压型钢板-混凝土组合楼板的承载能力研究

压型钢板-混凝土组合楼板的承载能力受楼板叠合面的纵向抗剪能力控制。本文通过3组组合楼板的荷载试验,研究了单跨简支组合楼板和两跨连续组合楼板的极限抗剪和抗弯性能。试验结果表明:组合楼板的极限承载能力受叠合面的纵向抗剪能力控制;与简支组合楼板相比,连续组合楼板承载能力有明显提高,跨中挠度显著减小,端部支座剪力出现滑移时与简支板端部剪力值相近,显示了连续组合板的端部滑移与剪力的关系与简支板的情况相似。但与简支组合板不同的是,连续组合板端部出现滑移后,其极限承载能力明显高于相同跨度简支板极限承载力。根据试验结果,得到了组合楼板叠合面纵向抗剪能力的计算公式。在组合楼板的承载力设计中,应对支座端部的竖向剪力进行叠合面的纵向抗剪能力验算,文中提出了连续组合楼板的承载力计算方法。     

钢-混凝土组合楼板实用抗火设计方法

利用钢-混凝土组合楼盖抗火性能非线性有限元分析程序对不同荷载大小、不同压型钢板厚度、不同配筋的压型钢板-混凝土组合楼板进行了抗火性能分析,找出了火灾影响下组合楼板结构性能的因素,给出了计算组合楼板耐火时间的拟合公式,得到了一些适用于压型钢板-混凝土组合楼板抗火设计的结论和建议。     

压型钢板组合楼板承载力的有限元分析

压型钢板组合楼板是 2 0世纪发展起来的一种新型结构形式。它具有显著的优势 ,如轻质、高强 ,施工快捷等 ,将在未来的建筑领域中大有作为。组合楼板的承载力主要取决于钢板 -混凝土界面处的抗剪强度。建立了一个二维有限元模型来研究单向组合板的性能。并将计算结果与试验数据进行对比 ,验证了模型的有效性     

缩口型压型钢板-混凝土组合板的承载力及变形(二):考虑滑移效应的折减刚度

压型钢板与混凝土之间的相对滑移对压型钢板-混凝土组合板的变形影响较大。现行有关规范在计算组合板挠度时,未考虑滑移效应,导致变形计算值偏低,偏于不安全。在钢-混凝土组合梁挠度计算的折减刚度法基础上,考虑组合板自身的受力特点,提出了考虑滑移效应的组合板折减刚度公式。试验结果表明,该法能较准确地预测组合板在正常使用状态下的挠度。     

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.     

Influence of tensile strength on toppling failure in centrifuge tests

In toppling of rock slopes, thin slabs of rock displace out of the slope, eventually forming a rupture surface. This toppling process involves slip between the thin slabs and tensile rupture across the slabs. A numerical modelling methodology based on a discrete element framework was used to investigate centrifuge model tests of a toppling slope. The methodology, which includes internal flaws in the intact rock slabs, was able to predict the rupture surface inside the rock mass more accurately than is possible with the conventional discrete element method. Also, this modelling approach predicted the horizontal deformation patterns observed in the experimental study. The effect of tensile strength on the flexural toppling failures was investigated to further our understanding of the flexural toppling. The tensile strength was found to be a key factor in this failure mechanism, and the failure load was found to be controlled by the tensile strength. Moreover, the friction angle of the intact rock did not have a significant effect on the toppling failure mechanism.     

