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Within the scope of literature, the influence of openings within the infill walls that are bounded by a reinforced concrete frame and excited by seismic drift forces in both in- and out-of-plane direction is still uncharted. Therefore, a 3D micromodel was developed and calibrated thereafter, to gain more insight in the topic. The micromodels were calibrated against their equivalent physical test specimens of in-plane, out-of-plane drift driven tests on frames with and without infill walls and openings, as well as out-of-plane bend test of masonry walls. Micromodels were rectified based on their behavior and damage states. As a result of the calibration process, it was found that micromodels were sensitive and insensitive to various parameters, regarding the model’s behavior and computational stability. It was found that, even within the same material model, some parameters had more effects when attributed to concrete rather than on masonry. Generally, the in-plane behavior of infilled frames was found to be largely governed by the interface material model. The out-of-plane masonry wall simulations were governed by the tensile strength of both the interface and masonry material model. Yet, the out-of-plane drift driven test was governed by the concrete material properties.

The dilatation of the high-rise building by inserted field is the main topic of this paper. This building contains of two “towers” with different heights (8-storey and 25-storey), which are linked by inserted field. The description of the building and applied loads are shortly mentioned. The paper is mainly focused on the importance of the dilatation and its types, the modelling of inserted field and its structural solutions. The comparisons of horizontal forces due to the wind load and seismic load are presented at the end. The solution was recalculated for four seismic areas in Slovakia, where different values of basic seismic acceleration ar are. Also, the maximum horizontal deflections calculated for three alternatives of the building (without dilatation, with continuous dilatation 50 mm located between two “towers” passing through the foundation, with dilatation by inserted field between two “towers”) due to static wind load are presented here.

The basic seismic load parameters for the upcoming national design regulation for DIN EN 1998-1/NA result from the reassessment of the seismic hazard supported by the German Institution for Civil Engineering (DIBt). This 2016 version of the national seismic hazard assessment for Germany is based on a comprehensive involvement of all accessible uncertainties in models and parameters and includes the provision of a rational framework for integrating ranges of epistemic uncertainties and aleatory variabilities in a comprehensive and transparent way. The developed seismic hazard model incorporates significant improvements over previous versions. It is based on updated and extended databases, it includes robust methods to evolve sets of models representing epistemic uncertainties, and a selection of the latest generation of ground motion prediction equations. The new earthquake model is presented here, which consists of a logic tree with 4040 end branches and essential innovations employed for a realistic approach. The output specifications were designed according to the user oriented needs as suggested by two review teams supervising the entire project. Seismic load parameters, for rock conditions of \\[v_{S30}\\] = 800 m/s, are calculated for three hazard levels (10, 5 and 2% probability of occurrence or exceedance within 50 years) and delivered in the form of uniform hazard spectra, within the spectral period range 0.02–3 s, and seismic hazard maps for peak ground acceleration, spectral response accelerations and for macroseismic intensities. Results are supplied as the mean, the median and the 84th percentile. A broad analysis of resulting uncertainties of calculated seismic load parameters is included. The stability of the hazard maps with respect to previous versions and the cross-border comparison is emphasized.

This study aims to analyze the structural performance of castellated steel columns under axial load and seismic displacements, focusing on the effect of different strengthening techniques on load-bearing capacity and ductility. The purpose of this study is to determine the best method for strengthening these columns to improve their seismic response and reduce the risk of collapse. To achieve this, four specimens were analyzed: non-strengthened column, a horizontally strengthened column, a vertically strengthened column, and a column strengthened with horizontal and vertical plates. All specimens were subjected to a static axial load test of 40 kN, while lateral displacement was modelled using seismic data from a real event. The results showed that vertical strengthening was the most effective in enhancing load-bearing capacity and improving seismic response. Maximum lateral loads increased by 63% in the vertically strengthened columns, 55% in the vertically and horizontally strengthened columns, and only 13% in the horizontally strengthened columns. This strengthening also reduced stress concentrations around the hexagonal openings, helping prevent collapse in those areas. Vertical strengthening represents the optimal solution for improving the seismic performance of castellated steel columns, providing an effective balance between load resistance and improved structural stability. Accordingly, the study recommends further research to develop more efficient strengthened techniques that enhance the resistance of steel columns in seismic applications.

