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A neural network modelling of steel joint block shear capacity

A neural network modelling of steel joint block shear capaci...

9th International Conference on the Application of Artificial Intelligence to civil, Structural and Environmental engineering, AIcivil-Comp 2007

作者： Rodrigues, F. Neto, L. Biondi Da S. Vellasco, P.C.G. De Lima, L.R.O. Vellasco, M.M.B.R. Post-Graduate Program in Civil Engineering Brazil Electronic Engineering Department Brazil Structural Engineering Department State University Rio de Janeiro Brazil Electrical Engineering Department Pontifical Catholic University Rio de Janeiro Brazil

ISBN: (纸本)9781905088201

Despite the multiple failure modes associated to bolted steel joints the block shear failure is frequently the controlling limit state of gusset plates, tension members and coped beam joints. The block shear rupture is characterised by a condition where a steel block area, nearby the holes of bolted joint region, reaches its maximum capacity dictated by a tension to shear interaction. If the joint is loaded beyond this limit a steel block is eventually separated from the main structure. Many models have been proposed to avoid shear block failure in steel design. These models incorporate a combination of the various hypotheses that control the structural rupture. In the majority of cases, it involves a combination of rupture and yielding in the tension and shear planes of the designed joint. Various design formula for this structural engineering problem were proposed all over the years but a closed solution has not yet been reached, due to the influence of several independent parameters. Many studies have already been carried out with the available experimental data, however, non negligible errors are still present in the current design formulae. The main objective of the present paper is to present a back propagation neural network evaluation of the block shear phenomenon. The main neural network input parameters were the geometrical and material variables that control the block shear design. The neural network output parameter was the block shear capacity. The neural network training was based on experimental results present in literature and adopted cross validation techniques to avoid the neural network overfitting. The neural network results were promising, with reduced associated errors and confirmed the possibility of using this methodology to generate trustworthy data. These new data, coupled with the existent experiments, can help the production of more accurate design formulae. © civil-Comp Press, 2007.

关键词： Neural networks

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Acoustic performance of closing panels used in steel-structured buildings

Acoustic performance of closing panels used in steel-structu...

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18th International Congress on Sound and Vibration 2011, ICSV 2011

作者： Ribas, Rovadávia A.J. Souza, Henor A. Civil Engineering Post-Graduate Program Universidade Federal de Ouro Preto Escola de Minas Campus Morro do Cruzeiro 35400-000 Ouro Preto - MG Brazil

ISBN: (纸本)9781618392596

In this research, it was made the evaluation of the acoustic performance of some closing systems mostly used in steel-structured buildings in Brazil, for instance walls made of the cement plates, precast concrete panels and plasterboard walls. The acoustic performance was evaluated by estimating the sound transmission loss that occurs through them using a simplified graphical method. It was studied the performance of these kinds of panels and their combinations forming double panels, with and without sound-absorbing material between them. Copyright © (2011) by the International Institute of Acoustics & Vibration.

关键词： Precast concrete

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Finite element modelling of steel beams with web openings

Finite element modelling of steel beams with web openings

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11th International Conference on civil, Structural and Environmental engineering Computing, civil-Comp 2007

作者： Rodrigues, F. Da Vellasco, P.C.G.S. De Lima, L.R.O. De Andrade, S.A.L. Da Silva, J.G.S. Post-Graduate Program in Civil Engineering State University of Rio de Janeiro Brazil Structural Engineering Department State University of Rio de Janeiro Brazil Mechanical Engineering Department State University of Rio de Janeiro Brazil

ISBN: (纸本)9781905088157

Height limitations are frequent in multi-storey buildings due to zoning regulations, economic requirements and esthetical considerations. On the other hand, substantial spaces are normally required to enable the passage of large pipes and ducts beneath steel beams leading to uneconomic floor heights. The most adopted solution is the use of holes at the steel beam webs in order to enable the passage of services. Chung et al. [1], [3] state that nowadays services that require web openings up to 75% of the beam height are not uncommon. These openings could lead to a significant decrease of the beam load carrying capacity depending on the adopted holes shape, size and location. This motivated the present study that used finite elements simulations to quantitative and qualitative evaluates the structural behaviour of steel beams with web openings. This paper presents the developed finite element models using the ANSYS [6] program to investigate the structural response of steel beams with web openings. The analysis incorporated geometric and material non-linearities and were calibrated against numerical and test results to validate the proposed finite element models. The investigation also contemplated the simulations of beams with a series of holes distributed all over their length known as cellular beams. The imulations were centred at the evaluation of the different steel beams with web penings failure mechanisms and the main reasons for yours collapse modes. © 2007 civil-Comp Press.

关键词： Finite element method

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Experimental evaluation of composite tubular columns CFDST (Stainless steel-concrete-carbon steel) 9

Experimental evaluation of composite tubular columns CFDST (...

