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The impact of reinforced concrete beam-column joints on the shear strength of a building under cyclic loading depends on the types of joints applied. This study considers models of the uniaxial and biaxial joint shear strength of exterior beam-column joints. Prediction models of the uniaxial shear strength under uniaxial cyclic loading based on ACI 352, ASCE 41, and gene expression programming (GEP) have been developed. The ACI 352, ASCE 41, and GEP formulas have the potential to achieve improved results. This study considers a means by which to improve the results of previous models through a proposed deep neural network (DNN) model with three hidden layers among the artificial neural network structures. The R-squared value and mean absolute error determined through this DNN model are 97.94% and 34.13% for the uniaxial model and 98.28% and 2.70% for the biaxial model, respectively. These results indicate that the DNN model is more suitable than the ACI 352, ASCE 41, and GEP models for joint shear strength predictions.
Sang Ho Park; Doohyun Yoon; Sanghun Kim; Zong Woo Geem. Deep neural network applied to joint shear strength for exterior RC beam-column joints affected by cyclic loadings. Structures 2021, 33, 1819 -1832.
AMA StyleSang Ho Park, Doohyun Yoon, Sanghun Kim, Zong Woo Geem. Deep neural network applied to joint shear strength for exterior RC beam-column joints affected by cyclic loadings. Structures. 2021; 33 ():1819-1832.
Chicago/Turabian StyleSang Ho Park; Doohyun Yoon; Sanghun Kim; Zong Woo Geem. 2021. "Deep neural network applied to joint shear strength for exterior RC beam-column joints affected by cyclic loadings." Structures 33, no. : 1819-1832.
Total Potential Optimization using Metaheuristic Algorithms (TPO/MA) is an alternative tool for the analysis of structures. It is shown that this emerging method is advantageous in solving nonlinear problems like trusses, tensegrity structures, cable networks, and plane stress systems. In the present study, TPO/MA, which does not need any specific implementation for nonlinearity, is demonstrated to be successfully applied to the analysis of plane strain structures. A numerical investigation is performed using nine different metaheuristic algorithms and an adaptive harmony search in linear analysis of a structural mechanics problem having 8 free nodes defined as design variables in the minimization problem of total potential energy. For nonlinear stress-strain relation cases, two structural mechanics problems, one being a thick-walled pipe and the other being a cantilever retaining wall, are analyzed by employing adaptive harmony search, which was found to be the best one in linear analyses. The nonlinear stress-strain relations considered in these analyses are hypothetical ones due to the lack of any such relationship in the literature. The results have shown that TPO/MA can solve nonlinear plane strain problems that can be encountered as engineering problems in structural mechanics.
Yusuf Toklu; Gebrail Bekdaş; Melda Yücel; Sinan Nigdeli; Aylin Kayabekir; Sanghun Kim; Zong Geem. Total Potential Optimization Using Metaheuristic Algorithms for Solving Nonlinear Plane Strain Systems. Applied Sciences 2021, 11, 3220 .
AMA StyleYusuf Toklu, Gebrail Bekdaş, Melda Yücel, Sinan Nigdeli, Aylin Kayabekir, Sanghun Kim, Zong Geem. Total Potential Optimization Using Metaheuristic Algorithms for Solving Nonlinear Plane Strain Systems. Applied Sciences. 2021; 11 (7):3220.
Chicago/Turabian StyleYusuf Toklu; Gebrail Bekdaş; Melda Yücel; Sinan Nigdeli; Aylin Kayabekir; Sanghun Kim; Zong Geem. 2021. "Total Potential Optimization Using Metaheuristic Algorithms for Solving Nonlinear Plane Strain Systems." Applied Sciences 11, no. 7: 3220.