This paper establishes a dynamic response analysis model of natural gas boilers composed of shell elements and beam elements. Stress, and deformation under the effects of self-weight, temperature loads, and seismic loads are used as evaluation indicators. The strength of natural gas boilers under two working conditions: hot state with low load, and full load, is analyzed. The results indicate that the boiler has high stiffness in the vertical direction, while the lower part of the rear wall is a relatively weak point in terms of stiffness. This provides a reference for further optimization of the boiler structure. Additionally, it was found that the first natural frequency of the boiler decreased by 36.7% and 38.1% compared to the static and free modes, respectively, after applying thermal loads, indicating a significant reduction in the stiffness of the boiler when heated.

The method of inputting the seismic wave determines the accuracy of the simulation of soil-structure dynamic interaction. The wave method is a commonly used approach for seismic wave input, which converts the incident wave into equivalent loads on the cutoff boundaries. The wave method has high precision, but the implementation is complicated, especially for three-dimensional models. By deducing another form of equivalent input seismic loads in the finite element model, a new seismic wave input method is proposed. In the new method, by imposing the displacements of the free wave field on the nodes of the substructure composed of elements that contain artificial boundaries, the equivalent input seismic loads are obtained through dynamic analysis of the substructure. Subsequently, the equivalent input seismic loads are imposed on the artificial boundary nodes to complete the seismic wave input and perform seismic analysis of the soil-structure dynamic interaction model. Compared with the wave method, the new method is simplified by avoiding the complex processes of calculating the equivalent input seismic loads. The validity of the new method is verified by the dynamic analysis numerical examples of the homogeneous and layered half space under vertical and oblique incident seismic waves.

The present study demonstrates the feasibility of using longitudinal hybrid reinforcement in concrete columns in seismic zones. In this research, four concrete columns were constructed and subjected to quasi-static cyclic loading, featuring a combination of steel and glass fiber-reinforced polymer (GFRP) longitudinal reinforcement. Two reference columns were fabricated and reinforced in the longitudinal direction with steel bars. These columns had a 400 x 400 mm (15.8 x 15.8 in.) cross section and 1850 mm (72.8 in.) overall height. All the columns were reinforced with GFRP crossties and spirals in the horizontal direction. The variable parameters were the transverse reinforcement spacing, axial load ratio, and column configuration. The outcomes of this research clearly showed that reinforced concrete (RC) columns that are properly designed and detailed longitudinally with hybrid reinforcement (GFRP/steel) could achieve the drift limitation in building codes with no strength degradation. Further, these hybrid-RC columns displayed enhanced energy dissipation capacity, superior ductility, and improved post-earthquake recoverability compared to columns reinforced longitudinally with steel. The promising results of this study represent a step toward the use of longitudinal hybrid reinforcement in lateral-resisting systems. Keywords: design codes; ductility; energy dissipation capacity; glass fiber-reinforced polymer (GFRP); hybrid reinforcement; hysteresis response; quasi-static cyclic load; reinforced concrete (RC) columns; residual deformation; seismic load; stiffness degradation.

This research study focused on the dynamic response and mechanical performance of fiber-reinforced concrete columns using hybrid numerical algorithms. Whereas test data has non-linearity, an artificial intelligence (AI) algorithm has been incorporated with different metaheuristic algorithms. About 317 datasets have been applied from the real test results to detect the promising factor of strength subjected to the seismic loads. Adaptive neuro-fuzzy inference system (ANFIS) was carried out as an AI beside the combination of particle swarm optimization (PSO) and genetic algorithm (GA). Extreme Machine Learning (ELM) was also performed in order to approve the obtained results. According to the findings, it is demonstrated that ANFIS-PSO predicts the lateral load with promising evaluation indexes [R (test) = 0.86, R (train) = 0.90]. Mechanical performance prediction was also carried out in this study, and the results showed that ELM predicts the compressive strength with promising evaluation indexes [R (test) = 0.66, R (train) = 0.86]. Finally, both ANFIS-GA and ANFIS-PSO techniques illustrated a reliable performance for prediction, which encourage scholars to replace costly and time-consuming experimental tests with predicting utilities.

