Seismic behaviour of beam-to-column partial-strength joints for steel-concrete composite frames

The paper presents a large experimental campaign carried out on ten steel-concrete composite beam-to-column sub-assemblages employing monotonic and cyclic loading test protocols. Structural members (beams, columns and slabs) were defined through the design of a full-scale 3D prototype frame subjected to PSD testing campaign; main design hypothesis was to dissipate seismic energy in the joints designed as partial-strength. Testing programme on beam-to-column sub-assemblages was executed in order to assess seismic performance varying structural details at beam-to-column connection level and material qualities. Different mechanical connecting systems between concrete slab and column, two end-plate configurations, weak and strong column web panel, two steel qualities and different concrete strengths.The analysis of sub-assemblages performance was realized in two steps: a first step in which the joints behaviour was assessed, characterizing response at local level (e.g. moment-rotation curves); a second step in which the response was assessed at global level (e.g. force-displacement curves). The structural behaviour (i.e. resistance, plastic deformation and stiffness) was evaluated at three stages-identified as initial, service and maximum load-in order to monitor the evolution of sub-assemblage response increasing solicitation level. Moreover, seismic behaviour of specimens-in terms of dissipated energy, ductility, over-strength and equivalent viscous damping-was also executed. Comparison between experimental results was made in order to identify those parameter suitable for improved and reliable seismic behaviour of steel-concrete composite partial-strength joints.     

栓钉连接件时变受剪承载力对组合梁施工阶段受力性能的影响

为了对钢-混凝土组合梁施工阶段的受力性能进行准确分析,针对我国常用的隔板式组合梁,通过推出试验研究栓钉连接件受剪承载力随混凝土龄期的变化规律,采用ANSYS有限元分析软件分析栓钉连接件时变受剪承载力对某连续曲线组合梁施工阶段受力性能的影响。分析结果表明：在混凝土龄期很短时栓钉连接件就具有一定的受剪承载力和抗剪刚度,且早期增长快,后期增长慢;混凝土板分段浇筑时组合梁的应力和变形随浇筑时间间隔的增加逐渐减小,在本文实例中,与不考虑浇筑过程中混凝土与钢梁的组合作用时相比,浇筑时间间隔为6 h的组合梁径向变形减小26.5%;与考虑28 d龄期混凝土与钢梁的组合作用时相比,浇筑时间间隔为3 d的组合梁切向应力增大14.2%。因此,当组合梁混凝土板浇筑时间间隔在6 h至3 d之内时,均应采用栓钉连接件的时变受剪承载力来分析浇筑过程中混凝土与钢梁的时变组合作用对组合梁施工阶段受力性能的影响。     

Non-linear analysis of steel-concrete composite frames with full and partial shear connection subjected to seismic loads

The seismic performance of moment-resisting frames consisting of steel-concrete composite beams with full and partial shear connection is investigated. To this end, six full scale composite substructures with headed stud shear connectors have been tested and the corresponding inelastic response to both monotonic and variable reversed displacements have been investigated. Three-dimensional finite element models of the substructures set with the ABAQUS code and based on shell elements are established in order to evaluate different modelling assumptions and local effects; and to calibrate a one-dimensional model conceived with the Drain-3DX code relying on layered beam-column elements. The one-dimensional model is then exploited for a parametric study on two four-storey frames by means of non-linear dynamic analyses. The analyses have revealed that composite frames with a low shear connection degree of about 0.4 perform as well as their companion frames with full shear connection under severe seismic loads. Nonetheless, the shear connection degree should be high enough in order to protect shear connectors in the central part of beams from failure. Although their equivalent damping is not very high, shear connectors could reduce the ductility demand on other parts of a composite frame, such as beam ends or partial strength beam-to-column joints. This design option could provide a further means to achieve a favourable performance of a composite moment-resisting frame, in addition to the benefit of cost reduction.     

Seismic behavior of CFRSTC composite frames considering slab effects

This paper reports on an experimental and numerical investigation conducted on the seismic behavior of concrete-filled rectangular steel tubular columns (CFRSTC) composite frames. The experimental study was conducted by subjecting two full-scale composite frames to simulated seismic loads. Both frames were composed of CFRSTC and steel beams. One specimen was placed on a reinforce concrete (RC) floor slab and the other was not. The purpose of the test was to investigate the elasto-plastic performance of the CFRSTC composite frame system and to examine the effects of composite action on the behavior of composite frames. The test results showed that the stiffness, strength and energy-dissipating capacity of the CFRSTC frame increased significantly with the presence of the floor slab. Compared with a bare steel beam, the composite beam experienced a decrease in the rotation capacity from 0.046 rad to 0.026 rad. The shear deformation of the panel zone grew because of the composite action, which delayed the fracture of the beam. Finite element (FE) models were established to simulate the tested frames. The results of the FE model fit well with that of the test model in terms of stiffness, strength, hysteretic behavior and component deformation.     

