Impact of Groundwater Level Change on Natural Frequencies of RC Buildings

Ratnika, Lasma; Gaile, Līga; Vatin, Nikolai

doi:10.3390/buildings11070265

Cited by 6 publications

(7 citation statements)

References 23 publications

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“…Due to the high accuracy and consistency with experiments, the nonlinear dynamic high-fidelity models of RC structures could also be used in damage identification methods for structural health monitoring under different operational and environmental conditions [48]. It can help determine the presence of damage in a structure, identify the geometric location of damage, quantify damage severity, and even predict the remaining service life of a structure.…”

Section: Discussionmentioning

confidence: 99%

“…Such actions can be both dynamic (earthquake, internal gas explosion, external blast, vehicle impact, buckling, extreme fire action, demolition [33,[43][44][45][46][47]) and quasi-static (soil changes due to changes in the groundwater level, karst processes, etc. [48]). Since the initial local failure duration is almost impossible to determine reliably, it is often assumed equal to zero.…”

Section: Introductionmentioning

confidence: 99%

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Comparison of Different Procedures for Progressive Collapse Analysis of RC Flat Slab Structures under Corner Column Loss Scenario

Dmitriev

Lalin

2021

Buildings

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Progressive collapse is the failure of the whole structure caused by local damage, which leads to significant economic and human losses. Therefore, structures should be designed to sustain local failures and resist subsequent nonproportional damage. This paper compared four procedures for a progressive collapse analysis of two RC structures subjected to a corner column loss scenario. The study is mainly based on the methods outlined in the current Russian standard (linear static (LS) pulldown, nonlinear static (ND) pulldown, and nonlinear dynamic), but also includes LS and NS pushdown procedures suggested by the American guidelines and linear dynamic procedure. We developed detailed finite element models for ANSYS Mechanical and ANSYS/LS-DYNA simulations, explicitly including concrete and reinforcement elements. We applied the Continuous Surface Cap Model (MAT_CSCM) to account for the physical nonlinearity of concrete. We also validated results obtained following these procedures against known experimental data. Simulations using linear static pulldown and linear dynamic procedures lead to 50–70% lower results than the experimental because they do not account for the nonlinear behavior of concrete and reinforcement. Displacements obtained from the NS pulldown method exceed the test data by 10–400%. It is found that correct results for both RC structures can only be found using a nonlinear dynamic procedure, and the mismatch with the test data do not exceed 7%. Compared to static pulldown methods, LS and NS pushdown methods are more accurate and differ from the experiment by 28% and 14%, respectively. This relative accuracy is provided by more correct load multipliers depending on the structure type.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Comparison of Different Procedures for Progressive Collapse Analysis of RC Flat Slab Structures under Corner Column Loss Scenario

Dmitriev

Lalin

2021

Buildings

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“…Studies [3,5] emphasize that one of the most important factors of influence is the interaction of soil with the building. The works pay attention to the interaction of low-and medium-rise buildings with the wall structural system and the foundation.…”

Section: Introductionmentioning

confidence: 99%

Analysis of the influence of different soil types on the natural frequencies of multi-storey reinforced concrete buildings

Kovrova,

Volkova

2023

OMTC

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According to current concepts, the construction of multi-storey and high-rise buildings is quite topical. Increasing the number of storeys and building density provokes an increase in loads and forces on the structural elements of the building, as well as on the soil base. It is necessary to take into account the mechanical characteristics of the soils underlying multi-storey buildings to improve the design models of objects when determining the forces and deformations in their elements. A vital indicator in monitoring the structural characteristics of buildings is global stiffness. Natural frequencies determined by modal analysis are used to detect its change. The purpose of this study is a numerical analysis of the effect of changes in the parameters of the soil base on the natural frequencies and values of vibrations of multi-storey reinforced concrete frame buildings using software systems. In this study, four variants of design models with rigidly fixed foundations and elastic foundations with different types of soils were developed.In the models with elastic foundations, stable soils were used, such as sandy, moderately stable, represented by loams and sandy loams, and weak soils containing a layer of peat. The building scheme was developed using the SCAD software package with the application of the finite element method. Taking into account that 90% of the territory of Ukraine is located in complex engineering and geological conditions, the use of the finite element method allows to effectively solve complex problems of interaction of heterogeneous elements, including in a nonlinear approach. As a result, it was found that the type of soil foundation affects the change in the natural vibration frequencies of a building. In the model with a rigidly fixed foundation, the frequencies are the highest, and the eigenvalues of oscillations are the lowest. A point that should be mentioned is that in the variants with an elastic foundation, the lowest frequencies are observed in the model on weak soils, and the highest values are typical for sandy foundation soils.

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“…One way to overcome this problem could be by performing a modal decomposition so that the shapes associated with the structural vibrations of the building are separated from the shape associated with the rocking motion. Then, the structural damage can be analyzed using the fixed foundation model, and the changes in the soil parameters (e.g., due to groundwater fluctuations [ 13 ]) can be analyzed using the rocking mode shape frequency.…”

Section: Introductionmentioning

confidence: 99%

RC Medium-Rise Building Damage Sensitivity with SSI Effect

2022

Self Cite

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Global vibration-based methods in the field of structural health monitoring are intended to capture structural stiffness changes of buildings or other civil engineering structures. Natural frequencies of buildings or bridges are commonly used parameters to monitor these stiffness changes. Therefore, it is essential to clarify the limit at which this method is no longer sensitive enough to be useful for structural health monitoring purposes. This paper numerically investigates the effect of structural damage and soil–structure interaction on cellular-type reinforced concrete buildings’ natural frequencies. These buildings are a common housing stock of Eastern Europe but are rarely investigated in this context. Comparisons with a reinforced concrete frame and infill structure building are made. Finite element models representing three structural system types of nine-story reinforced concrete buildings were used for the numerical simulations. Furthermore, a five-story finite element model was used for a damage sensitivity comparison. It is established that, for cellular-type structure buildings to detect damage comparable to that investigated in the paper, structural health (fixed base model frequency) should be monitored directly. Then, a statistical significance level for frequency changes of no more than 0.1% should be adopted. Conversely, the rocking frequency is a very sensitive parameter to monitor building base condition changes. These changes are often a cause of the cracking of building elements.

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Impact of Groundwater Level Change on Natural Frequencies of RC Buildings

Cited by 6 publications

References 23 publications

Comparison of Different Procedures for Progressive Collapse Analysis of RC Flat Slab Structures under Corner Column Loss Scenario

Comparison of Different Procedures for Progressive Collapse Analysis of RC Flat Slab Structures under Corner Column Loss Scenario

Analysis of the influence of different soil types on the natural frequencies of multi-storey reinforced concrete buildings

RC Medium-Rise Building Damage Sensitivity with SSI Effect

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