钢-混凝土预制板组合梁栓钉连接件的试验研究

为了研究钢-混凝土预制板组合梁中栓钉剪力连接件的性能,对不同的预留孔型、孔内不同的填充材料等12个推出试件进行试验研究。根据现有的组合梁理论,作者对试验结果进行对比分析,提出了对钢-混凝土预制板组合梁栓钉剪力连接件设计的建议。     

浅谈钢--混凝土组合梁的剪力连接件

简要介绍了钢一混凝土组合梁中常见剪力连接件的形式。重点讲述目前最常用的栓钉连接件的破坏机理及其承载力计算方法，并介绍了近年来新型剪力连接件的发展。     

钢─混凝土组合梁中栓钉连接件实际抗剪承载能力的计算

本文通过试验研究栓钉剪力连接件在钢─混凝土组合梁中的实际承载能力,对我国现行《钢结构设计规范》中栓钉连接件设计抗剪承载能力计算公式的限制条件提出了修正建议,并对部分剪力连接组合梁中的检钉承载能力做了初步探讨,它对钢─混凝土组合梁设计具有实用参考价值。     

钢─混凝土组合梁中栓钉连接件实际抗剪承载能力的计算

本文通过试验研究栓钉剪力连接件在钢─混凝土组合梁中的实际承载能力，对我国现行《钢结构设计规范》中栓钉连接件设计抗剪承载能力计算公式的限制条件提出了修正建议，并对部分剪力连接组合梁中的检钉承载能力做了初步探讨，它对钢─混凝土组合梁设计具有实用参考价值。     

钢-高强混凝土组合梁中栓钉连接件的分析

在分析国内外钢-混凝土组合梁各种剪切连接件形式的基础上，着重阐述了钢-高强混凝土组合梁中栓钉连接件的受力性能和承载力计算方法，提出了有待完善的地方。     

预制装配式组合梁栓钉连接件抗剪性能试验研究

钢-混凝土组合梁广泛应用于各类建筑与桥梁等结构,为适应装配式组合结构的发展需求,提出了一种将带预制圆孔的混凝土板与焊接栓钉的钢梁安装定位后在预制孔内后填高强填料以固定栓钉连接件的预制装配式钢-混凝土组合梁。通过静力推出试验,研究栓钉直径、预留孔成孔方式与孔径比(预留孔径和栓钉直径比值)对预制装配式组合梁栓钉抗剪连接件的破坏形态、抗剪承载力和滑移性能的影响规律,并进行了普通现浇组合梁栓钉抗剪连接件的对比试验。试验结果表明:破坏形态均为栓钉剪断和混凝土板开裂,螺栓直径和预制成孔后的高强填料对破坏形态有一定影响。装配式抗剪连接件承载力均大于现浇试件承载力,且大于国内外相关规范计算值,采用波纹管成孔的连接件比普通成孔连接件承载力略有提高。提出的组合梁栓钉连接件预制装配构造形式具备应用于实践的可行性,且构造形式简单、施工高效,经合理设计可满足现行规范要求。     

剪力连接程度对钢—混凝土组合梁极限抗弯强度的影响及其计算

采用栓钉等柔性抗剪连接件的钢-混凝土组合梁在强度和变形许可的条件下采用部分剪力连接对于方便施工和降低造价等都极为有利。部分剪力连接对组合梁的抗弯刚度和承载力均有影响。R.P.Johnson按剪力连接程度进行线性插值提出的简化计算方法所得的极限抗弯强度值偏小,应用于工程实际中偏于保守。本文通过对国内外20多根组合梁极限抗弯强度的试验结果进行研究和分析,建立了考虑剪力连接程度影响的组合梁极限抗弯强度的两种计算公式:修正的R.P.John-son公式(经验公式)和极限平衡理论公式(理论公式)。结果表明,按照上述两种公式所得的计算值与实测值吻合良好。     

