mahdi kolbadi
@kntu.ac.ir
Department of Civil Engineering
KN Toosi University of Technology
Civil Engineer
RESEARCH INTERESTS
Earthquake Engineering, Structural Dynamic, Dam Engineering
Scopus Publications
Scholar Citations
Scholar h-index
Scholar i10-index
Scopus Publications
Seyed-Mohammad Seyed-Kolbadi, Mohammad Safi, Ayoub Keshmiri, S. Mahdi S. Kolbadi, and Masoud Mirtaheri
Hindawi Limited
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Seyed-Mohammad Seyed-Kolbadi, Mohammad Safi, Ayoub Keshmiri, S. Mahdi S. Kolbadi, and Masoud Mirtaheri
Hindawi Limited
It is so important to consider the passive defense problem in any places there have been attacks by varies kinds of military threats and terrorists. It is certain that social security is related to overcoming on these perils and protection from country. Vital facilities are one of examples that should be protected. Vital facilities include roads, bridges, transmission lines, and telecom and media network. With attention to the intense dependent to export and transmit of oil and gas and with consideration of this point that many places are full of gas and oil resource, the protection of these lines is very important. In recent years, occurrence of varies kinds of terrorist accidents in relation to important structures in all the world causes that the explosion loads have special attention. Explosion can generate much damage with vibration in vast soil media. Thus, it is important to predict the dynamic impact load and its treatment response. With attention to regardable development of numerical methods in recent decades, it is possible to investigate the explosion effects on surface and underground structures. In this research, the newest applied method modeling of the explosion phenomenon has been investigated and comprehensive information has been earned. In this investigation, problem of explosion wave’s propagation effects on buried pipes simulated by ABAQUS/CAE 6.10-1 was studied based on the finite element method. Surface explosion effects on gas buried pipe lines and their dynamic response have been investigated depending on properties and their characteristics. The variation of buried pipe depth effects and variation effects in soil properties around pipe in different cases has been considered, and the results are here. The results showed that in buried pipes under surface explosions, displacements, major stresses, and strains decrease in clay, dense, and loose sands with increase of buried depth. These results obtain that because of increase of closuring of pipes in soil when internal friction angle increases for a kind of soil, the stress on pipe rim will decrease also. It was also observed that the pipe performance in clay and loose sands is better than that in compacted sand, respectively.
Moien Barkhori, Shervin Maleki, M. Mirtaheri, Meissam Nazeryan and S.Mahdi S. Kolbadi
Seyed Mohammad Seyed Kolbadi, Nemat Hassani, and Mohammad Safi
Hindawi Limited
One of the major challenges for the oil and gas industry is to keep buried metal pipes safe from faulting. This paper discusses about a solution to keep buried pipes safe. In this study, after examining the different dimensions of the effect of wave connection on improving the performance of buried metal pipes, by changing the geometric shape of the wave connection such as doubling it, the behavior of the pipe is greatly improved. Waved connections, by their local deformation, create a rotational joint in a limited area so that other parts of the pipe remain intact. In this paper, the behavior of buried pipes due to slip direction fault displacement by modelling with Abacus software version 2017 and selection of 4-node shell element and 8-node shell element have been used for pipe and soil modelling, respectively. In this paper, by comparing to a single waved connection with a double waved connection, the performance of the pipe due to the faulting phenomenon was evaluated. The results show the improvement of the excellent performance of the double joint by reducing the plastic strain values. In addition to increasing the ductility of the pipe, the double connection has been able to reduce the strain values by about 50% compared to the single connection. In general, this paper shows that the use of wave connections can significantly increase the level of safety of buried gas pipelines without increasing the cost.
Seyed Mohamad Seyed Kolbadi, Hosein Piri, Ali Keyhani, S.Mahdi Seyed-Kolbadi, and Masoud Mirtaheri
Hindawi Limited
The equivalent statistical methods, spectral analysis, and time history analysis are usually offered in the steel structure design regulations. Among these methods, the third one is more accurate; however, it requires more time to align the accelerometers due to a large number of analyses. In the endurance time (ET) method, incremental acceleration functions gradually and uniformly increases over time while their linear and nonlinear response spectra are proportional to the mean of the real seismic spectrum. These functions are used as input functions to analyze the nonlinear time history of structures, and the performance of structures is evaluated based on the maximum length of time they can meet specified performance goals. A three-story steel bending frame with (slotted web) SW and (web unslotted flange) WUF connection is examined through the performance time method in performance-based design. This article aimed at evaluating the seismic performance of these connections in the bending frame through endurance time analysis to predict the structural response in the probabilistic evaluation of the seismic performance of the structures. It is found that the endurance time analysis is justified with the seismic performance of the connections with low computational cost and proper accuracy. The results of comparing both SW and WUF connections indicated that the SW connection prevents the connection welding area from being failed due to transferring the plastic joint into the beam and in an area away from the column face and causes less damage compared to the WUF connection.
