A study on bearing characteristic and failure mechanism of thin-walled structure of a prefabricated subway station

In order to study the bearing performance of a new type of prefabricated subway station structure(PSSS),firstly,a three-dimensional finite element model of the PSSS was established to study the nonlinear mechanics and deformation performance.Secondly,the bearing mechanism of a PSSS was investigated in detail.Finally,the development law of damages to a thin-walled prefabricated component and the failure evolution mechanism of a PSSS were discussed.The results showed that this new type of the PSSS had good bearing capacity.The top arch structure was a three-hinged arch bearing system,and the enclosure structure and the substructure were respectively used as the horizontal and vertical support systems of the three-hinged arch structure to ensure the integrity and stability of the overall structure.Moreover,the tongue-and-groove joints could effectively transmit the internal force between the components and keep the components deformed in harmony.The rigidity degradation of the PSSS caused by the accumulation of damages to the spandrel,hance,arch foot,and enclosure structure was the main reason of its loss of bearing capacity.The existing thin-walled components design had significant advantages in weight reduction,concrete temperature control,components hoisting,transportation and assembly construction,which achieved a good balance between safety,usability and economy.

Experimental and numerical investigation of the flexural performance of channel steel-bolt joint for prefabricated subway stations

Flexural performance of joints is critical for prefabricated structures.This study presents a novel channel steel-bolt(CB)joint for prefabricated subway stations.Full-scale tests are carried out to investigate the flexural behavior of the CB joint under the design loads of the test-case station.In addition,a three dimensional(3D)finite element(FE)model of the CB joint is established,incorporating viscous contact to simulate the bonding and detachment behaviors of the interface between channel steel and concrete.Based on the 3D FE model,the study examines the flexural bearing mechanism and influencing factors for the flexural performance of the CB joint.The results indicate that the flexural behavior of the CB joint exhibits significant nonlinear characteristics,which can be divided into four stages.To illustrate the piecewise linearity of the bending moment-rotational angle curve,a four-stage simplified model is proposed,which is easily applicable in engineering practice.The study reveals that axial force can enhance the flexural capacity of the CB joint,while the preload of the bolt has a negligible effect.The flexural capacity of the CB joint is approximate twice the value of the designed bending moment,demonstrating that the joint is suitable for the test-case station.