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12.07: Numerical assessment of stayed austenitic steel columns

ce/papers 2017年第2-3期1卷 3519-3526页

作者： Ribeiro, Danielle M. da S. Vellasco, Pedro C. G. de Araujo, Ricardo R. de Lima, Luciano R. O. da Silva, André T. PGECIV – Civil Engineering Post-Graduate Program State University of Rio de Janeiro – UERJ Brazil Structural Engineering Department State University of Rio de Janeiro – UERJ Brazil Civil Engineering Department Federal Center for Technologic Education Celso Suckow da Fonseca – CEFET/RJ Brazil

The use of prestressed steel stayed columns systems in construction has numerous advantages related to its light weight, load bearing capacity and assembly process flexibility. A practical application of these structural systems could be recently observed in Brazil for the erection of the Rock in Rio III world stage. In this event the use of prestressed stayed carbon steel columns were used for temporary shoring, optimizing the erection sequence. The main stage had a 82 meters span with a 40 m clear height and a 4500 m2 area. Two stayed column were used, both with a 20 m length. Up to the present the majority of investigations of these stayed systems have been focused on carbon steel columns. In view of these facts the present paper aimed to present an investigation of the structural behaviour of columns made with the austenitic stainless steel. Numerical models were developed in the Ansys software, focusing on the structural system load carrying capacity and the optimal level of prestress to be used. The optimal level of prestress to be used was also determined considering the influence of initial imperfections. The results confirmed that the use of prestress in the cables significantly enhance the ultimate loads and ductility capacity of the columns. © Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH & Co. KG, Berlin.

关键词： Austenitic stainless steel

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Selection of sensitive features for damage identification in a railway bridge

Selection of sensitive features for damage identification in...

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作者： Meixedo, A. Alves, V. Ribeiro, D. Calçada, R. Faculty of Engineering University of Porto Portugal Post-Graduate Program in Civil Engineering Federal University of Ouro Preto Brazil School of Engineering Polytechnic of Porto Portugal

This paper aims selects sensitive features for damage identification in a railway bridge. For this purpose, a damage identification methodology based on a genetic algorithm and its application to the numerical model of a railway bridge is proposed. The identification method is based on an iterative process that in each iteration compares the values of the dynamic responses of a bridge for a test damage scenario with the response values for a reference damage scenario. The introduction of damage in the test numerical model is based on the modification of preselected numerical parameters values. The genetic algorithm allows the identification of damage by minimizing the residue of an objective function constructed from the responses of the test and reference model, and based on damage indicators. In this study damage indicators, based on the deck accelerations of the bridge subject to the action of the Alfa Pendular train defined as a set of moving loads, are defined and tested. The proposed methodology for identifying damage has been tested using a two-dimensional numerical finite element model of a railway bridge including the railway track. The results enabled the evaluation of the efficiency and reliability of the methodology and of the damage indicators which, in most situations, showed potential for the detection, location and quantification of the severity of the damage. © civil-Comp Press, 2016.

关键词： Genetic algorithms

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Determination of time zero in high strength concrete containing superabsorbent polymer and nano-silica

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Journal of Building Pathology and Rehabilitation 2016年第1期1卷 1-12页

作者： Cunha, T.A. Francinete, P. Manzano, M.A. Aidar, L.A. Borges, J.G. Silva, E.F. Post-Graduate Program in Structures and Civil Construction (PECC/UnB) University of Brasília Brasília Federal District Brazil Civil Engineering Department (ENC/UnB) University of Brasília Brasília Federal District Brazil

