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A decision tree-based damage estimation approach for preliminary seismic assessment of reinforced concrete buildings 基于决策树的钢筋混凝土建筑物地震预估损伤估计方法
IF 1.4 4区 工程技术 Pub Date : 2023-01-01 DOI: 10.7764/rdlc.22.1.5
Ayşe Elif Özsoy Özbay
This study aims to introduce an earthquake-induced damage classification approach for seismic vulnerability assessment of reinforced concrete buildings. Through the use of the damage data collected from post-earthquake inspections after the 2003 Bingöl Earthquake in Turkey, two models were constructed by the decision tree classification technique considering nine building-specific features as the estimation variables in the analysis. The first model was developed for the prediction of the observed damage states of the buildings, whereas the second one concerning the life safety level assessment, was proposed for distinguishing the extremely vulnerable buildings for seismic prioritization. In the validation process, the leave-one-out cross validation technique was adopted to deal with the small sample size of the building inventory. Among the estimation variables, the priority index and the existence of short columns were found to have the highest importance in classification. Results have revealed that the proposed model for life safety level assessment was capable of discriminating the cluster of severely damaged and collapsed buildings from the entire database with an accuracy of 70.59%. Hence, the damage classification approach adopted in this study has the potential for improving effective tools for seismic risk assessment of the existing buildings.
本研究旨在介绍一种用于钢筋混凝土建筑物地震易损性评估的震害分类方法。利用2003年Bingöl土耳其地震后的震害检测数据,采用决策树分类技术,以9个建筑特征作为分析的估计变量,构建了两个模型。第一个模型用于预测建筑物的观测损伤状态,第二个模型用于评估生命安全水平,用于区分极易危建筑物进行地震优先排序。在验证过程中,针对建筑库存样本量小的问题,采用留一交叉验证技术。在这些估计变量中,优先级指数和短列的存在性对分类的重要性最高。结果表明,该生命安全等级评价模型能够从整个数据库中识别出严重受损和倒塌的建筑物群,准确率为70.59%。因此,本研究采用的损伤分类方法有可能改进现有建筑地震风险评估的有效工具。
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引用次数: 0
Experimental investigation on mechanical properties of HSSCC containing waste steel fibers obtained from end-of-life tires 含废旧轮胎废钢纤维的HSSCC力学性能试验研究
IF 1.4 4区 工程技术 Pub Date : 2023-01-01 DOI: 10.7764/rdlc.22.1.87
Kutalmış Recep Akça, M. İpek, Sevgi Çelenk, Aykut Karabulak
In this study, use of end-of-life tires (ELTs) in self-consolidating concretes (SCC), which enable higher rates of fiber use than conventional concrete due to its superior flow properties, for the elimination of the environmental negative impacts and recycling of them were aimed. Besides, it is aimed to investigate the behavior of waste steel wires with different aspect ratio obtained from different types of tires, contrary to what is mostly researched in the literature. Therefore, bead, cord and base wires, obtained from tires, were used in high-strength self-consolidating concrete (HSSCC) production as fiber reinforcement. Fresh and hardened state properties of the waste wire-reinforced (1-2-3%) samples of different sizes that were produced, were compared with industrial steel-reinforced and non-fibrous samples. In this regard, slump flow and T50 durations were determined, compression and bending tests were performed. Significant improvements in the mechanical properties of conventional concretes were observed with the use of waste wire. Using the optimum ratio of waste wire, an increase of approximately 102% in flexural strength and 14% in compressive strength was observed compared to the reference specimen. Aspect ratio was recognized as one of the most effective factor on optimum fiber content. Moreover, experimental results were analyzed with "paired sample t-test", and it was seen that there were no considerable differences in the mechanical properties of the samples in which industrial fiber and waste-wire had been used. Besides, cost analysis was carried out to assess the economic benefits of the use of waste tire wires in the concrete industry.
