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Modified calculation method of earth pressure and internal force of the abutment-pile in integral abutment jointless bridges

Huang Fuyun, Li Lan, Javanmardi Ahad, Zhang Hongjung, Izadifar Mohammadreza

Archives of Civil and Mechanical Engineering

2022

Vol. 22, no. 4

art. no. e205, 2022

The girder, abutment and pile of integral abutment jointless bridges (IAJB) are integrated. In IAJBs, the backfill soil behind abutments is directly subjected to the horizontal cyclic displacements originated by the expansion and contraction of girders under thermal loadings. Meanwhile, the monolithic behavior of the abutment and pile of IAJBs causes more complexity in calculating the backfill earth pressure in IAJBs as compared with other bridges and earth retaining structures. In this paper, it is shown that the existing earth pressure calculation methods are inaccurate for IAJBs; therefore, a modified method for calculating the backfill earth pressure behind the abutment and the internal forces of the piles of the IAJBs is proposed. For this purpose, a quasi-static cyclic test was performed on a scaled specimen to understand the behavior of backfill earth pressure and internal forces of the integral abutment and the pile during expansion and contraction of the bridge considering the soil-structure interaction. The test results including bending moment and shear force of the abutment and pile were briefly discussed. In addition, the external forces at the bottom of the abutment calculated by the existing earth pressure methods were compared, and the internal forces of the pile based on the elastic foundation beam method were discussed. The analysis results showed that the bending moment distribution of the pile under the positive displacement loads (during the expansion when the abutment was pushed toward the backfill) was significantly larger than that under the negative displacement loads (during the contraction when the abutment was pulled away from the backfill). The internal forces of the pile calculated by the existing earth pressure theories based on the elastic foundation beam method were much different from the test results. Meanwhile, the internal forces of the pile calculated by the proposed method were more accurate and can be used as a reference for the design of IAJBs.

Development of a new hexagonal honeycomb steel damper

Javanmardi Ahad, Ghaedi Khaled, Ibrahim Zainah, Huang Fuyun, Xu Pu

Archives of Civil and Mechanical Engineering

2020

Vol. 20, no. 2

490--508

This paper presents a new metallic damper called hexagonal honeycomb steel damper (HHSD) for damage mitigation in structures subjected to earthquake excitations. The HHSD is composed of steel plates having several hexagonal and welded to the top and bottom anchor plates. The damper takes the advantages of hexagonal honeycomb geometry and steel material capability to dissipate seismic energy. The quasi-static cyclic test was performed experimentally and numerically on a series of specimens to evaluate the robustness of the HHSD. A three-dimensional finite element analysis of HHSD was carried out and verified with the experimental results. The results showed that the HHSD has low yield displacement, stable hysteretic behavior, a good range of ductility and high-energy dissipation capability. Additionally, the constitutive formulas of the damper are also derived based on the obtained results. Furthermore, it is found to have lightweight and inexpensive with ease of implementation as a potential alternative for new structures or seismic retrofitting of the existing structures.