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9th International Conference on Advances in Steel Structures, ICASS 2018

作者： Rodrigues, Pedro F. da Vellasco, Pedro C. G. S. de Lima, Luciano R.O. da Silva, André T. Rodrigues, Monique C. Sarmanho, Arlene M.C. Civil Engineering Post-Graduate Program State University of Rio de Janeiro UERJ Rio de Janeiro Brazil Structural Engineering Department State University of Rio de Janeiro UERJ Brazil Civil Engineering Department Federal University of Ouro Preto UFOP Brazil

ISBN: (纸本)9889914093

This paper is centred on the structural response of double skin composite columns made of two concentric tubes of stainless and carbon steels filled with concrete. These structural solutions can be used in new structures or even in cases where a reinforcement or retrofit is required to enhance their corrosion resistances or structural capacities. An experimental programme was conducted to investigate this innovative structural system by means of comparisons to standard concrete encased tubular steel stub columns. The experimental results widened their applications to cases where a high reserve of post-collapse resistance is required like in seismic design. An assessment of the Eurocode 4 predictions for these tubular columns indicated the design prediction formulae are too conservative, partly explained by the lack of consistent numerical and experimental results that could enable a better design calibration. Copyright © 2018 by The Hong Kong Institute of Steel Construction.

关键词： Tubular steel structures

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The Behavior of Recycled Concrete through the Application of an Isotropic Damage Model

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Open Journal of civil engineering 2015年第3期5卷 339-351页

作者： Marcelo Pedreira da Silva Magno Teixeira Mota Anderson de Souza Matos Gadea Monica Batista Leite Koji de Jesus Nagahama Civil and Environmental Engineering Post-Graduate Program State University of Feira de SantanaFeira de SantanaBrazil

The main goal of this paper is to describe the mechanical behavior of the CDW recycled concrete in compression, using an isotropic damage model adapted to the variation of the replacement rate of natural aggregates by recycled ones. The isotropic model by Mazars was used as a constitutive equation for the CDW concrete and its adjustment parameters, A and B, were written as quadratic polynomials according to the aggregates replacement rate. The model was evaluated for conventional and recycled concretes. For the latter ones, the aggregates replacement ratios evaluated were 50% and 100%. The results show good approximation between the analytical and numerical values obtained with the adapted isotropic damage model and experimental concrete results for both compressive and flexural strength.

关键词： Recycled Concrete Construction and Demolition Waste Isotropic Damage Mazars Isotropic Model

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Bioclimatic Architecture in Warm Climates 1

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1000年

作者： Manuel Correia Guedes Gustavo Cantuaria

ISBN: (数字)9783030120368

ISBN: (纸本)9783030120351;9783030120382

This book provides a comprehensive, hands-on approach to bioclimatic building design in Africa. Bioclimatic design is at the core of urban sustainability, and is a critical issue in Africa, where “imported” building typologies are being used at an increasing pace, disregarding the local context and consequently causing damage to the environment, to the economy, and to the culture itself. This book provides a concise set of sustainable design guidelines to be applied in both new buildings and the refurbishment of old buildings, and integrates bioclimatic design strategies with other sustainability issues such as: cultural aspects, affordability, and urban planning. Chapters are fully illustrated with photographs and drawings and include best-practice examples and strategies making it accessible to engineers, architects, students and a broad range of professionals in the building industry.

关键词： Renewable and Green Energy Building Construction and Design Building Physics, HVAC Sustainable Development

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Spatial pattern of sediment transport for analysis of precipitation direction and magnitude in the upper Lematang river sub-basin 4

Spatial pattern of sediment transport for analysis of precip...

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4th Geomatics International Conference 2019, GeoICON 2019

作者： Sarino Yuono, Agus Lestari Putranto Dinar, D.A. Civil Engineering and Planning Study Program Faculty of Engineering University of Sriwijaya Jl. Raya Inderalaya Km. 32 Ogan Ilir Regency Inderalaya South Sumatera Province Indonesia Civil Engineering Post Graduate Study Program Faculty of Engineering University of Sriwijaya Jl. R. Soeprapto Bukit Besar Palembang City South Sumatera Province Indonesia

The high level of erosion that occur in Musi river basin has improved a tremendous impact on sedimentation in downstream areas and has resulted in many infrastructure of water is disturbed, such as silting of irrigation channels, siltation of rivers which disrupt the flow of transport stream and increasing the risk of flooding, high sedimentation in the port basin, low quality of water and the rising costs of water treatment. This study utilizes techniques terrain models Digital (Digital Elevation Model/DEM) to analysis the spatial distribution of the potential for erosion and sources of sedimentation, as well as the direction of the flow of sediment into channels as well as its relationship with outlet in branching river as the supplies to be sediment to the river flow. The method used in this study using a spatial model analysis with the help of GIS in analysing and presenting the level of erosion and deposition by utilizing modelling slope and kinetic energy of rainfall to estimate the index erosivity and distribution pattern of sediment into the river channel. This research was conducted at the upper Lematang river sub basin with area 412,638 Ha, which are classified into 11 sub-chatments with the highest altitude is 3.159 m above sea level (Dempo Valley) and the lowest is 126 m above sea level (Talang tinggi Valley). Analytical results have been tested by taking a fine sediment sampling in each sub-watershed in the analysis and is taken along the channel network and compare the observed patterns with the results predicted by the model analysis of soil erosion. Overall, erosion by high intensity tends to occur in the relationship between the different vegetation coverage, the barren land and open land used for farms and land used for mining. Approximately 45-65.5% slope bad condition because the vegetation has been open, so it can be seen the amount of erosion in the area is 2.139 ton/ha/year, at the sloping is 1.8239 ton/ha/year. © 2019 Published under licence

