In the safety analysis of concrete gravity dams it is necessary to consider the external load and internal load of the dam body within a reasonable range, in which the influence of strong earthquake ...can not be ignored. The modified Mohr-Coulomb strength criterion is introduced into the numerical manifold method (NMM), meanwhile, the calculation mechanism of dynamic load is introduced, and the calculation part considering the Hydro-Mechanical coupling principle is added to the NMM. The effectiveness and accuracy of the improved NMM are verified by the displacement of the central point of the circular arch under dynamic load containing an analytical solution. Based on the improved NMM, the crack propagation of concrete gravity dam is predicted and analyzed. The crack propagation of Koyna concrete gravity dam under seismic conditions is analyzed, and the results are compared with XFEM and experimental results. The influence of adding Hydro-Mechanical coupling module on crack propagation and seismic response of concrete gravity dam is discussed and it is proved that the improved NMM can accurately predict the crack propagation of concrete gravity dams under dynamic load and the advantage of NMM in dealing with continuous-discontinuous problems.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The article presents a methodology for assessing the stability of construction objects to seismic impacts of the probabilistic approach, which can be used as the basis for the implementation of ...algorithms for automating the corresponding calculations during the design and operation of buildings and structures. The article also develops a technique for constructing finite elements, which makes it possible to consider the stress-strain state of deep-laid pile foundations for bridge supports on an elastic base with piecewise constant parameters. The developed technique based on the properties of Fourier images of finite functions, which allows calculating piles with end and surface widenings for dynamic effects.
The elevated water tank comprises important structural elements which includes slabs, beams, columns, and footings, facilitating the transfer of loads amongst these contributors and subsequently to ...the subgrade of the soil. This paper goals is to comprehensively analyze the structural behaviours exhibited by elevated water tanks underneath various loading conditions. The behaviours of multiplied water tanks variety underneath various styles of loadings, inclusive of dead, live, and seismic loads, that are comprehensively analyzed. This paper primarily aims to conduct a hydrostatic evaluation of circular water tanks and emphasizes the necessity of a parametric study. To obtain this goal, 2, 2.5, and 3 lakh litters of tanks are being considered for the analysis which are all examined underneath area III seismic situations whilst keeping a normal height and varying diameters during the simulation. The examination focuses on carrying out a comparative evaluation of critical structural parameters, such as moment, maximum displacement, and maximum base shear. By means of analysing those parameters across various tank capacities, precious insights into the structural reaction of circular elevated water tanks under seismic loading conditions are gained. Those findings contribute to enhancing the design and overall performance of such structures, enhancing their resilience and protection in earthquake-susceptible regions.
In order to study the dynamics of a very large monopile offshore wind turbine under emergency shutdown, the DTU 10 MW monopile offshore wind turbine is used as the research object to establish a ...turbulent wind-wave-earthquake load multi-physics field model with wind and wave correlation and construction of soil-structure coupling model by p-y curve method, Q-z curve method and Winkler model. The dynamics of the wind turbine under normal operation, shutdown and emergency shutdown were studied. The results show that the wind turbine is most affected by the seismic load under the shutdown condition, and the extreme differences of the forward-backward and lateral displacements of the tower top increase by 249.22% and 1 869.14%, respectively, and the peak shear stress of the support structure increases by 333.33% compared with that without the earthquake. During the emergency shutdown operation, the shear stress of the support structure and the strain energy of the tower were greater than the normal operation at t
•The nonlinear extended finite element method (NXFEM) was introduced.•The seismic resistance of the cracked clayey backfill was assessed.•The displacement and vibration mechanism of the clayey ...backfill were investigated.•The crack’s interactions were investigated.•The failure mechanism of the model was predicted.
Applying nonlinear multidirectional forces to the earth retaining structure causes expansion and compression of existing soil crack and this phenomenon occurs in complicated form for clay. The cracked clayey backfill subjected to multi-directional seismic loads has not been reported in the literature. An analytical method was used for identifying the length of the crack. Two types of models with 7 and 15 cracks were assumed and simulated. By introducing the nonlinear extended finite element method (NXFEM), the nonlinear displacement, strain, and stress of the models were simulated. The results revealed that the number of the soil cracks modifies the vibration mechanism, nonlinear displacement, stress, and strain behavior of the model. The research methodology was validated by comparing the results of the numerical simulation with those available in the literature. The novelty of the present study is related to introducing NXFEM.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Technical codes adopted literature formulations for the prediction of the out-of-plane strength of unreinforced masonry infills without an extensive assessment of their effectiveness. This study ...presents such formulations in detail. The influence of the external load shape on infills' out-of-plane strength is discussed and strength formulations are modified to account for this issue. An experimental database is collected to assess the predictive capacity of these models and identify the most effective one. The selected mechanical-based model is simplified to propose a reliable formulation for the prediction of the out-of-plane strength of infills under seismic and other external loads.
