The effects of structural modeling （bar slip in lap splice）, ground motion selection process （epsilon effect） and size of a structure （number of bays and stories） on the fragility of reinforced concrete ordinary...The effects of structural modeling （bar slip in lap splice）, ground motion selection process （epsilon effect） and size of a structure （number of bays and stories） on the fragility of reinforced concrete ordinary moment resisting frames are investigated. An analytical model is developed to account for bar slip in lap splice, which exhibits good correlation with existing experimental data. Then, incremental dynamic analysis is used to derive the fragility curves for four model structures. The model structures simulate frames with a different number of bays and stories. Finally, the fragility curves are corrected for the epsilon effect. The results show that slip in the lap splice can significantly increase the failure probability, especially for the collapse prevention limit state. At the same time, it is found that spectral shape has a significant impact on the fragility curves. It is also found that accounting for or ignoring bar slip or epsilon effects increases the probability of failure for larger structures. This indicates an unconservative bias in the safety of larger structures.展开更多
In the actual monitoring of deep hole displacement,the identification of slip surfaces is primarily based on abrupt changes observed in the inclinometric curve.In conventional identification methods,inclinometric curv...In the actual monitoring of deep hole displacement,the identification of slip surfaces is primarily based on abrupt changes observed in the inclinometric curve.In conventional identification methods,inclinometric curves exhibiting indications of sliding can be categorized into three types:B-type,D-type,and r-type.The position of the slip surface is typically determined by identifying the depth corresponding to the point of maximum displacement mutation.However,this method is sensitive to the interval of measurement points and the observation scale of the coordinate axes and suffers from unclear sliding surfaces and uncertain values.Based on the variation characteristics of these diagonal curves,we classified the landslide into three components:the sliding body,the sliding interval,and the immobile body.Moreover,three different generalization models were established to analyze the relationships between the curve form and the slip surface location based on different physical indicators such as displacement rate,relative displacement,and acceleration.The results show that the displacement rate curves of an r-type slope exhibit a clustering feature in the sliding interval,and by solving for the depth of discrete points within the step phase,it is possible to determine the location of the slip surface.On the other hand,D-type slopes have inflection points in the relative displacement curve located at the slip surface.The acceleration curves of B-type slopes exhibit clustering characteristics during the sliding interval,while the scattered acceleration data demonstrate wandering characteristics.Consequently,the slip surface location can be revealed by solving the depth corresponding to the maximum acceleration with cubic spline interpolation.The approach proposed in this paper was applied to the monitoring data of a landslide in Yunnan Province,China.The results indicate that our approach can accurately identify the slip surface location and enable computability of its position,thereby enhancing applicability and relia展开更多
In the study of plastic constitutive relations, due to the 'single curve' hypothesis andthe yield conditions of the phenomenological theory, some theoretic problems about the proc-ess of plastic deformation ha...In the study of plastic constitutive relations, due to the 'single curve' hypothesis andthe yield conditions of the phenomenological theory, some theoretic problems about the proc-ess of plastic deformation have not yet been solved, and moreover, the constitutive relationsobtained with this method can only be approximately applied to some materials of excellentplastic performances. Plastic deformation in σ_m, τ_p, S_2 spaces has been analyzed according tothe 'similar curve' hypothesis and the rational yield condition obtained in σ_m, τ_p, S_2 spaces,a constitutive relationship of deformation theory of plasticity has been set up, which des-cribes better the laws of plastic deformation and voluminal deformation of all engineeringmaterials subjected to various stresses. By the characteristics of σ_m, τ_p, and S_2 and the inde-pendent deformations caused by them respectively, the problem about deviation from simpleloading has been solved, the cause of the loss of stability of materials under tension hasbeen theoretically given, some difficuties in the basic theory of plasticity have been over-come, and thus the basis has been laid down for a new theory system of plasticity.展开更多
文摘The effects of structural modeling （bar slip in lap splice）, ground motion selection process （epsilon effect） and size of a structure （number of bays and stories） on the fragility of reinforced concrete ordinary moment resisting frames are investigated. An analytical model is developed to account for bar slip in lap splice, which exhibits good correlation with existing experimental data. Then, incremental dynamic analysis is used to derive the fragility curves for four model structures. The model structures simulate frames with a different number of bays and stories. Finally, the fragility curves are corrected for the epsilon effect. The results show that slip in the lap splice can significantly increase the failure probability, especially for the collapse prevention limit state. At the same time, it is found that spectral shape has a significant impact on the fragility curves. It is also found that accounting for or ignoring bar slip or epsilon effects increases the probability of failure for larger structures. This indicates an unconservative bias in the safety of larger structures.
基金supported by the Scientific and Technological Research and Development Programs of China Railway Group Limited(Grant No.2022 Major Special Project-07)Gansu Provincial Technology Innovation Guidance Program-Special Funding for Capacity Building of Enterprise R&D Institutions(Grant No.23CXJA0011)Key R&D and transformation plan of Qinghai Province,China(Special Project for Transformation of Scientific and Technological Achievements No.2022-SF-158).
文摘In the actual monitoring of deep hole displacement,the identification of slip surfaces is primarily based on abrupt changes observed in the inclinometric curve.In conventional identification methods,inclinometric curves exhibiting indications of sliding can be categorized into three types:B-type,D-type,and r-type.The position of the slip surface is typically determined by identifying the depth corresponding to the point of maximum displacement mutation.However,this method is sensitive to the interval of measurement points and the observation scale of the coordinate axes and suffers from unclear sliding surfaces and uncertain values.Based on the variation characteristics of these diagonal curves,we classified the landslide into three components:the sliding body,the sliding interval,and the immobile body.Moreover,three different generalization models were established to analyze the relationships between the curve form and the slip surface location based on different physical indicators such as displacement rate,relative displacement,and acceleration.The results show that the displacement rate curves of an r-type slope exhibit a clustering feature in the sliding interval,and by solving for the depth of discrete points within the step phase,it is possible to determine the location of the slip surface.On the other hand,D-type slopes have inflection points in the relative displacement curve located at the slip surface.The acceleration curves of B-type slopes exhibit clustering characteristics during the sliding interval,while the scattered acceleration data demonstrate wandering characteristics.Consequently,the slip surface location can be revealed by solving the depth corresponding to the maximum acceleration with cubic spline interpolation.The approach proposed in this paper was applied to the monitoring data of a landslide in Yunnan Province,China.The results indicate that our approach can accurately identify the slip surface location and enable computability of its position,thereby enhancing applicability and relia
文摘In the study of plastic constitutive relations, due to the 'single curve' hypothesis andthe yield conditions of the phenomenological theory, some theoretic problems about the proc-ess of plastic deformation have not yet been solved, and moreover, the constitutive relationsobtained with this method can only be approximately applied to some materials of excellentplastic performances. Plastic deformation in σ_m, τ_p, S_2 spaces has been analyzed according tothe 'similar curve' hypothesis and the rational yield condition obtained in σ_m, τ_p, S_2 spaces,a constitutive relationship of deformation theory of plasticity has been set up, which des-cribes better the laws of plastic deformation and voluminal deformation of all engineeringmaterials subjected to various stresses. By the characteristics of σ_m, τ_p, and S_2 and the inde-pendent deformations caused by them respectively, the problem about deviation from simpleloading has been solved, the cause of the loss of stability of materials under tension hasbeen theoretically given, some difficuties in the basic theory of plasticity have been over-come, and thus the basis has been laid down for a new theory system of plasticity.
