Moment rotation prediction of precast beam to column connections using extreme learning machine

Maryam Safa,Nguyen Thoi Trung,Ayub Shahgoli Fazli,Yousef Zandi,Mahdi Shariati,Karzan Wakil,Majid Khorami 국제구조공학회 2019 Structural Engineering and Mechanics, An Int'l Jou Vol.70 No.5

The performance of precast concrete structures is greatly influenced by the behaviour of beam-to-column connections. A single connection may be required to transfer several loads simultaneously so each one of those loads must be considered in the design. A good connection combines practicality and economy, which requires an understanding of several factors; including strength, serviceability, erection and economics. This research work focuses on the performance aspect of a specific type of beam-to-column connection using partly hidden corbel in precast concrete structures. In this study, the results of experimental assessment of the proposed beam-to-column connection in precast concrete frames was used. The purpose of this research is to develop and apply the Extreme Learning Machine (ELM) for moment-rotation prediction of precast beam-to-column connections. The ELM results are compared with genetic programming (GP) and artificial neural network (ANN). The reliability of the computational models was accessed based on simulation results and using several statistical indicators.

Experimental study of the behavior of composite timber columns confined with hollow rectangular steel sections under compression

Leila Razavian,Morteza Naghipour,Mahdi Shariati,Maryam Safa 국제구조공학회 2020 Structural Engineering and Mechanics, An Int'l Jou Vol.74 No.1

There are separate merits and demerits to wood and steel. The combination of wood and steel as a compound section is able to improve the properties of both and ultimately increase their final bearing capacity. The composite cross-section made of steel and wood has higher hardness while showing more ductility and the local buckling of steel is delayed or completely prevented. The purpose of this study is to investigate the behavior of composite columns enclosed in wooden logs and the hollow sections of steel that will be examined in a laboratory environment under the axial load to determine the final bearing capacity and sample deformation. In terms of methodology, steel sheet and carbon fiber reinforced polymer sheet (FRP) are tested to construct hollow rectangular sections and reinforce timber. Besides, the method of connecting hollow sections and timber including glue and screw has been also investigated. As a result, timber lumber enclosed with carbon fiber-reinforced polymer sheets in which fibers are horizontally located at 90 ° are more resistant with better ductility.

Therapeutic Outcomes of Pectoralis Major Muscle Turnover Flap in Mediastinitis

Reza Bagheri,Mohammad Abbasi Tashnizi,Seyed Ziaollah Haghi,Maryam Salehi,Ata’ollah Rajabnejad,Mohsen Hatami Ghale Safa,Mohammad Vejdani 대한흉부외과학회 2015 Journal of Chest Surgery (J Chest Surg) Vol.48 No.4

Background: This study aimed to evaluate the therapeutic results and safety of pectoralis major muscle turnover flaps in the treatment of mediastinitis after coronary artery bypass grafting (CABG) procedures. Methods: Data regarding 33 patients with post-CABG deep sternal wound infections (DSWIs) who underwent pectoralis major muscle turnover flap procedures in the Emam Reza and Ghaem Hospitals of Mashhad, Iran were reviewed in this study. For each patient, age, sex, hospital stay duration, remission, recurrence, and associated morbidity and mortality were evaluated. Results: Of the 2,447 CABG procedures that were carried out during the time period encompassed by our study, DSWIs occurred in 61 patients (2.5%). Of these 61 patients, 33 patients (nine females [27.3%] and 24 males [72.7%]) with an average age of 63±4.54 years underwent pectoralis major muscle turnover flap placement. Symptoms of infection mainly occurred within the first 10 days after surgery (mean, 10.24±13.62 days). The most common risk factor for DSWIs was obesity (n=16, 48.4%) followed by diabetes mellitus (n=13, 39.4%). Bilateral and unilateral pectoralis major muscle turnover flaps were performed in 20 patients (60.6%) and 13 patients (39.4%), respectively. Complete remission was achieved in 25 patients (75.7%), with no recurrence in the follow-up period. Four patients (12.1%) needed reoperation. The mean hospitalization time was 11.69±6.516 days. Four patients (12.1%) died during the course of the study: three due to the postoperative complication of respiratory failure and one due to pulmonary thromboembolism. Conclusion: Pectoralis major muscle turnover flaps are an optimal technique in the treatment of post-CABG mediastinitis. In addition to leading to favorable therapeutic results, this flap is associated with minimal morbidity and mortality, as well as a short hospitalization time.

Application of waste tire rubber aggregate in porous concrete

Mahdi Shariati,Arian Heyrati,Yousef Zandi,Hossein Laka,Ali Toghroli,Peiman Kianmehr,Maryam Safa,Musab N.A. Salih,Shek Poi-Ngian 국제구조공학회 2019 Smart Structures and Systems, An International Jou Vol.24 No.4

This study aimed to categorize pervious rubberized concrete into fresh and hardened concrete analyzing its durability, permeability and strength. During the globalization of modern life, growing population and industry rate have signified a sustainable approach to all aspects of modern life. In recent years, pervious concrete (porous concrete) has significantly substituted for pavements due to its mechanical and environmental properties. On the other hand, scrap rubber tire has been also contributed with several disposal challenges. Considering the huge amount of annually tire wastes tossing out, the conditions become worse. Pervious concrete (PC) gap has graded surface assisted with storm water management, recharging groundwater sources and alleviate water run-offs. The results have shown that the use of waste tires as aggregate built into pervious concrete has tremendously reduced the scrap tire wastes enhancing environmental compliance.

