双墩柱大悬臂预应力混凝土盖梁荷载试验方法

根据广东省某条高速公路上双墩柱大悬臂预应力盖梁桥梁的荷载试验,对该桥梁的荷载试验方案的主要内容及实施过程进行详细描述,并对试验数据进行了细致的分析。对评定双墩柱大悬臂预应力盖梁在静力荷载作用工作状态下,综合分析判断双墩柱大悬臂预应力盖梁的承载能力和使用条件有一定的指导意义,同时对双墩柱大悬臂预应力盖梁竖向裂缝成因作定性判定。

双柱墩和中系梁桁架整体移动施工技术分析

在西南山区某高速公路桥梁下部结构施工中,运用双柱墩与中系梁桁架整体移动施工技术。该技术在滑模、翻模施工基础上,将传统的滑模、翻模施工工艺相结合,对桁架进行改进,通过滑模桁架提升,进行立模、拆模、翻升立模,循环施工。在常规作业工序繁杂的情况下,该技术降低了大型起重设备使用率和施工成本,缩短了施工周期,保证了混凝土质量,提高了高空作业的安全。

Seismic performance of double- skin steel- concrete composite box piers: Part Ⅰ——Bidirectional quasi-static testing

To study the seismic performance of double-skin steelconcrete composite box（ DSCB） piers, a total of 11 DSCB pier specimens were tested under bidirectional cyclic loading. The effects of the loading pattern, the steel plate thickness, the axial load ratio, the slenderness ratio and the aspect ratio were taken into consideration. The damage evolution process and failure modes of the tested specimens are presented in detail. Test results are also discussed in terms of the hysteretic curve, skeleton curve, ductility and energy dissipation capacity of DSCB pier specimens. It can be concluded that the hysteretic performance of DSCB piers in one direction is affected and weakened by the cyclic loading in the other direction. DSCB piers under bidirectional cyclic loading exhibit good performance in terms of load carrying capacity, ductility, and energy dissipation capacity. Overall, DSCB piers can meet the basic aseismic requirements. The research results can be taken as a reference for using DSCB piers as high piers in bridges in strong earthquakeprone areas.

Seismic performance of double-skin steel-concrete composite box piers: Part Ⅱ—Nonlinear finite element analysis

An accurate finite element （ FE） model was constructed to examine the hysteretic behavior of double-skin steel-concrete composite box （ DSCB） piers for further understanding the seismic performance of DSCB piers; where the local buckling behavior of steel tubes, the confinement of the in-filled concrete and the interface action between steel tube and in-filled concrete were considered. The accuracy of the proposed FE model was verified by the bidirectional cyclic loading test results. Based on the validated FE model, the effects of some key parameters, such as section width to steel thickness ratio, slenderness ratio, aspect ratio and axial load ratio on the hysteretic behavior of DSCB piers were investigated. Finally, the skeleton curve model of DSCB piers was proposed. The numerical simulation results reveal that the peak strength and elastic stiffness decrease with the increase of the section width to steel thickness ratio. Moreover, the increase of the slenderness ratio may result in a significant reduction in the peak strength and elastic stiffness while the ultimate displacement increases. The proposed skeleton curve model can be taken as a reference for seismic performance analyses of the DSCB piers.

Cyclic test and numerical study of seismic performance of precast segmental concrete double-columns

The comparative research on the seismic performance of grouted sleeve connected pier(GS)and prestressed precast segmental concrete pier(PC)is mostly carried out by numerical simulation.In this study,the GS pier and the PC pier of the new railway project from Hetian to Ruoqiang are taken into consideration.Two kinds of 1/5-scale assembled double-column specimens are made,and the quasi-static tests are carried out.The overall seismic performance of the two spliced piers is studied,and compared in terms of failure mechanism,bearing capacity,ductility,stiffness and energy dissipation capacity.The results show that the failure modes of both GS pier and PC pier are characterized by bending.However,the specific failure location and form are different.The GS pier presents a complete hysteretic curve,large equivalent stiffness and strong energy dissipation capacity.The hysteretic area of the PC pier is small.However,it has good self-reset ability and quasi-static residual displacement.Finite element models are set up using DispBeamColumn fiber elements and ZeroLength elements.The models that are calibrated with the test data can effectively simulate the damage development under monotonic loading.The load−displacement curves are in good agreement with the backbone curves of the test results.