Areas Of Civil Engineering Research Articles

Virtual mix design: Prediction of compressive strength of concrete with industrial wastes using deep data augmentation

The adding of industrial wastes, including blast furnace slag and fly ash, to concrete materials will not only improve the working performance, but also significantly reduce the carbon emissions and promote the green development in civil engineering area. The traditional material designs are mainly indoor laboratory-based, which is complex and time-consuming. In this study, a virtual material design method, including deep data augmentation methods and deep learning methods, was employed to predict the compressive strength of concrete with industrial wastes. Three types of Generative Adversarial Networks (GANs) were employed to augment the original data and the results were evaluated. The test was conducted based on a small experiment dataset from previous literature, comparing with traditional machine learning methods. Test results show that the deep learning methods have the highest accuracy in compressive strength prediction, increasing from 0.90 to 0.98 (Visual Geometry Group, VGG) and from 0.83 to 0.96 (One-Dimensional Convolutional Neural Network, 1D CNN) after deep data augmentation, where the prediction accuracy of Random Forest (RF) and Support Vector Regressive (SVR) in traditional machine learning algorithms increase from 0.91 to 0.96 and from 0.78 to 0.86, respectively. In addition, a lightweight deep convolutional neural network was designed based on the augmented dataset. The results show that the lightweight model can improve the computation efficiency, reduce the complexity of the model compared with the original model, and reach a great prediction accuracy. The proposed study can facilitate the concrete material design with industrial wastes with less labor and time cost compared with traditional ones, thus can provide a cleaner solution for the whole industry.

Mineral admixtures utilization in different areas: A review

Nowadays, the electricity required in the developing countries are mostly dependent on Coal-Based thermal Power plants. During the course of production of electricity, the solid waste residue namely Fly Ash (FA), which is left behind causes serious impact to the environment. On the other hand, another residue, Ground Granulated Blast Furnace Slag (GGBS) which is produced from the molten iron slag is also disposed on the land surface, resulting which several bad impacts occur on the heath of the environment. Apart from these mineral admixtures, one more such ash namely Rice Husk Ash (RHA) is also produced by the processes of burning of the rice husk itself. Some of the ashes which are directly produced by the burning of hard Bituminous coal together with hard Anthracite give rise to the mineral admixture to be often known as Silica Fume. Metakolin is also another type of Mineral Admixture which is produced by the burning of kaolin clay. In some countries, the production of Palm Tree is so high that electricity is generated there by burning of Palm shell and husk. During production, the residue, which is equally harmful to the environment, is known as Palm Oil Fly Ash (POFA). The problem does not lie with alone; the major issues is of storage of all these mineral admixtures. In most of the countries these solid waste mineral admixtures are placed on a large open area of the land. Such mineral admixtures are toxically associated with heavy metals which cause to leach the ground water and the soil as well. But researchers have found that these mineral admixtures being considered as solid waste, are, in fact, very useful materials and have also proven their worth over a period of time. This paper aims at focusing on the various ways of utilizing the different Mineral Admixtures in various areas of Civil Engineering. Also in the paper, there is strategical focus on the proper management of mineral admixtures to make use of these solid wastes, in order to save our Environment.

Compressive strength prediction of fly ash-based geopolymer concrete via advanced machine learning techniques

Concrete is a widely used construction material, and cement is its main constituent. Production and utilization of cement severely affect the environment due to the emission of various gases. The application of geopolymer concrete plays a vital role in reducing this flaw. This study used supervised machine learning algorithms, decision tree (DT), bagging regressor (BR), and AdaBoost regressor (AR) to estimate the compressive strength of fly ash-based geopolymer concrete. The coefficient of determination (R2), mean absolute error, mean square error, and root mean square error were used to evaluate the model's performance. The model's performance was further confirmed using the k-fold cross-validation technique. Compared to the DT and AR model, the bagging model was more effective in predicting results, with an R2 value of 0.97. The lesser values of the errors (MAE, MSE, RMSE) and higher values of the R2 were the clear indications of the better performance of the model. Additionally, a sensitivity analysis was conducted to ascertain the degree of contribution of each parameter towards the prediction of the results. The application of machine learning techniques to predict concrete's mechanical properties will benefit the area of civil engineering by saving time, effort, and resources.

