再生混凝土叠合梁板受弯性能数值分析

在已完成的再生混凝土叠合梁板受弯性能试验的基础上,运用Abaqus软件对叠合梁板进行了非线性有限元分析。验证了有限元模型的正确性之后,引进一种新的叠合型式,预制部分采用再生混凝土而现浇部分采用普通混凝土,然后用Abaqus对新叠合梁板进行分析。分析结果表明,新叠合型式更合理地利用了混凝土材料,进一步提高了结构的受力性能。     

预制装配式大跨钢板-再生混凝土空心叠合板受弯性能研究

总结现有钢筋混凝土地铁车站楼板结构形式,确定此类结构设计要点;提出适用于大跨度组合结构车站的钢板-再生混凝土空心叠合板形式,并对其受弯性能进行有限元分析。研究结果表明,目前我国地铁车站一般为矩形截面并多采用现浇混凝土梁板结构,部分工程也验证了钢筋混凝土叠合板应用的可行性;采用ABAQUS建模技术可有效模拟钢筋混凝土空心叠合板的受弯性能,提出的钢板-再生混凝土空心叠合板构件具有较好的受弯性能。     

再生混凝土叠合梁受弯力学性能试验研究

设计了3根再生混凝土叠合梁,受拉钢筋配筋率分别为0.5%、1.0%、1.5%,预制部分采用普通混凝土,叠合部分采用100%再生粗骨料取代率的再生混凝土。另外设计了1根整浇梁,全部采用再生粗骨料取代率的再生混凝土。通过受弯性能试验,得到挠度和裂缝发展规律以及破坏特征。运用Ansys软件对叠合梁进行了非线性有限元分析。试验结果和数值分析表明,再生混凝土叠合梁的受弯力学性能和普通混凝土梁受弯性能接近,其受弯承载力可采用普通混凝土梁的计算方法进行计算。采用再生混凝土的弹性模量,利用现有规范GB 50010—2002短期刚度计算公式得到的挠度,需乘以0.8的修正系数后才适用于再生混凝土叠合梁。     

再生混凝土叠合板受弯力学性能试验

设计了3块再生混凝土叠合板,配筋率分别为0.5％、1.0％、1.5％,预制部分采用普通混凝土,叠合部分采用100％再生粗骨料取代率的再生混凝土,叠合面采用人工粗糙面.另外设计了1块整浇板,全部采用100％再生粗骨料取代率的再生混凝土,以进行对比试验.通过受弯性能试验,得到了挠度和裂缝发展规律以及破坏特征.试验结果表明,再生混凝土叠合板的受弯力学性能和普通混凝土板受弯性能接近,其极限承载力可采用普通混凝土叠合板的计算方法进行计算.当配筋率不低于1％时,采用再生混凝土的弹性模量,按现有规范短期刚度公式计算的挠度乘以0.9的修正系数后仍适用于再生混凝土叠合板.     

含烧结砖骨料预制再生混凝土叠合梁抗弯性能试验研究

设计了C35和C45混凝土叠合梁各4根,其中预制部分采用含烧结砖骨料再生混凝土,后浇部分采用普通混凝土,预制部分含烧结砖再生骨料取代率分别为0％、33.3％、66.7％和100％,并进行了预制再生混凝土叠合梁抗弯试验,以研究不同混凝土强度等级、再生骨料取代率对混凝土叠合梁抗弯性能的影响.试验结果表明:预制部分再生骨料的...     

含烧结砖骨料预制再生混凝土叠合梁抗弯性能试验研究

设计了C35和C45混凝土叠合梁各4根,其中预制部分采用含烧结砖骨料再生混凝土,后浇部分采用普通混凝土,预制部分含烧结砖再生骨料取代率分别为0%、33.3%、66.7%和100%,并进行了预制再生混凝土叠合梁抗弯试验,以研究不同混凝土强度等级、再生骨料取代率对混凝土叠合梁抗弯性能的影响。试验结果表明:预制部分再生骨料的取代率与梁的刚度并未有明显关联;预制部分再生骨料取代率并不会明显改变混凝土梁的延性,极限状态没有明显区别;预制再生混凝土叠合梁的抗弯承载力、刚度与规范值接近,实际工程中可以在混凝土叠合梁的预制部分采用较高取代率的再生混凝土;在适用性方面,预制部分再生骨料取代率的提高会加剧裂缝宽度的发展。     

预应力再生混凝土叠合梁受弯性能试验研究

为研究无黏结预应力再生混凝土叠合梁构件的受弯性能,以再生混凝土在叠合梁中的位置、叠合层高度、构件的配筋率为参数,对1根预应力普通混凝土整浇梁、1根预应力再生混凝土整浇梁和6根预应力再生混凝土叠合梁构件进行弯曲加载试验,分析了试验梁构件的受力过程和破坏形态,探讨了各参数对试验梁构件极限承载力的影响.基于试验数据,对承载力...     

