Causes of the accident Collapse of Cần Thơ Bridge

bridge tower construction, of june 2007.

the ministries of transport , of public security created investigative team, led lieutenant-general phạm nam tào, head of police division of ministry of public security, determine cause of collapse. several possibilities forwarded:

reuters reported officials had said recent heavy rains might have softened foundations.
dr. trần chủng, head of national construction qa/qc authority under ministry of construction of vietnam, suggested collapse might have been caused movement of scaffolding while concrete supports - poured 2 days earlier - not sufficiently stable.
minister of transport ho nghia dung said sinking of scaffolding, had bear 6000 metric ton concrete structure, might have caused collapse; told reporters, ...preliminary information has shown there have been signs of settlement of foundation of scaffolding.
other sources suggested there had been landslides near river shore had displaced , destabilized scaffolding.

long before collapse, on 12 january, japanese construction consultant, hiroshi kudo, had recommended specific measures installing temporary poles scaffolding, , load tests piling should carried out in accordance international standards , codes. according kudo, loading capacity of scaffolding, per detailed design proposed contractors, met 15% of required loading. remarked that:

the contractors had multiplied pile overloading ratio 1.15 instead of 1.25 in accordance american standard or 1.35 in accordance japanese standard;
when calculating wind force on temporary piles, contractors had applied wind force of 0.5 kpa, low; should have been 2.5 kpa. (according nce.co.uk, 2.5 coefficient wind loading [1].)

he had therefore required contractors redo temporary pile , scaffolding designs.

top officials of japanese contracting companies flew vietnam , made bows in meeting apologize victims , families. hayama kanji, chairman of taisei corporation, said in meeting vietnamese authorities: sincerely express deepest apology people , government of vietnam .

on march 6, 2008, minister of construction nguyen hong quan released report containing results of eight-month-long investigation accident @ press conference in hanoi. sinking of bridge s makeshift foundation pinpointed primary reason collapse, report said. dipping phenomenon caused bridge support tumble, breaking 2 bridge spans. report added sinking of foundation unfortunate situation , hard project in design process.