World Multidisciplinary Civil Engineering-Architecture-Urban Planning Symposium - WMCAUS 2021

The current “IOP Conference Series: Material Science and Engineering” volume includes papers presented in the capital city of the Czech Republic, Prague for the 6th Anniversary of the “World Multidisciplinary Civil Engineering-Architecture-Urban Planning Symposium” from 30 August to 3 September 2021. The purpose of the WMCAUS 2021 is to give a place to converse and consider the current data, discoveries, and mechanics in various areas of Civil Engineering, Architecture, and Urban Planning, to provide favourable circumstances for forthcoming cooperation. It is a stage for contributing information and skills in the areas of Civil Engineering, Architecture, and Urban Planning by arranging a conference for researchers at the beginning of their career and letting them present their findings, and leave them space to discuss it with for the presentation of their work and discussion of their ideas with specialists in diverse fields of Civil Engineering, Architecture, and City and Urban Planning.The designed period for WMCAUS 2021 was from the 14th of June till the 18th of June 2021. Nevertheless, it was deferred to 30 August till 3 September 2021 due to the Covid-19 pandemic and therefore was held in Prague in person to match participants' needs.All the missions of the World Multidisciplinary Civil Engineering-Architecture-Urban Planning Symposium – WMCAUS 2021 were achieved, and 285 peer-reviewed articles were published. The team of the WMCAUS would like to give thanks to all reviewers for their great work and for the high quality of articles that were published.List of Editors of WMCAUS 2021, Committee WMCAUS 2021 are available in this pdf.

Deep void detection with 3D full waveform inversion of surface-based and in-depth source seismic wavefields

Detection of subsurface voids using nondestructive seismic methods is an ongoing problem in many areas of civil and environmental engineering (e.g., sinkholes and caves), homeland security (e.g., tunnel detection), and mining applications (e.g., abandoned mines). Recent advances in 3D full waveform inversion (FWI) technology have made it possible to scan large volumes of the underlying materials efficiently, providing a glimpse into the state of subsurface conditions. A challenge in applying 3D FWI methods to the detection of voids emerges from their embedment depths. Shallower voids are easier to detect due to their large signature on the surface seismic response, whereas deeper voids have a much smaller signature and are therefore much harder to detect. This is not a limitation of the FWI method, but rather that of the seismic field-testing techniques and data gathering processes. The goal of this study is to investigate ways to overcome these limitations and improve void detection depths. One way to achieve this is through the application of a large surface source, generating more energy at lower frequencies (longer wavelengths), thereby increasing the penetration depth. Another way is by increasing the contribution of body waves and utilizing the diffraction/transmission information embedded in the waveforms. The latter is achieved through the application of a recently developed SPT-seismic method, where the standard penetration test (SPT) device is used to generate wave motion from within the subsurface. Both source methods and a newly developed 3D Gauss-Newton FWI method are utilized here to detect a deep void (25–45 m depth) in limestone, on the southern peninsula of Florida. The results are compared with SPT and Sonar profiles obtained from the test site. Overall, a good image of the deep void is achieved, matching observations from the invasive results. The findings provide useful insight into the application of FWI technology for detecting deep subsurface voids and anomalies that are typically hard to identify.

Numerical Modeling of Soil Erosion with Three Wall Laws at the Soil-Water Interface