在本研究中,在自固结混凝土(SCC)中使用报废轮胎(elt),由于其优越的流动性能,可以比传统混凝土使用更高的纤维使用率,以消除对环境的负面影响并回收利用它们。此外,与文献研究的主要内容相反,本文旨在研究从不同类型轮胎中获得的不同宽高比废钢丝的性能。因此,从轮胎中获得的钢丝头、帘子线和基线被用作高强度自固结混凝土(HSSCC)生产中的纤维增强材料。对所制备的不同尺寸废钢丝增强(1-2-3 -3%)试样的新鲜和硬化状态性能与工业钢增强和非纤维试样进行了比较。为此,确定了坍落度流动和T50持续时间,并进行了压缩和弯曲试验。废电线的使用显著改善了传统混凝土的力学性能。采用最佳废丝配比,与参考试样相比,试件的抗折强度提高约102%,抗压强度提高约14%。长径比是影响纤维含量的最有效因素之一。此外,对实验结果进行“配对样本t检验”分析,发现使用工业纤维和废电线的样品的力学性能没有太大差异。并进行了成本分析,评价了废轮胎钢丝在混凝土行业的经济效益。
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引用次数: 0
Incorporating vegetal fibers for sustainable sandy soil 将植物纤维纳入可持续沙质土壤
IF 1.4 4区 工程技术 Pub Date : 2023-01-01 DOI: 10.7764/rdlc.22.1.135
Hachemi Adda Berkane, N. Della, Sidali Denine, Mahdi Missoum Benziane
Incorporating fibers into the soil is a reinforcement remediation technique to improve its physical and mechanical properties. Depending on the type of fibers, synthetic fibers, have negative impacts on the environment linked to the waste of their chemical industry. Currently, vegetal fibers consider an economic and ecological alternative to soil reinforcement. Therefore, this study aims to evaluate the influence of two types of randomly distributed fibers (Alfa and Sisal fibers) on the mechanical properties of sandy soil. Direct shear tests were performed on Chlef sand at relative density (Dr = 75% and 40%) and of fiber contents varying from 1, 2, 3 and 4% for sand samples reinforced with Alfa fibers and 0.1, 0.3, 0.5 and 0.7% for sand samples reinforced with Sisal fibers. The test results show that the inclusion of vegetal fibers in sandy soil improves the peak and residual shear strength. In addition, soil resistance was found to attain a maximum with the optimums of 0.7% for sisal fiber content and 3% for Alfa fibers.
将纤维掺入土壤是一种改善土壤物理力学性能的加固修复技术。根据纤维的类型,合成纤维对环境的负面影响与化学工业的废物有关。目前,植物纤维被认为是一种经济和生态的土壤加固替代方案。因此,本研究旨在评价两种随机分布的纤维(阿尔法纤维和剑麻纤维)对沙质土力学性能的影响。在相对密度(Dr = 75%和40%)和纤维含量分别为1、2、3和4% (α纤维增强)和0.1、0.3、0.5和0.7%(剑麻纤维增强)的情况下,对Chlef砂进行了直接剪切试验。试验结果表明,植物纤维的掺入提高了砂土的峰值抗剪强度和残余抗剪强度。此外,当剑麻纤维含量为0.7%、阿尔法纤维含量为3%时,土壤抗性达到最大值。
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引用次数: 0
Prediction of the mechanical properties of concrete incorporating simultaneous utilization of fine and coarse recycled aggregate 细粗再生骨料同时使用混凝土力学性能预测
IF 1.4 4区 工程技术 Pub Date : 2023-01-01 DOI: 10.7764/rdlc.22.1.178
Herbert Sinduja Joseph, Thamilselvi Pachiappan, Siva Avudaiappan, P. Guindos
The mechanical properties of concrete were optimized using response surface methodology (RSM) and fuzzy logic. The aggregate portion of the concrete was replaced with recycled aggregate to address the environmental problems caused by building demolition wastes. The essential key factors that influenced the suitability of recycled aggregate in concrete applications are the compressive strength (CS), flexural strength (FS), and the split tensile strength (STS). The experiments were designed with nine combinations of two input factors (percentage of coarse and fine recycled aggregates) at different levels 30, 60, and 100%. Furthermore, optimization techniques were used to determine the strong correlations between the variables and the mechanical parameters. Such optimization techniques helped to identify the optimistic maximum strength for replacing 44% coarse and 65% fine recycled aggregate. Using RSM, the maximum strength results were found to be: CS at 7, 28, 56, and 90 days were 23.61, 35.04, 40.02, and 43.63 N/mm2, respectively, FS 3.6 N/mm2 and STS 2.0 N/mm2. The maximum strength parameters were found using fuzzy logic: CS at 7, 28, 56, and 90 days were 23.5, 35.8, 41, and 46.7 N/mm2, respectively, FS 4.13 N/mm2 and STS 1.97 N/mm2. Such optimization can be carried out to lower the material wastage, energy consumption, and expenses for the production.
