Abstract: Irradiation with a laser beam is performed along a welding bead, while the laser beam is aimed, as an irradiation point of the laser beam, at a contact point between a deck plate and a U-rib that is contained in a non-welded portion of a root part, from a side of the welding bead of the root part. Thereby, it is possible to remove a crack beginning at the non-welded portion of the root part generated at a joining portion between the deck plate and the U-rib of a steel floor slab, by the irradiation with the laser beam.

Abstract: A welding method wherein the root gap aperture displacement is measured before welding begins, and a welding material having a Mn/S ratio and a Mn/Si ratio compatible with the measured root gap aperture displacement is selected from gas-shielded arc welding materials. Gas-shielded arc welding is then performed using the selected welding material.

Abstract: A method for measuring the degree of fusion involves: a step for creating a dividing pulse amplitude curve by using a probe that emits ultrasound beams; a step for scanning the probe that emits ultrasound beams at a predetermined angle on a surface that has weld beads of multiple welding specimens having different degrees of fusion and for obtaining beam path length information from the dividing pulse amplitude curve and the height of an F echo that returned to the probe after hitting the fused section of a welding site; and a step for obtaining a regression formula expressing the relationship between the beam path length information and the degree of fusion.

Abstract: An interface inspection method according to the present invention includes a step S1 of transmitting ultrasound to a composite structure to be inspected, via an ultrasound generating unit adapted to generate ultrasound of a frequency suitable for a member making up the composite structure and acquiring a signal waveform by receiving a reflected wave from the composite structure using a receiving unit; a step S2 of performing signal processing on the acquired signal waveform and acquiring signal amplitude versus frequency characteristics; and a step S3 of determining an interface condition of the composite structure based on an amplitude in a frequency band unique to the composite structure as observed on the signal waveform subjected to signal processing.

Abstract: A plurality of movable temporary hangers 7 are placed on a stay cable 4B hung in tension above a target stay cable 4C, and then the target stay cable 4C is held on a lower portion of the temporary hangers 7. Then, the target stay cable 4C held with the temporary hanger 7 is detached from a bridge deck 3 and a main tower 2. Then, the target stay cable 4C and the temporary hangers 7 holding the target stay cable 4C are moved toward the bridge deck 3 and removed.

Abstract: A suspension bridge is supported by a cable having one or more cable bands. An anti-rusting device is comprised of one or more covers, each of the covers including an inner peripheral surface and covering the cable so as to leave a gap between the inner peripheral surface and an outer periphery of the cable, the gap being capable of conveying a gas along the outer periphery of the cable; and a ventilator configured to dry and feed the gas into the gap, the ventilator air-tightly communicating with the gap.

Abstract: A suspension bridge is supported by a cable with one or more cable bands. The rust-preventing device comprises one or more covers for so covering the cable that the gaps allowing a gas to longitudinally flow along the outer surface of the cable are formed between the inner peripheral surfaces of the covers and the outer surface of the cable, and an air blower which is in airtight communication with the gaps and supplies air into the gaps after drying it.