In the area of civil engineering and especially hydraulic structures, we find multiple anomalies that weakens mechanical characteristics of dikes, one of the most common anomalies is erosion phenomenon specifically pipe flow erosion which causes major damage to dam structures. This phenomenon is caused by a hole which is the result of the high pressure of water that facilitate the soil migration between the two sides of the dam. It becomes only a question of time until the diameter of the hole expands and causes destruction of the dam structure. This problem pushed physicist to perform many tests to quantify erosion kinetics, one of the most used tests to have logical and trusted results is the HET (hole erosion test). Meanwhile there is not much research regarding the models that govern these types of tests. Objectives: In this paper we modeled the HET using modeling software based on the Navier Stokes equations, this model tackles also the singularity of the interface structure/water using wall laws for a flow turbulence. Methods/Analysis: The studied soil in this paper is a clay soil, clay soil has the property of containing water more than most other soils. Three wall laws were applied on the soil / water interface to calculate the erosion rate in order to avoid the rupture of such a structure. The modlisitation was made on the ANSYS software. Findings: In this work, two-dimensional modeling was carried of the soil.in contrast of the early models which is one-dimensional model, the first one had shown that the wall-shear stress which is not uniform along the whole wall. Then using the linear erosion law to predict the non-uniform erosion along the whole length. The previous study found that the wall laws have a significant impact on the wall-shear stress, which affects the erosion interface in the fluid/soil, particularly at the hole's extremes. Our experiment revealed that the degraded profile is not uniform. Doi: 10.28991/cej-2021-03091742 Full Text: PDF

Soil bioengineering in northeastern Brazil: An Overview

This article presents an overview of the application of soil bioengineering techniques, also modeled as natural engineering, in the state of Sergipe, northeastern Brazil, showing the importance of integrating living and inert elements to protect river banks from erosion. The employed techniques are different, ranging from the characterization of susceptibility to erosion to the use of biotechniques, considering knowledge in the areas of agronomic engineering, forestry engineering, civil engineering, biology, pedology, geology, geomorphology and geotechnics. It is an approach that uses techniques and methodologies in a multidisciplinary way, seeking to maximize synergies (for example, natural engineering techniques to combine inert materials in ways that help plants to develop increasingly efficient systems). This approach also considers maintenance-cost optimization in the conduction of the works, using different materials, differing from traditional engineering, which uses predominantly inert materials. The research work carried out in different locations sought the availability of local materials such as rocks, geotextiles made from fibers from the native flora or even available on the market, in addition to the use of native species to recovery of the banks or slopes, according to the ecological conditions of the northeastern Brazil. Size and technological and ecological reach were also considered, in addition to different biotechnical aesthetic objectives adapted to different situations.

Preface

International Conference on Contemporary and Sustainable Infrastructure (ICCSI-2021), 21st & 22nd May 2021, SJB Institute of Technology, Bangalore, Karnataka, India This volume of the IOP Conference Series: Earth and Environmental Science (EES) contains papers presented at the International Conference on Contemporary and Sustainable Infrastructure, which took place on the 21st & 22nd of May 2021, at the SJB Institute of Technology, Bangalore, Karnataka, India.In view of the COVID-19 pandemic, a complete lockdown was imposed by the Indian Government. Public gatherings were strictly restricted and treated as a high offence by the task force not only within the country, but world over. Travel was completely banned in India. Therefore, in order to abide by the government rules and to not risk the lives of the public, the conference was held online through “Microsoft Teams”. The platform conveniently provided the facilities of seamless and uninterrupted interactions amongst all the conference participants which involved researchers and speakers from different parts of the world coming together under one roof to conduct the event as per planned to avoid postponement. Conducting it offline was not a viable option as it would be possible only after the pandemic, causing a long delay, which can be easily prevented through a virtual meeting. We are delighted to announce that the all the conference proceedings were successfully executed through the will and co-operation of all its organizers, hosts, participants and all other contributors.The ICCSI Proceedings presents novel and original works undertaken in the area of Civil engineering and its applications by experts and budding researchers, across the world. This conference provided opportunities for researchers to exchange new ideas and application experiences to establish research relations and to find global partners for future collaboration. It covers a variety of topics, including Sustainable Design and Materials, Advanced Composites in Construction, Advanced Computational Mechanics, Repair and Rehabilitation, Construction Technology and Management, Earthquake Engineering, Soil Mechanics and Geotechnical Engineering, Environmental Issues and Safety, Water resource and Management, Construction Safety, Geospatial Technology, Disaster Management, Transportation and Highway Technology. It proved to be a common sharing ground for the researchers, engineers and academicians from all over the world to present their research results and development activities based on these domains.List of Chief Patron, Patrons, General Chair, Convener, Publication Chair, Publication Co-Chair, Organizing Chair, Technical Committee Chair, Advisory Committee, Technical Program Committee, Registration Committee, Finance Committee, Publicity Committee are available in this pdf.

