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Testing the applicability of design code provisions - case of unconventional shear reinforcement 检验设计规范规定的适用性。非常规抗剪加固实例
IF 1.1 Q3 Engineering Pub Date : 2021-07-29 DOI: 10.1080/13287982.2021.1958507
K. Jaafar
ABSTRACT Common transverse reinforcement of reinforced concrete members with circular cross-section consists of round ties or spirals. Its purpose in members that are not subjected to significant shear loading is to provide proper confinement for concrete, and eliminate buckling of the longitudinal reinforcement bars. If spirals are to be used as both shear enabler and confiner for reinforced concrete beams, then under combined action of moment and shear, spirals will be required to provide or contribute to proper shear resistance. Hence a proper assessment for spiral shear contribution is required. The validity of concepts which underlines current methods for shear design used in design codes will be investigated in this paper especially for beams with the shear configuration used, which violates basic code rules in truss formation. A simplified model based on sectional crack analysis for assessing spiral shear contribution is proposed for practical design consideration.
一般圆形截面钢筋混凝土构件的横向配筋由圆扣或螺旋组成。在不受显著剪切载荷的构件中,其目的是为混凝土提供适当的约束,并消除纵向钢筋的屈曲。如果螺旋既用作钢筋混凝土梁的抗剪促进器,又用作约束器,那么在弯矩和剪力的共同作用下,螺旋将需要提供或有助于适当的抗剪能力。因此,需要对螺旋剪切的贡献进行适当的评估。本文将研究现行设计规范中剪力设计方法中所强调的概念的有效性,特别是对于采用剪力结构的梁,它违反了桁架结构的基本规范规则。提出了一种基于截面裂纹分析的螺旋剪切贡献评估简化模型,以供实际设计参考。
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引用次数: 0
RC walls in Australia: displacement-based seismic design in accordance with AS 1170.4 and AS 3600 澳大利亚的钢筋混凝土墙:根据AS 1170.4和AS 3600的基于位移的抗震设计
IF 1.1 Q3 Engineering Pub Date : 2021-07-03 DOI: 10.1080/13287982.2021.1954306
S. Menegon, H. Tsang, John L. Wilson, N. Lam
ABSTRACT Displacement-based methods, such as a non-linear static pushover analysis (e.g. the capacity spectrum method), have many advantages compared to traditional force-based design methods. However, implementing a non-linear analysis and design method in accordance with the Australian Standard for concrete structures (AS 3600) introduces many difficult technical issues into the design, of which the standard provides little guidance. The aim of this study is to provide a framework and general guidance for designers who wish to perform non-linear displacement-based analysis methods for RC wall buildings. The paper will present how these methods can be used in accordance with the Australian Standard for earthquake actions (AS 1170.4) to assess seismic compliance and then provide recommendations for the requirements stipulated by AS 3600, which includes an experimentally validated tension stiffening model, nonlinear stress-strain material curves, mean material properties and material strain limits. The paper is concluded with a case study example of how a displacement-based seismic assessment can be performed using a typical case study building.