In this study, multi-story structures with different combinations (on each floor and only the first floor) of active tendon control systems driven by a proportional–integral–derivative (PID) controller were actively controlled. The PID parameters, Kp (proportional gain), Td (derivative gain), and Ti (integral gain) for each structure, were optimally tuned by using both the harmony search algorithm (HS) and flower pollination algorithm (FPA), which are metaheuristic algorithms. In two different active-controlled structures, which are formed according to the position of the PID, the structural responses under near-fault records defined in FEMA P-695 are examined to determine the appropriate feedback which was applied for displacement, velocity, acceleration, and total acceleration. The performance of the different feedback strategies on these two active-controlled structures is evaluated. As a result, the acceleration feedback is suitable for all combinations of the active control system with a PID controller. The HS algorithm outperforms the optimum results found according to the FPA.
Serdar Ulusoy; Gebrail Bekdaş; Sinan Nigdeli; Sanghun Kim; Zong Geem. Performance of Optimum Tuned PID Controller with Different Feedback Strategies on Active-Controlled Structures. Applied Sciences 2021, 11, 1682 .
AMA StyleSerdar Ulusoy, Gebrail Bekdaş, Sinan Nigdeli, Sanghun Kim, Zong Geem. Performance of Optimum Tuned PID Controller with Different Feedback Strategies on Active-Controlled Structures. Applied Sciences. 2021; 11 (4):1682.
Chicago/Turabian StyleSerdar Ulusoy; Gebrail Bekdaş; Sinan Nigdeli; Sanghun Kim; Zong Geem. 2021. "Performance of Optimum Tuned PID Controller with Different Feedback Strategies on Active-Controlled Structures." Applied Sciences 11, no. 4: 1682.
In the optimum design of reinforced concrete (RC) structural members, the robustness of the employed method is important as well as solving the optimization problem. In some cases where the algorithm parameters are defined as non-effective values, local-optimum solutions may prevail over the existing global optimum results. Any metaheuristic algorithm can be effective to solve the optimization problem but must give the same results for several runs. Due to the randomization nature of these algorithms, the performance may vary with respect to time. The essential and novel work done in this study is the comparative investigation of 10 different metaheuristic algorithms and two modifications of harmony search (HS) algorithm on the optimum cost design of RC retaining walls constrained with geotechnical and structural state limits. The employed algorithms include classical ones (genetic algorithm (GA), differential evaluation (DE), and particle swarm optimization (PSO)), proved ones on structural engineering applications (harmony search, artificial bee colony, firefly algorithm), and recent algorithms (teaching–learning-based optimization (TLBO), flower pollination algorithm (FPA), grey wolf optimization, Jaya algorithm (JA)). The modifications of HS include adaptive HS (AHS) concerning the automatic change of algorithm parameters and hybridization of AHS with JA that is developed for the investigated problem. According to the numerical investigations, recent algorithms such as TLBO, FPA, and JA are generally the best at finding the optimum values with less deviation than the others. The adaptive-hybrid HS proposed in this study is also competitive with these algorithms, while it can reach the best solution by using a lower population number which can lead to timesaving in the optimization process. By the minimization of material used in construction via best optimization, sustainable structures that support multiple types of constraints are provided.
Melda Yücel; Aylin Ece Kayabekir; Gebrail Bekdaş; Sinan Melih Nigdeli; Sanghun Kim; Zong Woo Geem. Adaptive-Hybrid Harmony Search Algorithm for Multi-Constrained Optimum Eco-Design of Reinforced Concrete Retaining Walls. Sustainability 2021, 13, 1639 .
AMA StyleMelda Yücel, Aylin Ece Kayabekir, Gebrail Bekdaş, Sinan Melih Nigdeli, Sanghun Kim, Zong Woo Geem. Adaptive-Hybrid Harmony Search Algorithm for Multi-Constrained Optimum Eco-Design of Reinforced Concrete Retaining Walls. Sustainability. 2021; 13 (4):1639.
Chicago/Turabian StyleMelda Yücel; Aylin Ece Kayabekir; Gebrail Bekdaş; Sinan Melih Nigdeli; Sanghun Kim; Zong Woo Geem. 2021. "Adaptive-Hybrid Harmony Search Algorithm for Multi-Constrained Optimum Eco-Design of Reinforced Concrete Retaining Walls." Sustainability 13, no. 4: 1639.
