Bridge construction method using preflex girder and integral abutment

A construction method of a bridge using a preflex girder and an integral abutment is provided to increase constructability, trafficability and usability against deflection and vibration and to make maintenance easy. The construction method of a bridge using a preflex girder and an integral abutment comprises the steps of: integrating I-bearing piles and a primary abutment by driving many I-bearing piles(10) into the ground in a line or pre-boring the ground and laying I-bearing piles, welding a pair of perforated bent plates for connecting two flanges and placing concrete on a primary abutment(22); integrating a secondary abutment and a preflex girder by putting a preflex girder(30) on the concrete of the primary abutment, placing concrete on a bridge deck(40) and placing concrete on a secondary abutment(24) finally; piling up back-filling materials manufactured in the type of a gabion(50) on the rear of an abutment to the appointed height; and constructing an approach slab(60) between the bridge deck and a road(82), putting an expansion joint(72) between the approach slab and the road and installing a sleeper slab(74) under the expansion joint.