scholarly journals Multiobjective optimal design of reinforced concrete frames using two metaheuristic algorithms

2021 ◽  
Vol 9 (4B) ◽  
Author(s):  
Mehdi Babaei ◽  
◽  
Masoud Mollayi ◽  
Keyword(s):  
Reinforced Concrete ◽  
Optimal Design ◽  
Optimization Problem ◽  
Numerical Models ◽  
Steel Structures ◽  
Metaheuristic Algorithms ◽  
Rc Structures ◽  
Weighted Sum Method ◽  
Rc Frames ◽  
Single Objective

Genetic algorithm (GA) and differential evolution (DE) are metaheuristic algorithms that have shown a favorable performance in the optimization of complex problems. In recent years, only GA has been widely used for single-objective optimal design of reinforced concrete (RC) structures; however, it has been applied for multiobjective optimization of steel structures. In this article, the total structural cost and the roof displacement are considered as objective functions for the optimal design of the RC frames. Using the weighted sum method (WSM) approach, the two-objective optimization problem is converted to a single-objective optimization problem. The size of the beams and columns are considered as design variables, and the design requirements of the ACI-318 are employed as constraints. Five numerical models are studied to test the efficiency of the GA and DE algorithms. Pareto front curves are obtained for the building models using both algorithms. The detailed results show the accuracy and convergence speed of the algorithms.

scholarly journals Pounding Effects on the Earthquake Response of Adjacent Reinforced Concrete Structures Strengthened by Cable Elements

2014 ◽  
Vol 44 (2) ◽  
pp. 41-56 ◽  
Author(s):  
Angelos Liolios ◽  
Asterios Liolios ◽  
George Hatzigeorgiou ◽  
Stefan Radev
Keyword(s):  
Reinforced Concrete ◽  
Numerical Approach ◽  
Earthquake Response ◽  
Existing Buildings ◽  
The Finite Element Method ◽  
Time Step ◽  
Engineering Structures ◽  
Rc Structures ◽  
Incremental Approach ◽  
Rc Frames

Abstract A numerical approach for estimating the effects of pounding (seismic interaction) on the response of adjacent Civil Engineering structures is presented. Emphasis is given to reinforced concrete (RC) frames of existing buildings which are seismically strengthened by cable-elements. A double discretization, in space by the Finite Element Method and in time by a direct incremental approach is used. The unilateral behaviours of both, the cable-elements and the interfaces contact-constraints, are taken strictly into account and result to inequality constitutive conditions. So, in each time-step, a non-convex linear complementarity problem is solved. It is found that pounding and cable strengthening have significant effects on the earthquake response and, hence, on the seismic upgrading of existing adjacent RC structures.

scholarly journals Damage Source Identification of Reinforced Concrete Structure Using Acoustic Emission Technique

2013 ◽  
Vol 2013 ◽  
pp. 1-5
Author(s):  
Alireza Panjsetooni ◽  
Norazura Muhamad Bunnori ◽  
Amir Hossein Vakili
Keyword(s):  
Acoustic Emission ◽  
Reinforced Concrete ◽  
Nondestructive Evaluation ◽  
Analysis Method ◽  
Reinforced Concrete Structure ◽  
Acoustic Emission Technique ◽  
Rc Structures ◽  
Rc Frames ◽  
Damage Monitoring ◽  
Investigation Process

Acoustic emission (AE) technique is one of the nondestructive evaluation (NDE) techniques that have been considered as the prime candidate for structural health and damage monitoring in loaded structures. This technique was employed for investigation process of damage in reinforced concrete (RC) frame specimens. A number of reinforced concrete RC frames were tested under loading cycle and were simultaneously monitored using AE. The AE test data were analyzed using the AE source location analysis method. The results showed that AE technique is suitable to identify the sources location of damage in RC structures.

