma Bridge feature the decorative grooves on exterior facades,and the parapets are thickest in the center,gradually go thinner upwards and downwards,and extend downwards with a portion stretching below the roadway deck.Based on the analysis of all-precast and all cast-in-situ options,a precast and cast-in-situ combined construction technique was proposed.Split the parapets into two parts along the bridge longitudinal axis,the interior part connecting the deck was cast in situ in 9 m-long segments and the exterior part was precast off site in 1.5 m-long segments,while 6 m-and 7 m-long adjustment segments were placed to coincide with the lamp posts,to achieve the modularized construction.The segments of the exterior part of the parapets were precast in a lying manner with the casting beds and formwork in the fabrication yard,after coated with retarder,the stitches containing protruding reinforced bars to create continuity were cleared and roughened.With the assistance of the embedded lifting lugs and supporting angle steels,the prefabricated segments were installed,afterwards,the casting of the interior part began.The parapets were fixed with the deck panels via the reserved reinforced bars.A number of 1 300 segments of the parapets were prefabricated per month,and 3 600 m-long segments were cast per month.The casting of the interior part of the parapets was finished in 5 months,and the visual quality of the concrete components was sound after the parapet construction.
bridge engineeringreinforced concrete parapetsemi-prefabrication and semi-castingmodularizationanchor reinforced barconstruction technique
NETL
NSTL
万方数据
