Reliability Analysis Of Failure Risk Of Unbonded Prestressed Concrete Frame Structure

Unbonded prestressed concrete is a new structure in the field of concrete. The stochastic finite element and reliability analysis of unbonded prestressed concrete frame structure, along with the failure risk analysis of the structure, is one of the key and hot spots in the field of structural engineering. Generally believed that by applying prestress, the structure’s stiffness and crack resistance increase while the ductility reduces, and it is seismic unfavorable. Because of prestressed structure, the ability to reduce component of deflection, limiting section crack, improve operational performance of the structure, but for the prestressed concrete structure research, the seismic performance has long been a research focus, however, the reliability study of the structural failure also is very be necessary.Prestressed degree can directly affect the structural seismic performance. Reasonable prestressed degree can improve the energy dissipation capacity of the prestressed concrete structures, the more prestressed, the lower energy dissipation capacity. In this way, concrete beams can maintain good seismic performance by selecting the appropriate prestressed degree. In this study, first, the failure mode of unbonded prestressed concrete frame structure is analyzed, with interlayer displacement angle as the measurement index of structure failure, then the static elastoplastic analysis of concrete frame structure with different prestressed degree was carried out by using midas-gen. The results show that the structure has a good seismic performance when the degree of prestress was between 0.4 and 0.8, and the requirements for seismic resistance can be satisfied, prestressed degree of structure resistance and didn’t have too big effect, In addition, maximum interlayer displacement angle is 0.01299, are less than 0.04, is not structural failure.In this study, the reliability of the structure failure was analyzed by using the theory of reliability based on the static elastoplastic analysis of concrete frame structure, then the structure failure was quantified through the reliable indicator. A comparison between the quantified value and the specification value was made to determine the structural damage types and the corresponding measures to guarantee the ductility of the structure.By the analysis, reliable indicator of the value is increased with the increase of prestress degree, When the prestressed degree is 0.4 to 0.8, the reliability index is closer to 3.2, which is more close to the ductile fracture, Prestressed degree is 1.0, the reliability index values closer to brittle failure, through a series of construction measures to ensure the ductility of the member.