Nonlinear FE simulations of structural behavior parameters of reinforced concrete beam with epoxy-bonded FRP

2015 ◽  
Vol 24 (1-2) ◽  
pp. 35-46 ◽  
Author(s):  
Saptarshi Sasmal ◽  
S. Kalidoss
Keyword(s):  
Reinforced Concrete ◽  
Numerical Models ◽  
Adhesive Layer ◽  
Control Mode ◽  
Hydraulic Actuator ◽  
Element Analysis ◽  
Interfacial Stresses ◽  
Rc Structures ◽  
Laminate Thickness ◽  
Reinforcement Strain

AbstractIn the present study, investigations on fiber-reinforced plastic (FRP) plated-reinforced concrete (RC) beam are carried out. Numerical investigations are performed by using a nonlinear finite element analysis by incorporating cracking and crushing of concrete. The numerical models developed in the present study are validated with the results obtained from the experiment under monotonic load using the servo-hydraulic actuator in displacement control mode. Further, the validated numerical models are used to evaluate the influence of different parameters. It is found from the investigations that increase in the elastic modulus of adhesive layer and CFRP laminate increases the interfacial stresses whereas increase in laminate modulus decreases the displacement and reinforcement strain of the beam. It is also observed that increase in the adhesive layer can largely reduce the interfacial stresses, whereas increase in laminate thickness increases it. However, increase in laminate thickness decreases the displacement and reinforcement strain of the beam significantly. It is mention worthy that increase in laminate length reduces the interfacial stresses, whereas CFRP width change does not affect the interfacial stresses. The study will be useful for the design and practicing engineers for arriving at the FRP-based strengthening schemes for RC structures judiciously.

A General Formulation of the Optimal Frame Problem

1970 ◽  
Vol 37 (2) ◽  
pp. 356-360 ◽  
Author(s):  
D. E. Grierson ◽  
M. Z. Cohn
Keyword(s):  
Reinforced Concrete ◽  
Optimal Design ◽  
Elastic Limit ◽  
Limit Equilibrium ◽  
Steel Structures ◽  
Optimal Designs ◽  
Frame Problem ◽  
Material Consumption ◽  
Limit Stage ◽  
Simplifying Assumptions

Optimal design techniques have been extensively applied to steel structures and, to a lesser degree, to reinforced concrete structures. In the latter case, for given geometry and preassigned stiffnesses, optimal designs have been found which simultaneously satisfy (a) limit equilibrium (plastic limit stage), (b) serviceability (elastic limit stage), and (c) optimality (minimum material consumption). The limitations to these designs are: 1. A subsequent check of plastic compatibility may invalidate the design. 2. The resulting member stiffnesses may differ appreciably from the preassigned values. 3. A different geometry may result in a better solution while still satisfying all design criteria. The present paper attempts to eliminate these limitations through a more general formulation of the optimal frame problem wherein design plastic moments, member stiffnesses, and frame geometry are all treated as variables and are found for simultaneous satisfaction of (a) optimality, (b) limit equilibrium, (c) serviceability, (d) plastic compatibility, and (e) elastic compatibility. With some simplifying assumptions to linearize the problem, the general formulation is illustrated for a reinforced concrete continuous beam example. The resulting optimal design is compared with conventional elastic and plastic designs with respect to safety, serviceability, compatibility, and efficiency.

scholarly journals An Adaptive Evolutionary Multi-Objective Approach Based on Simulated Annealing

2011 ◽  
Vol 19 (4) ◽  
pp. 561-595 ◽  
Author(s):  
H. Li ◽  
D. Landa-Silva
Keyword(s):  
Simulated Annealing ◽  
Optimization Problem ◽  
Weight Vector ◽  
Metaheuristic Algorithms ◽  
Search Performance ◽  
Multi Objective Optimization ◽  
Search Technique ◽  
Multi Objective ◽  
Initial Setting ◽  
Single Objective