In light of the global development of construction, particularly tall buildings and skyscrapers, researchers have spent years studying and developing types of foundations that are suitable in terms of endurance in heavily loaded and economic terms, particularly in weak soils under dynamic loading. In the event of high-rise buildings or weak soil media, the piled-raft foundation system is considered an efficient system that fits the design criteria. Several factors influence the performance of the piled-raft foundation system, among pile length, which was taken into account in the numerical study using the Plaxis 3D program. Four pile length scenarios are explored using 28 piles in a pattern 4 × 7 group with a rectangular raft of 10 × 20 and 1.5 m thickness. The central piles 3 × 2 are all the same length of 12 m or 20 m, but the others vary to 10 m, 8 m, and 6 m. In addition to the El-Centro seismic loading, a uniform static load of 300 kN/m 2 was applied to the weak C- ϕ soil. The results reveal that the length of the asymmetric pile has a substantial effect on the behavior of the piled raft foundation. The symmetry pile’s length has greater static and dynamic load sharing than the asymmetry pile’s length. Static load sharing is greater than dynamic load sharing in all models, with static sharing values of 73.2% for the uniform pile’s length group L12 + 12 and 68.82%, 63.33%, and 55.96% for the asymmetry groups L12 + 10, L12 + 8, and L12 + 6, respectively. With decreasing external pile length, the dynamic load sharing values under 0.1 g intensity are 72.3%, 67.4%, 60.6%, and 55.2%, respectively. When the seismic intensity increases to 0.2 g, these values decrease by around 3%, and so on for 0.3 g. Vertical settlement increases as the exterior pile length decreases and the seismic energy increases. The maximum settlement values for L12 + 12, L12 + 10, L12 + 8, and L12 + 6 at 0.3 g seismic intensity are 137.9, 158.1, 169.7, and 171 mm, respectively. The differential settlement caused by seismic load is greater in the case of the asymmetry pile length group (L12 + 10). The differential settling increases with increasing seismic intensity in all models. The maximum lateral displacement increases as seismic intensity increases, whereas the length of the pile has no impact on the lateral displacement. When compared to a 12-m pile length, a 20-m pile will have a larger load sharing and less settlement, but exhibit a similar trend. The external pile’s length has a slight effect on the factor of safety where the reduction under the seismic load by about 18% for the both symmetry and asymmetry cases respectively in comparison to static case.

Pre-Engineered Buildings (PEBs) are the most preferred choice for construction due to their cost-effectiveness and quick construction process. In comparison to traditional steel buildings, PEBs are optimized steel structures that save material about 20 to 30%. This study focuses on the comparision of PEB and CSB in terms of steel take off. The aim of this study is to give valuable insights into efficiency and cost effectiveness of utilizing steel in these two construction methods. Also, to improve understanding of optimal steel usage practices for multiple construction projects by examining the differences between pre-engineered and conventional steel buildings. Based on the building’s geometrical characteristics such as roof angle, length, breadth, height, bay spacing, and location of the structure, the need for steel is determined. A typical PEB and CSB have been modelled and analysed based on several factors in this project work using Staad Pro software. Based on IS 875 and IS 1893, different types of loads have been computed. These loads have been applied to the Staad Pro model and examined. For the analysis, more than 70 different load combinations were taken into account. The various response parameters such as shear force, bending moment, axial force, support reactions are compared. The amount of steel required for a PEB against a CSB has been compared. The structures have been analysed both for wind load and seismic loads and the critical load combination has been determined. The amount of steel required for PEB is lesser by 24.90 % compared to CSB.