压型钢板-竹胶板组合楼板的力学性能试验研究

为拓宽竹材的应用范围,实现建筑结构构件材料和形式的多样化,本文在阐述竹材的构造和力学性能以及竹材改性产品的基础上提出了一种新型的组合楼板──将竹胶板与压型钢板用结构胶粘结成为压型钢板-竹胶板组合楼板,并针对这一新型组合楼板进行了试验研究及理论分析。以竹胶板厚度、芯部压型钢板厚度及组合楼板跨度为参数进行了6块组合楼板的力学性能试验。结果表明,压型钢板-竹胶板组合楼板的整体工作性能优良,竹胶板与钢板之间具有很好的组合效应,能够提供较高的承载力和刚度,其力学性能可以满足作为建筑楼板的需要。根据组合楼板在正常使用阶段的变形范围内呈现出理想弹性性能的试验结果,提出了组合楼板抗弯刚度的计算方法;根据破坏阶段的应力状态提出了组合楼板极限受弯承载力计算方法,据此计算的组合楼板跨中挠度及受弯承载力的计算值与试验值吻合较好。     

Experimental and numerical study on restrained composite slab during heating and cooling

In this paper, a series of fire tests on restrained composite slabs, carried out at the University of Manchester, is presented. A total of six composite slabs were tested under different fire scenarios, with different load ratios. The tests were particularly concerned with the variation of internal forces within the slabs during both heating and cooling phases. In addition to the testing programme, two separate nonlinear finite element models have been developed to simulate the thermal and mechanical behaviour of composite slabs during heating and cooling, which is introduced in detail in this paper. In the thermal analysis model, plane elements were adopted to obtain a detailed thermal behaviour. In the structural analysis model, the concrete, steel deck and mesh were simulated by solid elements, shell elements and truss elements respectively. The interaction between the concrete and steel sheet was simplified to spring elements. According to the experimental results and FE modelling, the behaviour of composite slabs was analysed in detail. At last, the parametric study was performed where the effect of concrete strength, steel deck thickness and mesh size was analysed.     

加热和冷却过程中约束复合板的试验及数值研究

在曼彻斯特大学,对约束复合板进行一系列耐火试验。在不同火灾场景下,对6块不同荷载比下的复合板进行试验,观察加热和冷却过程中板内力的变化。设计试验方案,建立两种不同的非线性有限元模型,模拟复合板在加热和冷却过程中的热学和力学性能。在热分析模型中,采用平面单元模拟。在结构分析中,混凝土、钢板、锚钉分别采用实体单元、壳单元、桁架单元模拟。混凝土和钢板间的连接简化为弹簧单元。根据试验结果和有限元计算结果,详细分析了复合板的性能。最后,进行参数研究,分析了混凝土强度、钢板厚度和锚钉尺寸的影响。     

Shear bond mechanism of composite slabs — A universal FE approach

The strength of concrete slabs composited with cold-formed profiled steel decks is normally governed by the longitudinal shear bond failure at the steel concrete interface. The design methods for the longitudinal shear bond strength adopted in the current construction practice such as the m-k method and partial interaction method all based on the full-size tests, which are expensive and time consuming, however are also semi-empirical. A universal FE approach of composite slabs is presented, in which the shear bond interaction between the steel deck and the concrete is treated as a contact problem considering adhesion and friction. Both geometrical and material nonlinearities are all considered in the FE model. The preliminary FE analysis is verified in simulation of the pull-out tests as far as the cohesion and the frictional bond of the contact interface are considered. The fine FE analysis using the contact model is further carried out in study of the composite slabs in flexural bending. The FE analysis based on the nonlinear contact concept is verified and validated by comparing the test results for both the pull out and bending tests of the composite slabs. Comparisons of the experimental and the FE analytical results indicate that the FE analysis based on the interface contact model, agree well with the test results, and is capable of predicting the performance and the load carrying capacity of composite slabs.     

组合楼板的最新发展——钢纤维网片混凝土承板组合楼板

众所周知 ,组合楼板的承载力主要取决于钢板 -混凝土界面处的抗剪强度 ,而许多因素影响抗剪强度。现在美国开发出一种新型组合板形式 :钢纤维网片混凝土承板———SIMCON承板组合楼板 ,性能优越 ,有大力推广的潜力     

Analysis of Shear Connector of Steel–Concrete Composite Box-Girder Bridge Considering Interfacial Bonding and Friction

