To enhance the understanding of the seismic behavior of reinforced concrete (RC) hollow piers, a sensitivity analysis of design parameters is conducted. A novel analytical model named the Axial–Flexure–Shear-Interaction-Membrane-Beam-Truss-Element-Model (AFSI-MBTEM) is proposed to account for the flexure–shear coupling. To avoid size effects, three full-scale rectangular RC hollow piers are simulated and validated using the AFSI-MBTEM. Based on a benchmark model, the influence of parameters on seismic responses is explored under cyclic loading, earthquakes, and different PGAs. The AFSI-MBTEM can efficiently and accurately capture the symmetric and asymmetric hysteretic curves of RC hollow piers. The influence of parameters under cyclic loading is generally consistent with that under strong earthquakes. The aspect ratio, width-to-depth ratio, wall thickness ratio, axial load ratio, and longitudinal rebar ratio have a significant influence under cyclic loading, earthquakes, and different PGAs. The influence of stirrup ratio, concrete strength, and longitudinal rebar strength becomes clear under earthquakes, especially for residual deformation. The suggested parameter values for hollow piers are as follows: aspect ratio of 4–6, width-to-depth ratio of 1.0–2.0, wall thickness ratio of 20–40%, axial load ratio of 0.05–0.10, longitudinal rebar ratio of 1.2–2.2%, stirrup ratio of 0.8–1.2%, concrete strength of C40, and longitudinal rebar strength of 400 MPa and 500 MPa.

This study develops a novel transverse steel damper (TSD) to enhance the seismic performance of tall-pier girder bridges, featuring superior lateral strength and energy dissipation capacity. The TSD’s design and arrangement are presented, with its hysteretic behavior simulated in ABAQUS. Key parameters (yield strength: 3000 kN; initial gap: 100 mm; post-yield stiffness ratio: 15%) are optimized through seismic analysis under near-fault ground motions, incorporating pulse characteristic investigations. The optimized TSD effectively reduces bearing displacements and results in smaller pier top displacements and internal forces compared to the bridge with fixed bearings. Due to the higher-order mode effects, there is no direct correlation between top displacements and bottom internal forces. As pier height decreases, the S-shaped shear force and bending moment envelopes gradually become linear, reflecting the reduced influence of these modes. Medium- to long-period pulse-like motions amplify seismic responses due to resonance (pulse period ≈ fundamental period) or susceptibility to large low-frequency spectral values. Higher-order mode effects on bending moments and shear forces intensify under prominent high-frequency components. However, the main velocity pulse typically masks the influence of high-order modes by the overwhelming seismic responses due to large spectral values at medium to long periods.

Tall-pier girder bridges with fluid viscous dampers (FVDs) are widely used in earthquake-prone mountainous areas. However, the influence of higher-order modes and near-field earthquakes on tall piers has rarely been studied. Based on an asymmetric tall-pier girder bridge, a finite element model is established, and the parameters of FVDs are optimized using SAP2000. The higher-order mode effects on tall piers are explored by proportionally reducing the pier heights. The pulse effects of near-field earthquakes on FVD mitigation and higher-order modes are analyzed. The optimal FVDs can coordinate the force distribution among tall piers, effectively reducing displacement responses and internal forces. Due to higher-order modes, the internal force envelopes of tall piers exhibit concave-convex distributions. As pier heights decrease, the internal force envelopes gradually become linear, implying reduced higher-order mode effects. Long-period pulse-like motions produce the maximum seismic responses because the slender tall-pier bridge is sensitive to high spectral accelerations in medium-to-long periods. The higher-order modes are more easily excited by near-field motions with large spectral values in the high-frequency range. Overall, FVDs can simultaneously reduce the seismic responses of tall piers and diminish the influence of higher-order modes.

Enhancing the seismic resilience of urban water distribution networks (WDNs) requires the improvement of both earthquake resistance and rapid recovery capabilities within the system. This paper proposes a multi-objective method to enhance the seismic resilience of the WDNs, focusing on system restoration capabilities while comprehensively considering the hydraulic recovery index, maintenance time, and maintenance cost. The method utilizes a random simulation approach to generate various damage scenarios for the WDN, considering pipe leakage, pipe bursts, and variations in node flow resulting from changes in water pressure. It characterizes the functions of the WDN through hydraulic service satisfaction and quantifies system resilience using a performance response function. Additionally, it determines the optimal dispatch strategy for emergency repair teams and the optimal emergency repair sequence for earthquake-damaged networks using a genetic algorithm. Furthermore, a comprehensive computational platform has been developed to systematically analyze and optimize seismic resilience strategies for WDNs. The feasibility of the proposed method is demonstrated through an example involving the WDN in Xi’an City. The results indicate that the single-objective seismic resilience improvement method based on the hydraulic recovery index is the most effective for enhancing the seismic resilience of the WDN. In contrast, the multi-objective method proposed in this article reduces repair time by 17.9% and repair costs by 3.4%, while only resulting in a 0.2% decrease in the seismic resilience of the WDN. This method demonstrates the most favorable comprehensive restoration effect, and the success of our method in achieving a symmetrically balanced restoration outcome demonstrates its value. The proposed methodology and software can provide both theoretical frameworks and technical support for urban WDN administrators.