On February 6, 2023, two devastating seismic events, the Kahramanmaras, earthquakes, struck the Eastern Anatolian Fault Line (EAF) at 9-h intervals. The first earthquake, with a moment magnitude (Mw) of 7.7, struck the Pazarc & imath;k district, followed by a second earthquake with a moment magnitude (Mw) of 7.6 in the Elbistan district, both within the Kahramanmaras, province. These dual earthquakes directly impacted eleven provinces in Eastern and Southeastern Anatolia leading to significant loss of life and extensive damage to property and infrastructure. This study focuses on revealing the main parameters causing to the collapse of reinforced concrete (RC) buildings by examining their compliance with legislation and earthquake codes in force at the time of construction. For this purpose, detailed examinations such as field observations, collection of general information and official documents about the buildings, determination of material properties and soil characteristics, and three-dimensional finite element (FE) analysis of 400 totally collapsed RC buildings in the Kahramanmaras,, Ad & imath;yaman, Hatay, and Gaziantep provinces, which were among the cities affected by the Kahramanmaras, earthquakes were performed. The findings of this study contribute to a better understanding of the seismic deficiencies of buildings in earthquake-prone regions and provide information on which strategies to develop to increase the resilience of buildings with similar characteristics in other earthquake regions against future seismic events. Considering that the time from the beginning of the construction of the building until its completion consists of several stages, it can be seen that 43.58 % of the errors that cause damage and collapse of the buildings in this study are made in the construction stage, 25.57 % in the FE analysis stage, 24.77 % in the license stage, and 6.07 % in the after construction stage. Thanks to the development process of earthquake codes, regulations in building inspection practices and easier access to quality materials have greatly reduced the damage and collapse of buildings constructed in recent years.

This paper investigates the pullout behaviours of horizontal rectangular plate anchors under inclined loading in sand using three - dimensional finite element (3D-FE) analysis. An advanced bounding surface plasticity model incorporating the critical state framework is developed to capture the stress-strain relationship of sand. The model is firstly validated against various analytical solutions and centrifuge test data. Then, a series of FE analysis is conducted to consider the effects of plate anchor aspect ratio, initial embedment depth, sand relative density and inclined loading angle on the pullout capacities. Results show that shallow anchors develop failure zones reaching the soil surface, and vertical pullout capacity exceeds that under pure vertical loading when the load is slightly inclined. For deep anchors, failure zones are confined below the surface, and horizontal pullout capacity exceeds that under pure horizontal loading when the load is slightly inclined. The transitional embedment depth depends on anchor aspect ratio and sand density. A modified analytical solution is proposed to estimate the vertical pullout capacity of plate anchors from shallow to deep depths. Failure envelopes established from probe tests provide practical guidance for assessing rectangular anchor failures under various inclined loadings.

This paper discusses the challenges of installing monopile offshore wind foundations in bedrock and introduces a new hybrid-monopile design as an alternative to rock-socketed monopiles. The performance of the hybridmonopile is evaluated through 1-dimension beam-spring theory and 3-dimension Finite Element analyses, with a focus on soil-foundation interaction and cyclic loading behaviour. The hybrid-monopile design is optimized and validated at two offshore sites in Korea. It is shown that optimized design can reduce required monopile penetration to avoid rock-socketed monopiles. The hybrid-monopile design shows a positive impact on reducing lateral pile displacement and rotation, particularly in soft ground conditions. The suggested 3D FE (Finite element) design approach and optimization with an additional seabed-level support structure can reliably avoid the need for rock-socketed monopiles.

In the Niigata-ken Chuetsu-oki Earthquake of 2007, ground liquefaction was outstanding at the foot of a sand dune and in old river channels. Although no distinct disaster was found in the clayey ground after the earthquake, the long-term settlement of the ground was observed after the earthquake in the Shinbashi district of Kashiwazaki City. At one observation site, the cumulated ground subsidence of the layers from the ground surface to a depth of 23 m had reached 71 mm 14 years after the earthquake. In order to study the mechanism of the deformation during the earthquake and the long-term settlement after the earthquake, ground investigations, such as a boring survey at the observation site and indoor element tests on sampled soil, were conducted in this study. The results showed that the sampled soil was very soft, strongly compressible, and relatively highly structured. Subsequently, the transformation stress-cyclic mobility (TS-CM) constitutive model, developed by Zhang et al. (2007), was used to simulate the results of the indoor element tests, and the soil parameters were determined based on the results of these tests. The TS-CM model contains the concepts of subloading, described by Hashiguchi (1977), and superloading, described by Asaoka et al. (2002). Therefore, the subsidence behavior of the ground was simulated by a soil-water coupling elasto-plastic finite element (FE) analysis using the TS-CM constitutive model and the determined parameters. The FE simulation results agreed well with the actual site subsidence observation data. Based on the simulation results, the post- earthquake behavior of the soft clay and its mechanism were discussed, and the successive subsidence was predicted forward. According to the simulation results, the relatively highly structured susceptible clay at this site was found to have greater potential in terms of longterm consolidation than relatively less structured susceptible clay due to the large excess pore water pressure generation during the ground motion and the consolidation process after the earthquake. This conclusion was verified by consolidation tests on two types of clay. (c) 2024 Production and hosting by Elsevier B.V. on behalf of The Japanese Geotechnical Society. This is an open access article under the CC BY- NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

