This paper deals with the contribution of the soil-structure interaction (SSI) effects to the seismic analysis of cultural heritage buildings. This issue is addressed by considering, as a case study, the Mosque-Cathedral of Cordoba (Spain). This study is focussed on the Abd al-Rahman I sector, which is the most ancient part, that dates from the 8th century. The building is a UNESCO World Heritage Site and it is located in a moderate seismic hazard zone. It is built on soft alluvial strata, which amplifies the SSI. Since invasive tests are not allowed in heritage buildings, in this work a non-destructive test campaign has been performed for the characterisation of the structure and the soil. Ambient vibration tests have been used to calibrate a refined 3D macro-mechanical-based finite element model. The soil parameters have been obtained through an in situ geotechnical campaign, that has included geophysical tests. The SSI has been accounted for by following the direct method. Nonlinear static and dynamic time-history analyses have been carried out to assess the seismic behaviour. The results showed that the performance of the building, if the SSI is accounted for, is reduced by up to 20 % and 13 % in the direction of the arcades and in the perpendicular direction, respectively. Also, if the SSI is taken into account, the damage increased. This study showed that considering the SSI is important to properly assess the seismic behaviour of masonry buildings on soft strata. Finally, it should be highlighted that special attention should be paid to the SSI, which is normally omitted in this type of studies, to obtain a reliable dynamic identification of the built heritage.

This study investigates the seismic performance of a theoretical hospital building designed as a Fixed-Base (FB) structure according to TSC-2018 (Turkish Seismic Code) and evaluates its behavior under three scenarios: FixedBase (FB), Soil-Structure Interaction (SSI), and Base-Isolated (SSI+ISO). The study employs Nonlinear Time History Analysis (NLTHA) using scaled acceleration records, including one from the 2023 Maras, earthquake. Structural performance is assessed based on maximum roof displacements, interstory drift ratios (IDR), and isolator displacements. Results show that base isolation systems significantly reduce drift demands and roof displacements, keeping the structure within slight damage limits even under extreme seismic loads. In contrast, SSI effects amplify interstory drift demands, increasing the likelihood of exceeding moderate damage thresholds. The analysis highlights the Maras, Education and Research Hospital, which suffered severe damage and became non-operational during the 2023 Kahramanmaras earthquake. This outcome underscores the limitations of fixedbase designs in regions with soft soil conditions and the necessity of incorporating base isolation systems to improve seismic resilience. The findings emphasize the importance of mandatory adoption of base isolation systems in hospital designs, proper consideration of SSI effects, and the retrofitting of existing hospital buildings to meet modern seismic code requirements (TSC-2018) and prevent similar failures in future seismic events.

Structural damages occurred during any earthquake arise not only from structural design flaw but also from the variability of sub-base soil behavior and the foundation system. For this reason, structure-soil-pile interaction has an important place in evaluating the behavior of a structure under dynamic effects. Bored pile application, which is one of the deep foundation systems, is a widely used method in the world to transfer the loads coming from the structure to the ground safely in problematic grounds. For this reason, in pile foundation system designs, how bored pile foundation systems will affect the structural design under earthquake loads is considered an important issue. In particular, how diagonally braced steel structures with piled raft foundation systems will behave under earthquake effects has been evaluated as a subject that needs to be examined. For this reason, this situation was evaluated as the main purpose of this study. The effect of the bored pile systems designed in different orientations on the behavior of diagonally braced steel structures during an earthquake under kinematic and inertial effects was investigated in detail within the scope of this study. Numerical analyses, based on data from shake table experiments on a scaled superstructure, examine various pile design scenarios. Experimental base shear force measurements informed the development of numerical scenarios, which varied pile lengths and inter-pile distances while maintaining constant pile diameters. This study analyzed the kinematic and inertial effects on the piles, offering insights into their structural behavior under seismic conditions. The increase in pile length and the increase in the distance between the piles caused a significant increase in the bending moment and shear force, which have an important place in pile design.

