Seismic Fragility Analysis Of Precast Prestressed Frame Structures With Unbonded Tendons

Precast prestressed structures with unbonded tendons has the characteristic of high construction speed, saving construction materials, the restoration ability and other characteristics, is starting to get the attention of the researchers,however,the existing research mainly focused on the component level, rare in structure seismic performance. Seismic fragility analysis is an important part of performance-based seismic design, through the seismic fragility analysis, can evaluate the structure of the seismic performance and weaknesses. In this paper, analysing the seismic fragility of precast prestressed structures with the method of incremental dynamic analysis, the specific research results are as follows:First of all, this paper briefly introduces the OpenSEES software, according to the character of the unbonded prestressed with unbonded tendons, the zerolength element is adopted to release the stiffness of the beam.By comparing with the the test, proving the reliability of the connection modeling method.Secondly, designing a six-story precast prestressed frame structures with unbonded tendons and a six-story cast-in-suit reinforced concrete frame structure, According to the wave selecte principle by the ATC selecting 18 of the ground motion records, adopting the maximum interlayer displacement Angle and the bottom of the prestressed steel structure internal force as the damage measure, analysing the seismic fragility with the the method of IDA. Introducing collapse margin ratio CMR assessment collapse resistance performancr of the precast prestressed frame structures. Studies show that:when the seismic intensity is small, two kinds of structure seismic performance difference is not obvious, with the increase of the ground motion intensity, the seismic performance of the cast-in-suit structure is superior to the precast prestressed structure in collapse prevernt; the collapse probability of precast prestressed structure model under the action of seismic fortification with rarely met earthquake is 0.2%, has better ability to resist collapse.In conclusion, this paper presented the Precast prestressed joint with unbonded tendons modeling thought based of OpenSEES, analysing the seismic fragility of precast prestressed structures and cast-in-situ concrete structures with the method of IDA, in order to provide references for the study of the fabricated structure of seismic performance.