In order to compare the impact of thickness of different layers on fatigue lives of different semi-rigid asphalt pavement structures, the mechanical results from finite element models in ABAQUS are incorporated with t...In order to compare the impact of thickness of different layers on fatigue lives of different semi-rigid asphalt pavement structures, the mechanical results from finite element models in ABAQUS are incorporated with the fatigue results from fatigue models in FE-SAFE to calculate the mechanical response and fatigue lives of semi-rigid pavement structures under heavy traffic loads. Then the influences on fatigue lives caused by the changes in the thickness of layers in pavement structures are also evaluated. The numerical simulation results show that the aggregated base and the large stone porous mixture （LSPM） base have better anti-cracking performance than the conventional semi-rigid base. The appropriate thickness range for the aggregated layer in the aggregated base is 15 to 18 cm. The thickness of the LSPM layer in the LSPM base is recommended to be less than 15 cm.展开更多
The seismic behavior of frames with semi rigid connections and rotational dampers is examined.The ground acceleration due to earthquake is regarded as a stochastic process,and a pseudo excitation algorithm in frequen...The seismic behavior of frames with semi rigid connections and rotational dampers is examined.The ground acceleration due to earthquake is regarded as a stochastic process,and a pseudo excitation algorithm in frequency domain is implemented in a computer program to handle non orthogonal damping properties of the system.The computer program which incorporates detailed connection models and rotational damping models is used to investigate the effect of the connection of the semi rigid frame.It is shown from analytical studies that semi rigid frames with rotational dampers improve the seismic response of the building and may provide an effective and reliable earthquake resistant design solution.展开更多
Based on the nonlinear displacement-strain relationship,the virtual work principle method was used to establish the nonlinear equilibrium equations of steel beams with semi-rigid connections under vertical uniform loa...Based on the nonlinear displacement-strain relationship,the virtual work principle method was used to establish the nonlinear equilibrium equations of steel beams with semi-rigid connections under vertical uniform loads and temperature change.Considering the non-uniform temperature distribution across the thickness of beams,the formulas for stresses and vertical displacements were presented.On the basis of a flowchart for analysis of the numerical example,the effect of temperature change on the elastic behavior of steel beams was investigated.It is found that the maximal stress is mainly influenced by axial temperature change,and the maximal vertical displacement is principally affected by temperature gradients.And the effect of temperature gradients on the maximal vertical displacement decreases with the increase of rotational stiffness of joints.Both the maximal stress and vertical displacement decrease with the increase of rotational stiffness of joints.It can be concluded that the effects of temperature changes and rotational stiffness of joints on the elastic behavior of steel beams are significant.However,the influence of rotational stiffness becomes smaller when the rotational stiffness is larger.展开更多
基金The National Natural Science Foundation of China(No.51378121)
文摘In order to compare the impact of thickness of different layers on fatigue lives of different semi-rigid asphalt pavement structures, the mechanical results from finite element models in ABAQUS are incorporated with the fatigue results from fatigue models in FE-SAFE to calculate the mechanical response and fatigue lives of semi-rigid pavement structures under heavy traffic loads. Then the influences on fatigue lives caused by the changes in the thickness of layers in pavement structures are also evaluated. The numerical simulation results show that the aggregated base and the large stone porous mixture （LSPM） base have better anti-cracking performance than the conventional semi-rigid base. The appropriate thickness range for the aggregated layer in the aggregated base is 15 to 18 cm. The thickness of the LSPM layer in the LSPM base is recommended to be less than 15 cm.
文摘The seismic behavior of frames with semi rigid connections and rotational dampers is examined.The ground acceleration due to earthquake is regarded as a stochastic process,and a pseudo excitation algorithm in frequency domain is implemented in a computer program to handle non orthogonal damping properties of the system.The computer program which incorporates detailed connection models and rotational damping models is used to investigate the effect of the connection of the semi rigid frame.It is shown from analytical studies that semi rigid frames with rotational dampers improve the seismic response of the building and may provide an effective and reliable earthquake resistant design solution.
基金Project(50478075) supported by the National Natural Science Foundation of ChinaProject(YBJJ0817) supported by Scientific Research Foundation of Graduate School of Southeast University
文摘Based on the nonlinear displacement-strain relationship,the virtual work principle method was used to establish the nonlinear equilibrium equations of steel beams with semi-rigid connections under vertical uniform loads and temperature change.Considering the non-uniform temperature distribution across the thickness of beams,the formulas for stresses and vertical displacements were presented.On the basis of a flowchart for analysis of the numerical example,the effect of temperature change on the elastic behavior of steel beams was investigated.It is found that the maximal stress is mainly influenced by axial temperature change,and the maximal vertical displacement is principally affected by temperature gradients.And the effect of temperature gradients on the maximal vertical displacement decreases with the increase of rotational stiffness of joints.Both the maximal stress and vertical displacement decrease with the increase of rotational stiffness of joints.It can be concluded that the effects of temperature changes and rotational stiffness of joints on the elastic behavior of steel beams are significant.However,the influence of rotational stiffness becomes smaller when the rotational stiffness is larger.
