Moment resistance of the assembly steel joint intended for composite structures

This research concentrated on the nonlinear finite element (FE) modeling of one-way composite floor slab system comprising of profiled steel deck and two types of concrete namely, Engineered Cementitious Composites (ECC) and Self-Consolidating Concrete (SCC). Two FE models were developed based experimental results of composite slabs subjected to in-plane monotonic loading. The simulated load-deflection response, moment resistance, and shear bond capacity using two FE models were in reasonable good agreement with experimental results. The FE models were used in a comprehensive parametric study to investigate the effect of numerical model parameters such as mesh size, dilation angle, steel sheet-concrete interaction contact, material properties and composite slab span. In addition, FE models were used to determine shear bond parameters of ECC and SCC composite slabs that can be used for design purposes.

This research concentrated on the nonlinear finite element (FE) modeling of one-way composite floor slab system comprising of profiled steel deck and two types of concrete namely, Engineered Cementitious Composites (ECC) and Self-Consolidating Concrete (SCC). Two FE models were developed based experimental results of composite slabs subjected to in-plane monotonic loading. The simulated load-deflection response, moment resistance, and shear bond capacity using two FE models were in reasonable good agreement with experimental results. The FE models were used in a comprehensive parametric study to investigate the effect of numerical model parameters such as mesh size, dilation angle, steel sheet-concrete interaction contact, material properties and composite slab span. In addition, FE models were used to determine shear bond parameters of ECC and SCC composite slabs that can be used for design purposes.

This paper investigates the application of Artificial Neural Networks (ANNs) for structural data augmentation, using welded beam-to-column steel joints as a representative case study within a broader research effort aimed at improving the reliability-based design of ductile steel joints. While simplified design methods such as the component method are widely adopted, they often underestimate joint resistance in ductile failure scenarios, limiting the exploitation of the full resistance and deformation capacity of steel joints. To develop improved resistance criteria and satisfy the target reliability levels defined in EN 1990, a large volume of high-fidelity structural data is required, making traditional experimental and finite element (FE) approaches computationally unfeasible for Monte Carlo simulations. As a preliminary step, this study evaluates the performance of ANNs trained on deterministic (nominal) input data derived from a validated FEM database of 2,400 welded joint configurations, enabling efficient prediction of initial stiffness and moment resistance. A second investigation then assesses the ANN's capacity to generalize when applied to stochastically varied input parameters, as required for probabilistic applications. Results show that deterministic-trained models underperform in this setting, underscoring the need for tailored training strategies. While this paper establishes a robust ANN-based methodology for deterministic modeling, it also sets the stage for future work on stochastic ANN training and reliability-based joint assessment.

Test on seismic behaviors of stainless steel bolted extended end-plate beam-column joints

Hybrid reinforced concrete steel (RCS) frames consisting of reinforced concrete (RC) column and steel (S) are used frequently in practice for mid-to-high-rise buildings. RCS frames possess several advantages from structural, economical and construction view point compare to either traditional RC or steel frames. One of the most important elements in RCS frames is the composite shear wall consisting of several steel sections encased in reinforced concrete. Regarding the RC walls reinforced by more than one steel profile, namely “Hybrid” wall, although number of researchers have focused on its various aspects, they are currently not covered by standards because they are neither reinforced concrete structures in the sense of Eurocode 2 (1992) or ACI-318 (2005) nor composite steel-concrete structures in the sense of Eurocode 4 (1994) or AISC-2010 (2010). An experimental study on the static behavior of hybrid walls with several embedded steel profiles subjected to combined shear and bending is presented. Six hybrid walls with different types of the structural steel-concrete connection and reinforcement detailing are tested. The specimens exhibited ductility behavior. The experimental results indicate that the load bearing capacity of the hybrid specimens considerably grows, as result of the encased steel profiles. The specimens with shear connectors (i.e. headed studs, stiffeners) were more ductile in terms of displacement ductility than the ones without connectors.

Capacity of semi-rigid composite joints in accommodating column loss

This paper is focusing on the experimental investigation of composite beam-to-column joint formed by a composite concrete slab and two lipped cold-formed steel C-sections placed back-to-back as beam and column. As the bare joint of cold-formed sections might not have higher moment resistant, a composite action from the composite concrete slab is utilized and expected to enhance the load carrying capacity of the joint. Two specimens namely the composite joint and non-composite joint are constructed and tested until failure under a point load at a certain eccentricity from the face of the column to induce moment to the joint. All components which are the decking, hot rolled plate, bolts and reinforcement bar used were the same for both specimens except the arrangement of the longitudinal bars. The relationship between the load and deflection, and subsequently, the moment and rotation of the joints are obtained specifically, the ultimate load and the respective moment resistance. It is found out that the composite joint yields higher ultimate load and moment resistance compare to the non-composite joint. The results also indicate that a composite joint has credible rotation and moment resistance, and the fracture of the joint occurs after substantial rotational deformation has been achieved.

