Bulletin of Earthquake Engineering

In order to improve the applicability of precast bridge columns in high intensity zones, a precast segmental column, equivalent to the cast-in-place(CIP) column was proposed, in which the ultra-high-perfornce concrete (UHPC) was used to connect precast column components. Two 1/4-scale precast segmental bridge columns assembled with UHPC and one monolithic CIP circular column with the same dimensions were designed and tested by applying cyclic quasi-static loading. Test and analysis results show that the UHPC-connected precast columns have the same typical characteristics as a conventional monolithic CIP column with respect to plastic hinge forming mechanism, failure mode, hysteretic behavior and energy dissipation capacity. There were no noteworthy cracks and damages observed around the UHPC connection areas, which may validate that the CIP column components can be firmly and reliably connected using UHPC due to its remarkable bond and confinement performance. Finally, a set of key parameters included by the Bouc-Wen-Baber-Noori (BWBN) model were identified based on the data recorded in the test. By means of the established BWBN model, the cyclic loading responses were recalculated, which matched well those from the test. This model can be further used for the seismic time- history analysis of bridge structural systems that include the UHPC connected precast columns proposed in this paper.

We present a Bayesian model for the estimation of ground-motion models that allows one to account for truncated data. Truncated data occurs in ground-motion model development because instruments do not record continuously, but only when triggered. The model is formulated as a multi-level model and incorporates event and station terms. The model considers truncation on one variable [e.g., peak ground acceleration (PGA)], and models the joint occurrence of PGA and other ground-motion intensity measures, while conditioning on the truncation for PGA. Initially, we perform numerical experiments on simulated data sets and show that not taking data truncation into account leads to biased models. Regressions using the proposed truncated model can recapture the functions used in the simulation well, and perform comparable to alternative approaches used in the past. Subsequently, we show the impact of the truncated model on observed ground-motion data representing moderate and high trigger levels, 2–4 gal and 10 gal, respectively. Differences to a model that does not take truncation into account occur at larger distances, and are more severe for the high trigger level data. For untruncated regression, the values of the standard deviations are underestimated.

Soil exhibits inherent spatial variability, creating a significant source of uncertainty in geotechnical assessments. This variability becomes particularly critical when evaluating the seismic performance of infrastructure such as multi-span highway bridges, since traditional methodologies in bridge design often oversimplify soil properties by assuming uniformity. This approach, however, may lead to considerable inaccuracies in determining structural response under seismic activity. The complexity of soil–structure interaction (SSI) in such multi-span structures further exacerbates the influence of soil spatial variability on the overall structural response to seismic events. Although numerous studies have explored the impact of spatial variation in ground motions on seismic performance, a noticeable gap exists in the literature addressing soil spatial variability in the SSI modeling and its impact in the seismic response of multi-span bridges. Accordingly, this research aims to address this gap by proposing a numerical framework that integrates the inherent spatial variability of soil in SSI modeling by means of random fields theory and 3D nonlinear dynamic finite element models into the seismic performance analysis of multi-span bridges. The findings from a case study reveals a significant influence of soil spatial variability on structural response, leading to discrepancies in vulnerability assessment between different bridge components and highlighting the importance of incorporating spatial variability in soil parameters into seismic assessments of bridges. Moreover, soil variability appeared to slightly impact system-level vulnerability. Although the main conclusions are developed from a case study and are applicable to bridges with similar characteristics and seismic demand, the proposed approach can readily be applied to other bridge configurations and seismic environments.

Reuse of the 1.5 billion waste tyres that are produced annually is a one of the major worldwide challenges, as waste tyres are toxic and cause pollution to the environment. In recognition of this problem, this paper introduces the reuse of tyres, in the form of derived aggregates in mixtures with granulated soil materials, as previous studies indicated the potential benefits of these materials in the seismic performance of structures. The objective of the present research study is to investigate whether use of rubberised backfills benefits the seismic response of Integral Abutment Bridges (IABs) by enhancing soil-structure interaction (SSI) effects. Numerical models including typical integral abutments on surface foundation with nonlinear conventional backfill material and its alternative form as soil-rubber mixtures are analysed and their response parameters are compared. The research is conducted on the basis of parametric analysis, which aims to evaluate the influence of different rubber-soil mixtures on the dynamic response of the abutment-backfill system under various seismic excitations, accounting for dynamic soil-abutment interaction. The results provide evidence that the use of rubberised backfill leads to reductions in the backfill settlements, the horizontal displacements of the bridge deck, the residual horizontal displacements of the top of the abutment and the pressures acting on the abutment, up to 55, 18, 43 and 47 % respectively, with respect to a conventional backfill comprising of clean sand. Small change in bending moments and shear forces on the abutment wall is also observed. Therefore, rubberised backfills offer promising solution to mitigate the earthquake risk, towards economic design with minimal damage objectives for the resilience of transportation networks.