关键词： Erosion

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Assessment of Stainless Steel Tubular T-joints Under Chord Sidewall Failure Mode by a Semi-analytical Formulation

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ce/papers 2022年第4期5卷 574-583页

作者： Nogueira, Mateus M. de Lima, Luciano R. O. da S. Vellasco, Pedro C. G. Young, Ben PGECIV - Civil Engineering Post-Graduate Program UERJ – State University of Rio de Janeiro Brazil Structural Engineering Department UERJ – State University of Rio de Janeiro Brazil Department of Civil and Environmental Engineering The Hong Kong Polytechnic University Hong Kong

There are numerous benefits of tubular profiles that make them increasingly used in civil engineering. At the same time, stainless steel is a material with excellent properties and high corrosion resistance. However, stainless steel's high initial material cost has limited its use primarily to specialist and prestige applications, which makes it necessary to develop more accurate design rules for this material. When tubular profiles are used, it is necessary to assess the joint strengths, considering that they can fail by different mechanisms. The present work aims to develop a semi-analytical formulation to predict stainless steel tubular T-joint resistances. Joints with the brace-to-chord width ratio equal to 1 were considered in this study;therefore, the failure occurs in the chord sidewall. To assess the sidewall instability critical load, the exact stress fields were determined using Mathieu's theory, and then the Ritz energy method was applied. Considering that the joints are made of stainless steel, the next step is to transform the load found from linear to the non-linear regime. For that, a new formulation based on Ramberg-Osgood equations was developed. Finally, the results obtained from the proposed method were compared with the experimental results obtained by Feng and Young (2008) and the results from the main current standards and literature. It was observed that the proposed method presented satisfactory results, while the predictions from design codes were, in general, very conservative. © 2022 Ernst & Sohn GmbH.

关键词： Failure (mechanical)

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Effect of treatment of sisal fiber on morphology, mechanical properties and fiber-cement bond strength

Effect of treatment of sisal fiber on morphology, mechanical...

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作者： Santos, Rogério De Jesus Lima, Paulo Roberto Lopes Post-graduate Program of Civil and Environmental Engineering Department of Technology State University of Feira de Santana Av. Transnordestina S/N-Novo Horizonte Feira de Santana Bahia44036-900 Brazil

The dimensional instability of vegetable fibers due to hygroscopicity results in a gradual loss of adherence in cement based composites which, when in service, are submitted to a natural variation of humidity. Such an effect reduces the contribution of the fiber as a reinforcement and can cause the early rupture of the material. In this work, a treatment of the sisal fibers is performed with the applying of wetting-drying cycles in order to alter their crystalline structure and improve the dimensional stability of the fiber to withstand the variation of humidity: 6, 10, 20, 30 and 34 cycles were applied in order to evaluate the effect on the properties of fiber;a tensile test, the morphological characterization (MEV) and the evaluation of the chemical structure of fiber were carried out. The effect of the treatment on fiber-matrix behavior was evaluated using the pull-out test. Embedded lengths of 16, 20, 30, 40 and 44 mm were defined through a factorial design and used in the test. It is verified that the use of 10 wetting-drying cycles causes less damage to the tensile strength and the elastic modulus of the fiber and contributes to a better adherence with the matrix, with an increase of up to 23 % compared with the untreated fiber. The statistical analysis of the interaction effect between the studied factors, using 2K factorial design with central composite design, indicates that the number of cycles can be decreased when using a longer length of the embedded fiber. © (2015) Trans Tech Publications, Switzerland.

关键词： Tensile strength

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Numerical assessment of stainless steel tubular T-joints subjected to brace and chord axial forces

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ce/papers 2021年第2-4期4卷 2495-2503页

The utilisation of tubular sections in steel structures has increased significantly worldwide. The use of stainless steel provides several benefits for structures, including high corrosion resistance, durability, fire resistance and ease of maintenance. A significant issue in the design of tubular structures is the joints failure since they are highly susceptible to local failures that influence their actual overall behavior. The design rules of welded carbon steel tubular joints are available, such as Eurocode 3, part 1-8, NBR 16239, ISO 14346 and CIDECT guides. When stainless steel tubular joints are considered, the AS/NZS 4673 Australian/New Zealand Standard is the only available specification that can be used. An experimental and numerical analysis of these tubular joints are recommended since they enable a more accurate evaluation of their structural performance. Concerning these aspects, this work aims to investigate stainless steel tubular T-joints fabricated by SHS and RHS cold-formed profiles that focused on the effect of chord pre-loading. For this purpose, a numerical study based on finite element analysis was performed. The finite element model was developed and calibrated against experiments. The results were subsequently compared with the aforementioned design predictions. © 2021 Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH & Co. KG, Berlin.

关键词： Finite element method

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