与传统的基于力的设计方法相比,基于位移的方法,如非线性静态推覆分析(如容量谱方法)具有许多优点。然而,按照澳大利亚混凝土结构标准(AS 3600)实施非线性分析和设计方法,给设计带来了许多困难的技术问题,标准对这些问题的指导作用很小。本研究的目的是为那些希望对钢筋混凝土墙体建筑进行非线性位移分析方法的设计师提供一个框架和一般指导。本文将介绍如何根据澳大利亚地震作用标准(AS 1170.4)使用这些方法来评估地震合规性,然后为AS 3600规定的要求提供建议,其中包括实验验证的拉伸加劲模型,非线性应力-应变材料曲线,平均材料性能和材料应变极限。最后,本文给出了一个案例,说明如何使用典型的案例研究建筑进行基于位移的地震评估。
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引用次数: 2
Statistical analysis of material properties and recommended values for the assessment of RC structures in Australia 澳大利亚钢筋混凝土结构材料性能的统计分析及评估建议值
IF 1.1 Q3 Engineering Pub Date : 2021-07-03 DOI: 10.1080/13287982.2021.1946993
S. Menegon, H. Tsang, John L. Wilson, N. Lam
ABSTRACT This paper presents a statistical analysis of the actual mean material properties for typical grades of concrete and reinforcement available in Australia. The analysis was performed using a database of 3,447 concrete cylinder test results and 15,201 reinforcement tensile test results. The test results were taken over a period from 2009 to 2021. The paper provides a summary of the mean values and respective coefficient of variation values for the different grades of concrete and reinforcement that make up the database. Distinctive manufacturing trends and variability between suppliers were observed for reinforcement samples and appropriate recommendations have been proposed. Researchers or designers can adopt these values to undertake probabilistic assessments of RC structures. The paper also provides recommendations for mean material properties for the purpose of undertaking non-linear analysis of RC structures. The database of test results also includes early age strength data for concrete, which have been used to provide recommendations for predicting the early age strength of various standard grades of concrete available in Australia. The paper also presents an assessment of the theoretical characteristic values from the database for the various grades of reinforcement and concrete and how they compare to respective specified code requirements.
摘要本文介绍了澳大利亚典型等级混凝土和钢筋的实际平均材料性能的统计分析。分析使用数据库中的3,447个混凝土圆柱体试验结果和15,201个钢筋拉伸试验结果进行。测试结果是在2009年至2021年期间进行的。本文总结了组成数据库的不同等级的混凝土和钢筋的平均值和各自的变异系数值。观察到不同的制造趋势和供应商之间的可变性对加固样品,并提出了适当的建议。研究人员或设计人员可以采用这些值来进行RC结构的概率评估。本文还为钢筋混凝土结构的非线性分析提供了平均材料性能的建议。测试结果数据库还包括混凝土的早期强度数据,这些数据已被用于提供预测澳大利亚各种标准等级混凝土早期强度的建议。本文还对数据库中各种等级的钢筋和混凝土的理论特征值进行了评估,并将它们与各自规定的规范要求进行了比较。
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引用次数: 2
Behaviour of interlocking concrete slab and steel composite beam incorporated bolt shear connector 混凝土板与钢组合梁结合螺栓剪切连接件的互锁性能
IF 1.1 Q3 Engineering Pub Date : 2021-07-03 DOI: 10.1080/13287982.2021.1957553
Nadiah Loqman, N. A. Safiee, Wong Hui Kah, N. Abu Bakar, N. A. Mohd. Nasir
ABSTRACT The complexity of concrete and steel in composite beam has been addressed in many studies previously. However, the use of precast concrete slab in steel–concrete composite construction is considered as new, hence many factors that affect its behaviour need to be investigated. It becomes interesting when the application of interlocking tongue and groove joints between precast concrete slabs is introduced. For this purpose, a performance comparison between normal precast slab and interlocking tongue and groove precast slab in composite construction is conducted using finite element analysis. Both are designed to have full composite action using bolted shear connector. In this research, a total of five models including a control model were developed to study the flexural behaviour of designated composite beam. The model has been verified against experimental results, which showed a good agreement . Parametric studies were performed to investigate the effects of bolt size and height on flexural behaviour of the beam. The present study demonstrated that the presence of interlocking joints between slabs with larger diameter bolt can efficiently improve the stiffness of the composite system.
