Showing papers in "Archives of civil engineering in 2017"
TL;DR: In this paper, the buckling and postbuckling response of thin-walled composite plates investigated experimentally and determinated analytically and numerically is compared with real dimension specimens of composite plates weakened by cut-out subjected to uniform compression in laboratory buckling tests.
Abstract: Abstract Buckling and postbuckling response of thin-walled composite plates investigated experimentally and determinated analytically and numerically is compared. Real dimension specimens of composite plates weakened by cut-out subjected to uniform compression in laboratory buckling tests have been modelled in the finite element method and examined analytically based on P-w2 and P-w3 methods. All results were obtained during the experimental investigations and the numerical FEM analysis of a thin-walled composite plate made of a carbon–epoxy laminate with a symmetrical eight-layer arrangement of [90/-45/45/0]s. The instrument used for this purpose was a numerical ABAQUS® program.
19 citations
TL;DR: In this paper, the scale of temperature changes which workers are exposed to on scaffoldings is analyzed, showing that high temperatures and significant temperature variations frequently occur on the scaffolding, which leads to a lack of adaptability and consequently to tiredness or decreased alertness.
Abstract: Abstract Work in unfavorable, changing environmental conditions negatively affects people working on scaffoldings used on construction sites, which may increase the risk of occurrence of dangerous situations. The purpose of this article is to show the scale of temperature changes which workers are exposed to. The paper compares examples of temperature measurements obtained from a metrological station and during tests on scaffoldings located in the Lodz and Warsaw regions. This article also presents the methodology of examining environmental parameters of the surroundings where employees work on scaffoldings. Analysis results show that high temperatures and significant temperature variations frequently occur on the scaffoldings, which leads to a lack of adaptability and consequently to tiredness or decreased alertness. Unfavorable environmental conditions can lead to behaviors which, in turn, can cause accidents.
16 citations
TL;DR: In this article, the durability characteristics of ECC with various fibers such as polypropylene and glass were investigated in view of developing composites with high resistance to cracking, which offer large potential for durable civil infrastructure due to their high tensile strain capacity and controlled micro-crack width.
Abstract: Abstract The durability characteristics of Engineered Cementitious Composites (ECC) with various fibers such as polypropylene and glass were investigated in view of developing composites with high resistance to cracking. ECC offer large potential for durable civil infrastructure due to their high tensile strain capacity and controlled micro-crack width. In this study, fibre volume fractions (0.5%, 1%, 1.5%, and 2%) of both polypropylene and glass fibers varied and durability measures such as a rapid chloride penetration test, sorptivity, water absorption, acid attack, and sulphate attack were measured. Increasing the fiber content up to 1.5% improved the durability properties of ECC. The test results indicate that the glass fiber-reinforced Engineered Cementitious Composites have better durability characteristics than polypropylene fiber-reinforced ECC.
15 citations
TL;DR: Numerical simulations using the explicit finite element system Ls-Dyna reveal that the distance between the barrier and the curb has little impact on the working width of the barrier.
Abstract: Abstract This paper addresses the problem of road safety regarding barrier placement as relative to the curb. A short summary of existing regulations is presented. Numerical simulations using the explicit finite element system Ls-Dyna are shown. In the analysis, variable distance between the barrier and the curb is assumed. The obtained result reveals that the distance has little impact on the working width of the barrier.
15 citations
TL;DR: In this article, a numerical analysis of the tensioning cables anchorage zone of a bridge superstructure is presented, which aims to identify why severe concrete cracking occurs in the vicinity of anchor heads.
Abstract: Abstract Numerical analysis of the tensioning cables anchorage zone of a bridge superstructure is presented in this paper. It aims to identify why severe concrete cracking occurs during the tensioning process in the vicinity of anchor heads. In order to simulate the tensioning, among others, a so-called local numerical model of a section of the bridge superstructure was created in the Abaqus Finite Element Method (FEM) environment. The model contains all the important elements of the analyzed section of the concrete bridge superstructure, namely concrete, reinforcement and the anchoring system. FEM analyses are performed with the inclusion of both material and geometric nonlinearities. Concrete Damage Plasticity (CDP) constitutive relation from Abaqus is used to describe nonlinear concrete behaviour, which enables analysis of concrete damage and crack propagation. These numerical FEM results are then compared with actual crack patterns, which have been spotted and inventoried at the bridge construction site.