采用响应面法和模糊逻辑对混凝土力学性能进行了优化。混凝土的骨料部分用再生骨料代替,以解决建筑拆除废物造成的环境问题。影响再生骨料在混凝土应用中的适用性的关键因素是抗压强度(CS)、抗折强度(FS)和劈裂抗拉强度(STS)。试验采用粗、细再生骨料比例分别为30%、60%和100%的9种输入因子组合设计。此外,利用优化技术确定了变量与力学参数之间的强相关性。这些优化技术有助于确定替代44%粗骨料和65%细骨料的乐观最大强度。采用RSM方法,最大强度结果为:CS在7、28、56和90 d分别为23.61、35.04、40.02和43.63 N/mm2, FS为3.6 N/mm2, STS为2.0 N/mm2。采用模糊逻辑计算得到最大强度参数:第7、28、56和90天,CS分别为23.5、35.8、41和46.7 N/mm2, FS为4.13 N/mm2, STS为1.97 N/mm2。这样的优化可以降低生产的材料浪费、能源消耗和费用。
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引用次数: 0
Durability performance of alkali-activated concretes exposed to sulfuric acid attack 碱活化混凝土在硫酸侵蚀下的耐久性性能
IF 1.4 4区 工程技术 Pub Date : 2023-01-01 DOI: 10.7764/rdlc.22.1.16
A. Niş, Melis Bilenler Altundal
In this research, chemical durability performances of the alkali-activated slag (AAS), 50% ground granulated blast furnace slag and 50% fly ash (AFS), ordinary Portland cement (OPC), and geopolymer (GPC) concretes were investigated thoroughly under 5% sulfuric acid attack. All alkali-activated concrete specimens were produced considering the minimum binder content of 360 kg/m3 and the maximum alkali activator to binder ratio of 0.45 according to the XA3 environment given in EN 206-1 standard for OPC concrete. The visual inspection, weight change and compressive strength tests were performed to understand the influence of sulfuric acid attack on the resulting performances. Also, scanning electron microscope (SEM) and energy dispersive X-ray spectrometry (EDS) analyses were performed to examine the morphological variations in micro-scale. The mechanical performances and durability of alkali-activated concretes were also compared to the OPC concrete for structural utilization. The results revealed that AFS specimens showed the best durability, while GPC specimens exhibited the poorest durability. SEM/EDS results pointed out that AFS specimens exhibited denser and less porous microstructure, and the reductions in Al/Si and Ca/Si atomic ratios were observed under 5% sulfuric acid attack. In contrast, GPC specimens showed less dense and porous microstructure, and high aluminum leaching was observed. In addition, the wider interconnected macro cracks and high calcium leaching were observed in the AAS samples under 5% sulfuric acid attack. Finally, the AAS and AFS specimens can be utilized in structural applications, while GPC specimens should not be used with a minimum binder content proposed by EN 206-1 standard.