Steel–concrete composite bridges consist of steel and concrete parts which are connected by shear connector such as the widely-used headed stud. Through the chemistry bonding, interface friction and mechanical action the two different materials parts are combined as a composite structure system. Because of the structural mechanism, longitudinal and lateral relative slip and normal separation between the concrete deck and steel girder flange will inevitably exist during the loading process. Further, the complex interface mechanical behavior causes difficulties with nonlinear numerical analysis. Multiple broken lines mode cohesive zone model considering bonding and friction is used in this paper to describe the tangent slip and normal crack of the interface. A zero thickness cohesive element was implemented via the user-defined element subroutine UEL in ABAQUS. Using this method, numerical simulation analysis of a two span composite continuous box-girder was carried out. Results showed load–displacement curves of the structure, relative displacement between the steel girder and the concrete slab interface, interface stress distribution, and internal force of shear studs. Discontinuous deformation numerical simulation has been realized, and effectiveness of the proposed method and accuracy of the program were verified. Although shear stress was assumed to be transmitted by shear connector in the design stage, interface bonding and friction resistance can affect the force state of the shear connector. Results of this study can be used for detailed analysis and evaluation of the composite box-girder bridge without the need to rely on the constitutive laws of shear connectors obtained from push-out tests.     

压型钢板-混凝土组合楼板粘结试验研究

文章对压型钢板与混凝土的交界面上是否涂有四环胶水泥砂浆的两种组合楼板进行了试验。经分析比较得出这种新型粘结剂作为抗剪措施的可行性。     

Testing of composite steel top-and-seat-and-web angle joints at ambient and elevated temperatures, Part 1: Ambient tests

This paper presents six ambient tests on composite steel top-and-seat-and-web (TSW) angle joint specimens subject to monotonic loading. It is well known that the inherent strength and stiffness of composite semi-rigid joints can improve the structural behaviour of steel frame structures. However, experimental works on the composite steel TSW angle joints are very limited. The main objective of this study is to ascertain the ambient moment-rotation characteristics of composite steel TSW angle joints and to validate the authors’ mechanical model. The test results are presented and the joint failure modes are described. The effects of some parameters on the overall joint behaviour, such as longitudinal shear strengths of RC slabs, steel beam depths and tightening torques of bolts are investigated. With the development of a new joint component to represent the RC slab in tension, the authors’ mechanical model proves to be able to produce accurate and consistent predictions of the moment-rotation characteristics of composite steel TSW angle joints. The analytical results are compared with the test results and good agreement is achieved.     

标准升温下钢-混凝土组合板的抗火性能

应用有限元和有限差分相结合的方法,计算压型钢板组合板和肋筋模板组合板的温度场,并与试验结果进行比较。采用数值方法计算组合板的耐火极限,同时分析有关的影响参数。结果表明:由于混凝土的吸热作用,组合板的耐火性能要优于无保护的钢构件;组合板的耐火极限随着板厚和混凝土强度的提高而提高,随着含钢率的增加而降低。最后本文计算了组合板的耐火保护层厚度,给出了耐火简化计算公式,有关结果可供工程实际参考。     

Steel-Concrete-Steel sandwich slabs with lightweight core — Static performance

This paper investigates the static performance of Steel-Concrete-Steel (SCS) sandwich slabs which consist of an ultra-lightweight concrete core sandwiched between two steel plates. Special J-hook connectors have been developed to develop composite action between the concrete core and the two steel plates. The core is made of lightweight concrete of density less than 1450 kg/m³. Laboratory tests were carried out on eight SCS sandwich slabs under centrally applied patch load. Test results showed that the mode of failure and crack pattern of SCS sandwich slabs were very similar to those of reinforced concrete slabs especially when the concrete core and steel plates act in a fully composite manner. Flexural and punching are the primary modes of failure. After flexural yielding, membrane action developed in the slab due to the effectiveness of J-hook connectors in maintaining composite action which further increases its load carrying capacity after flexural yielding. Theoretical models are proposed to predict the flexural and punching resistance and a good correlation with test results is obtained. A large deflection analysis considering plate membrane action is also proposed to predict the force deflection relation of SCS sandwich slabs.     