14 citations
TL;DR: In this article, a new hybrid Engineered Cementitious Composite (ECC) based on the steel short random fiber reinforcement has been developed to improve the tensile strength of cementitious material and enhance better flexural performance.
Abstract: Abstract This study focuses to develop a new hybrid Engineered Cementitious Composite (ECC) and assesses the performance of a new hybrid ECC based on the steel short random fiber reinforcement. This hybrid ECC aims to improve the tensile strength of cementitious material and enhance better flexural performance in an RC beam. In this study, four different mixes have been investigated. ECC with Poly Vinyl Alcohol (PVA) fiber and PolyPropylene (PP) fiber of 2.0% volume fraction are the two Mono fiber mixes; ECC mix with PVA fiber of 0.65% volume fraction hybridized with steel fiber of 1.35% volume fraction, PP fiber of 0.65% volume fraction hybridized with steel of 1.35% volume fraction are the two additional different hybrid mixes. The material properties of mono fiber ECC with 2.0 % of PVA is kept as the reference mix in this study. The hybridization with fibers has a notable achievement on the uniaxial tensile strength, compressive strength, Young’s modulus, and flexural behavior in ECC layered RC beams. From the results, it has been observed that the mix with PVA fiber of 0.65% volume fraction hybrid with steel fiber of 1.35% volume fraction exhibit improvements in tensile strength, flexural strength, and energy absorption. The PP fiber of 0.65% volume fraction hybridized with steel of 1.35% volume fraction mix has reasonable flexural performance and notable achievement in displacement ductility over the reference mix.
14 citations
TL;DR: Mixed integer linear programming is presented, which enables user to select optimal crew formation under limited resource supply and minimizes project duration and improves renewable resource utilization in construction linear projects.
Abstract: Abstract Production rates for various activities and overall construction project duration are significantly influenced by crew formation. Crews are composed of available renewable resources. Construction companies tend to reduce the number of permanent employees, which reduces fixed costs, but at the same time limits production capacity. Therefore, construction project planning must be carried out by means of scheduling methods which allow for resource constrains. Authors create a mathematical model for optimized scheduling of linear construction projects with consideration of resources and work continuity constraints. Proposed approach enables user to select optimal crew formation under limited resource supply. This minimizes project duration and improves renewable resource utilization in construction linear projects. This paper presents mixed integer linear programming to model this problem and uses a case study to illustrate it.
13 citations
TL;DR: In this article, the impacts of industrial wastewater contamination on the geotechnical properties of clayey soil have been studied in the research presented in this paper, and the results of the tests showed that the contaminant causes an increase of natural moisture content, field unit weight, Atterberg's limits, and maximum dry unit weight.
Abstract: Abstract The impacts of industrial wastewater contamination on the geotechnical properties of clayey soil have been studied in the research presented in this paper. The contaminant in question is industrial wastewater released from Thi-Qar oil refinery as a by-product of production, and the soil samples obtained from Thi-Qar oil refinery plant in Al-Nassyriah (a city located in the south of Iraq). The geotechnical properties of contaminated soil samples were compared with those of intact soil to measure the effects of such a contaminant. The soil samples were obtained from three locations in the study area; representing the highly contaminated area, the slightly contaminated area, and the intact area used as a reference for comparison of test results. The results of the tests showed that the contaminant causes an increase of natural moisture content, field unit weight, Atterberg’s limits, and maximum dry unit weight, as well as an increase of the compression index and the coefficient of vertical consolidation. Also, the contaminant causes a decrease in specific gravity, the optimum moisture content initial void ratio, the swelling index, the coefficient of permeability, and cohesion between soil particles.
13 citations
TL;DR: The article presents a general linear programming model of the planning of multiple-structure construction projects, as well as various values of each of the parameters that allow us to obtain different planning effects.