研究了碱活性矿渣(AAS)、50%磨粒矿渣+ 50%粉煤灰(AFS)、普通硅酸盐水泥(OPC)和地聚合物混凝土(GPC)在5%硫酸侵蚀下的化学耐久性。所有碱活化混凝土试样均按照EN 206-1 OPC混凝土标准中给出的XA3环境,考虑最小粘结剂含量为360 kg/m3,最大碱活化剂与粘结剂之比为0.45。通过目测、重量变化和抗压强度试验来了解硫酸侵蚀对所得性能的影响。利用扫描电镜(SEM)和能谱分析(EDS)分析了微尺度下的形态变化。并将碱活化混凝土的力学性能和耐久性与OPC混凝土进行了比较。结果表明,AFS试件的耐久性最好,GPC试件的耐久性最差。SEM/EDS结果表明,AFS试样的微观结构更致密,孔隙较少,在5%硫酸腐蚀下,Al/Si和Ca/Si原子比降低。相比之下,GPC试样的微观结构致密且多孔,铝浸出率较高。此外,在5%硫酸侵蚀下,AAS样品的宏观裂纹相互连接更宽,钙浸出率更高。最后,AAS和AFS试样可用于结构应用,而GPC试样不应使用EN 206-1标准提出的最低粘结剂含量。
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引用次数: 2
Water absorbing polymer balls as internal water curing agent in concrete to support hydration reaction 吸水聚合物球作为混凝土内水固化剂,支持水化反应
IF 1.4 4区 工程技术 Pub Date : 2022-01-01 DOI: 10.7764/rdlc.21.1.83
Vijayalakshmi Ramalingam, Kamalesh Ramesh, Madhankumar Duraipandi, Jayesh U, Selvam Kuppusamy
polymer balls can supply water to the mortar or concrete mixture when added during the initial stage of mixing the concrete ingredients. It supplies the absorbed water during the hydration process of concrete as an internal water source. Water Absorption polymers (WAP) can absorb water up to hundred times of their own weight. Using this idea, the concrete mixture has been prepared with WAP and without WAP (Control) and subjected to air curing and water curing respectively. In this work WAP has been added in two different percentages i.e., 2.5% and 5% of the weight of cement, and the hardened concrete has been subjected to compression load. The mechanical strength and the volumetric change of these mixes were compared with the water cured control mix (Concrete without WAP). From the result, it was concluded that the air-cured specimen showed strength of 30.37 MPa and 28.74 MPa for 2.5% and 5% of addition of WAP balls respectively. This strength is about 99% and 94.2% of the strength of control water-cured specimen. Results also showed that specimens in air behave for expansion while samples in the water acted for shrinkage. Experiment results also showed that air-cured concrete specimens with WAP balls show significant strength gain over a period of 84 days compared to water-cured normal concrete mix samples.
聚合物球在混合混凝土配料的初始阶段加入时,可以向砂浆或混凝土混合物供水。它作为内部水源供给混凝土水化过程中吸收的水。吸水聚合物(WAP)可以吸收高达自身重量数百倍的水。利用这一思想,配制了加WAP和不加WAP的混凝土混合料,并分别进行了空气养护和水养护。在本工程中,WAP以水泥重量的2.5%和5%两种不同比例加入,硬化混凝土承受压缩荷载。并与水固化对照混凝土(无WAP混凝土)进行了力学强度和体积变化的比较。结果表明,当WAP球添加量为2.5%和5%时,风干试样的强度分别为30.37 MPa和28.74 MPa。强度分别为水固化对照试件强度的99%和94.2%。结果还表明,试样在空气中表现为膨胀,而试样在水中表现为收缩。实验结果还表明,在84天的时间里,与水固化的普通混凝土混合料相比,空气固化的WAP球混凝土试件的强度有了显著的提高。
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引用次数: 0
The effect of local pozzolans and lime additions on the mineralogical, physical and mechanical properties of compressed earth blocks in Argentina 阿根廷当地火山灰和石灰添加量对压缩土块矿物学、物理和力学性质的影响
IF 1.4 4区 工程技术 Pub Date : 2022-01-01 DOI: 10.7764/rdlc.21.2.248
Santiago Cabrera, K. Elert, Anabela G. Guilarducci, Andrea Margasin
The purpose of this research is to evaluate the mineralogical, physical, and mechanical properties of compressed earth blocks (CEB) stabilized with lime and mineral admixtures easily obtained in Argentina: natural pozzolans and brick powder. the admixture mineralogical composition and their pozzolanic potential as well as the development of hydraulic phases upon reaction with calcium hydroxide (lime) were determined, emphasizing the formation of hydrated cementing compounds. Samples with different percentages of lime and mineral additions were prepared in order to test their compressive strength, wet erosion resistance, and water absorption, and contrasting the results with those of their counterparts stabilized exclusively with lime or cement. The results obtained allow us to affirm that both the brick powder and the pozzolan used have pozzolanic properties and, in combination with calcium hydroxide, form amorphous phases of C-(A)-S-H. However, the use of small amounts of both additions in combination with hydrated air lime in the manufacture of CEB, compared to CEB samples stabilized only with hydrated air lime, adversely affected their physical and mechanical properties.