闭口型压型钢板-混凝土组合板疲劳性能试验研究

为研究闭口型压型钢板-混凝土组合板的疲劳性能,完成14块闭口型压型钢板-混凝土组合板的疲劳试验研究。试验主要考察组合板端部栓钉布置、组合板板厚、疲劳荷载水平及组合板加载剪跨比等4个主要因素对组合板疲劳破坏模式及疲劳损伤程度的影响。试验过程中对组合板在各个关键阶段的动挠度、动滑移、压型钢板及混凝土应变、组合板残余挠度及组合板剩余承载能力等参数进行测量和分析。在试验研究基础上,根据组合板疲劳破坏形态及损伤发展情况,着重对组合板的疲劳性能进行较全面研究,初步提出组合板疲劳性能水平评估方法及组合板疲劳设计建议。试验研究结果表明,无栓钉组合板的疲劳性能明显差于带栓钉组合板,布置栓钉可大大提高组合板疲劳性能;无栓钉组合板的设计疲劳荷载上限可以取为40%的静力极限荷载,而带栓钉组合板的设计疲劳荷载上限可以取为60%的静力极限荷载。研究结果为闭口型压型钢板-混凝土组合板疲劳设计计算提供有利依据。     

Testing of composite steel top-and-seat-and-web angle joints at ambient and elevated temperatures: Part 2 — Elevated-temperature tests

An experimental programme of eight elevated-temperature tests on composite steel top-and-seat-and-web (TSW) angle joints was carried out to investigate the behaviour of this form of joints under fire conditions. It is found that the inherent strength and stiffness of composite joints can significantly improve the structural behaviour of steel framed structures under fire conditions. However, experimental works on composite steel TSW angle joints under fire conditions have not been published yet. To develop a versatile model to predict the joint moment-rotation characteristics, the authors have developed a component-based mechanical model for this form of joints. The objectives of this study are to ascertain the moment-rotation characteristic for this form of joint at elevated temperatures and to validate the authors’ mechanical model. The effects of some parameters on the overall joint behaviour, such as elevated temperatures, longitudinal shear strength of RC slabs, steel beam depth and bolt behaviour were observed and investigated. The mechanical model predictions are compared with the test results and showed good agreement.     

压型钢板-混凝土组合楼板粘结试验研究

压型钢板-混凝土组合楼板因其具有刚度大、延性好、施工方便、经济效益优越等特点,目前在我国得到较为广泛的应用。通过对3种共27块(2W、3W、BONDECK各9块,2W、3W为开口板,BONDECK为缩口板)镀锌压型钢板-混凝土组合楼板的试验研究,分析了不同剪跨下,混凝土强度、压型钢板厚度、组合楼板厚度等因素对组合楼板极限承载力的影响,总结了压型钢板-混凝土组合楼板剪切-粘结破坏的形态及受力变形性能,利用回归分析提出了以混凝土抗拉强度特征值ft表征的剪切-粘结承载力计算公式。     

钢板-混凝土组合板受弯性能试验研究

以钢板代替受力钢筋,通过栓钉将外侧钢板与内部混凝土板相连,二者共同作用形成钢板-混凝土组合板。根据钢板布置形式的不同,可将钢板-混凝土组合板分为单面钢板-混凝土组合板（SSC）和双面钢板-混凝土组合板（DSC）。通过对4个SSC试件和3个DSC试件的受弯试验研究,分析了不同钢板厚度、抗剪连接程度以及构造钢筋配置对组合板受弯性能和破坏形态的影响。试验结果表明,按完全抗剪连接设计的试件破坏形态与适筋梁相似,具有良好的受弯承载能力和延性;当受拉区钢板采用部分抗剪连接设计时,剪跨区栓钉易剪断导致承载力明显降低;当受压区钢板采用部分抗剪连接设计时,顶层钢板易发生局部屈曲,导致试件承载力和延性有所降低。基于试验结果,给出了钢板-混凝土组合板的受弯承载力计算式,计算值与试验值吻合较好。