The Effects of Amount and Location of Openings on Lateral Behavior of Masonry Infilled RC Frames

Elshan Ahani,Mir Naghi Mousavi,Ali Ahani,Mohammad Kheirollahi 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.5

Many design codes didn’t consider masonry infills as structural elements inside moment resisting frames. Therefore, their presence is not assumed in analysis and design process. While, in real they could affect strength, energy dissipation, ductility, stiffness and many other features of moment frames. The presence of masonry infills could also change the reaction of frames exposed to lateral loads like earthquake and wind. This issue becomes more important if the built frame was placed in seismically active region. In current study, the effects of opening location by placing openings in 3 different places and its percentage was evaluated. To this purpose an experimental scaled model was constructed and subjected to cyclic loading. Thereafter, by using simplified micromodeling, numerical modeling performed for extending studies. Subsequently, sensitivity analyses were done to survey the effects of opening ratio on the lateral behavior of intermediate RC moment frames. Analytical results indicate that the openings which were lo20cated at upper corner of the masonry infills will loss more strength. In all of the numerical specimens by increase in opening percentage the lateral strength was decreased. The lateral strength was negligible for infills with greater than 40% openings.

Studying the thermodynamic parameters of disperse dyeing of modified polyethylene terephthalate sheets using hyperbranched polymeric additive as a nanomaterial

Mina Ahani,Marziyeh Khatibzadeh,Mohsen Mohseni 한국공업화학회 2013 Journal of Industrial and Engineering Chemistry Vol.19 No.6

Thermodynamic parameters of disperse dyeing of modified PET sheets by various loads of a polyesteramide hyperbranched polymer are investigated in terms of standard affinity (Dm8), enthalpy change (DH8) and entropy change (DS8). The results show that the standard affinity of dye to the modified PET is higher than that to the virgin PET. The bath containing virgin PET displays the highest negative values of the DH8 and DS8, while the bath containing the modified PET with 2% hyperbranched polymer shows the lowest negative values of them. Surface morphology and thermal properties of the samples are analyzed by AFM and DSC.

Constructability optimal design of reinforced concrete retaining walls using a multi-objective genetic algorithm

Kaveh, A.,Kalateh-Ahani, M.,Fahimi-Farzam, M. Techno-Press 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.47 No.2

The term "constructability" in regard to cast-in-place concrete construction refers mainly to the ease of reinforcing steel placement. Bar congestion complicates steel placement, hinders concrete placement and as a result leads to improper consolidation of concrete around bars affecting the integrity of the structure. In this paper, a multi-objective approach, based on the non-dominated sorting genetic algorithm (NSGA-II) is developed for optimal design of reinforced concrete cantilever retaining walls, considering minimization of the economic cost and reinforcing bar congestion as the objective functions. The structural model to be optimized involves 35 design variables, which define the geometry, the type of concrete grades, and the reinforcement used. The seismic response of the retaining walls is investigated using the well-known Mononobe-Okabe analysis method to define the dynamic lateral earth pressure. The results obtained from numerical application of the proposed framework demonstrate its capabilities in solving the present multi-objective optimization problem.

Constructability optimal design of reinforced concrete retaining walls using a multi-objective genetic algorithm

A. Kaveh,M. Kalateh-Ahani,M. Fahimi-Farzam 국제구조공학회 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.47 No.2

The term “constructability” in regard to cast-in-place concrete construction refers mainly to the ease of reinforcing steel placement. Bar congestion complicates steel placement, hinders concrete placement and as a result leads to improper consolidation of concrete around bars affecting the integrity of the structure. In this paper, a multi-objective approach, based on the non-dominated sorting genetic algorithm (NSGA-II) is developed for optimal design of reinforced concrete cantilever retaining walls, considering minimization of the economic cost and reinforcing bar congestion as the objective functions. The structural model to be optimized involves 35 design variables, which define the geometry, the type of concrete grades, and the reinforcement used. The seismic response of the retaining walls is investigated using the well-known Mononobe-Okabe analysis method to define the dynamic lateral earth pressure. The results obtained from numerical application of the proposed framework demonstrate its capabilities in solving the present multi-objective optimization problem.

Time-history analysis based optimal design of space trusses: the CMA evolution strategy approach using GRNN and WA

A. Kaveh,M. Fahimi-Farzam,M. Kalateh-Ahani 국제구조공학회 2012 Structural Engineering and Mechanics, An Int'l Jou Vol.44 No.3

In recent years, the need for optimal design of structures under time-history loading aroused great attention in researchers. The main problem in this field is the extremely high computational demand of time-history analyses, which may convert the solution algorithm to an illogical one. In this paper, a new framework is developed to solve the size optimization problem of steel truss structures subjected to ground motions. In order to solve this problem, the covariance matrix adaptation evolution strategy algorithm is employed for the optimization procedure, while a generalized regression neural network is utilized as a meta-model for fitness approximation. Moreover, the computational cost of time-history analysis is decreased through a wavelet analysis. Capability and efficiency of the proposed framework is investigated via two design examples, comprising of a tower truss and a footbridge truss.