Abstract: Abstract The paper presents a method of priority scheduling that is useful during the planning of multiple-structure construction projects. This approach is an extension of the concept of interactive scheduling. In priority scheduling, it is the planner that can determine how important each of the technological and organisational constraints are to them. A planner’s preferences can be defined through developing a ranking list that defines which constraints are the most important, and those whose completion can come second. The planner will be able to model the constraints that appear at a construction site more flexibly. The article presents a general linear programming model of the planning of multiple-structure construction projects, as well as various values of each of the parameters that allow us to obtain different planning effects. The proposed model has been implemented in a computer program and its effectiveness has been presented on a calculation example.
11 citations
TL;DR: A newly developed model used to smoothe out schedules in terms of maintaining crew work continuity is presented and a full description of the algorithm and example usage are presented.
Abstract: Abstract The problem described in this paper deals with construction project scheduling for multi-object projects. The use of the flow shop model allows for quick execution through optimal, simultaneous means of production. The correct order of tasks according to assumed criteria is the subject of a lot of research. In this paper, we have focused on the aspect of multi-project work crews. In practice, we often observe cases where overburdened crews are supported by ones with downtime. This paper presents a newly developed model used to smoothe out schedules in terms of maintaining crew work continuity. A full description of the algorithm and example usage are presented.
10 citations
TL;DR: In this paper, a study has been carried out to determine the effects of additions of shear walls and also the optimum structural configuration of multistory buildings by changing the shear wall locations radically.
Abstract: Abstract Shear walls are the most commonly used lateral load resisting systems in high rises. They have high plane stiffness and strength which can be used to simultaneously resist large horizontal loads while also supporting gravity loads. Hence it is necessary to determine effective and ideal locations of shear walls. Shear wall arrangement must be absolutely accurate, if not, it may cause negative effects instead. In this project, a study has been carried out to determine the effects of additions of shear walls and also the optimum structural configuration of multistory buildings by changing the shear wall locations radically. Four different cases of shear wall positions for G+10 storey buildings have been analyzed by computer application software ETABS. The framed structure was subjected to lateral and gravity loading in accordance with the Indian Standards provision and the results were analyzed to determine the optimum positioning of the shear walls.
TL;DR: Construction risk assessment is the final and decisive stage of risk analysis when highly changeable conditions of works execution are predicted and risk is evaluated in the favorable, moderate, and difficult random conditions of construction.
Abstract: Abstract Construction risk assessment is the final and decisive stage of risk analysis. When highly changeable conditions of works execution are predicted, risk should be evaluated in the favorable, moderate, and difficult random conditions of construction. Given the random conditions, the schedule and cost estimate of the construction are developed. Based on these values, the risk of final deadline delay and the risk of total cost increase of construction completion are calculated. Next, the charts of the risks are elaborated. Risk changes are shown in the charts and are analyzed in the range [1, 0].
TL;DR: In this article, the authors investigated the building information technology BIM in the context of digital buildings, digital infrastructure, digital roads, digital railways, digital cities and digital cities from the perspective of technology challenge, but simply transfiguration of many fields of personal everyday life.
Abstract: Abstract In the paper the topic of Building Information Technology BIM is investigated. It is new in Polish circumstances technology for construction and for building product industry, which contribute to change and develop level of industrialization. Especially challenge raising from the information and introducing IT technology into daily practice is considered to provide changes in construction branch of economy. In Poland there is the hot need of start to introduce BIM as the common technology for owners of assets, facility management, construction entities, design offices, administration officers and many other players relative to construction data and processes. BIM technology introduction, basing on foreign case studies, results in cost savings, control and time reduction of investment processes and some more advantages. The perspective of digital buildings, digital infrastructure, digital roads, digital railways and digital cities is outlined at the perspective of technology challenge, but simply transfiguration of many fields of personal everyday life, where digitalization is already present and with the question when it will be common in professional activity, particularly in civil engineering.
TL;DR: The Probabilistic parameters of construction are identified and described by using the design characteristics model of the structure and the construction technology model, which contain basic probabilistic data for scheduling, cost estimating, and risk assessment of the construction.
