Structure – Steel frame （Piezoelectric joint sensor）

Comparison of Displacement Measurements in an Exposed Type Column Base Using Piezoelectric Vibration Sensors and Piezoelectric Limit Sensors

　　The Hyogoken Nanbu earthquake (Kobe earthquake), which occurred on January 17, 1995, caused extensive and severe damage to numerous buildings in Kobe city area. After the earthquake, numerous steel structures were constructed using exposed-type column-base joints. However, the capacity of these joints to absorb energy during earthquakes is small. For that reason, during the design of steel structures that use exposed-type column-base joints, higher earthquake-resistance characteristics must be provided specifically for those joints of the first floor. Moreover, structural health monitoring is recommended. This research examined the use of piezoelectric limit sensors to evaluate the resistance and displacement characteristics of exposed-type column-bases using simple measurements.

 

Weld joint development for steel column bases using piezoelectric joint sensors

　　Japan’s social capital stock was accumulated and concentrated particularly during its era of high economic growth. However, the future deterioration of that stock of infrastructure represents a mounting concern. Over the next 20 years, facilities 50 years old or older will become increasingly common. Therefore, an urgent need exists to maintain and renew such aging infrastructure. Unfortunately many steel structures were constructed using frame-welded joints of fillet welded construction and a welded base. These weld joints will not only be old: they will have little capacity to absorb energy during great earthquakes. Therefore, for designing steel structures incorporating welded joints, strong earthquake-resistance characteristics must be specially investigated and provided for those joints of steel welded bases. Moreover, structural monitoring will be necessary. This report describes, using simple measurements and simulations, our piezoelectric joint sensors for evaluating resistance and displacement characteristics of fillet-welded construction.

The measurement apparatus

Setting of piezoelectric joint sensor

 

Experiment of load and displacement load test devices

Cracked piezoelectric joint sensor surface

 

Development of Robot “SALLY” for Piezoelectric joint Sensors

（December 2020）