Optimum design of steel frame structures considering construction cost and seismic damage

A. Kaveh,M. Fahimi-Farzam,M. Kalateh-Ahani 국제구조공학회 2015 Smart Structures and Systems, An International Jou Vol.16 No.1

Minimizing construction cost and reducing seismic damage are two conflicting objectives in the design of any new structure. In the present work, we try to develop a framework in order to solve the optimum performance-based design problem considering the construction cost and the seismic damage of steel moment-frame structures. The Park-Ang damage index is selected as the seismic damage measure because it is one of the most realistic measures of structural damage. The non-dominated sorting genetic algorithm (NSGA-II) is employed as the optimization algorithm to search the Pareto optimal solutions. To improve the time efficiency of the proposed framework, three simplifying strategies are adopted: first, simplified nonlinear modeling investigating minimum level of structural modeling sophistication; second, fitness approximation decreasing the number of fitness function evaluations; third, wavelet decomposition of earthquake record decreasing the number of acceleration points involved in time-history loading. The constraints of the optimization problem are considered in accordance with Federal Emergency Management Agency\'s (FEMA) recommended seismic design specifications. The results from numerical application of the proposed framework demonstrate the efficiency of the framework in solving the present multi-objective optimization problem.

A compressed-sensing-based compressor for ECG

Vahi Izadi,Pouria Karimi Shahri,Hamed Ahani 대한의용생체공학회 2020 Biomedical Engineering Letters (BMEL) Vol.10 No.2

Electrocardiogram (ECG) data compression has numerous applications. The time for generating compressed samples is avital factor when we consider ambulatory devices, with the fact that data should be sent to the physician as soon as possible. In addition, there are some wearable ECG recorders that have limited power, and may only be capable of doing simplealgorithms. With the aim of increasing the speed and simplicity of the compressors, we propose a system architecture thatcan generate compressed ECG samples, in a linear method and with CR 75%. We used sparsity of the ECG signal andproposed a system based on compressed sensing (CS) that can compress ECG samples, almost in real-time. We applied CSin a very small size in order to accelerate the compression phase and accordingly reducing the power consumption. Also,in the recovery phase, we used the recently developed Kronecker technique to improve the quality of the recovered signal. The system designed based on full-adder/subtractor (FAS) and shift registers, without using any external processor or anytraining algorithm.

Time-history analysis based optimal design of space trusses: the CMA evolution strategy approach using GRNN and WA

Kaveh, A.,Fahimi-Farzam, M.,Kalateh-Ahani, M. Techno-Press 2012 Structural Engineering and Mechanics, An Int'l Jou Vol.44 No.3

In recent years, the need for optimal design of structures under time-history loading aroused great attention in researchers. The main problem in this field is the extremely high computational demand of time-history analyses, which may convert the solution algorithm to an illogical one. In this paper, a new framework is developed to solve the size optimization problem of steel truss structures subjected to ground motions. In order to solve this problem, the covariance matrix adaptation evolution strategy algorithm is employed for the optimization procedure, while a generalized regression neural network is utilized as a meta-model for fitness approximation. Moreover, the computational cost of time-history analysis is decreased through a wavelet analysis. Capability and efficiency of the proposed framework is investigated via two design examples, comprising of a tower truss and a footbridge truss.

Pulsatility Index in Different Modifications of Fontan Palliation: An Echocardiographic Assessment

Reza Shabanian,Parvin Akbari Asbagh,Abdullah Sedaghat,Minoo Dadkhah,Zahra Esmaeeli,Aliyeh Nikdoost,Manizheh Ahani,Mitra Rahimzadeh,Alireza Dehestani,Mohammad Ali Navabi 한국심초음파학회 2022 Journal of Cardiovascular Imaging (J Cardiovasc Im Vol.30 No.2

BACKGROUND: Adding pulsation to the Fontan circulation might change the fate of patients palliated by this procedure. Our aim was to compare the pulsatility index (PI) of the pulmonary artery (PA) between the various modifications of Fontan palliation. METHODS: Doppler-derived PI was measured in PA branches of a cohort of 28 patients palliated by 6 modifications of Fontan procedure. A group of normal individuals was included for comparison. RESULTS: Atriopulmonary connection (APC) group had the highest PA branches PI and statistically was close to the PI of the normal individuals (right pulmonary artery [RPA] PI of 1.58 vs. 1.63; p = 0.99 and left pulmonary artery [LPA] PI of 1.54 vs. 1.68; p = 0.46, respectively). The lowest PA branches PI was seen in the group of extracardiac total cavopulmonary connection (RPA PI of 0.62 and LPA PI of 0.65). Other 4 modifications including the extracardiac conduit with oversewn pulmonary valve, extracardiac conduit with preserved adjusted antegrade flow, extracardiac conduit from inferior vena cava onto the rudimentary right ventricle and lateral tunnel had a mean “RPA and LPA” PI of “1.19 and 1.17”, “1.16 and 1.11”, “1.13 and 1.11”, “0.82 and 0.84”, respectively. The modified Dunnett's post hoc test has shown a significant statistical decline in PI of all modifications compared to the normal individuals except for the APC group. CONCLUSIONS: Fontan palliated patients in different groups of surgical modification showed a spectrum of Doppler-derived PI with the highest amounts belong to the groups of pulsatile Fontan.