Abstract: Abstract Risks pertaining to construction work relate to situations in which various events may randomly change the duration and cost of the project or worsen its quality. Because of possible significant changes of random events, favorable, moderate, and difficult conditions of construction work are considered. It is the first stage of the construction risk analysis. The probabilistic parameters of construction are identified and described by using the design characteristics model of the structure and the construction technology model. The first describes the probabilistic properties of the structure execution’s technology. The second describes the probabilistic properties of the works execution. Both models contain basic probabilistic data for scheduling, cost estimating, and risk assessment of the construction.
TL;DR: In this article, the fasteners linking boards of sheathing with the timber frame were modeled applying shell finite element, with individual material parameters, and the main objective of the paper was the elaboration of the numerical model with high precision of mapping, and, at the same time, diminishing the number of the unknown simplifying the process of the modeling of timber structures.
Abstract: Abstract This paper presents new procedure modeling based on finite element method analysis of wood-framed timber structures. The fasteners linking boards of sheathing with the timber frame both modeled applying shell finite element, with individual material parameters, remain the main objective of this manuscript. Material parameters are obtained from experimental tests and numerical identification. The main objective of the paper is the elaboration of the numerical model with high precision of mapping, and, at the same time, diminishing the number of the unknown simplifying the process of the modeling of timber structures. The new presented method leads to a simplification of analysis of multistory wood-framed multifamily building structures.
TL;DR: In this paper, a method of design moment resistance calculation was presented taking into account that an entire cross-section shall reach its yield stress and a technique of stiffness calculation was investigated investigating the sum of deformations acquired at the bending moment and from shear forces which are transmitted from each beam bolt group.
Abstract: Abstract Cold-formed structure connections utilizing gusset plates are usually semi-rigid. This paper investigates the behaviours of rectangular gusset plates in cold-formed connections of elements whose columns and beams are made with lipped back-to-back C-sections. Methods of calculating strength and stiffness are necessary for such semi-rigid joints. The main task of this paper is to determine a method capable of calculating these characteristics. The proposed analytical method could then be easily adapted to the component method that is described in part 1993-1-8 of the Eurocode. This method allows us to calculate both the strength and stiffness of rectangular gusset plates, assuming that the joint deforms only in plane. This method of design moment resistance calculation was presented taking into account that an entire cross-section shall reach its yield stress. A technique of stiffness calculation was presented investigating the sum of deformations acquired at the bending moment and from shear forces which are transmitted from each beam bolt group. Calculation results according to the suggested method show good agreement of laboratory experimental results of specimens with numerical simulations. Two specimens of beam-to-column connections were tested in the laboratory. Lateral supports were used on the specimens to prevent lateral displacements in order to better investigate the behaviour of the rectangular gusset plate in plane. Experiments were simulated by modelling rectangular gusset plates using standard finite element software ANSYS Workbench 14.0. Three-dimensional solid elements were used for modelling and both geometric and material nonlinear analysis was performed.
TL;DR: In this paper, the authors introduced an investigation into limestone powder waste as a potential microfiller of polymer composites, and the results were compared with those of other materials which can be used as polymer composite microfillers.
Abstract: Abstract The preliminary stage of asphalt mixture production involves the drying and dedusting of coarse aggregates. The most common types of coarse aggregates used are limestone and basalt. In the process of drying and dedusting the dryer filter accumulates large quantities of waste in the form of mineral powder. This paper introduces an investigation into limestone powder waste as a potential microfiller of polymer composites. Physical characteristics such as the granulation the of powder collected from the filter - in terms of the season of its collection and the type of input materials used - were analysed. A scanning electron microscope (SEM) was used for the investigation described within this paper. The obtained results were compared against those of other materials which can be used as polymer composites microfillers.
TL;DR: In this article, the authors examined some durability aspects of ambient cured bottom ash geopolymer concrete (BA GPC) due to accelerated corrosion, sorptivity, and water absorption.