钢-混凝土组合梁栓钉剪力连接件抗剪承载力研究

为了探究钢-混凝土组合梁栓钉剪力连接件构造参数对其抗剪承载力的影响,采用ABAQUS有限元软件建立了数值分析模型,获得了荷载-滑移曲线,并与经验公式计算比较,二者吻合较好;通过改变结构的混凝土强度等级、栓钉直径、栓钉屈服强度和栓钉长度等构造参数,分析了栓钉抗剪承载力的变化规律。结果表明:栓钉剪力连接件的抗剪承载力随着混凝土强度等级、栓钉直径、栓钉屈服强度的增大而提高。     

钢-UHPC组合梁新型胶栓连接件受力研究

为了探究环氧胶与传统栓钉组合的新型剪力连接件的受力机理,文中浇筑8组UHPC试件进行推出试验,以有无环氧胶为对比试验。试验表明13mm直径的新型胶栓剪力连接件的组合效果是最好的,钢-UHPC组合梁栓钉连接件在加载过程中,首先由环氧胶承受荷载作用,栓钉受力与变形很小,当环氧胶破坏之后,栓钉再承受荷载作用直至被剪断。     

预制装配式栓钉连接件钢-混凝土组合梁抗弯性能试验研究

为适应装配式钢-混凝土组合梁的发展需求,研究了一种将带预制圆孔的混凝土板与焊接栓钉的钢梁安装定位后在预制孔内后填充高强填料以固定栓钉连接件的预制装配式钢-混凝土组合梁.通过梁式试验获得了该装配式组合梁的极限承载力、荷载-挠度关系、界面荷载-滑移关系以及截面的应变分布规律,并与普通现浇钢-混凝土组合梁的抗弯力学性能进行对比分析.试验结果表明:所有试验组合梁均发生弯曲破坏,装配式组合梁的抗弯承载能力稍好于现浇组合梁的抗弯承载能力.采用我国现行《钢结构设计标准》(GB 50017-2017)的组合梁塑性设计方法可偏于安全地预测该装配式组合梁的抗弯承载力,该组合梁预制装配方法可供工程实践参考.     

焊钉连接件时变抗剪性能的试验研究

对于无支架施工的长跨连续组合梁,在施工期间进行分阶段浇筑混凝土时,需考虑不同混凝土龄期的组合梁结合面上连接件的早期组合作用。为此,进行了混凝土不同龄期下焊钉连接件的推出试验,分析了焊钉连接件极限抗剪强度、极限滑移、设计抗剪强度和剪切刚度随时间的变化规律,并给出了相应的时变计算公式。研究发现,混凝土龄期小于3 d时推出试件主要为混凝土板劈裂破坏;在不同混凝土龄期时推出试件的剪力-滑移规律基本相同,但抗剪强度和刚度均随混凝土龄期的增长而增大,且早期增长较快,后期较慢,说明组合梁结合面的早期组合效应不能忽略。     

钢－混凝土组合梁中剪力连接件实际承载力的研究

设计实践表明，我国现行（钢结构设计规范）［５］关于栓钉和槽钢剪力连接件的抗剪承载力计算公式过于保守，导致设计计算所需要的连接件数量偏多、间距偏小。本文通过４０余根钢－混凝土组合梁试件的试验研究，定量分析了栓钉和槽钢剪力连接件在组合梁中的实际抗剪承载力，得到了现行公式偏于保守的程度，并在此基础上提出放宽对栓钉连接件承载力公式限制条件的建议。     

单调荷载下栓钉连接件受剪性能试验研究

栓钉是钢-混凝土组合梁中常用的柔性受剪连接件。通过18个栓钉受剪试件在单调荷载下的推出试验,较系统地研究了混凝土强度等级、栓钉直径以及钢梁类型等参数对栓钉的破坏形态、破坏机理、荷载-滑移规律和极限受剪承载力的影响。研究表明:栓钉的受剪承载力随着混凝土强度等级的提高以及栓钉直径的增大而增加;轧制工字钢试件中栓钉的受剪承载力比焊接工字钢试件中的高10%~30%。在试验的基础上提出了栓钉受剪承载力的计算方法。     