混凝土和钢在组合梁中的复杂性已经在许多研究中得到了解决。然而,预制混凝土板在钢-混凝土组合结构中的应用被认为是一种新技术,因此许多影响其性能的因素需要进行研究。介绍了混凝土预制板间舌槽联锁接缝的应用,引起了人们的兴趣。为此,采用有限元分析方法对普通预制板与互锁舌槽预制板在组合结构中的性能进行了比较。两者都设计为使用螺栓剪切连接器具有完全的复合作用。在本研究中,共建立了五个模型,包括一个控制模型,以研究指定组合梁的受弯性能。模型与实验结果进行了验证,结果吻合较好。参数研究进行了调查螺栓尺寸和高度对梁的弯曲行为的影响。研究表明,大直径锚杆板间联锁节点的存在可以有效地提高复合体系的刚度。
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引用次数: 0
Vibration control of structure by optimising the placement of semi-active dampers and fuzzy logic controllers 基于半主动阻尼器和模糊控制器的结构振动控制
IF 1.1 Q3 Engineering Pub Date : 2021-07-03 DOI: 10.1080/13287982.2021.1957198
Kambiz Takin, R. Doroudi, Siyamak Doroudi
ABSTRACT This study concentrates on applying semi-active dampers to control structures. In this paper, fuzzy algorithm types 1 and 2 have been used as controllers to evaluate the voltage of semi-active dampers. To design a proper fuzzy logic controller, membership functions and suitable rule sets need to be tuned and extracted. The location of a semi-active damper is very significant to reduce the responses of structure. In this paper, a 15-story building’s responses for both uncontrolled and controlled (with MR dampers) situations subject to different ground motions are evaluated. Type 1 and type 2 fuzzy logic controllers, and the location of three MR dampers are optimised by Grey Wolf Optimiser, and also dissipating energies are investigated. The results show that although both optimised controllers can successfully reduce the seismic response of the building, the performance of the fuzzy type 2 controller is slightly superior than type 1. It is confirmed that the best location for dampers would be in the upper stories.
本文主要研究半主动阻尼器在结构控制中的应用。本文采用模糊算法1和模糊算法2作为控制器对半主动阻尼器的电压进行评估。为了设计一个合适的模糊控制器,需要对隶属函数和合适的规则集进行调优和提取。半主动阻尼器的位置对减小结构的响应具有重要意义。本文对一栋15层建筑在不同地震动作用下的非受控和受控(带有MR阻尼器)情况下的响应进行了评估。利用灰狼优化器对1型和2型模糊控制器以及3个磁流变阻尼器的位置进行了优化,并对其耗散能量进行了研究。结果表明,虽然两种优化控制器都能成功地降低建筑物的地震响应,但模糊2型控制器的性能略优于模糊1型控制器。经证实,减震器的最佳位置是在上层。
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引用次数: 6
Glulam – closed form solution using statistical smearing, truncating, calibrating 胶合板-封闭形式溶液采用统计涂抹,截断,校准
IF 1.1 Q3 Engineering Pub Date : 2021-06-11 DOI: 10.1080/13287982.2021.1926062
H. Milner
ABSTRACT This paper describes a relatively simple closed form formula for predicting the strength of glulam assemblies in bending about the major axis based on statistical engineering mechanics using the tension strength of finger jointed of bonded lamination pairs. It has been calibrated against the strengths of full-size glulam beams ranging in depths from 150 mm to 1200 mm over spans of 2.7 m up to 19.5 m. Comparisons are made at both the mean strength and 5th percentile strength levels with the latter drawing attention to the fact that all test series invariably involve observation of minimum values that means the statistical distributions are invariably truncated. For Weibull distributions, this has an impact on the shape factor and, therefore, the local coefficient of variation of the lower tail, which plays an important role in size effects in glulam and potentially has wider implications.