本研究的目的是评估压缩土块(CEB)的矿物学、物理和机械性能,这些压缩土块是用石灰和在阿根廷容易获得的矿物外加剂(天然火山灰和砖粉)稳定的。测定了外加剂的矿物学组成及其与氢氧化钙(石灰)反应时的火山灰势和水力相的发展,强调水合胶结物的形成。为了测试其抗压强度、抗湿侵蚀性和吸水率,制备了不同比例的石灰和矿物添加物的样品,并将结果与仅用石灰或水泥稳定的样品进行了对比。得到的结果使我们确信砖粉和所用的火山灰都具有火山灰性质,并且与氢氧化钙结合形成C-(A)- s - h的无定形相。然而,与仅使用水合空气石灰稳定的CEB样品相比,在制造CEB时使用少量这两种添加剂和水合空气石灰会对其物理和机械性能产生不利影响。
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引用次数: 0
Torsional performance of reinforced concrete beam with carbon fiber and aramid fiber laminates 碳纤维和芳纶层合板钢筋混凝土梁的抗扭性能
IF 1.4 4区 工程技术 Pub Date : 2022-01-01 DOI: 10.7764/rdlc.21.2.329
S. Shanmugasundaram, R. Mohanraj, S. Senthilkumar, P. Padmapoorani
In the presented research paper, investigated the torsional performance of reinforced concrete beams with light emissions grade of cement utilizing Carbon fiber and its relative investigation with aramid fiber, for its torsional conduct, utilizing both exploratory and insightful strategies. A distinctive example of its strips folded over RC beams and the torsional conduct of these restrengthened beams is considered. Carbon fiber (CF) is utilized as outside support. Reinforced concrete beam retrofitted with CF tried for torsional disappointment utilizing lever arms exposed to torque. The beams have dimensions of 150mm in width and 200mm in depth and 1 m long, as planned according to IS456-2000. Three bars are intended for a twist. Steel has a stronger ultimate strength but a lower density than aramid FRP, as well as being easier to install and requiring no interim support until it reaches its full strength. The impact of various sorts and designs of CF on the initial stage of breaking load, extreme load conveying limit, and disappointment method of the beam are thought about and its relative examination utilizing finite element programming with aramid fiber gives a better outcome for additional investigation.
在本研究中,研究了碳纤维轻排放水泥混凝土梁的抗扭性能,并对芳纶纤维的抗扭性能进行了相关研究,采用了探索性和洞察力的策略。它的条带折叠在RC梁和这些加固梁的扭转行为的一个独特的例子被考虑。采用碳纤维(CF)作为外部支撑。用CF改造的钢筋混凝土梁利用暴露在扭矩下的杠杆臂进行扭转失望试验。梁的尺寸为宽150mm,深200mm,长1m,按照IS456-2000规划。三小节用于扭转。钢具有比芳纶FRP更强的极限强度,但密度更低,并且更容易安装,并且在达到其全部强度之前不需要临时支撑。考虑了不同种类和设计的碳纤维对梁的断裂荷载初始阶段、极限荷载传递极限和失望方法的影响,并利用芳纶纤维有限元程序对其进行了相应的检验,为进一步的研究提供了较好的结果。
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引用次数: 6
Integration of discrete event simulation with other modeling techniques to simulate construction engineering and management: an overview 离散事件模拟与其他建模技术的集成,以模拟建筑工程和管理:概述
IF 1.4 4区 工程技术 Pub Date : 2022-01-01 DOI: 10.7764/rdlc.21.2.338
F. Araya
Although Discrete Event Simulation (DES) has been the preferred simulation technique in construction operation studies, it suffers from limitations, such as narrowed focus at the operational level. To minimize the effect of DES limitations, researchers have proposed the integration of DES with other simulation techniques, such as agent-based modeling (ABM), system dynamics (SD), and virtual environments (VE). However, limited studies have discussed whether this integration process minimizes DES’ limitations and to what extent. This study summarizes 99 journal manuscripts in the existing literature published between 2010-2020, focusing on integrating DES with ABM, SD, and VE. This study found that the integration of DES with ABM, SD, and VE addressed multiple of DES’ limitations, namely, the lack of human behaviors in process-oriented modeling, the limited strategic perspective, and challenges related to the verification and validation of DES models’ outputs. Ultimately, this study calls for future studies to evaluate the simultaneous integration of DES, ABM, and SD modeling techniques so the complexity of construction projects can be truly accounted for, as comprehensive simulation tools will require the integration of multiple methods to counterbalance their limitations.