钢—混凝土组合结构的研究

针对钢—混凝土组合结构的受扭承载力、抗火性能、节点抗震性能进行了详细的实验研究,对比分析了钢—混凝土组合结构与普通混凝土结构的性能,指出钢—混凝土组合结构由于混凝土内部型钢的存在可使组合试件的性能得到更好的发挥。     

钢——混凝土组合梁的侧向扭转屈曲

通过对工字型钢-混凝土组合梁劁向失稳形式的理论分析,提出工字型组合梁稳定性分析的计算模型,并根据计算模型推导了组合梁负弯矩区受压下翼缘劁向屈曲的临界弯矩,然后通过与现行工字型组合梁的稳定理论和计算方法比较,确定了工字型组合梁负弯矩区稳定设计的修正方法和建议意见。     

Design method for long-term deflections of composite steel-concrete slabs considering non-uniform shrinkage effects

为研究沿截面高度混凝土非均匀收缩对钢-混凝土组合板长期挠度的影响,基于国内外现有组合板长期性能的试验研究确定了组合板非均匀收缩预测模型;采用MATLAB语言,建立了可考虑非均匀收缩、徐变及混凝土开裂综合影响的组合板非线性有限元模型,据此系统分析了各参数对组合板收缩挠度的影响;沿用现有组合板设计规范中有效刚度的概念,提出了可考虑非均匀收缩影响的组合板长期挠度计算公式。研究结果表明,由非均匀收缩引起的挠度占组合板长期挠度的58%~86%,组合板设计时不应忽略非均匀收缩的影响;混凝土抗压强度和组合板跨高比对组合板收缩挠度的影响较大;所提出的组合板长期挠度计算公式预测结果与有限元分析结果吻合较好,公式预测结果与有限元分析结果比值的均值为0.971~0.997,判定系数R2为0.803~0.815。     

钢-混凝土组合结构住宅的设计分析

介绍了多层及小高层住宅结构体系选用钢—混凝土组合结构的优越性 ,分析了结构受力构件的类型 ,指出钢—混凝土组合结构中 ,多采用热轧型钢构件 ,使其结构受力更合理     

预应力钢-混凝土组合梁的预加力效应

预应力组合结构应用中存在很多需要深入研究的问题 ,本文分析了预应力组合结构的预加力效应 ,并探讨了预应力组合结构的若干关键技术     

钢—混凝土组合箱梁的抗扭强度

共进行了9根钢-混凝土组合箱梁的扭转试验,其中4根用于研究纯扭性能.5根用于研究弯扭性能,初步掌握了该类型梁的抗扭机理.组合箱梁截面通过两种机制抵抗截面扭矩:U形钢梁和混凝土翼板组成的组合箱形截面(称为组合抗扭),及混凝土翼板开裂后形成的等效箱形截面(称为混凝土翼板抗扭).组合箱梁在扭转中,截面上存在组合作用,即混凝土翼板和钢梁间存在相互约束作用.U形钢梁的抗扭贡献在于:它不仅作为组合箱形截面的重要组成部分,自身承担较大的扭矩,而且向混凝土翼板提供纵向约束,抑制混凝土裂缝的开展.在试验分析的基础上,采用钢筋混凝土变角软化桁架模型,建立了适于分析钢-混凝土组合箱梁复合弯扭强度的三维桁架模型.该模型充分满足平衡条件、变形协调条件和材料本构方程,可以较准确地用于预测组合箱梁的极限强度.此外,还对组合箱梁的弯扭相关强度进行了研究.     

Strength of double skin steel-concrete composite walls

Double skin steel-concrete composite walls have been increasingly used in civil engineering applications. However, the advantages of these walls have not been fully recognized due to the lack of appropriate technical guidelines for capacity design. In this paper, the local buckling strength of steel plate were firstly reviewed in terms of specifications incorporated in several modern codes. A methodology to predict the strength of steel plate with restraint of both concrete and shear studs was proposed based on the explicit solution for local buckling of steel plate in composite shear walls subjected to uniform axial compression and with elastically rotational restraint at loaded and unloaded edges. The results were compared with various previous experimental data and good agreement was observed. Furthermore, the load carrying capacity of composite walls was derived from the superposition of the contribution of steel plate and concrete. The predicted values from the proposed equations, together with the resulted determined from modern codes, were compared with the experimental results. It was found that both the proposed method and JEAG 4618 offer reasonable predictions while AISC 360 and KEPIC-SNG always underestimate the actual values.     