S.M. Seyed-Kolbadi, M.A. Hariri-Ardebili, M. Mirtaheri, and F. Pourkamali-Anaraki
MDPI AG
This work evaluates the stability of the Boostan earth dam by investigating its long-term performance and interpreting the measured data. To measure the dam response, several sensitive locations are instrumented. This process includes measuring various quantities such as pore water pressure, water level, and internal stress ratios using inspection devices such as ordinary and Casagrande piezometers, and total pressure cells. The recorded data shows that the pore pressure is in good agreement with the initial (stable) design condition. The installed piezometers show that the drainage is efficient, and the water table in the body is adequate. The instrument also shows a reasonable horizontal stress in the dam body. Overall, the condition of the case study dam is assessed to be normal. The results of this case report can be used as a guide in similar dams for instrumented health monitoring.
L. Furgani, M. A. Hariri-Ardebili, M. Meghella, and S. M. Seyed-Kolbadi
MDPI AG
The purpose of this joint contribution is to study the maximum dynamic load concrete dams can withstand. The so-called “dynamic capacity functions” for these infrastructures seems now technically and commercially feasible thanks to the modern finite element techniques, hardware capabilities, and positive experiences collected so far. The key topics faced during the dynamic assessment of dams are also discussed using different point of view and examples, which include: the selection of dynamic parameters, the progressive level of detail for the numerical simulations, the implementation of nonlinear behaviors, and the concept of the service and collapse limit states. The approaches adopted by local institutions and engineers on the subject of dam capacity functions are discussed using the authors’ experiences, and an overview of time and resources is outlined to help decision makers. Three different concrete dam types (i.e., gravity, buttress, and arch) are used as case studies with different complexities. Finally, the paper is wrapped up with a list of suggestions for analysts, the procedure limitations, and future research needs.
S. Seyed-Kolbadi, J. Sadoghi-Yazdi, and M. Hariri-Ardebili
MDPI AG
Slope uncertainty predominantly originates from the imperfect analysis model and the inaccuracy and imprecision of the observations. The strength reduction method (SRM) is widely used to attain the safety factor (SF) of the slopes, which is similar to interpretation of the limit state (LS). In this paper, the spectral element method (SEM), using an elasto-plastic Mohr–Coulomb failure criterion, is employed to project the plausible LS of the soil slopes. An iterative SRM search method is proposed to evaluate the SF of the slopes regardless of the LS interpretation. The proposed SRM paradigm encompasses the design trigger to trace the uncertain parameters in decision-making. This method is applied to three numerical examples: (1) a homogeneous dry slope, (2) a dry slope with a weak layer, and (3) a partially-wet slope with a weak layer. It is shown that for the case study examples, the proposed SRM reasonably converges to the required precision. Results further are compared and contrasted with some of the conventional and standard techniques in slope stability. This hybrid procedure paves the road for fast and safe stability analysis of man-made and natural slopes.
M.A. Hariri-Ardebili, S.M. Seyed-Kolbadi, V.E. Saouma, J. Salamon, and B. Rajagopalan
Elsevier BV
Abstract The seismic response of gravity dams is typically derived under a deterministic finite element model for the dam-reservoir-foundation system. In the case where uncertainty in material properties should be incorporated into overall dam performance, the sensitive parameters can be treated as random variables. This paper presents the results of a study that considers the spatial distribution of random variables in the context of random field theory. Koyna Gravity Dam is used as a setting for numerical simulations. The concrete modulus of elasticity, mass density and tensile strength are all assumed to be random fields and generated based on the covariance matrix decomposition and midpoint discretization techniques. The anatomy of the random field seismic responses are presented first, followed by a set of parametric analyses. The impact of correlation length, a single- vs. double-random field, one- or two-dimensional material distributions, ground motion intensity and record-to-record variability and, lastly, dam class are all investigated herein. The uncertainty and dispersion of the seismic responses are quantified in each model; it is found that concrete heterogeneity affects the seismic performance evaluation and should be considered in a structural assessment and risk analysis.
Mohammad Amin Hariri-Ardebili, S. Mahdi Seyed-Kolbadi, and Mohammad Noori
Hindawi Limited
Recently, probabilistic simulations became an inseparable part of risk analysis. Managers and stakeholders prefer to make their decision knowing the existing uncertainties in the system. Nonlinear dynamic analysis and design of infrastructures are affected by two main uncertainty sources, i.e., epistemic and aleatory. In the present paper, the epistemic uncertainty is addressed in the context of material randomness. An old ultra-high arch dam is selected as a vehicle for numerical analyses. Four material properties are selected as random variables in the coupled dam-reservoir-foundation system, i.e., concrete elasticity, mass density, compressive (and tensile) strength, and the rock modulus of elasticity. The efficient Box-Behnken experimental design is adopted to minimize the required simulations. A response surface metamodel is developed for the system based on different outputs, i.e., displacement and damage index. The polynomial-based response surface model is subsequently validated with a large number of simulations based on Latin Hypercube sampling. Results confirm the high accuracy of proposed technique in material uncertainty quantification.
