The application of Accelerated Bridge Construction methods (ABC) to build, renovate and rehabilitate aging bridges is most likely to reduce the economic and social impacts of projects. This is especially relevant in countries with severe winter climates, where bridge construction is typically interrupted during the winter period. The objective of this study is to present the state of the art related to elements, systems, connections and materials used for bridge superstructures in ABC projects and to highlight their adaptability to cold or northern climate countries. The literature review and presentation of results are based on the gathering of Prefabricated/Precast Bridge Elements and Systems (PBES) used for ABC projects in North America and which are also used in many countries around the world. Following this inventory, and after grouping the PBES, connections and materials, the authors were able to identify the possibility of adapting the ABC method for countries with cold and northern climates. Products that can be used down to −6 °C for connections are presented, and future research orientations are proposed.

Seismic isolation is a powerful tool for mitigating seismic risk and improving structural performance. However, some parameters, such as earthquake inputs and soil characteristics, influence the technology’s performance. This research aims to investigate the effects of soil–structure interaction (SSI) with regard to different moderate earthquakes associated with different distances of the source to the site, frequency content, and different soil characteristics on the seismic response of the isolated bridges. Near-fault (NF) and far-field (FF) records are applied to the conventional and isolated bridge with and without considering the underlying soil. For this reason, using the direct and simplified methods, three soil properties representing rock, dense, and stiff soils are modeled in Abaqus software. Nonlinear time history analysis (NLTHA) is carried out, and structural responses of both approaches in terms of maximum deck acceleration, base shear, and displacement of the deck and the isolation system are studied. Results demonstrate that the difference between the two approaches is significant. Using the simplified method is a rather simple approach that roughly captures the important features of the record characteristics and SSI. Furthermore, careful attention should be paid to the base shear responses and the isolator displacement demands, as they are significantly amplified in softer soils. In addition, the peak ground acceleration to peak ground velocity ratio (PGA/PGV) plays a decisive role in all dynamic responses. Records with a lower PGA/PGV ratio cause higher dynamic responses in terms of displacement and acceleration/force, regardless of the distance of the ruptured fault, while NF records show higher dynamic responses compared to FF records.

The identification of the most pertinent site parameters to classify soils in terms of their amplification of seismic ground motions is still of prime interest to earthquake engineering and codes. This study investigates many options for improving soil classifications in order to reduce the deviation between “exact” predictions using wave propagation and the method used in seismic codes based on amplification (site) factors. To this end, an exhaustive parametric study is carried out to obtain nonlinear responses of sets of 324 clay and sand columns and to constitute the database for neuronal network methods used to predict the regression equations of the amplification factors in terms of seismic and site parameters. A wide variety of parameters and their combinations are considered in the study, namely, soil depth, shear wave velocity, the stiffness of the underlaying bedrock, and the intensity and frequency content of the seismic excitation. A database of AFs for 324 nonlinear soil profiles of sand and clay under multiple records with different intensities and frequency contents is obtained by wave propagation, where soil nonlinearity is accounted for through the equivalent linear model and an iterative procedure. Then, a Generalized Regression Neural Network (GRNN) is used on the obtained database to determine the most significant parameters affecting the AFs. A second neural network, the Radial Basis Function (RBF) network, is used to develop simple and practical prediction equations. Both the whole period range and specific short-, mid-, and long-period ranges associated with the AFs, F_a, F_v, and F_l, respectively, are considered. The results indicate that the amplification factor of an arbitrary soil profile can be satisfactorily approximated with a limited number of sites and the seismic record parameters (two to six). The best parameter pair is (PGA; resonance frequency, f₀), which leads to a standard deviation reduction of at least 65%. For improved performance, we propose the practical triplet $\left({PGA;V}_{s30};f_0\right)$ with V_s30 being the average shear wave velocity within the upper 30 m of soil below the foundation. Most other relevant results include the fact that the AFs for long periods (F_l) can be significantly higher than those for short or mid periods for soft soils. Finally, it is recommended to further refine this study by including additional soil parameters such as spatial configuration and by adopting more refined soil models.

Single-mode spectral analysis (SMSA) is a simple procedure efficiently used to evaluate the seismic demands of base-isolated bridges, particularly suitable for the design of simple bridges or preliminary design of complex bridges. However, bridge design codes, notably the Canadian code CSA-S6:19 (CSA-S6 2019), specify many limitations on the use of the method for final design. This paper evaluates the performance of SMSA and the efficiency of its limits of application as specified in the current codes through the results of a parametric study. The hysteretic properties of seismic isolation systems and the stiffness of bridge substructures are varied. Seismic demands predicted by SMSA and nonlinear time-history analyses (NLTHAs) are then compared, both inside and outside the current specified limit range in CSA-S6:19 (CSA-S6 2019). Results show that the most effective application conditions are those related to the maximum equivalent viscous damping and minimum restoring force. The upper limits of the effective period and the post-elastic period can be ignored. Further, to complement SMSA, a relation is proposed to estimate the expected residual displacement as a function of the restoring force at the design displacement. Regression relations allowing estimating the expected mean and confidence interval of the relative displacement deviation predicted by SMSA from that based on NLTHA are also proposed.