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BFBNIB, GIS, IJS, KISLJ, NUK, PNG, UL, UM, UPUK
This research investigated the seismic performance of multi-story reinforced concrete (RC) frames with infilled walls. The study employed a two-step numerical approach: first, a verification process ...ensured the model's accuracy by comparing it to past experimental results. Following validation, a parametric study explored various factors influencing the frames' behavior. These factors included the number of stories (3, 6, and 12), the earthquake ground motion (Vrancea, El Centro, and Kahramanmaraş), and the effect of removing an internal column. Additionally, the study examined the impact of incorporating polypropylene (P.P.) fibers into different parts of the structure: the RC frame itself, the mortar between infill wall bricks, or both. The findings revealed significant improvements in seismic performance due to the presence of infill walls. In the three-story frame, the wall reduced plastic drift by a remarkable 98.9 %. Furthermore, strengthening with P.P. fibers demonstrated exceptional effectiveness. For example, on the first floor of the three-story frame, the maximum drift value dropped from 0.751 to a 0.004 for the IRCPM model (fibers in the infill wall mortar only) and even lower (0.003) for the IPPM model (fibers in both the RC frame and infill wall mortar). These results highlight the potent ability of P.P. fibers to improve earthquake resistance. The study also assessed the efficacy of strengthened infill walls as partial replacements for lost columns. When an internal column was removed, the presence of a P.P. fiber-reinforced wall (IPRCL model) helped mitigate the structural impact, reducing the base shear force by 11 % compared to the control model without fibers (CIRCL). Similar trends were observed in taller frames. While including fibers in the RC frame of the 6-story model with a removed column resulted in an 11 % decrease in base shear force, models with fibers in the wall components of the 12-story frame exhibited a 31.62 % increase in base shear force after column removal.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The paper concerns the wide range of strategies used to protect structures against man-made dynamic excitation. The most popular approaches applied worldwide are compared, and the main differences ...and similarities are summarized. The literature studies are supported by the results of the measurements performed on different types of real structures, which are sensitive and insensitive to the dynamic load. To make the conclusions more general, various types of excitation forces are examined (long-term and short-term excitations, traffic load, and loads resulting from geotechnical works). The main issue raised in the paper is the problem of unequivocal and accurate assessment of the potential structure damage, based on the different legislations. It can be seen that the application of different codes can even result in opposite conclusions about the safety of the structure.
•Performance of non-seismic designed exterior beam-column joints improved by chamfers.•Joint shear capacity of strengthened joint increases with increasing size of chamfer.•Practical ratio of LC/LBC ...is recommended to be 0.67–1.0.•Diagonal compressive strut is enlarged by an additional strut in chamfer.•A load transfer mechanism is proposed for exterior joint with chamfer.
This study aims to understand the load transfer mechanism of exterior beam-column joints (BCJs) with unsymmetrical chamfers for strengthening. It comprises both experimental and numerical studies. Four 2/3-scale specimens were prepared including one without joint shear reinforcements as control, one with joint shear reinforcements and two specimens with chamfers installed. They were subjected to constant axial force and tested to failure under reversed horizontal displacements. Based on the experimental results, performance of BCJs can be improved by installing unsymmetrical chamfers. Secondly, parametric studies were conducted via non-linear finite element analysis. BCJs with different sizes of chamfer or ratios of LC/LBC ranging from 0.50 to 1.33 were modelled to study the effect of chamfer size on joint shear strength. Here, LC is size of chamfer; and LBC is minimum dimension of beam or column.
It is found that the joint shear strength is further improved with increasing size of chamfer. Minimum ratio of LC/LBC is recommended as 0.67. Lastly, a load transfer mechanism for exterior joint with chamfer is proposed based on strut and tie concept. It takes into account the benefit of additional compressive strut in chamfer in increasing the joint shear strength.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
