About 4,350 metres of Padma Bridge has become visible with the installation of its 29th span on Monday.   The 4a span, weighing 3,140 tonnes, was installed on pillars 19 and 20 of the bridge around 11am, said Executive Engineer (Bridge) Dewan Md Abdul Quader.   The span was brought from Kumarbhog Construction Yard on Sunday.   Earlier, the 28th span was installed on April 11 and the 27th span was installed on March 28.   The 30th span is likely to be installed in this month, said the engineer.   According to the Padma Bridge authorities, 12 more spans are yet be installed to make the whole 6.15-km Padma Bridge visible.   On January 20, Road Transport and Bridges Minister Obaidul Quader said the bridge will be opened to traffic by 2021.   Once in operation, the Padma Bridge, Bangladesh’s largest infrastructure project till date, will connect 21 southern districts with the capital and boost the GDP by 1 percent.