ABAQUS在钢板一混凝土复合材料结构中的应用

用ABAQUS有限元软件对钢板-混凝土复合材料进行了仿真模拟，通过不同工况的计算对比，显示出钢板-混凝土复合材料的优点，验证了在保证钢板与混凝土梁协同工作条件下，采用该结构的可行性。     

谈钢—混凝土组合结构耐火性

简要介绍了钢—混凝土组合结构的形式、优势及其抗火性能,运用ANSYS软件,分析了钢管混凝土的截面温度场分布,体现了其优越性,并总结了常见的耐火保护方法,以供参考。     

钢-混凝土组合结构桥梁研究新进展

钢-混凝土组合结构桥梁近年来在我国得到了迅速的发展。在传统桥梁结构形式的基础上,发展多种新型组合结构桥梁形式,拓宽组合结构桥梁的应用领域。介绍近年来在钢-混凝土组合结构桥梁方面的最新研究进展,内容包括波形钢腹板组合梁桥、槽型钢-混凝土组合梁桥、钢-混凝土组合刚构桥、双重组合作用连续组合梁桥和大跨斜拉桥组合桥面系。通过对传统结构形式的改进和发展,可充分发挥组合结构桥梁的综合优势,研究结果表明,钢-混凝土组合结构桥梁具有广阔的推广应用前景。     

钢—混凝土结合梁安装技术

针对钢—混凝土结合梁的特点,对钢—混凝土结合梁的施工工艺作了介绍,并对安装前准备、钢梁吊装架设、线形调整连接等施工环节进行了详细论述,以期取得最佳的施工效果,从而确保工程的质量。     

钢—混凝土组合梁的发展及研究

对钢—混凝土组合梁结构进行了介绍,较为系统地阐述了钢—混凝土组合梁的发展史、特点、研究方法及其应用状况,并介绍了有关钢—混凝土组合梁方面值得进一步研究的问题,以推动钢—混凝土组合梁的应用。     

钢－混凝土组合结构体系研究新进展

以钢-混凝土组合框架结构和框架-核心筒混合结构为对象,综述了在钢-混凝土组合结构体系方面的一些研究新进展。针对组合框架中楼盖的空间组合作用进行了试验研究,发展了三种组合结构地震反应分析模型,重点讨论了在杆系模型中考虑楼盖空间组合作用的方法,从而实现组合框架结构体系的大规模计算。通过刚度解析和数值分析,对框架-核心筒混合结构体系中框架与核心筒的刚度匹配、位移限值指标的取值进行探讨,并对不同混合结构体系的位移特性、失效模式以及安全性能进行对比,为框架-核心筒混合结构的体系优化提供参考。最后,对组合结构体系的研究进行了展望,建议进一步完善组合结构体系的计算手段及其优化指标。图13表3参17     

Comparative life-cycle analysis of steel-concrete composite bridges

Competitiveness of steel construction and, in particular, steel and composite bridges, requires a broader view that encompasses the concepts of sustainability and life-cycle assessment in parallel with the classical structural and geotechnical issues. Also, from the economical viewpoint, the progressive transfer of operational duties from the National Road Authorities to private companies in the context of design, build and operate contracts, reinforces the need for an integrated approach.It is the purpose of the present paper: (i) to present an integrated methodology for a life-cycle and sustainability analysis (LCA and LCCA); and (ii) to apply such an integrated approach to a case study of a composite bridge. The proposed approach, besides structural considerations, contemplates environmental aspects (energy consumption, raw materials, and environmental impacts), economical aspects and a brief discussion of degradation and maintenance aspects. The case study consists of a three-span continuous bridge with spans of 27.2 m + 35.0 m + 27.2 m, thus totalling 89.40 m. Finally, some comparisons are presented between alternative solutions.     

钢-混凝土组合桥面板挠度试验分析

由理论分析得出与实桥相应的桥面板模型,利用大型有限元分析软件ANSYS进行计算分析,并与试验得出的结果进行比较,验证了试验的可靠性。通过对钢—混凝土组合桥面板的挠度试验,得出其在静力荷载和疲劳荷载作用下的挠度发展情况。     

钢-混凝土组合转换框架试验研究

为研究钢-混凝土组合转换梁-矩形钢管混凝土柱构成的组合转换框架的受力性能,对1榀组合转换框架缩尺模型进行了竖向荷载和低周往复水平荷载试验。分析了组合转换梁在竖向荷载作用下的刚度及裂缝开展情况以及组合转换框架在水平往复荷载作用下的破坏特点、荷载-位移滞回曲线及骨架曲线、延性、屈服机制和耗能能力等力学性能。试验研究结果表明,在竖向荷载作用下,组合转换梁刚度大,抗裂性能好,满足结构正常使用要求;在水平荷载作用下,转换框架延性好,极限层间位移角大,滞回曲线对称、饱满,耗能能力强。