This paper presents a model for analyzing the seismic response of long-span bridges under oblique P-wave incidence. The model considers local topographical effects, soil nonlinearity and soil–structure interaction. Development of the model involves in application of the equivalent linear method to derive two-dimensional nonlinear free field site response, application of the equivalent load method for seismic wave input through viscous-spring artificial boundaries, and formulation of the dynamic response equation for the soil–bridge system. The two-dimensional nonlinear free field site response under oblique wave incidence is verified using a numerical example. The verification shows that the model is reliable and with high accuracy. The model is implemented into commercial software ANSYS for seismic analysis of a long-span bridge. The effects of angle of incidence, soil stiffness, local topography, and soil nonlinearity are explored by performing parametric studies. The parametric studies show that these factors may have significant impacts on structure response during earthquakes and shall be considered during seismic design of long-span bridges.

The present study aims at scrutinizing the static and dynamic behavior of pile-soil interaction in the context of p–y method using finite element analysis. For this purpose, a series of static and dynamic analyses are carried out for single pile, 2 × 2 and 3 × 3 group piles in homogeneous clayey soil. In the analysis, the nonlinear behavior of soil is taken into account using a kinematic hardening model, while piles are modeled as elastic. The soil model parameters are calibrated using experimental modulus degradation and damping curves. The pile-soil interface is modeled considering normal and shear behavior to account for separation and sliding between soil and pile elements. In the static analyses, variation of pile moments and displacements with depth and the back-calculated p–y curves are evaluated. The soil resistance is directly obtained by extracting the shear and normal forces of the nodes in a pile at any depth. The p-multipliers for 2 × 2 and 3 × 3 group piles are calculated and compared with that of the experiments. The variation of p-multipliers with depth and lateral displacement is also evaluated. In dynamic analyses, first, site response analyses are carried out and validated against one-dimensional results under different loading frequencies. Infinite elements are applied at the boundaries to provide non-reflective boundaries. Later, single, 2 × 2 and 3 × 3 group pile analyses are executed. The influence of loading amplitude and frequency on the response are investigated using moment-depth and displacement-depth relationships. Dynamic p–y curves are back-calculated and the results are deeply assessed by comparing with static curves.

A total of 144 free-field ground motions with closest site-to-rupture distances (Rrup) less than 200 km recorded during the 2010 Mw 7.2 El Mayor–Cucapah earthquake are used to investigate predictive capabilities of the next generation attenuation (NGA) ground-motion prediction equations (GMPE). The NGA GMPEs underpredict observed spectral accelerations at sites with shear wave velocity in the upper 30 m of the site (Vs30) between 180 and 366 m/s with Rrup from about 10 to 50 km and overpredict at sites with Rrup from about 50 to 200 km. Intra-event residuals of the NGA GMPEs exhibit a noticeable negative trend for peak ground acceleration and 0.3, 1.0, and 2.0 s periods. Comparison of the inter-event residual between the 2010 Mw 7.2 El Mayor–Cucapah earthquake and the NGA dataset reveals that short-period inter-event residuals from the 2010 Mw 7.2 El Mayor–Cucapah earthquake is within the scatter of inter-event residuals from the NGA dataset but long-period inter-event residuals do not appear within of the scatter of inter-event residuals from the NGA dataset. Spectral accelerations predicted by the NGA GMPEs are generally unbiased against Vs30 and periods of less than 4.0 s. Observed spectral accelerations show a stronger Vs30 dependence for both short and long periods compared with the NGA GMPEs. The Boore and Atkinson (Earthq Spectra 24(1):99–138, 2008) and Chiou and Youngs (Earthq Spectra 24(1):173–215, 2008) GMPEs perform better in predicting observed short-period spectral accelerations at the sites with Vs30 between 180 and 250 m/s than the Abrahamson and Silva (Earthq Spectra 24(1):67–97, 2008) and Campbell and Bozorgnia (Earthq Spectra 24(1):139–171, 2008) GMPEs.