The autogenous shrinkage is a phenomenon that occurs due to the appearance of tensile stresses in capillary pores. Inherent in the hydration process, not depending on external interference. In high strength concrete, autogenous shrinkage is most pronounced, due to the refinement of microstructure, the high cement content, presence of mineral addictions and low water/cement ratio, which interfere in the transport of water curing. In this context, Superabsorbent polymers (SAP) stand out for their ability to reduce or eliminate the autogenous shrinkage, because they absorb large amounts of water, which is subsequently released into the matrix, avoiding self-desiccation and the onset of tensile stresses (internal curing). However, studies show that SAP can reduce the mechanical strength, which can be compensated by addiction of Nano-silica (NS). In this paper, the effect of these additions in Time Zero (T₀) was evaluated. T₀ determines the time at which the material starts to behave as a solid, with the development of a rigid mineral skeleton to oppose the volumetric variations that occurs in the paste, which can lead to cracking, compromising esthetics, durability, and structures safety. The ultrasonic pulse velocity test performed the T₀, which measures the velocity of propagation of an ultrasonic wave through the material and is taken as the time when a sudden change occurs at this velocity. Nine blends were made containing SAP and NS, where it was found that SAP addition increases the T₀ (up to 11%), while NS decrease its value (in 55%). © 2016, Springer International Publishing Switzerland.

关键词： High performance concrete High strength concrete Nano-silica Superabsorbent polymer Time zero Ultrasonic pulse velocity

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Facades inspection with infrared thermography: cracks evaluation

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Journal of Building Pathology and Rehabilitation 2016年第1期1卷 1-7页

作者： Elton Bauer Elier Pavón Elias Oliveira Claudio H. F. Pereira Post-Graduate Program in Structures and Civil Construction Civil and Environmental Engineering Department University of Brasília Brasília Brazil Centro das Ciências Exatas e das Tecnologias Post-Graduate Program in Structures and Civil Construction - UnB Universidade Federal do Oeste da Bahia-UnB Barreiras Brazil

Infrared thermography is an evaluation technique that helps to identify anomalies and can provide information on their incidence and severity. The aim of this study is to apply quantitative thermography to study a case of severe cracks in facade analyzing the evolution of temperatures and Delta-T. The temperature evolution was studied over a day. There was sun incidence occurring during part of the day, allowing to calculate and assess the evolution of the associated temperatures. Thermograms were acquired hourly during the study period. The highest temperatures were observed at 12:00 noon, and the larger Delta-T between 10:00 and 12:00. There were differences between the Delta-T profiles among the three regions studied. The best time for analysis is when Delta-T is higher. Cracks with higher Delta-T were considered more degraded, and generalized branched cracks did not allow a comparative conclusion.

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Study of damage distribution and intensity in regions of the facade

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Journal of Building Pathology and Rehabilitation 2016年第1期1卷 1-9页

作者： de Souza, Jessica S. Bauer, Elton Nascimento, Matheus L. M. Capuzzo, Valdirene M. S. Zanoni, Vanda A. G. Post-Graduate Program in Structures and Civil Construction Civil and Environmental Engineering Department University of Brasília Campus Universitário Darcy Ribeiro Asa Norte Brasília 70910-900 DF Brazil Faculty of Architecture and Urbanism University of Brasília Campus Universitário Darcy Ribeiro Asa Norte Brasília 70910-900 DF Brazil

The ceramic coating systems applied to building facades have relevant aesthetic value and protection functions. The architectural and environmental conditions can greatly influence the degradation process of the facades, which may pose risks and compromise the durability and service life of the building and its components. The degradation process of facades changes according to the region where it takes place. To this end, the present study aims to determine damage intensity and distribution in the different regions of the facade. This study investigated the facades of three buildings that are part of the Materials Testing Laboratory (LEM) database of the Universidade de Brasilia. The degradation was quantified using a methodology proposed by Silva (2014) to generate a degradation index expressed in m². After the quantification of damages, few indexes associated with the percentage of degraded area, applied to the facade regions, are presented. These weighted indexes allowed to standardize the values observed in each region. Obtaining these indices is fundamental to the study of degradation. The results show that for a comparative analysis between the regions, the observed values should be corrected for the proportionality of the area of each region in relation to the total area of the facade. It was also noted that the continuous walls are the most affected regions, but they do not always present the highest damage intensity. © 2016, Springer International Publishing Switzerland.