Abstract: Abstract The present study examines some durability aspects of ambient cured bottom ash geopolymer concrete (BA GPC) due to accelerated corrosion, sorptivity, and water absorption. The bottom ash geopolymer concrete was prepared with sodium based alkaline activators under ambient curing temperatures. The sodium hydroxide used concentration was 8M. The performance of BA GPC was compared with conventional concrete. The test results indicate that BA GPC developes a strong passive layer against chloride ion diffusion and provides better protection against corrosion. Both the initial and final rates of water absorption of BA GPC were about two times less than those of conventional concrete. The BA GPC significantly enhanced performance over equivalent grade conventional concrete (CC).
TL;DR: In this paper, the authors present an integrated spatial development planning strategy for the development of the Fort Bema housing estates in the Warsaw district of Bemowo and highlight the relevance of the planning phase for the subsequent in-use (operating) phase.
Abstract: Abstract Insufficient due planning policy in Poland is subject to widespread and justified criticism. This applies to all levels of spatial management. Legal instruments governing spatial planning in Poland are passive - setting out only the legal framework corresponding to a particular area. They regulate what might be developed within its boundaries, however, they do not specify how it is to be accomplished. Therefore, there is a need to develop an integrated spatial development planning, in which also investors and/or stakeholders would be involved. Apart from answering to the question of what is going to be developed, it will also provide a very comprehensive and flexible implementation strategy having regard to different timelines and local amenities (facilities).This paper also brings an example showing how the spatial planning strategy was conducted for the development of the “Fort Bema” housing estates in the Warsaw district of Bemowo. It highlights the relevance of the planning phase for the subsequent in-use (operating) phase.
TL;DR: In order to find the best balance among cost, time, and quality related to construction projects using reinforced concrete in underground structures, a multi-objective mathematical model is proposed and the genetic algorithm NSGA-II is used.
Abstract: Abstract Underground spaces having features such as stability, resistance, and being undetected can play a key role in reducing vulnerability by relocating infrastructures and manpower. In recent years, the competitive business environment and limited resources have mostly focused on the importance of project management in order to achieve its objectives. In this research, in order to find the best balance among cost, time, and quality related to construction projects using reinforced concrete in underground structures, a multi-objective mathematical model is proposed. Several executive approaches have been considered for project activities and these approaches are analyzed via several factors. It is assumed that cost, time, and quality of activities in every defined approach can vary between compact and normal values, and the goal is to find the best execution for activities, achieving minimum cost and the maximum quality for the project. To solve the proposed multi-objective model, the genetic algorithm NSGA-II is used.
TL;DR: The proposed optimum design model yields rational, reliable, and practical designs of RC tension members according to Indian and European standard specifications.
Abstract: Abstract The aim of this study is to find the cost design of RC tension with varying conditions using the Artificial Neural Network. Design constraints were used to cover all reliable design parameters, such as limiting cross sectional dimensions and; their reinforcement ratio and even the beahviour of optimally designed sections. The design of the RC tension members were made using Indian and European standard specifications which were discussed. The designed tension members according to both codes satisfy the strength and serviceability criteria. While no literature is available on the optimal design of RC tension members, the cross-sectional dimensions of the tension membersfor different grades of concrete and steel, and area of formwork are considered as the variables in the present optimum design model. A design example is explained and the results are presented. It is concluded that the proposed optimum design model yields rational, reliable, and practical designs.
TL;DR: In this article, the authors investigated the behavior of axially-loaded tubular columns filled with M20 grade concrete and partially replaced concrete and found that an increase in the L/D ratio decrease the behaviour of the composite columns irrespective of the in filled materials.
Abstract: Abstract This paper investigates the behaviour of axially-loaded tubular columns filled with M20 grade concrete and partially replaced concrete. The parameters varying in the study are slenderness ratio (13.27, 16.58 & 19.9), and normal M20 grade concrete, partially replaced quarry dust and concrete debris. The effects of the various concrete mixes and composite action between the steel tube and the concrete core are studied and a graph visualizing the differences between the load carrying capacity and the axial deflection is plotted. Some of the performance indices like the Ductility Index (DI), Concrete Contribution Ratio (CCR), Confinement Index (θ) and Strength Index (SI) are also evaluated and compared amongst the CFST columns. From the results it has been noted that an increase in the L/D ratio decrease the behaviour of the composite columns irrespective of the in filled materials. The composite action was achieved in the CFST columns filled with partially replaced quarry dust and concrete debris when compared with hollow steel columns. The load carrying capacity of the CFST column increases by 32 % compared with the hollow tubular columns.