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。     

锈蚀栓钉连接件力学性能试验研究

为了解钢-混组合梁的栓钉连接件发生锈蚀后的静力工作性能,进行了4组栓钉试件的推出试验.首先通过人工电化学快速锈蚀方法使试件中的栓钉达到预定锈蚀状况,然后进行静载破坏试验,通过试验结果分析不同锈蚀状况对栓钉连接件力学性能的影响.结果表明:栓钉钉杆尤其是靠近结合面处发生锈蚀时,其极限承载力降低最大达到18％,相同荷载作用下...     

Performance of shear connection in composite beams with profiled steel sheeting

This paper describes the structural performance of shear connection in composite beams with profiled steel sheeting. An accurate and efficient nonlinear finite element model was developed to study the behaviour of headed stud shear connectors welded through-deck. The profiled steel sheeting had transverse ribs perpendicular to the steel beam. The material nonlinearities of concrete, headed stud, profiled steel sheeting, reinforcement and steel beam were included in the finite element model. The capacity of shear connection, load-slip behaviour of the headed stud, and failure modes were predicted. The results obtained from the finite element analysis were verified against experimental results. An extensive parametric study was conducted to study the effects on the capacity and behaviour of shear connection by changing the profiled steel sheeting geometries, the diameter and height of the headed stud, as well as the strength of concrete. The capacities of shear connection obtained from the finite element analysis were compared with the design strengths calculated using the American Specification, British Standard and European Code for headed stud shear connectors in composite slabs with profiled steel sheeting perpendicular to the steel beam. It is found that the design rules specified in the American and British specifications overestimated the capacity of shear connection, but the design rules specified in the European Code were generally conservative.     

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.     

Static and fatigue behavior of large stud shear connectors for steel-concrete composite bridges

For the design of shear connection in high shear areas of steel-concrete composite bridges, large shear studs can be an excellent alternative. Through the push-out tests on large stud shear connectors up to 30 mm diameter, which are beyond the limitation of current design codes, static and fatigue behavior was investigated and compared with design equations. The ultimate strength of the shear connection showed that the design shear strength in Eurocode-4 and AASHTO LRFD gives conservative values for large studs. The fatigue endurance obtained from the tests was slightly lower than the current design codes in Eurocode-4. Based on the push-out test results on large studs, partial composite beams with about 38% degree of shear connection were fabricated and static tests were performed. The ultimate strength and horizontal shear load redistribution of partial composite beams, which had parameters of stud shank diameters and distribution, were evaluated and group failure in shear span was observed. The ultimate strength of the shear connection had a value about 1.59 times larger than that from push-out tests.     

Capacities of headed stud shear connectors in composite steel beams with precast hollowcore slabs

In steel-concrete composite beams, the longitudinal shear force is transferred across the steel flange/concrete slab interface by the mechanical action of the shear connectors. The ability of the shear connectors to transfer these longitudinal shear forces depends on their strength, and also on the resistance of the concrete slab against longitudinal cracking induced by the high concentration of shear force. Most of the research in composite construction has concentrated on the more traditional reinforced concrete and metal deck construction, and little information is given on shear capacity of the headed studs in precast hollowcore slabs. In this paper, a standard push test procedure for use with composite beams with precast hollowcore slabs is proposed. Seven exploratory push tests were carried out on headed studs in solid RC slabs to validate the testing procedures, and the results showed that the new test is compatible with the results specified in the codes of practice for solid RC slabs. Once a standard procedure is established, 72 full-scale push tests on headed studs in hollowcore slabs were performed to determine the capacities of the headed stud connectors in precast hollowcore slabs and the results of the experimental study are analysed and findings on the effect of all the parameters on connectors’ strength and ductility are presented. Newly proposed design equations for calculating the shear connectors’ capacity for this form of composite construction are also be given.