In this paper, an alternative aseismic system for bridge with pile-cap foundation called a separated pile-cap with proper material set in the gap layer was proposed. To simulate the system, a 3-dimensional finite element model for a continuous beam bridge was built. The seismic responses of the model, including behavior of the restrainer, moment at the bottom of the pier and pullout force of the piles with different restrainer lengths under 3 longitudinal artificial earthquake waves were analyzed. The results show that this system can reduce the seismic response significantly.

The objective of the present work is to propose a new composite seismic isolation system device based on the cable-sliding friction aseismic bearing (CSFAB). Multi-chip steel spiral spring (MSSS) are characterized by unique mechanical properties due to elastic recovery capability. An isolation bearing system based on a MSSS elastic effect is intended to provide recovery properties to reduce or eliminate the residual deformations. The device concept is based on two separate systems, one to transmit the vertical load and to act as a lateral restrainer at meantime, the other contributes to the automatic reset functions in the system. This article presents in detail the mechanical components of the innovative device focusing on its main properties. The load-deformation curve established in this paper is verified to be efficient in describing the mechanical characteristics of the device through experiment. The results could provide reference for study and application of the new composite seismic isolation system.

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On the background of Lanzhou-Chongqing railway Guangyuan Jialing river (82+172+82) m long-span continuous beam-arch combination bridge, the beam-arch joint stress distribution rules of a railway continuous beam-arch bridge has been studied, which the main span is over 150m, the construction and services stages are separated.By taking a finite element analysis which whole first and local second, a whole bridge three-dimensional model has been established. After that, the most typical worst loading cases of beam-arch combining joint construction and services stages have been determined. A detailed finite element model of beam-arch combining site has been established, the stress field distribution rules and its main influencing factors have been investigated, and suggestions about optimization in design are presented. Researches show that, under the typical worst-cases of load, beam-arch combining site has reasonable force, and mainly dominated by longitudinal compression; Stress concentration appears primarily in the support and the corner between the arch foot and No.0 block with local tensile stress overrun; The tensile stress in the roof and floor is 0.30~1.27MPa; the contribution rate of secondary dead load, live load and additional force to stress respectively are 22.1%、 23.5% and 11.2%; With regard to large tensile stress area such as the arch foot stiffness transition section and the juncture between skewback and arch springing, strengthening measure such as ease the transition section should be taken.