In recent decades, buried flexible corrugated metal culverts (CMCs) and corrugated metal pipes (CMPs) have increasingly contributed to the development of infrastructure networks. The primary design aspect of these structures is the soil-structure interaction under different modes of loading. Surface static loading caused by traffic flow frequently leads to the development of deformations and internal forces in buried structures. Thus, the investigation of the soil-structure interaction mechanism under surface static loading can yield a deeper understanding of the culvert response, to enhance current design approaches. Furthermore, to assure their continued serviceability over time, the regular inspection of in-service culverts is vital to assess their status in terms of potential damage and material deterioration due to aging factors such as corrosion and/or mechanical abrasion. In this study, laboratory tests were used to monitor the performance of buried flexible open-bottom arch corrugated metal culverts under surface static loading. Following the backfilling of soil surrounding each culvert, surface static loading was initiated via a top loading steel plate. Impacts of the soil cover depth and culvert condition (i.e., intact or deteriorated) were investigated via three test configurations: an intact culvert with a cover depth of 600 mm (C-01), an intact culvert with a cover depth of 300 mm (C-02), and a deteriorated culvert with a cover depth of 300 mm (C-03). During each static loading test, the load-settlement curve of the top loading steel plate, the increase in vertical soil stresses, and culvert deformations and internal forces were recorded. Furthermore, 3D finite element models of the three test configurations were developed by simulating the culvert responses to surface static loading, and the numerical modelling results were then validated against the laboratory measurements. In addition, to investigate the impact of culvert deterioration on the performance of the soil-culvert interaction, numerical models were used to simulate different damage scenarios.

Understanding how buried structures respond to cyclic loading is crucial for designing earthquake-resistant underground infrastructure. The complexity of the dynamic response of these underground structures is accentuated when accounting for their interaction with adjacent buildings. This study focuses on the impact of the lateral distance between a shallow rectangular tunnel and an adjacent residential structure on dynamic soil-structure interaction, employing two dynamic centrifuge tests. Particle Image Velocimetry technique was adopted to observe the developed mechanisms of liquefied soil deformation, tunnel uplift, and foundation settlement. Results show the pronounced effects on soil deformation above the tunnel crown with a reduction in the tunnel-building separation distance. The distribution of excess pore pressure along the tunnel lining will be presented. Tunnel manifested additional lateral movement and reduced uplift when the adjacent building was in close proximity. A decrease in the tunnel-building distance contributed to a reduction of building rotation, primarily due to the significant mitigation of non-uniform settlement under the footing. Overall, the soil deformation mechanism around the tunnel and the building will be shown to change depending on the separation distance between them.

Buried pipelines subjected to permanent ground deformations (through, e.g., earthquake-induced liquefaction or fault rupture) often experience widespread damage. Regardless of the direction of ground movement, pipelines tend to respond and experience damage axially due to their directional stiffness characteristics. In addition, case studies and previous testing have shown that damage is concentrated at the pipe joints due to their lower strength compared with a pipe barrel. Previous testing has also shown that axial forces increase significantly when pipe connections have jointing mechanisms, such as coupling restraints, with larger diameters than the pipe barrel alone. These enlarged joints act as anchors along the pipe, increasing the soil resistance at these locations. Current methods for predicting the axial force along a pipe underpredict the force demands and oversimplify the mechanics of soil resistance on the joint face. This study conducts a series of 12 pipe-pull tests in a centrifuge, varying joint diameter and burial depth, to quantify the axial forces developed. A strong linear correlation was observed between the soil resistance on a joint face and the joint surface area and burial depth. The study also proposes an analytical solution based on pullout capacity design equations for vertical anchor plates as a function of soil and pipe joint properties. The proposed solution to calculate joint resistance is in good agreement with the centrifuge tests performed for this study and previous full- and model-scale experiments. The proposed prediction equation is anticipated to have future applications to other buried structures because it is based on mechanisms of passive resistance commonly encountered in underground structures and lifelines.