Spent ground coffee – awaking the sustainability prospects

This paper outlines the threat of spent coffee ground (SCG) towards environmental health and some promising remedial efforts carried out by the scientific community working against it. To maintain human and earth wellbeing, massive biowastes left behind by the rising popularity of coffee drinking and its processing must be properly addressed. The recent waste to wealth value engineering efforts carried out to repurpose these biowastes are first presented. Some promising applications of SCGs in various prospective civil engineering areas alongside their favorable findings are then summarized. Attributed to beneficial properties as reported in existing studies, silica fume is recommended as the potential constituent to mix with SCG for future construction materials exploration in overcoming both the biowaste and industrial waste issues.

Rompimento de barragens na literatura científica internacional: Uma análise bibliométrica

O rompimento de barragens é um tema que recentemente ganhou destaque na mídia, sobretudo, devido a grandes desastres envolvendo perdas de vidas humanas. Uma análise bibliométrica do tema é oportuna para que se possa sistematizar estudos com embasamento científico para subsidiar medidas de segurança e prevesão deste tipo de acidente. Neste sentido, este trabalho analisou a produção científica internacional sobre rompimento de barragens através de uma abordagem quantitativa que objetivou mensurar a dinâmica bibliométrica do tema no período compreendido entre os anos de 1945 e início de 2021. Foi feita uma pesquisa na coleção principal da base de dados interdisciplinar Web of Science considerando-se como principais critérios o recorte temporal supracitado e a ocorrência da palavra-chave “Dam Break” no título das publicações. Pesquisou-se apenas pela modalidade artigo, publicado na língua inglesa. Os metadados da pesquisa foram baixados no formato de planilha do Excel e foram aplicadas estatísticas descritivas para classificar e quantificar as informações. Os resultados mostram que a ocorrência do tema na literatura internacional só se verifica a partir do ano de 1980, tendo como principal veículo de comunicação o Journal of Hydraulic Research, e o principal país de origem, a China. O total de publicações encontradas foi de 306 artigos, sendo 44 considerados de maior impacto na literatura científica, de acordo com o H-index. Conclui-se que o tema pesquisado vem crescendo em importância nos últimos anos com o aumento do número de publicações, principalmente nas áreas de Recursos Hídricos e Engenharia Civil, a partir do ano de 2006.

Prediction of Joint Shear Strength of RC Beam-Column Joint Subjected to Seismic loading using Artificial Neural Network

BC (Beam-column) joints are critical locations in RC frames subjected to severe earthquake attack. Failure of Joint which is of shear type is not an appreciable structural behaviour. Present study proposes an artificial neural network model for joint shear strength of reinforced exterior BC connections. ANN is a component of artificial intelligence which mimics the human brain characteristics and learns from previous experiences and has recently gained popularity in the area of civil engineering. A dataset of specimen dimensions, material properties, Area of Reinforcement used in Beam and column and failure mode are established from past experimental investigations on BC joints subjected to seismic type loading and are used for ANN modelling. ANN model is developed with eleven input parameters to predict the Joint shear strength of Exterior BC Joints. The Proposed model is compared with the equation given in design codes and empirical formula. Proposed ANN model has predicted the shear strength more accurately. Thus the proposed ANN model can be used for Prediction of Joint shear strength of Reinforced concrete exterior BC joints subjected to seismic loading.
 Keywords— Joint Shear strength, Beam-Column Joint, Artificial neural network

A review of the recent trends on core structures and impact response of sandwich panels

It is a challenging task to advance the excellent strength and structural performance of sandwich structures, while continuing to reduce the weight and cost parameters. Thousands of researchers have studied and developed the core structural innovation with periodical achievements. This review paper concentrates on the core structural trends and impact response of sandwich panels, which highlights the novel design concepts and impact failure modes. Three kinds of core structures have been classified, which are foam-core, two- and three-dimensional periodic cores. It is shown that the core structure of sandwich panels plays a vital role in structural performance and applications. Three common types of loading conditions have been considered, i.e. compression, projectile impact and three-point bending. Examples of novel core structures are further studied and summarised under corresponding impact loadings. Recent applications of sandwich structures are briefly concentrated on aerospace, automotive, marine and civil engineering areas. Furthermore, future research and development prospect of sandwich structures are suggested and predicted.