摘要本文基于统计工程力学,利用胶合层合副手指接头的抗拉强度,给出了一个相对简单的封闭形式公式,用于预测胶合层合件在主轴弯曲时的强度。它已根据全尺寸胶合木梁的强度进行校准,深度从150毫米到1200毫米,跨度从2.7米到19.5米。在平均强度和第5百分位强度水平上进行比较,后者提请注意这样一个事实,即所有测试系列总是涉及最小值的观察,这意味着统计分布总是被截断。对于威布尔分布,这会影响形状因子,从而影响下尾的局部变异系数,后者在胶合材的尺寸效应中起着重要作用,并可能具有更广泛的影响。
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引用次数: 0
Evaluation of self-healing performance of concrete containing fly ash and fibres 掺粉煤灰和纤维混凝土自愈性能评价
IF 1.1 Q3 Engineering Pub Date : 2021-06-09 DOI: 10.1080/13287982.2021.1935426
S. Sajjadi, R. Madandoust
ABSTRACT Since the existence of cracks reduces the concrete service life, the self-healing ability of concrete has attracted the attention of researchers. In this article, effects of fly ash and steel/polypropylene fibres on the self-healing ability of concrete were investigated separately and together. The cylindrical specimens were pre-cracked by means of a tensile strength test at 28 days. Secondary tensile test was performed immediately after pre-cracking and 28 and 56 days after re-curing in water. Also, to monitor microcracks in concrete after pre-cracking and during the self-healing period, the ultrasonic pulse velocity and permeability tests were conducted. The results showed that 15% fly ash replacement led to 94% reduction in permeability and almost complete recovery in secondary tensile strength after 8 weeks of re-curing. Although the specimen with polypropylene lost lower tensile strength among specimens with fibre immediately after pre-loading (22%), the improvement rate of those during the self-healing period was only 27%.
由于裂缝的存在降低了混凝土的使用寿命,混凝土的自愈能力引起了研究者的关注。本文分别和共同研究了粉煤灰和钢/聚丙烯纤维对混凝土自愈能力的影响。通过28天的拉伸强度试验对圆柱形试样进行预裂。预裂后立即进行二次拉伸试验,水中再固化后28和56 d进行二次拉伸试验。为了监测混凝土预裂后和自愈期的微裂缝,进行了超声脉冲速度和渗透性试验。结果表明,掺加15%粉煤灰后,再养护8周后,渗透率降低94%,二次抗拉强度几乎完全恢复。预加载后聚丙烯试样的抗拉强度损失较纤维试样低(22%),但自愈期的改善率仅为27%。
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引用次数: 1
Product performance - a review of construction product conformity assessment 产品性能——建筑产品合格评定的评审
IF 1.1 Q3 Engineering Pub Date : 2021-04-03 DOI: 10.1080/13287982.2021.1909814
E. Gad, L. Pham, Jessey Lee, A. Amirsardari
ABSTRACT There is a need to improve the Australian conformance practice for construction products. This paper presents an overview of the current operating environment of Australia and discusses the different ways in which a product may not be fit for its intended use. Issues discussed in this paper include methods for identifying problematic products, multi-level conformity assessment system and how to make the Australian system perform better. Various institutions have made independent proposals to improve different aspects of the system. These efforts will be much more effective if coordinated into a national system.
有必要改进澳大利亚建筑产品的一致性实践。本文概述了澳大利亚目前的经营环境,并讨论了产品可能不适合其预期用途的不同方式。本文讨论的问题包括识别问题产品的方法,多层次合格评定体系以及如何使澳大利亚的体系更好地发挥作用。各机构提出了各自的建议,以改善该制度的不同方面。如果将这些努力协调成一个国家系统,将会有效得多。
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引用次数: 0
A Data-Driven Damage Assessment Tool for Truss-Type Railroad Bridges Using Train Induced Strain Time-History Response 基于列车应变时程响应的桁架式铁路桥梁损伤评估工具
IF 1.1 Q3 Engineering Pub Date : 2021-04-03 DOI: 10.1080/13287982.2021.1908710
Md Riasat Azim
ABSTRACT In this paper, a non-parametric damage detection method for truss-type railroad bridges is presented. The method uses operational strain time-history responses to detect damage in truss elements, and change in support behaviour. Dynamic strain time-history responses obtained under baseline and unknown-state bridge conditions are used to compute the magnitudes of differences in strain values between two successive time-steps. A new damage-sensitive feature (DSF) is proposed as the change in percentage of the square root of the sum of squared values of these magnitudes. After establishing a threshold DSF based on the baseline bridge, further structural change or damage in the bridge could be detected and located by observing the values of the DSFs. The validity of the method is investigated through finite element analysis of a steel-truss railway bridge. It is demonstrated that the proposed method yields promising results for identifying, locating, and relatively assessing the damage, and could be useful even when different operational conditions (i.e. different train speeds and loads) and measurement noise influence the strain data. Therefore, the proposed method has the potential to assist in developing effective maintenance strategies for railway bridges.