双面叠合剪力墙叶板连接形式对构件受力影响的分析

双面叠合剪力墙由两侧预制混凝土叶板和中间后浇混凝土叠合层组成,因其节省模板,减轻自重利于吊装,故应用前景广阔.传统叠合剪力墙一般使用桁架筋对两侧叶板拉结,但随着研究发展,三一筑工研发的SPCS体系叠合剪力墙开始采用预制钢筋笼对叶板拉结.围绕这2种连接形式,采用通用有限元软件Abaqus进行建模分析,在2种轴压比下,提取应力云图和滞回曲线,根据计算结果分析不同叶板连接形式对构件受力造成的影响.     

部分再生混凝土T形截面叠合梁抗弯性能试验研究

通过4根部分再生混凝土T形截面叠合梁和1根普通混凝土T形截面叠合梁受弯试验结果的对比分析,研究了各试验梁荷载作用下跨中正截面的受荷性能及极限破坏形态。试验结果表明,部分再生混凝土T形截面叠合梁的受力性能及破坏机理与普通混凝土类似;混凝土梁正截面的平截面假定依然成立;随再生骨料取代率的增加,试验梁的开裂荷载及极限承载力均略有降低。     

再生混凝土U型叠合梁抗剪性能

通过3根再生混凝土U型叠合梁和1根再生混凝土整浇梁的抗剪性能对比试验,研究了U型叠合梁和整浇梁的裂缝发展、破坏形式和抗剪承载力.试验结果表明:再生混凝土U型叠合梁的抗剪破坏形式和受力机理与整浇混凝土梁类似,再生混凝土U型叠合梁的抗剪承载力计算可参照整浇梁的抗剪承载力计算方法.     

Long-term deflection of cracked composite beams with nonlinear partial shear interaction — A study using neural networks

A new study of the short- and long-term deflections of simply-supported composite beams using finite element analysis and artificial neural networks (ANNs) is presented. In this study, two ANN models are developed and trained using the results of a finite element model developed by the authors in a companion paper. The finite element model accounted for the nonlinear load–slip relationship of shear connectors as well as the creep, shrinkage, and cracking of concrete slabs. The effects of creep and shrinkage of the concrete slab are considered only for non-cracked concrete. A large database representing a wide range of different design parameters was constructed for the purpose of training and verifying the two ANN models. It was found that the two ANN models were capable of predicting deflections of composite beams not used as part of the training process. The ANN models were then used to evaluate the effects of non-geometric design variables on the short- and long-term deflections of simply-supported composite beams. Finally, the short- and long-term deflections computed based on the approaches given in the AISC specification and Eurocode 4 were assessed using the results of the finite element model. It was found that the AISC approach underestimates short-term deflections and overestimate long-term deflections when compared with the results of the finite element method.     

钢筋再生混凝土结构研究进展及其工程应用

再生混凝土绿色、环保,是实现建筑垃圾资源化再利用的重要途径。为了进一步推动钢筋再生混凝土结构的研究发展与工程应用,分析了钢筋再生混凝土梁、板、柱、剪力墙、梁-柱节点及框架结构的受力性能、抗震性能、抗火性能、氯离子侵蚀后性能、徐变及抗冻性能的研究现状及存在的不足,列举了典型工程案例,指出了需要深化研究的问题。研究表明,钢筋再生混凝土梁、板、柱、剪力墙、梁-柱节点及框架结构的上述多数性能较同类钢筋普通混凝土构件(结构)的均有不同程度的劣化,但可通过合理设计实现其与普通混凝土相当甚至更好的性能,可用于实际工程中。     

压型钢板组合梁滑移性能的有限元分析

利用ANSYS有限元软件对压型钢板组合梁模型进行了有限元数值模拟分析,将有限元分析结果与试验结果进行了比较,验证了模型的合理性,利用ANSYS软件对压型钢板组合梁在栓钉布置方式和混凝土板强度影响下交界面的滑移性能进行了探讨.     