A multi-objective optimization problem can be solved by decomposing it into one or more single objective subproblems in some multi-objective metaheuristic algorithms. Each subproblem corresponds to one weighted aggregation function. For example, MOEA/D is an evolutionary multi-objective optimization (EMO) algorithm that attempts to optimize multiple subproblems simultaneously by evolving a population of solutions. However, the performance of MOEA/D highly depends on the initial setting and diversity of the weight vectors. In this paper, we present an improved version of MOEA/D, called EMOSA, which incorporates an advanced local search technique (simulated annealing) and adapts the search directions (weight vectors) corresponding to various subproblems. In EMOSA, the weight vector of each subproblem is adaptively modified at the lowest temperature in order to diversify the search toward the unexplored parts of the Pareto-optimal front. Our computational results show that EMOSA outperforms six other well established multi-objective metaheuristic algorithms on both the (constrained) multi-objective knapsack problem and the (unconstrained) multi-objective traveling salesman problem. Moreover, the effects of the main algorithmic components and parameter sensitivities on the search performance of EMOSA are experimentally investigated.

scholarly journals Response Modification Factor of RC Frames Strengthened with RC Haunches

2020 ◽  
Vol 2020 ◽  
pp. 1-18
Author(s):  
Junaid Akbar ◽  
Naveed Ahmad ◽  
Muhammad Rizwan ◽  
Sairash Javed ◽  
Bashir Alam
Keyword(s):  
Reinforced Concrete ◽  
Numerical Models ◽  
Lateral Force ◽  
Roof Displacement ◽  
Response Modification Factor ◽  
Capacity Curves ◽  
Displacement Capacity ◽  
Rc Frames ◽  
Modification Factor ◽  
Force Displacement

This paper presents experimental and numerical studies carried out on two-story reinforced concrete (RC) frames having weaker beam-column joints, which were retrofitted with reinforced concrete haunches to avoid joint panel damage under seismic actions. The design philosophy of the retrofit solution is to allow beam-column members to deform inelastically and dissipate seismic energy. Shake table tests were performed on three 1 : 3 reduced scale two-story RC frame models, including one model incorporating construction deficiencies common in developing countries, which was retrofitted with two retrofit schemes using RC haunches. The focus of the experimental study was to understand the seismic behaviour of both as-built and retrofitted models and obtain the seismic response properties, i.e., lateral force-displacement capacity curves and time histories of model response displacement. The derived capacity curves were used to quantify overstrength and ductility factors of both as-built and retrofitted frames. Finite element- (FE-) based software SeismoStruct was used to develop representative numerical models, which were calibrated with the experimental data in simulating the time history response of structure roof displacement and in predicting peak roof-displacement and peak base shear force. Moreover, the FE-based numerical models were subjected to a suite of spectrum natural accelerograms, linearly scaled to multiple intensity levels for performing incremental dynamic analysis. Lateral force-displacement capacity and response curves were developed, which were analyzed to calculate the structure ductility and overstrength factors. The structure R factor is the product of ductility and overstrength factors, which exhibited substantial increase due to the proposed retrofitting technique. A case study was presented for the seismic performance assessment of RC frames with/without RC haunches in various seismic zones using the static force procedure given in seismic code and using response modification factor quantified in the present research.

Metaheuristic algorithms in optimum design of reinforced concrete beam by investigating strength of concrete

2020 ◽  
Vol 11 (2) ◽  
pp. 26 ◽  
Author(s):  
Serdar Ulusoy ◽  
Aylin Ece Kayabekir ◽  
Gebrail Bekdaş ◽  
Sinan Melih Nigdeli
Keyword(s):  
Reinforced Concrete ◽  
Optimum Design ◽  
Cost Minimization ◽  
Harmony Search ◽  
High Strength ◽  
Bat Algorithm ◽  
Engineering Problem ◽  
Metaheuristic Algorithms ◽  
Rc Structures ◽  
Strength Material

The locations of structural members can be provided according to architectural projects in the design of reinforced concrete (RC) structures. The design of dimensions is the subject of civil engineering, and these designs are done according to the experience of the designer by considering the regulation suggestions, but these dimensions and the required reinforcement plan may not be optimum. For that reason, the dimensions and detailed reinforcement design of RC structures can be found by using optimization methods. To reach optimum results, metaheuristic algorithms can be used. In this study, several metaheuristic algorithms such as harmony search, bat algorithm and teaching learning-based optimization are used in the design of several RC beams for cost minimization. The optimum results are presented for different strength of concrete. The results show that using high strength material for high flexural moment capacity has lower cost than low stretch concrete since doubly reinforced design is not an optimum choice. The results prove that a definite metaheuristic algorithm cannot be proposed for the best optimum design of an engineering problem. According to the investigation of compressive strength of concrete, it can be said that a low strength material are optimum for low flexural moment, while a high strength material may be the optimum one by the increase of the flexural moment as expected.