尽管离散事件模拟(DES)已成为建筑施工操作研究中首选的模拟技术,但它存在局限性,例如在操作层面的关注点狭窄。为了最大限度地减少DES限制的影响,研究人员提出将DES与其他仿真技术相结合,如基于代理的建模(ABM)、系统动力学(SD)和虚拟环境(VE)。然而,有限的研究讨论了这种整合过程是否最小化了DES的局限性以及在多大程度上最小化了DES的局限性。本研究总结了2010-2020年间发表的99篇期刊论文,重点研究了DES与ABM、SD和VE的整合。本研究发现,DES与ABM、SD和VE的集成解决了DES的多个局限性,即在面向过程的建模中缺乏人类行为,有限的战略视角,以及与DES模型输出的验证和验证相关的挑战。最后,本研究呼吁未来的研究评估DES、ABM和SD建模技术的同时集成,以便真正考虑建筑项目的复杂性,因为综合仿真工具将需要集成多种方法来抵消其局限性。
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引用次数: 0
Investigation on behavior and seismic performance of reduced beam sections 减截面梁的性能及抗震性能研究
IF 1.4 4区 工程技术 Pub Date : 2022-01-01 DOI: 10.7764/rdlc.21.2.427
İbrahim Ermeydan, Alirıza İlker Akgönen
Engineers prefer reduced beam section (RBS) connections in steel moment frames built in earthquake zones due to their many benefits. The RBS shape design significantly affects joint behavior. This paper examines the effect of RBS geometry on joint behavior and seismic performance using ANSYS finite element analysis software. RBS connections are investigated using European profiles and steel grades due to the limited number of studies using European profiles in the literature. The simulation study is carried out in three stages. In the first stage, an experimental study in the literature is simulated, and the reliability of the created finite element model is checked. In the second stage, geometric changes are made to the verified numerical model, and the obtained new models are examined under monotonic loading to observe the effect of RBS geometry on moment-rotation behavior. In the third stage, the effect of the change in the RBS geometry on the seismic performance is investigated under cyclic loading. As a result of the study, the effects of various changes made in the RBS geometry on the joint behavior and seismic performance are presented graphically. By using the results of the analysis under monotonic loading, the regression analysis is carried out, and the formulas giving the elastic-plastic stiffness, elastic moment capacity, and elastic rotation angle of the support are derived. Besides, simulation models show that the RBS joints' seismic performance met the minimum criteria specified in the earthquake code (AISC/ANSI 341-16) when European steel profiles and quality are applied.
工程师们更喜欢在地震带建造的钢弯矩框架中采用减梁截面连接,因为它们有许多好处。RBS形状设计对接头行为有显著影响。本文利用ANSYS有限元分析软件研究了RBS几何结构对节点性能和抗震性能的影响。由于文献中使用欧洲型材的研究数量有限,因此使用欧洲型材和钢牌号对RBS连接进行了调查。仿真研究分三个阶段进行。第一阶段,对文献中的实验研究进行了仿真,并对所建立的有限元模型的可靠性进行了校核。第二阶段,对验证后的数值模型进行几何变化,并在单调荷载下对得到的新模型进行检验,观察RBS几何对矩转行为的影响。在第三阶段,研究了循环荷载作用下RBS几何形状变化对其抗震性能的影响。通过研究,以图形形式展示了各种RBS几何形状变化对节理行为和抗震性能的影响。利用单调荷载作用下的分析结果,进行回归分析,推导出支座弹塑性刚度、弹性弯矩承载力和弹性转角的计算公式。此外,仿真模型表明,当采用欧钢型材和质量时,RBS节点的抗震性能满足抗震规范(AISC/ANSI 341-16)的最低要求。
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引用次数: 1
期刊
Revista de la Construccion
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