In this study, finite element (FE) analysis of underground structure is carried out, which is subjected to the internal blast loading and the structure is surrounded with soil media. Three different methods to analyze the effect of blast loading on structure, i.e. ConWep, smooth particle hydrodynamics (SPH), and couple Eulerian-Lagrangian (CEL) are used for the simulation of blast loading using ABAQUS/Explicit (R) . Concrete damage plasticity (CDP), Mohr-Coulomb, Johnson-Cook (JC) plasticity model, Jones-Wilkins-Lee (JWL) equation of state and ideal gas are utilized for defining behavior of concrete, soil, steel, explosive and air, respectively. FE analysis is performed to compare the behavior of structure under different blast modelling methods. The effect of different explosive weights is considered to see the impact of the blast load on the structure. For parametric analysis, three explosive weights, 3kg, 5kg, and 10kg of TNT (trinitro toluene), and three concrete grades, M30, M35, and M40 are considered to see the stability of the structure. The effect of varied explosive weights and varied concrete grades is compared in terms of stress, pressure, and displacement at critical locations of the structure. The outcome of this shows that the change in explosive weight and concrete grade considerably affects the stability of the structure. As the explosive weight increases, damage to the structure increases, and with the increase in the concrete grade, the blast load resistance capacity of the structure increases. It is observed that buried part of the structure is more resistant to blast load compared to the structure visible above ground.

Uniform support from the surrounding soil is important for maintaining the stable operation of buried pipelines. For segmented prestressed concrete cylinder pipe (PCCP), localized soil voids around the joint due to leakage or engineering activities make the pipe unsupported partially and threaten its integrity and strength. In this paper, the impact of a localized soil void on a pipe joint is qualitatively assessed using a beam-on-elastic-spring approximation model. It further provides quantitative analysis through a nonlinear finite element (FE) model of PCCPs and the surrounding soil. The derived algebraic solutions indicate that a unilateral local void induces shear force and rotation at the joint, whereas shear force becomes negligible when the void spans the joint, leading to increased rotation. Moreover, the rotation angle shows a positive correlation with soil load and a negative correlation with pipe diameter. Numerical analysis reveals that void elongation along the pipe length has a more pronounced effect on structural response than void depth and angle. When the void length reaches 2.5 m, the maximum principal stress on the mortar layer of the PCCP increases approximately eight-fold compared to the scenario without voids. Due to the rigidity and safety factor of the PCCP, small voids in the bedding typically do not cause immediate pipe damage or joint leakage; however, they can significantly alter the stress distribution within both the pipe and surrounding soil. As the void develops, the soil may collapse and compromise support, leading to additional secondary disaster risks and potential threats to pipeline safety. This research emphasizes the importance of effective pipe-soil interactions and provides theoretical insights for developing repair strategies for PCCP.

This study investigates the dynamic response of RC lined rectangular tunnel in soil subjected to internal blast load. For this purpose, a three-dimensional non-linear finite element model comprising of tunnel lining, reinforcement, and soil is analyzed in Abaqus/Explicit. The behaviors of soil, concrete, and steel are simulated using Drucker-Prager plasticity, concrete damaged plasticity, and Johnson-Cook (J-C) plasticity models, respectively. The effect of various grades of concrete (C30, C40, and C50) and lining thickness (300 mm, 400 mm, and 500 mm) on the dynamic response of the tunnel structure and the surrounding soil is investigated. It is observed from the results that deformations of tunnel lining increase with a decrease in the grade of concrete and decrease with an increase in lining thickness. The results suggest it is advantageous to increase the thickness of the liner for a certain grade of concrete, rather than increasing the grade of concrete for the same liner thickness for better blast response. The vulnerability of the tunnel liner is high at the roof-sidewall junction suggesting the need for better reinforcement detailing.

Offshore wind farms are located in marine environments with complex hydrological, meteorological and submarine geological conditions, which pose difficulties for wind turbine foundation design and construction. Therefore, the study of the key technologies of offshore wind turbine foundation design has important theoretical value and practical significance for the assurance of structural safety, the optimization of structural design and the extension of structural service life. In this paper, a numerical simulation model of three pile foundation is established, and a detailed FEA model of grouted area is calculated and analyzed, and influence of grout on performance under different loading conditions is calculated and analyzed. The results show that it is feasible to use the p-y curve method to describe the pile-soil interaction of the three-pile foundation of the offshore wind turbine, the stress check of the whole foundation structure under ultimate load conditions and normal load conditions meets the requirements of the DNV specification, and the result of the fatigue damage check is that the fatigue strength requirement is met in 26.7 years, which indicates that the three-pile foundation structure of the offshore wind turbine is safe and reliable and can be operated safely.