Evaluation of the parameters affecting the Schmidt rebound hammer reading using ANFIS method

Ali Toghroli,Ehsan Darvishmoghaddam,Yousef Zandi,Mahdi Parvan,Maryam Safa,Mu’azu Mohammed Abdullahi,Abbas Heydari,Karzan Wakil,Saad A.M. Gebreel,Majid Khorami 사단법인 한국계산역학회 2018 Computers and Concrete, An International Journal Vol.21 No.5

As a nondestructive testing method, the Schmidt rebound hammer is widely used for structural health monitoring. During application, a Schmidt hammer hits the surface of a concrete mass. According to the principle of rebound, concrete strength depends on the hardness of the concrete energy surface. Study aims to identify the main variables affecting the results of Schmidt rebound hammer reading and consequently the results of structural health monitoring of concrete structures using adaptive neuro-fuzzy inference system (ANFIS). The ANFIS process for variable selection was applied for this purpose. This procedure comprises some methods that determine a subsection of the entire set of detailed factors, which present analytical capability. ANFIS was applied to complete a flexible search. Afterward, this method was applied to conclude how the five main factors (namely, age, silica fume, fine aggregate, coarse aggregate, and water) used in designing concrete mixture influence the Schmidt rebound hammer reading and consequently the structural health monitoring accuracy. Results show that water is considered the most significant parameter of the Schmidt rebound hammer reading. The details of this study are discussed thoroughly.

Optimization dynamic responses of laminated multiphase shell in thermo-electro-mechanical conditions

Fan, Linyuan,Kong, Degang,Song, Jun,Moradi, Zohre,Safa, Maryam,Khadimallah, Mohamed Amine Techno-Press 2022 Advances in nano research Vol.13 No.1

The optimization for dynamic response associated with a cylindrical shell which is made of laminated composites embedded in a piezoelectric layer which is subjected to temperature rises and is resting on an elastic foundation is investigated for the first time. The first shear order theory (FSDT) is utilized in order to obtain the strain relations of the shell. Then, using the energy method, the equations of motions as well as boundary condition of the problem are attained. The formulation of this study together with the solution procedure which is a numerical solution method, differential quadrature method (DQM) is validated using other researches. This paper presents a thorough study on the parameters which impacts the vibration frequency of the laminated shell. The results of this paper shows that any type of laminated composite shell can reduce the vibration frequency providing that the angle related to layer are higher than 85 degrees. Also, in order to reduce the effect of temperature rises, the laminated composites instead of orthotropic one can be used.

Estimation of moment and rotation of steel rack connections using extreme learning machine

Mahdi Shariati,Nguyen Thoi Trung,Karzan Wakil,Peyman Mehrabi,Maryam Safa,Majid Khorami 국제구조공학회 2019 Steel and Composite Structures, An International J Vol.31 No.5

The estimation of moment and rotation in steel rack connections could be significantly helpful parameters for designers and constructors in the initial designing and construction phases. Accordingly, Extreme Learning Machine (ELM) has been optimized to estimate the moment and rotation in steel rack connection based on variable input characteristics as beam depth, column thickness, connector depth, moment and loading. The prediction and estimating of ELM has been juxtaposed with genetic programming (GP) and artificial neural networks (ANNs) methods. Test outcomes have indicated a surpass in accuracy predicting and the capability of generalization in ELM approach than GP or ANN. Therefore, the application of ELM has been basically promised as an alternative way to estimate the moment and rotation of steel rack connection. Further particulars are presented in details in results and discussion.

Application of ANFIS technique on performance of C and L shaped angle shear connectors

Yadollah Sedghi,Yousef Zandi,Mahdi Shariati,Ebrahim Ahmadi,Vahid Moghimi Azar,Ali Toghroli,Maryam Safa,Edy Tonnizam Mohamad,Majid Khorami,Karzan Wakil 국제구조공학회 2018 Smart Structures and Systems, An International Jou Vol.22 No.3

The behavior of concrete slabs in composite beam with C and L shaped angle shear connectors has been studied in this paper. These two types of angle shear connectors' instalment have been commonly utilized. In this study, the finite element (FE) analysis and soft computing method have been used both to present the shear connectors' push out tests and providing data results used later in soft computing method. The current study has been performed to present the aforementioned shear connectors' behavior based on the variable factors aiming the study of diverse factors' effects on C and L shaped angle in shear connectors. ANFIS (Adaptive Neuro Fuzzy Inference System), has been manipulated in providing the effective parameters in shear strength forecasting by providing input-data comprising: height, length, thickness of shear connectors together with concrete strength and the respective slip of shear connectors. ANFIS has been also used to identify the predominant parameters influencing the shear strength forecast in C and L formed angle shear connectors.

Application of ANFIS technique on performance of C and L shaped angle shear connectors

Sedghi, Yadollah,Zandi, Yousef,Shariati, Mahdi,Ahmadi, Ebrahim,Azar, Vahid Moghimi,Toghroli, Ali,Safa, Maryam,Mohamad, Edy Tonnizam,Khorami, Majid,Wakil, Karzan Techno-Press 2018 Smart Structures and Systems, An International Jou Vol.22 No.3

The behavior of concrete slabs in composite beam with C and L shaped angle shear connectors has been studied in this paper. These two types of angle shear connectors' instalment have been commonly utilized. In this study, the finite element (FE) analysis and soft computing method have been used both to present the shear connectors' push out tests and providing data results used later in soft computing method. The current study has been performed to present the aforementioned shear connectors' behavior based on the variable factors aiming the study of diverse factors' effects on C and L shaped angle in shear connectors. ANFIS (Adaptive Neuro Fuzzy Inference System), has been manipulated in providing the effective parameters in shear strength forecasting by providing input-data comprising: height, length, thickness of shear connectors together with concrete strength and the respective slip of shear connectors. ANFIS has been also used to identify the predominant parameters influencing the shear strength forecast in C and L formed angle shear connectors.