Architectural aspects of buildings, such as the shape of the plan, play an important role in defining the seismic behavior of the building and the future damages structural and non-structural elements may go through. Several items, like the aesthetic aspects and limitations in the field under construction, make an irregular plan shape to be selected as a desirable option. Correctly understanding the building's behavior on the irregular plan is necessary in this case. With that being said, this research aims to evaluate the seismic performance of buckling restrained braced frames (BRBFs) steel structures having an L-shaped irregular plan. An irregular L-shaped plan amplifies the torsional response of the building and causes stress concentration because of the re-entrant corners. Since the lack of a comprehensive study on the L-shaped plan irregularity in buildings equipped with BRBs and the effect of Soil-structure interaction (SSI) would be felt, three types of buildings, low-, mid-, and high-rise, were considered to study the demands of this system on an L-shaped plan. SSI effects were also considered by the cone method in the frequency domain for a more accurate evaluation of the building's behavior during an earthquake event. Each building is studied having three different base conditions: 1- fixed base, 2- SSI with soil type C, and 3- SSI with soil type D. Structural demands, including base shear, overturning and torsional moment, lateral displacement, inter-story drift, and column capacity were measured for different models with fixed and flexible bases by performing time history analyses. The results signify the significant SSI's impact on the building's demands.

This study investigates the effects of adjacent deep excavation on the seismic performance of buildings. For that purpose, the numerical models are constructed for different buildings (i.e., 5-Story building and 15-Story building) considering the deep excavation-soil-structure interaction (ESSI) and soil-structure interaction (SSI). The results achieved from the ESSI and SSI systems are discussed and compared. Fully nonlinear numerical models with material, geometric, and contact nonlinearities are developed. Eleven earthquakes with different intensities, epicentral distances, significant durations, and frequency contents are applied to the models; and, the numerical results are given in terms of average records. The buildings are carefully designed and verified based on common design codes. The numerical modelling procedure of the deep excavation-soil system is validated using centrifuge test data. The comparisons between the ESSI and SSI systems are carried out in terms of accelerations, lateral displacements, inter-story drifts, story shear forces, and the nonlinear behavior of the soil medium under the buildings. The results show that it is necessary to consider the ESSI effect, and it might significantly change the seismic behavior of buildings adjacent to the deep excavations. The findings from this study can provide valuable recommendations for engineers to design buildings close to deep excavations under earthquakes.

It is important to determine the dynamic behaviour of underground structures under cyclic loading for the seismic underground structural design. The dynamic response of such underground structures is further complicated when considering the interaction with surface buildings. This paper presents a series of dynamic centrifuge tests and 2D numerical modelling to investigate the dynamic response of a shallow cut-and-cover rectangular tunnel and the nearby building in the liquefiable sandy ground. Dynamic soil responses such as the wave propagation and excess pore pressure are successfully captured in both centrifuge testing and numerical modelling. Tunnel uplift, building settlement and soil deformation are determined by the particle image velocimetry (PIV) technique. Results show the existence of the nearby building can cause significant effects to the tunnel lateral movement and tunnel rotations. The tunnel floatation mechanism is also discussed with a simplified vertical force equation. In addition, the presence of the buried tunnel causes non-uniform settlement distribution along the building range. The comparison of the experimental, numerical building settlement with the analytical and empirical estimations proves the limitation of these methods in considering the building interaction with other structures.

It is important to determine dynamic tunnel behaviour under cyclic loading for the seismic underground structural design. The dynamic response of tunnels is further complicated when considering the interaction with surface buildings. This paper investigates a series of 2D plane -strain numerical models to study the dynamic response of a shallow cut -and -cover rectangular tunnel in loose, cohesionless soil. Both dry and saturated conditions are considered. Input motion includes sinusoidal waves with 10 cycles of shaking. A raft foundation with a 50 kPa structural surcharge is adopted to simulate the effect of the surface building. Soil displacements, wave propagation, earth pressures and tunnel lining structural response are determined. These results show that the soil liquefaction introduced by accumulated excess pore pressures causes the attenuation of soil horizontal acceleration, reduction of soil effective stresses and promotes tunnel flotation. The existence of a building not only reduces the liquefaction ratio of sub -surface soil right below the foundation but also effects the earth pressure distribution on the adjacent tunnel sidewall. In addition, the presence of the tunnel may affect adversely the rotation of the foundation especially in saturated soils.