Evaluation and comparison of concrete constitutive models in numerical simulation of reinforced concrete slabs under blast load

2021 ◽  
pp. 204141962110489
Author(s):  
Hani Mahdavi Talaromi ◽  
Farhad Sakhaee
Keyword(s):  
Reinforced Concrete ◽  
Numerical Models ◽  
Concrete Slab ◽  
Constitutive Models ◽  
Computation Time ◽  
Material Model ◽  
Reinforced Concrete Slab ◽  
Rc Structures ◽  
Reinforced Concrete Slabs ◽  
Concrete Damage

Numerical models have been used recently to analyze concrete structures subjected to high-impulsive loads. A material model that can well capture the mechanical behaviors is crucial to obtain reliable results. Present study, focused on reinforced concrete slab as a major load carrying element of the RC structures under blast loading. By performing several simulations in popular and powerful concrete constitutive models, including concrete damage R3, HJC, CSCM, and Winfrith the accuracy of these models was investigated. Maximum deflections have been compared with each other and expanded further to compare with experiments. Result showed all models have an acceptable accuracy in estimating maximum slab deflection. Concrete Damage R3 presented the highest accuracy. HJC has the second rank and CSCM and Winfrith have the third and the fourth places, respectively. HJC needed the minimum computation time. CSCM had minimum input parameters but includes maximum calculation time. Winfrith had the lowest accuracy, however this model presented very conservative results. Uniaxial compressive and tensile stress-strain curves showed that the models which presented higher values of strength, evaluated lower maximum values of deflection.

scholarly journals Interior Point Algorithm for Multi-UAVs Formation Autonomous Reconfiguration

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Wang Jian-hong ◽  
Rana Javed Masood
Keyword(s):  
Multiobjective Optimization ◽  
Interior Point ◽  
Optimization Problem ◽  
Inequality Constraints ◽  
Interior Point Algorithm ◽  
Weighted Sum ◽  
Multiobjective Optimization Problem ◽  
Weighted Sum Method ◽  
Nonlinear Dynamic Equations ◽  
Single Objective

Here the problem of designing multi-UAVs formation autonomous reconfiguration is considered. Combined with three kinds of cost functions, nonlinear dynamic equations, and four inequality constraints, one nonlinear multiobjective optimization problem is constructed. After applying weighted sum method and separating all equality or inequality constraints, the former nonlinear multiobjective optimization problem can be converted into a standard nonlinear single objective optimization problem. Then the interior point algorithm is applied to solve it. Further some improvements are proposed to avoid rank deficiency of some matrices. The equivalence property between multiobjective optimization and single objective optimization through weighted sum method is proved. Finally the efficiency of the proposed strategy can be confirmed by the simulation example results.

Optimum Design of Reinforced Concrete Beams

2020 ◽  
pp. 71-91
Keyword(s):  
Reinforced Concrete ◽  
Optimum Design ◽  
Nonlinear Behavior ◽  
Optimization Method ◽  
Reinforced Concrete Beams ◽  
Metaheuristic Algorithms ◽  
Rc Beam ◽  
Rc Structures ◽  
Eurocode 2 ◽  
The Cost

The design of reinforced concrete (RC) beams need special conditions to provide a ductile design. In this design, the maximum amount of tensile reinforcement must be limited to singly reinforced design. After the singly reinforced limit, the cost of doubly reinforced RC beam rapidly increases, and it may not be an optimum design. To consider this nonlinear behavior and other rules used in RC structures according to regulations such as ACI 318: Building code requirements for structural concrete and Eurocode 2: Design of concrete structures, an algorithmic and iteration optimization method is needed. In this chapter, two examples are presented, and optimum results are shared for methodologies employing several metaheuristic algorithms. The importance of using metaheuristic algorithms can be seen in this chapter.

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