Subject Review: A Comparison of Lightweight Concrete Made With Sawdust

Lightweight concrete is a very useful and advantageous material in the modern civil industry. It is lighter than normal-weight concrete. This paper investigates the review of the significant applications and advantages of using lightweight concrete in the area of civil engineering. Also, therefore, the use of lightweight concrete has a great impact on developing countries as it permits design flexibility and substantial saving in the cost of construction. In this paper, the background for many experimental studies of lightweight concrete made with sawdust is provided and a comparison between these studies.

Structural design and construction of an office building with laminated bamboo lumber

With so many advantages such as environmental friendliness, fast-growing, high strength-to-weight ratio, sustainability, and the capability of being reused or recycled, bamboo structures has gained more and more attention for scientists. This paper shows the feasibility of the design of an office building using laminated bamboo lumbers in compliance with the Chinese standards as GB50009-2012, GB50011-2010, GB50016-2014, and GB 50005-2017. Detailed information about the materials and building were offered. A lot of related construction photos were offered to show the building process. This case is a very good application example for laminated bamboo lumber buildings and has attracted many engineers’ attention in industrial field. Laminated bamboo lumber structures should have a bright future. It should become one main structure form in civil engineering area. However, due to none existing engineered bamboo structures design standard now, engineers have to take reference to standards for timber structures. Setting up the standard system is very important for engineered bamboo structures’ application. Through more and more scientists’ hard working, it might be not a long way to build the code system.

Preface

The 6th International Conference on Hydraulic and Civil Engineering (ICHCE 2020) is hosted by Shaanxi Society of Geometics and Engineering, Xi’an University of Architecture and Technology, xijing university, Shaanxi Key Laboratory of geotechnical and underground space engineering and Youth Working Committee of shaanxi Institute of Geometics and Engineering, co-organized Xi’an University of Technology, Xi’an Jiaotong University, Hehai University, Chongqing Jiaotong University, Northwest A & F University, Chang’an University, Xi’an University of science and technology, Anhui Jianzhu University, Xi’an University of Technology, Education Committee of the Society of Geomethrology and Engineering of Shaanxi Province, Yulin College, Northern University of Technology, Xi’an Petroleum University, China First Highway Survey and Design Research Institute Co., Ltd, China Power Engineering Consultants Northwest Power Design Institute, Xi’an Research Institute, China Coal Science and Technology Group, China Railway First Survey and Design Institute, Northwest Survey and Design Research Institute of China Hydropower Consulting Group. The conference was successfully held during December 11th to 13th, 2020 at Xi’an China. It mainly focused on the research fields of water conservancy and civil engineering, and is dedicated to provide the experts, scholars, engineers, etc. from different colleges and universities, research institutes, enterprises and institutions from home and abroad, with an academic platform for sharing of academic research findings, exploration of the cutting-edge engineering issues and discussion on the current opportunities and challenges, in a concerted effort to promote international cooperation and communication and the industrialization of scientific research results.The conference model was divided into two sessions, including oral presentations and keynote speeches. In the first part, some scholars, whose submissions were selected as the excellent papers, were given 15 minutes to perform their oral presentations one by one. Then in the second part, keynote speakers were each allocated 30-45 minutes to hold their speeches.There were over 130 experts and scholars in the area of Hydraulic and Civil Engineering representing different famous universities and institutes around the globe to attend the conference. During the conference, we were pleased to invite six distinguished experts to present their insightful speeches. Jianping Zhou, Chief engineer of China Power Construction Group Co., Ltd. His report title: Current situation and future development trend of hydropower in the world. Hongwei Wu, Associate vice president, Hong Kong University of science and technology, held a speech: Theory and technology of vegetation slope protection based on unsaturated soil mechanics. Chongshi Gu, Dean of School of water conservancy and hydropower, Hohai University, shared a speech on his specialty related to Theory and method of disease mechanism and health diagnosis of major water projects. Shengshui Chen, President of Nanjing Institute of water resources, talked about Key technical problems and Countermeasures of Dashixia extra high concrete face sand gravel dam. The others keynote speakers, Prof. Deyi Wu from Anhui Jianzhu University and Prof. Liaojun Zhang from Hohai University also presented a wonderful speech.The participants of the conference were from most part of the world, with background of either academia or industry, even well-known enterprise. The success and prosperity of the conference is reflected high level of the papers received. The proceedings are a compilation of the accepted papers and represent an interesting outcome of the conference. (ICHCE 2020) for exchange of research findings, analysis, information, and knowledge in areas which include but are not limited to: Water Project, Civil Engineering, Geotechnical Engineering, Traffic and Bridge Engineering, Disaster Prevention and Mitigation and Protection Engineering and other related topics.We would like to acknowledge all of those who supported ICHCE 2020. Each individual and institutional help were very important for the success of this conference. Especially we would like to thank the organizing committee for their valuable advices in the organization and helpful peer review of the papers. We sincerely hope that ICHCE 2020 will be a forum for excellent discussions that will put forward new ideas and promote collaborative researches. We are sure that the proceedings will serve as an important research source of references and the knowledge, which will lead to not only scientific and engineering progress but also other new products and processes.The Organizing Committee of ICHCE 2020List of Committee member are avalible in the pdf.