锈蚀钢筋再生混凝土梁力学性能试验研究及ANSYS分析

通过对钢筋通电加速锈蚀的方法,对12根不同钢筋锈蚀率下粗骨料取代率为100%再生混凝土梁的三分点加载试验,分析相同强度条件下不同钢筋直径和锈蚀率的再生混凝土梁力学性能的影响。结果表明:当钢筋锈蚀率小于10%时,钢筋与再生混凝土的粘结强度足以保证两者能够共同工作,此时试验梁发生材料强度破坏模式;当钢筋锈蚀率超过了10%时,钢筋与再生混凝土的粘结强度不足以保证两者共同工作,此时试验梁发生粘结失效破坏模式。基于ANSYS有限元软件对不同钢筋锈蚀率的再生混凝土梁进行模拟分析,并对锈蚀钢筋再生混凝土梁跨中截面的荷载应力关系曲线进行验算,通过有限元结果与试验结果对比,验证了有限元分析模型的可靠性。     

非线性局部剪力交互作用下的开裂组合梁长期变形神经网络研究

结合有限元分析和人工神经网络,提出一种新的思路,研究简支组合梁的短期和长期变形。本文建立两个神经网络模型,采用相关论文中有限元模型的结果进行样本训练。有限元模型考虑了抗剪连接件的非线性荷载-滑移关系,以及蠕变、收缩和混凝土板的裂缝。而对没开裂的混凝土只考虑了蠕变、收缩的影响。为训练及验证两个神经网络模型,建立了一个包括不同设计参数的大数据库。研究发现,两个神经网络模型均能预测组合梁的变形。因此,神经网络模型可用以评估非几何设计参数对简支组合梁的短、长期变形影响。最后,根据AISC规范和欧洲规范4方法计算简支组合梁的短、长期变形,并与有限元模型结果进行比较。结果表明,与有限元方法相比,AISC方法低估了短期变形而高估了长期变形。     

钢-再生混凝土组合结构力学性能研究综述

综述了钢一再生混凝土研究的最新进展,主要包括：钢管再生混凝土、钢骨再生混凝土短柱、压型钢板一再生混凝土组合板等。综合国内外学者试验和理论研究表明,钢一再生混凝土与普通钢一混凝土具有相类似的工作性能,通过组合能够提高再生混凝土的力学性能,改善再生混凝土的耐久性。     

Behaviour of headed stud shear connectors for composite steel-concrete beams at elevated temperatures

The behaviour of composite steel-concrete beams at elevated temperatures is an important problem. A three-dimensional push test model is developed herein with a two-dimensional temperature distribution field based on the finite element method (FEM) and which may be applied to steel-concrete composite beams. The motivation for this paper is to increase the awareness of the structural engineering community to the concepts behind composite steel-concrete structural design for fire exposure. The behaviour of reinforced concrete slabs under fire conditions strongly depends on the interaction of the slabs with the surrounding elements which include the structural steel beam, steel reinforcing and shear connectors. This study was carried out to consider the effects of elevated temperatures on the behaviour of composite steel-concrete beams for both solid and profiled steel sheeting slabs. This investigation considers the load-slip relationship and ultimate load behaviour for push tests with a three-dimensional non-linear finite element program ABAQUS. As a result of elevated temperatures, the material properties change with temperature. The studies were compared with experimental tests under both ambient and elevated temperatures. Furthermore, for the elevated temperature study, the models were loaded progressively up to the ultimate load to illustrate the capability of the structure to withstand load during a fire. It is concluded that finite element analysis showed that the shear connector strength under fire exposure was very sensitive. It is also shown that profiled steel sheeting slabs exhibit greater fire resistance when compared with that of a solid slab as a function of their ambient temperature strength.     

Strength and post‐yield behavior of T‐section steel encased by structural concrete

In this study, the seismic performance of unsymmetrical steel–concrete composite precast beams with T‐shaped steel section were numerically explored and validated by their earlier experimental investigation. This design is based on the proposed calibrated finite element model in which key damage parameters for the evaluation of the nonlinear, post‐yield behavior of the precast composite steel beams were identified. The proposed nonlinear finite‐element‐based numerical model uses various parameters, including the dilatation angle and concrete‐damaged plasticity, to simulate the nonlinear behavior of unsymmetrical composite precast beams with T‐section steel. Greater seismic capacity with greater ductility, contributing to a maximized structural capacity within the composite precast beams was introduced by the effective use of the 2 materials, steel and concrete, and shown by the nonlinear hysteretic investigation of unsymmetrical steel–concrete composite precast beams that was validated experimentally. The post‐yield structural capacity found via the numerical analysis agrees with experimental results when the concrete‐damaged plasticity of the plastic‐damaged seismic model for concrete and the von Mises criteria of the steel section were introduced into the finite element model. Practical design parameters and recommendations were eventually suggested by examining the influence of precast composite beams with unsymmetrical steel sections on the concrete degradations and damage evolution.