2c:T4e0,

Longitudinally coupled prefabricated slab track is prone to slab warping under the non-uniform temperature field. Analytical expressions for the displacement field of the track slab during the warping process are developed hereby based on equilibrium differential equations, and the expressions are verified through a numerical model by finite element method in ANSYS package. Through analyzing the factors such as types of temperature distribution, slab gravity, and rail weight, regulations of warping deformation for the track slab are systematically analyzed. Research shows that the displacements in the x and z directions are linearly related to the respective components during the warping deformation. The displacement in y direction has a quadratic relationship with x and z components. Temperature gradient is the pivotal factor to lead the warping of the track slab, and the type of temperature distribution has less effect on the warping displacement. If track slab remains unwarped under the effect of slab gravity, temperature gradient should be maintained in the range of –18°C/m–13°C/m. Rail weight has less influence on slab warping.

2d:T50f,

Double-layer barrel vault roofs with double-layer vertical walls are frequently used as a structural system for highly important public buildings; therefore, their seismic design needs special considerations. In this article, the seismic collapse behavior of these structures, used as a lateral load-resisting system, is evaluated by carrying out incremental dynamic analysis. For this purpose, different rise-to-span and height-to-span ratios are considered for the roofs and the walls, respectively. The structures are first designed in accordance with Iranian design codes and then they are modeled in OpenSees. The material and geometric nonlinearities are considered in the analyses, including the buckling response of the compression members. At the next stage, the models are subjected to incremental dynamic analysis and their median collapse capacities are extracted. Collapse margin ratios of various structures are finally derived, following FEMA-P695 methodology, and compared against the established acceptable limits. The obtained results show that collapse of the structures occurs mainly due to the buckling-mode failure of the roof. The collapse performance of the structures with large rise-to-span ratio of roofs and large height-to-span ratio of walls is unacceptable.

2e:T510,

To investigate the rotational behavior of concrete segmental joints with gaskets, bending tests are performed by detailed three-dimensional continuum numerical models for joints with and without gaskets. Based on the numerical results, an analytical model is proposed to analyze the rotational stiffness of the segmental joint and extend the simulation with related parametric studies. The bending tests reveal that the rotational behavior of the segmental joint with gaskets can be divided into four stages for both the sagging and hogging moment cases. The analytical results reveal that the sealing gasket has little inﬂuence on the joint rotational behavior, while the elastic gasket has a significant effect of reducing the joint rotational stiffness. Besides, the rotational behavior of the joint with gaskets is affected by the axial force and the bolt pre-tightening force to a certain degree. The proposed analytical model allows the effect of the properties of bolts and various gaskets, the concrete contact force, the geometry of the joint section, and the subjected loads to be taken into consideration. The analytical results are well consistent with the numerical results, and the analytical model can be adopted for simulation of the segmental joint with various gaskets.

2f:T4b1,

As the most widely used coupling structure in electromechanical systems, bolt coupling is the important part in these systems. The reliability and strength of bolted joint are affected by pretension force, which is one of