Preface

Preface Icsss’19 Proceedings of International Conference on SUSTAINABLE SYSTEMS AND STRUCTURES 15-16, November 2019 (Sponsored by AICTE, New Delhi) INTRODUCTION It gives me immense pleasure in writing the preface for the proceedings of The International Conference on Sustainable Systems and Structures (ICSSS’19) that was organised during November 15-16, 2019 by the Department of Civil Engineering, MVGR College of Engineering (Autonomous), Vizianagaram, 535005, Andhra Pradesh, INDIA. A proposal for GOC (Grant for Organising Conference) was submitted by myself Dr P Markandeya Raju, Professor, Department of Civil Engineering, MVGR in 2017. A matching grant of Rs. 5 Lakhs was sanctioned by AICTE, New Delhi (F. No. 67-20/RIFD/GOC/Policy-1/2017 dated 28-02-2019) . The Conference was scheduled to be held in person and organised during November 15th - 16th 2019. The program included Five keynote lectures given by experts in various fields and 37 oral presentations given by renowned Professors, practising engineers and research scholars working in various areas of Sustainable Civil Engineering. All the five invited speakers delivered keynote lectures on topics of their expertise related to recent trends in sustainable Civil Engineering followed by brief interaction. Four technical sessions were organised during which authors made oral presentations followed by question and answer. One best paper was chosen from among the papers presented on each day based on the novelty, presentation and response to questions and the Best paper award were presented. The conference was held in the A/C Auditorium of MVGR. This preface presents an overview of this conference, details of Organising committee members, themes and sub-themes of the conference, review process adopted and schedule of the conference including the details of keynote lectures. An Annexure with details of the Management, College and the Department has been included at the end followed by Photo gallery of the conference.List of About the Conference, Advisory Committee, Chief Patrons,Patron, Members, Technical Advisory Board, International, National, Organizing Committee, Chairman, Organizing Secretary, Coordinators, Members, Conference Themes And Sub-Themes, Review Process, Program Schedule, Annexure and Photos are available in this pdf.

New Perspectives for BIM Usage in Transportation Infrastructure Projects

Although there is already a great amount of scientific literature dealing with the use of building information modeling (BIM) in engineering activities, the majority refer to successful case studies using the usual methods and technology of building construction but rarely bring up the real problems for implementing BIM methodology to the field of transportation infrastructure. It must be also considered that the construction activity is only a part of the infrastructure life and the stakeholder must consider the works of enlargement, renewal, and maintenance of the infrastructure. The purpose of this paper is not only to show a mere review of the existing literature but also present a rational analysis for the use of BIM in different areas of civil engineering. For that purpose, the gathered experience in the use of BIM in civil engineering projects in the final course of Civil Engineering Master Studies in the Civil Engineering School (ETSICCP) at Universidad Politécnica de Madrid were compared with the reported literature. This way, a complete and updated information regarding tendencies, applications, and practice along with limitations and benefits can be presented. The significance of this research relies on the original insight of BIM for civil engineering applications through four case studies. Two of them were focused on construction possibilities and the other two on the possibilities in the exploitation, rehabilitation, and maintenance. The results showed that despite the lack of previous experiences, the use of BIM methodology is possible for activities such as maintenance, managing, or expansion of infrastructure by applying different specific software packages. Among the main problems needing to be addressed are the following: handling of big data files, the integration of new data non-related with the modeled object, and interchange of data without losing information. That proves the need of new more efficient techniques to overcome the challenge of the full use of BIM in the civil engineering field and obtain the mutual advantage of the co-operation of the academic and industrial worlds.