关键词： Damage distribution Degradation Degradation index Facades Pathology

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Wind-driven rain incidence parameters obtained by hygrothermal simulation

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Journal of Building Pathology and Rehabilitation 2016年第1期1卷 1-7页

作者： Nascimento, M.L.M. Bauer, E. de Souza, J.S. Zanoni, V.A.G. Post-Graduate Program in Structures and Civil Construction Civil and Environmental Engineering Department University of Brasília Campus Universitário Darcy Ribeiro Asa Norte Brasília 70910-900 DF Brazil Faculty of Architecture and Urbanism University of Brasília Campus Universitário Darcy Ribeiro Asa Norte Brasília 70910-900 DF Brazil

The association of rain and wind composes wind-driven rain (WDR), and its incidence may be crucial to the emergence of anomalies on the facades of buildings. Moisture from the WDR can influence the humidification and drying process, therefore the durability and hygrothermal performance are conditioned by the amount of incident water. The quantification of WDR can be an indispensable tool for understanding its related phenomena and the service life of buildings. The most widely used methods of quantification are the semi-empirical, with theoretical basis, but coefficients partially determined from measurements. These methods may take into account the building exposure conditions related to the envelope, solar orientation, height of the building, and other parameters. In this context, in order to contribute to the studies on quantification of WDR, the purpose of this paper is to apply hygrothermal simulation software WUFI^® on quantification of WDR focusing on buildings degradation of Brasília-Brazil. For the simulation it was used a Typical Meteorological Year file with the wind and precipitation measurement data indispensable for simulation. The quantification of incidence of WDR considered the orientations North, Northeast, East, Southeast, South, Southwest, West, and Northwest. The use of semi-empirical WUFI^® quantification method allowed finding the highest values and consequently critical orientations North, Northwest, and Northeast, moreover, this results showed the relation with the degradation of facades in these orientations. WUFI proved to be an easy, fast and efficient method of WDR quantification, without hiding seasonal weather effects. © 2016, Springer International Publishing Switzerland.

关键词： Degradation Facade Hygrothermal simulation Wind-driven rain

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12.15: Structural performance of stainless lap bolted joints

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ce/papers 2017年第2-3期1卷

作者： Raphael Freire Pedro Colmar Gonçalves da Silva Vellasco André Tenchini da Silva Luciano Rodrigues Ornelas de Lima PGECIV – Civil Engineering Post-Graduate Program State of Rio de Janeiro – UERJ Structural Engineering Department State University of Rio de Janeiro – UERJ

The stainless steel employed in the structural elements present high corrosion resistance, durability, fire resistance and high aesthetic value compared to those constructed using carbon steel. In contrast, the stainless steel structures design is made following the requirements based on the carbon steel analogies. In fact, the structural performance of stainless steel is complex and dissimilar where some stainless grades presenting nonlinear tension versus strain curves without a defined yield plateau and large strain hardening. These properties influence on structural performance of the lap bolted joints. The Eurocode 3 pt. 1.4, one of the most adopted design codes, recommends two structural design criteria for the stainless steel elements under tension: ultimate resistance of the net cross-section at holes or plastic resistance of the gross cross-section. The present work aimed to investigate the structural response of lap bolted joints made of three stainless steel grades: austenitic, ferritic and duplex. Nonlinear numerical analyses has been carried out using ABAQUS 6.14 program where the response have shown a good agreement in terms of the maximum loads and failure modes when compared to the performed experiments. The results indicated a conservative level of safety from Eurocode 3 pt. 1.4 code provisions in comparison to the experimental results.

关键词： stainless steel lap bolted joint experimental analysis numerical finite element simulations

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Determination of the bridge maintenance and rehabilitation priority scale in kabupaten Pinrang

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Journal of Physics: Conference Series 2017年第1期795卷

作者： Asrul Nurdin S.A Kristiawan Handayani Dewi Civil Engineering of Post Graduate Program Sebelas Maret University Jl. Ir. Sutami 36A Kentingan Jebres Surakarta 57126 INDONESIA