提出了一种桁架型铁路桥梁的非参数损伤检测方法。该方法使用工作应变时程响应来检测桁架元件的损伤和支持行为的变化。在基线和未知状态桥梁条件下获得的动态应变时程响应用于计算两个连续时间步之间应变值的差值。提出了一种新的损伤敏感特征(DSF),即这些震级平方和的平方根的百分比变化。在基于基线桥梁建立阈值DSF后,通过观察DSF值可以检测和定位桥梁进一步的结构变化或损伤。通过对一座钢桁架铁路桥梁的有限元分析,验证了该方法的有效性。结果表明,所提出的方法在识别、定位和相对评估损伤方面取得了很好的结果,并且即使在不同的运行条件(即不同的列车速度和负载)和测量噪声影响应变数据时也是有用的。因此,所提出的方法有可能有助于制定有效的铁路桥梁维修策略。
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引用次数: 2
Correlation between compressive strength and elastic modulus of light weight self-compacting concrete using coconut shell as coarse aggregate 椰壳粗骨料自重自密实混凝土抗压强度与弹性模量的关系
IF 1.1 Q3 Engineering Pub Date : 2021-04-03 DOI: 10.1080/13287982.2021.1926061
K. Poongodi, P. Murthi
ABSTRACT Aggregates are the fundamental ingredient for making concrete. The incremental demand for aggregates in concrete is affecting the environment due to excessive exploitation of natural rocks. In an effort to conserve the natural resources and minimise the adverse impacts of industrial by-products in the environment, it is essential to explore the suitable alternate materials for construction. Under such circumstances, an attempt was made with coconut shell aggregate (CSA) as a substitute for conventional coarse aggregate (CA) in self-compacting concrete (SCC). In this investigation, binary and ternary blended SCC were developed using the mineral admixtures such as rice husk ash (RHA) and silica fume (SF). Two series of SCC were designed with the total powder content of 450 and 550 kg/m3 , respectively, for investigation. The effects of CSA in SCC on fresh and hardened properties were studied and compared with the results obtained without CSA. The results revealed that use of 75% CSA in SCC reduced the density below the threshold level of structural lightweight concrete (1850 kg/m3) in dry state. The CSA-based lightweight self-compacting concrete (LWSCC) possesses good fluidity, deformability, passing ability and filling ability in its fresh state. The compressive strength and elastic modulus of LWSCC were determined and found that the results are decreased after the substitution of more than 75% of CSA. Further, the paper intended to predict an appropriate correlation between compressive strength and elastic modulus of CSA-based LWSCC.
集料是制造混凝土的基本成分。由于对天然岩石的过度开采,混凝土中骨料需求的增加正在影响环境。为了保护自然资源和尽量减少工业副产品对环境的不利影响,探索合适的替代建筑材料至关重要。在这种情况下,尝试用椰子壳骨料(CSA)代替常规粗骨料(CA)在自密实混凝土(SCC)中应用。本研究采用稻壳灰(RHA)和硅灰(SF)等矿物外加剂,研制了二元和三元混合SCC。设计了总粉量分别为450和550 kg/m3的两个系列的SCC进行研究。研究了SCC中添加CSA对其新鲜和硬化性能的影响,并与未添加CSA的结果进行了比较。结果表明,在SCC中使用75%的CSA,在干燥状态下,密度降低到结构轻量化混凝土的阈值水平(1850 kg/m3)以下。csa基轻质自密实混凝土在新鲜状态下具有良好的流动性、变形性、通过性和填充性。测定了LWSCC的抗压强度和弹性模量,发现CSA替代量超过75%后,结果有所下降。此外,本文旨在预测基于csa的LWSCC的抗压强度与弹性模量之间的适当相关性。
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引用次数: 5
期刊
Australian Journal of Structural Engineering
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