TL;DR: It can be stated that both methods of joint modelling recommended in this paper, can be applied in engineering practices.
Abstract: Abstract This paper concerns an approach to model the ledger-stand joints of modular scaffolds. Based on the analysis of the working range of the ledger (represented by a linear relationship between load and displacement), two models of the ledger-stand joint are analysed: first - with flexibility joints and second - with rigid joints and with a transition part of lower stiffness. Parameters are selected based on displacement measurements and numerical analyses of joints, then they are verified. On the basis of performed research, it can be stated that both methods of joint modelling recommended in this paper, can be applied in engineering practices.
TL;DR: The aim of the presented paper is to show the results of shape optimization of railway polynomial transition curves (TCs) of 5th, 7th, and 9th degrees through the use of the full vehicle model and new criteria of assessement concerning the jerk value.
Abstract: Abstract The aim of the presented paper is to show the results of shape optimization of railway polynomial transition curves (TCs) of 5th, 7th, and 9th degrees through the use of the full vehicle model and new criteria of assessement concerning the jerk value. The search for the proper shape of TCs means that in this work, the evaluation of TC properties is based on select quantities and the generation of such a shape through the use of mathematically understood optimization methods. The studies presented have got a character of the numerical tests. For this work, advanced vehicle models describing dynamical track-vehicle and vehicle-passenger interactions as well as optimization methods were exploited. In the software vehicle model of a 2-axle freight car, the track discrete model, non-linear descriptions of wheel-rail contact are applied. This part of the software, the vehicle simulation software, is combined with a library optimization procedure into the final computer program.
TL;DR: This article aims to identify which factors have the greatest impact on the allocation of a section of road to the corresponding SFG, based on short-term measurements, using models of artificial neural networks, discriminatory analysis.
Abstract: Abstract The characteristics of seasonal variations in traffic volumes are used for a variety of purposes, for example to determine the basic parameters describing annual average daily traffic – AADT, and design hourly volume – DHV, analyses of road network reliability, and traffic management. Via these analyses proper classification of road sections into appropriate seasonal factor groups (SFGs) has a decisive influence on results. This article, on the basis of computational experiments (models of artificial neural networks, discriminatory analysis), aims to identify which factors have the greatest impact on the allocation of a section of road to the corresponding SFG, based on short-term measurements. These factors are presented as qualitative data: the Polish region, spatial relationships, functions of road, cross-sections, technical class; and quantitative data: rush hour traffic volume.
TL;DR: Wang et al. as mentioned in this paper analyzed the feasibility and energy conservation properties of cleaning air-conditioning technology in operating rooms, proposed some solutions to the problem, and performed a feasible simulation, which provides a reference for practical engineering.
Abstract: Abstract This study aims to design a novel air cleaning facility which conforms to the current situation in China, and moreover can satisfy our demand on air purification under the condition of poor air quality, as well as discuss the development means of a prototype product. Air conditions in the operating room of a hospital were measured as the research subject of this study. First, a suitable turbulence model and boundary conditions were selected and computational fluid dynamics (CFD) software was used to simulate indoor air distribution. The analysis and comparison of the simulation results suggested that increasing the area of air supply outlets and the number of return air inlets would not only increase the area of unidirectional flow region in main flow region, but also avoid an indoor vortex and turbulivity of the operating area. Based on the summary of heat and humidity management methods, the system operation mode and relevant parameter technologies as well as the characteristics of the thermal-humidity load of the operating room were analyzed and compiled. According to the load value and parameters of indoor design obtained after our calculations, the airflow distribution of purifying the air-conditioning system in a clean operating room was designed and checked. The research results suggested that the application of a secondary return air system in the summer could reduce energy consumption and be consistent with the concept of primaiy humidity control. This study analyzed the feasibility and energy conservation properties of cleaning air-conditioning technology in operating rooms, proposed some solutions to the problem, and performed a feasible simulation, which provides a reference for practical engineering.
