The crystal bridge across the Grand Canal has been described as “a carpet of light reflected on water”, but a meeting today will decide its fate. After 11 years and €10 million (£7 million), the spectacular new gateway to Venice is in danger of being scrapped – because it is too heavy.

Designed by Santiago Calatrava, the award-winning Spanish architect, the 94-metre (310ft) glass and steel single-span bridge is intended to link the two main entry points to the city: the car park at Piazzale Roma and the railway station.

Its slender, translucent appearance is deceptive, however. Engineers say that the 52-tonne structure will create a “deadly” downward pressure of 1,500 tonnes, equivalent to the weight of 75 fully loaded lorries. This could cause the fragile canal embankments, built over soft and muddy foundations, to collapse – taking the bridge with them.

“The bridge’s structure does not in itself pose a problem,” Massimo Cacciari, the Mayor of Venice, told La Repubblica. “But we must be absolutely sure that it is safe and that the banks on which it will rest will hold.” He said that he would hold emergency talks with Mr Calatrava today to see if the target date of July 15 for the completion of the bridge could still be met.

Mr Cacciari has called in Giorgio Romaro, an engineering professor from the University of Padua, who helped to resolve last-minute problems over the sliding roof on Mr Calatrava’s Velodrome stadium, which was designed for the Athens Olympics in 2004.

Experts said that the pavements on either side of the canal could be reinforced with 16 powerful hydraulic jacks. Apart from doubts over whether this would work, the jacks would add an extra €1.2 million to the cost of the bridge. The cost has already tripled since it was conceived in 1996, when its budget was €3.5 million.

The Bridge of Light has gone through five redesigns so far. Objections that its traditional stepped Venetian design did not cater for the disabled caused delays three years ago.

The centre-right opposition on the Venice council accused Mr Cacciari yesterday of wasting public money on the crystal bridge, which is under construction on the mainland before it is transported to the Grand Canal. It was originally scheduled for completion in 2003.

The bridge – the city’s 435th and the fourth over the Grand Canal – will stand ten10 metres above canal level, with a nine-metre-wide walkway of glass and white Istrian stone and a bronze handrail. It has been described as “the most important new project in Venice since the Second World War”.

Other designs by Mr Calatrava include Trinity footbridge over the River Irwell at Salford and the James Joyce Bridge over the Liffey in Dublin.

Last month Mr Cacciari broke new ground by suggesting that a sponsor such as Bill Gates, the billionaire founder of Microsoft, could have the Accademia Bridge across the Grand Canal named after him if he funded its rebuilding.

Times Recommends

• Henning Mankell: ‘If Wallander was alive, I wouldn’t be a friend of his’
• Secret society's skull and crossbones for sale
• Nigerian leader vanishes after medical treatment