Bolt loosening detection using impedance based non-destructive method and probabilistic neural network technique with minimal training data

For centuries, bolted fastening has been widely used in aerospace, civil and mechanical engineering areas to achieve joining of parts. However, studies have shown that vibration occurs virtually in all dynamic systems such as in machines and structures which seems to be the main cause of bolt loosening. As this can significantly reduce the load bearing capacities of a system, it is important to monitor the state of bolts to ensure safety. In this study, piezoelectric transducer based method known as the electromechanical impedance (EMI) technique with probabilistic neural networks (PNN) was used to identify torque loss of bolts on three bolted structure specimens. The training data from the first specimen was used to predict torque loss of different specimens to evaluate the possibility of the proposed idea. Results show over 90% accuracy with the PNN algorithm designed for this work bringing one step close for the piezoelectric based non-destructive testing technique to be applied to real structures.

Chaos in one-dimensional structural mechanics

Notwithstanding the presence of some books summarizing specific research bodies on structural systems, reviews on nonlinear dynamics and chaos in mechanical systems and structures are quite few. This paper aims at giving a first contribution in this direction, focusing on chaos in one-dimensional structural mechanics, and reviewing fundamental studies and main outcomes obtained for macromechanical systems and applications in classical areas of mechanical, aeronautical and civil engineering. Research material is presented according to a tentatively comprehensive perspective, by suitably framing the overviewed complex dynamic phenomena of a given class of structures within the underlying continuous/reduced modelling context and the regular phenomena from which they ensue. This is a demanding perspective, which also entails leaving a number of important topics aside. Chaos in cable, beam/arch, and coupled cable-beam structures is reviewed, as highlighted in both engineering-oriented studies and theoretically driven ones, paying attention also to some relevant applications.

Numerical Modelling of Unreinforced and Geosynthetic-Reinforced Sandy Soil Cover over Large-Diameter HDPE and PVC pipes

A realistic estimation of load distribution over the buried structures is necessary for proper analysis of pipes/conduit, culverts and tunnel lining. Pipelines are often constructed in the areas of civil engineering, mining engineering, agriculture and some other areas. For the design of pipeline, it is essential to know the load over it. Load distribution over the buried structures has been investigated scientifically during the past several decades. The method of investigation includes experimental, analytical and numerical methods. The finite-element models based on some commercial software have been developed for load analyses for design of the pipeline and buried structures. The geosynthetic is an effective reinforcement layer to reduce the load over the buried structure. Although some small-scale studies have indicated that the geosynthetic layer can reduce the load over the buried structure, the investigation on a large scale is limited. Therefore, in this paper, an attempt is made to investigate the load-distribution behaviour of geosynthetic layer as a reinforcement within the soil cover over the HDPE and PVC pipes. The study has been carried out by developing a numerical model of the problem using the commercial software PLAXIS 3D. The comparison of HDPE and PVC pips shows that the pressure around the PVC pipe is greater than the pressure around HDPE pipe, while pressure around the larger diameter HDPE pipe is lower than the pressure around the smaller diameter HDPE pipe. The pressure on the crown of the pipe decreases with presence of the geosynthetic reinforcement layer; the optimal distance between geosynthetic reinforcement layer and pipe is equal to the pipe diameter. The pressure reductions on the crown of the HDPE and PVC pipes, having a diameter of 914 mm, are 31% and 27%, respectively. The graphical presentations may be used as the design charts for designing the buried pipes.