TL;DR: In this paper, the application method of Laplace transform in solving the free vibration problems of continuous beams, having great significance in the proper use of the transform method, is described. But the model is incorrect and the frequency equation derived from the first simplified model contains multiple expressions which might not be equivalent to each other.
Abstract: Abstract Laplace Transform is often used in solving the free vibration problems of structural beams. In existing research, there are two types of simplified models of continuous beam placement. The first is to regard the continuous beam as a single-span beam, the middle bearing of which is replaced by the bearing reaction force; the second is to divide the continuous beam into several simply supported beams, with the bending moment of the continuous beam at the middle bearing considered as the external force. Research shows that the second simplified model is incorrect, and the frequency equation derived from the first simplified model contains multiple expressions which might not be equivalent to each other. This paper specifies the application method of Laplace Transform in solving the free vibration problems of continuous beams, having great significance in the proper use of the transform method.
TL;DR: Two distinct advantages of enhanced versions of standard PSO and GSA, namely, better capability to escape from local optima and a faster convergence rate, have been tested for the hybrid algorithm.
Abstract: Abstract The present study has been taken up to emphasize the role of the hybridization process for optimizing a given reinforced concrete (RC) frame. Although various primary techniques have been hybrid in the past with varying degree of success, the effect of hybridization of enhanced versions of standard optimization techniques has found little attention. The focus of the current study is to see if it is possible to maintain and carry the positive effects of enhanced versions of two different techniques while using their hybrid algorithms. For this purpose, enhanced versions of standard particle swarm optimization (PSO) and a standard gravitational search algorithm (GSA), were considered for optimizing an RC frame. The enhanced version of PSO involves its democratization by considering all good and bad experiences of the particles, whereas the enhanced version of the GSA is made self-adaptive by considering a specific range for certain parameters, like the gravitational constant and a set of agents with the best fitness values. The optimization process, being iterative in nature, has been coded in C++. The analysis and design procedure is based on the specifications of Indian codes. Two distinct advantages of enhanced versions of standard PSO and GSA, namely, better capability to escape from local optima and a faster convergence rate, have been tested for the hybrid algorithm. The entire formulation for optimal cost design of a frame includes the cost of beams and columns. The variables of each element of structural frame have been considered as continuous and rounded off appropriately to consider practical limitations. An example has also been considered to emphasize the validity of this optimum design procedure.
TL;DR: In this article, the authors explored the performance of glass-sand soil to judge the feasibility of backfilled glass sand soil backfilled in the drainage consolidation of sand-drained ground.
Abstract: Abstract The drainage consolidation method has been efficiently used to deal with soft ground improvement. Nowadays, it has been suggested to use a new sand soil which is a composite of sand and recycled glass waste. The permeability performance of glass-sand soil was explored to judge the feasibility of glass-sand soil backfilled in the drainage consolidation of sand-drained ground. For comparison purposes, different mix proportions of recycled glass waste, fineness modulus, and glass particle size were analyzed to certify the impact on the permeability coefficient and the degree of consolidation. The numerical results show that adding a proper amount of recycled glass waste could promote the permeability performance of glass-sand soil, and the glasssand soil drain could be consolidated more quickly than a sand drain. Experiments showed that glass-sand soil with the a 20% mix of recycled glass waste reveals the optimum performance of permeability.
TL;DR: In this article, the ABAQUS finite-element program is used to model the deformation of deformable foundations for a specific system of sandwich beams and plates, separated by an elastic core layer, subjected to the action of point and distributed moving loads.
Abstract: Abstract This paper presents the capabilities of ABAQUS finite-element program [1] in modelling sandwich beams and plates resting on deformable foundations. Specific systems of sandwich beams and plates separated by an elastic core layer were subjected to the action of point and distributed moving loads. A few theoretical examples are provided to present different techniques of modelling the foundations and the moving loads. The effects of the boundary conditions and of the foundation parameters on the deflections of the analysed structures are also presented.