M.A. Hariri-Ardebili, S.M. Seyed-Kolbadi, and M.R. Kianoush
Elsevier BV
Abstract This paper studies computer-aided parametric analysis on the finite element model of a typical concrete gravity dam. The coupled dam–foundation–reservoir system is modeled based on Lagrangian–Eulerian approach. The nonlinearity in the dam is originated from a developed rotating smeared crack model. Different types of input ground motions are used for excitation of the structural system, i.e. near-fault vs. far-field, real vs. artificial, and uniform vs. non-uniform. The spatial varying ground motions and endurance time acceleration functions are generated based on a non-stationary random process. Finally, results are presented in terms of displacement and crack propagation. Relative importance of different parameters is compared and an optimum numerical model is suggested for potential applications.
M.A. Hariri-Ardebili and S.M. Seyed-Kolbadi
Elsevier BV
Abstract Modeling the material behavior and estimation of the cracking capacity of concrete dams under the dynamic loading is important for safety operation purposes. In the present paper, an improved 3D co-axial rotating smeared crack model is used with the ability of updating the variable shear transfer coefficient. The model is implemented in the finite element code to assess the seismic cracking of three types of concrete dams, i.e. gravity, buttress, and arch dams. Results of the crack profiles confirm importance of the shear transfer coefficient in dynamic analysis of large concrete structures. It is found that the proposed model lead to less diffused cracks in concrete dams and can reasonably matches with the results obtained from experimental tests.
H. Mirzabozorg, M.A. Hariri-Ardebili, M. Heshmati, and S.M. Seyed-Kolbadi
Elsevier BV
Abstract In the present paper, a comprehensive finite element model of Karun III double curvature arch dam is calibrated based on the micro geodesies measurements and instrumentation. Thermal properties of concrete are obtained by transient thermal analysis and the results are compared with those obtained from thermometers. Thermal analysis features include air temperature, water layers temperatures, and the solar radiation on the exposed faces. Structural calibration features include thermal distribution within the dam body, dam self-weight, hydrostatic pressure, and silt load applied on the model of dam–reservoir–foundation system. Finite element model calibration provides updated information related to the current dam status and can be used for further safety evaluations.
H. Mirzabozorg, M. A. Hariri-Ardebili, M. Shirkhan, and S. M. Seyed-Kolbadi
Hindawi Limited
The effect of solar radiation on thermal distribution in thin high arch dams is investigated. The differential equation governing thermal behavior of mass concrete in three-dimensional space is solved applying appropriate boundary conditions. Solar radiation is implemented considering the dam face direction relative to the sun, the slop relative to horizon, the region cloud cover, and the surrounding topography. It has been observed that solar radiation changes the surface temperature drastically and leads to nonuniform temperature distribution. Solar radiation effects should be considered in thermal transient analysis of thin arch dams.
Alireza Golestani, S.Mahdi S.Kolbadi, and Ali Akbar Heshmati
Elsevier BV
Abstract SASW method is a nondestructive in situ testing method that is used to determine the dynamic properties of soil sites and pavement systems. Phase information and dispersion characteristics of a wave propagating through these systems have a significant role in the processing of recorded data. Inversion of the dispersive phase data provides information on the variation of shear-wave velocity with depth. However, in the case of sanded residual soil, it is not easy to produce the reliable phase spectrum curve. Due to natural noises and other human intervention in surface wave date generation deal with to reliable phase spectrum curve for sanded residual soil turn into the complex issue for geological scientist. In this paper, a time–frequency analysis based on complex Gaussian Derivative wavelet was applied to detect and localize all the events that are not identifiable by conventional signal processing methods. Then, the performance of discrete wavelet transform (DWT) in noise reduction of these recorded seismic signals was evaluated. Furthermore, in particular the influence of the decomposition level choice was investigated on efficiency of this process. This method is developed by various wavelet thresholding techniques which provide many options for controllable de-noising at each level of signal decomposition. Also, it obviates the need for high computation time compare with continuous wavelet transform. According to the results, the proposed method is powerful to visualize the interested spectrum range of seismic signals and to de-noise at low level decomposition.
Mohammad Amin Hariri-Ardebili, Seyed Mahdi Seyed-Kolbadi, and Hasan Mirzabozorg
Techno-Press
In the present paper, a coaxial rotating smeared crack model is proposed for mass concrete in three-dimensional space. The model is capable of applying both the constant and variable shear transfer coefficients in the cracking process. The model considers an advanced yield function for concrete failure under both static and dynamic loadings and calculates cracking or crushing of concrete taking into account the fracture energy effects. The model was utilized on Koyna Dam using finite element technique. Dam-water and dam-foundation interactions were considered in dynamic analysis. The behavior of dam was studied for different shear transfer coefficients considering/neglecting fracture energy effects. The results were extracted at crest displacement and crack profile within the dam body. The results show the importance of both shear transfer coefficient and the fracture energy in seismic analysis of concrete dams under high hydrostatic pressure.
Mohammad Amin Hariri Ard, S. Mahdi S. Kolbadi, Masoud Heshmati, and Hasan Mirzabozor
Science Alert