In this paper, the Harmony Search (HS) algorithm is utilized to perform single and multivariate parametric studies to acquire the optimization of both size and cost of reinforced concrete (RC) retaining walls embedded in pure frictional soils. The geotechnical properties of the backfill and foundation soil such as shear strength angle, unit weight, and the ultimate bearing pressure of the soil have been used to create different cases for evaluating the effects of site properties on the size and cost of the wall. The change of depth of excavation and surcharge loading condition is fictionalized for generating different environmental conditions for all envisaged soil profiles to predict possible rates of influences. The unit cost of the concrete has also been evaluated as a variant to show the economic constraints on the selection of structural materials. The results of the analyses represent the integrated influences of different significant parameters on the achievement of minimum cost-dimension optimization. Besides, a well-known commercial geotechnical engineering software is used to compare the appropriateness of the suggested designs in terms of both the attainment of geotechnical stability and the structural requirements. Consequently, this study can guide both researchers and designers to select the proper and optimal sections of RC-retaining wall systems with simultaneous analyses of parameters that are influenced by the design process. Furthermore, the optimization results indicate that a significant cost reduction may be achieved when compared with the traditional pre-design method.
Zülal Arama; Aylin Kayabekir; Gebrail Bekdaş; Sanghun Kim; Zong Geem. The Usage of the Harmony Search Algorithm for the Optimal Design Problem of Reinforced Concrete Retaining Walls. Applied Sciences 2021, 11, 1343 .
AMA StyleZülal Arama, Aylin Kayabekir, Gebrail Bekdaş, Sanghun Kim, Zong Geem. The Usage of the Harmony Search Algorithm for the Optimal Design Problem of Reinforced Concrete Retaining Walls. Applied Sciences. 2021; 11 (3):1343.
Chicago/Turabian StyleZülal Arama; Aylin Kayabekir; Gebrail Bekdaş; Sanghun Kim; Zong Geem. 2021. "The Usage of the Harmony Search Algorithm for the Optimal Design Problem of Reinforced Concrete Retaining Walls." Applied Sciences 11, no. 3: 1343.
The shear buckling of web plates and lateral–torsional buckling are among the major failure modes of plate girders. The importance of the lateral–torsional buckling capacity of plate girders was further evidenced when several plate girders of a bridge in Edmonton, Alberta, Canada failed in 2015, because insufficient bracing led to the lateral buckling of the plate girders. In this study, we focus on the optimisation of the cross-sections of plate girders using a well-known and extremely efficient meta-heuristic optimisation algorithm called the harmony search algorithm. The objective of this optimisation is to design the cross-sections of the plate girders with the minimum area that satisfies requirements, such as the lateral–torsional buckling load and ultimate shear stress. The base geometry, material properties, applied load and boundary conditions were taken from an experimental study and optimised. It was revealed that the same amount of load-carrying capacity demonstrated by this model can be achieved with a cross-sectional area 16% smaller than that of the original specimen. Furthermore, the slenderness of the web plate was found to have a decisive effect on the cost-efficiency of the plate girder design.
Celal Cakiroglu; Gebrail Bekdaş; Sanghun Kim; Zong Woo Geem. Optimisation of Shear and Lateral–Torsional Buckling of Steel Plate Girders Using Meta-Heuristic Algorithms. Applied Sciences 2020, 10, 3639 .
AMA StyleCelal Cakiroglu, Gebrail Bekdaş, Sanghun Kim, Zong Woo Geem. Optimisation of Shear and Lateral–Torsional Buckling of Steel Plate Girders Using Meta-Heuristic Algorithms. Applied Sciences. 2020; 10 (10):3639.
Chicago/Turabian StyleCelal Cakiroglu; Gebrail Bekdaş; Sanghun Kim; Zong Woo Geem. 2020. "Optimisation of Shear and Lateral–Torsional Buckling of Steel Plate Girders Using Meta-Heuristic Algorithms." Applied Sciences 10, no. 10: 3639.