This study attempts to get the support system to help stakeholders and the decision makers in the determination of priorities the maintenance and rehabilitation of the *** location of the study is done in Kabupaten Pinrang. Bridge damage value is specified using assessment standard Bridge Management System (BMS). There are 13 Bridges by details as follows: good condition with the condition 1 in 6 Bridge, damaged with the condition two as many as five fruit Bridges and there are two Bridges by value condition of three which means need handling rehabilitation. From our observation examination Bridges and it has been obtained the results of then afterward determined the priority scale by using the method Analytic Hierarchy Process. The discussion or interview of 27 respondents in completion question to determines the priorities of handling bridges by three (3) criteria and three sub- criteria with weights each: a condition of damage with weights 0,491 or amounting to 49,1 % followed by criteria policy with weights 0,324 % then criteria volume traffic weight of 0,185 or 18.5 %. Based on the results of this can be concluded that the implementation of a method of Analytic Hierarchy Processing is effective in determining the scale of priorities for the stakeholders. Having acquired value bridge condition and weights of the assessment results of the, then is needed to Analysis of spatial use application ArcGIS to obtain information condition Bridge Map.

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Energy efficiency evaluation of hospital building office

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Journal of Physics: Conference Series 2017年第1期795卷

作者： Indah Fitriani Senot Sangadji S.A. Kristiawan Civil Engineering Post graduate Program Sebelas Maret University Jl. Ir. Sutami 36A Kentingan Jebres Surakarta 57126 INDONESIA

One of the strategy employed in building design is reducing energy consumption while maintaining the best comfort zone in building indoor climate. The first step to improve office buildings energy performance by evaluating its existing energy usage using energy consumption intensity (Intensitas Konsumsi Energi, IKE) index. Energy evaluation of office building for hospital dr. Sayidiman at Kabupaten Magetan has been carried out in the initial investigation. The office building is operated with active cooling (air conditioning, AC) and use limited daylighting which consumes 14.61 kWh/m2/month. This IKE value is attributed into a slightly inefficient category. Further investigation was carried out by modeling and simulating thermal energy load and room lighting in every building zone using of Ecotect from Autodesk. Three scenarios of building energy and lighting retrofit have been performed simulating representing energy efficiency using cross ventilation, room openings, and passive cooling. The results of the numerical simulation indicate that the third scenario by employing additional windows, reflector media and skylight exhibit the best result and in accordance with SNI 03-6575-2001 lighting standard. Total thermal load of the existing building which includes fabric gains, indirect solar gains, direct solar gains, ventilation fans, internal gains, inter-zonal gains and cooling load were 162,145.40 kWh. Based on the three scenarios, the thermal load value (kWh) obtained was lowest achieved scenario 2 with the thermal value of 117,539.08 *** final results are interpreted from the total energy emissions evaluated using the Ecotect software, the heating and cooling demand value and specific design of the windows are important factors to determine the energy efficiency of the buildings.

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The simulation of cropping pattern to improve the performance of irrigation network in Cau irrigation area

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Journal of Physics: Conference Series 2017年第1期795卷

作者： Retno Wahyuningsih RR Rintis Hadiani Sobriyah Civil Engineering Department of Post Graduate Program Sebelas Maret University Jl. Ir. Sutami 36A Kentingan Jebres Surakarta 57126 INDONESIA

Cau irrigation area located in Madiun district, East Java Province, irrigates 1.232 Ha of land which covers Cau primary channel irrigation network, Wungu Secondary channel irrigation network, and Grape secondary channel irrigation network. The problems in Cau irrigation area are limited availability of water especially during the dry season (planting season II and III) and non-compliance to cropping patterns. The evaluation of irrigation system performance of Cau irrigation area needs to be done in order to know how far the irrigation system performance is, especially based on planting productivity aspect. The improvement of irrigation network performance through cropping pattern optimization is based on the increase of water necessity fulfillment (k factor), the realization of planting area and rice productivity. The research method of irrigation system performance is by analyzing the secondary data based on the Regulation of Ministry of Public Work and State Minister for Public Housing Number: 12/PRT/M/2015. The analysis of water necessity fulfillment (k factor) uses Public Work Plan Criteria Method. The performance level of planting productivity aspect in existing condition is 87.10%, alternative 1 is 93.90% dan alternative 2 is 96.90%. It means that the performance of the irrigation network from productivity aspect increases 6.80% for alternative 1 and 9.80% for alternative 2.

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