Two series of experimental tests to study the cyclic behaviour of usual types of shear connectors in buildings and their influence on the global behaviour of beam-to-column composite joints are presented in this paper. The first series involves 30 push-pull tests to evaluate the shear resistance, the slip capacity and the low-cycle fatigue resistance of two types of shear connectors associated with solid or composite slabs. The second series of tests involves 11 full scale composite joints. Main results and their interpretation deal with moment resistance, rotational stiffness, absorbed energy and rotation capacity linked with risks of rupture by low cycle fatigue either in the bolted end plate steelwork part or in the shear connection of the beam adjacent to the joint. An equivalent static approach seems significant to evaluate the skeleton curve of the cyclic moment-rotation characteristics. From the so-interpreted results a preliminary proposal may be suggested for the seismic design of the shear connection of frame spans.

Influence of seat angles on the behaviour of cold-formed steel concrete composite joints

Rotational behavior of glulam moment-resisting connections with long self-tapping screws

ABSTRACTDue to the demand for sustainable constructions, composite structures become more important and lead to slim and economic solutions. The determination of moment resistance for composite beams follows the rules for composite structures according to EN 1994‐1‐1.For the plastic design it is still assumed, that each cross‐sectional fibre can plastify without any limitation of strains. For normal composite beams in case of sagging moments and a high‐lying plastic neutral axis, the real moment resistance is slightly higher than the plastic resistance. This is based on the large strains at the bottom side of the section, so that the lower steel flange reaches the solidification range. In case of sections with a large compression zone height xpl, a concrete failure in the compression zone can happen before reaching the plastic moment resistance. In these cases a strain limit design, based on the strain‐stress relationships of concrete and steel, becomes decisive. EN 1994‐1‐1 provides only for cross‐sections of classes 1 and 2 in steel grades S420 and S460 a limitation of plastic design. It is to point out, that the rotation capacity of a composite section is not only conditioned by the b/t ratio of the steel section, but also the concrete part has a significant impact. This applies not only for high steel grades. Though, in Eurocode 4 there are no further regulations given for sections with lower steel grades. Especially, the more and more upcoming integrated and compact composite sections underline the importance of such requirements.Therefore, the objective of the recent research is concentrated on the development of additional regulations, to consider the influence of concrete compression zone height onto the moment resistance of composite beams.

This study analyzed the connection using finite element (FE) simulations and nonlinear analysis to determine its moment resistance and mode of failure. In this work, FEA (finite element analysis) is employed to analyze the triangular web profiled (TRIWP) steel section as a beam element and extended end plate connection. The connection model has been developed with different thicknesses of extended end plate, beam flange, and beam web, and these parameters were analyzed to determine the relationship between all three cases with the failure connections and moment-rotation curve. Furthermore, the results obtained from the analysis of using extended end plate connections have been compared with previous studies where flush end plate connections are used to compare the behavior of the two end plates' connections. Twelve LUSAS analysis models were used, varying parameters such as the thickness of the flange beam, web beam, and end plate. Results indicated that an increased end plate thickness led to a higher moment resistance. A comparison of the moment resistance between the extended end plate and flush end plate connections, from a previous study, showed a difference of 48%. This finding is attributed to the extended end plate's ability to sustain a higher moment compared to the flush end plate. Therefore, the extended end plate connection is stronger than the flush end plate connection. Failure modes showed that buckling occurred at the top flange, which was similar for both types of connections. The use of a triangular shape is used to create contrast as this is prominent from the other shapes used commonly in web design.

Moment-rotation curves of ultra-large capacity end-plate joints based on component method

This paper presents an experimental study on the behavior of composite floor slab comprised by a new steel sheet and concrete slab. The strength of composite slabs depends mainly on the strength of the connection between the steel sheet and concrete, which is denoted by longitudinal shear strength. The composite slabs have three main failures modes, failure by bending, vertical shear failure and longitudinal shear failure. These modes are based on the load versus deflection curves that are obtained in bending tests. The longitudinal shear failure is brittle due to the mechanical connection was not capable of transferring the shear force until the failure by bending occurs. The vertical shear failure is observed in slabs with short span, large heights and high concentrated loads subjected near the supports. In order to analyze the behavior of the composite slab with a new steel sheet, six bending tests were undertaken aiming to provide information on their longitudinal shear strength, and to assess the failure mechanisms of the proposed connections. Two groups of slabs were tested, one with 3000 mm in length and other with 1500 mm in length. The tested composite slabs showed satisfactory composite behavior and longitudinal shear resistance, as good as well, the analysis confirmed that the developed sheet is suitable for use in composite structures without damage to the global behavior.

Through extensive research, there exist a new type of connection between railway bridge girders and steel-concrete composite panels. In addition to conventional shear connectors, newly developed blind bolts have been recently adopted for retrofitting. However, the body of knowledge on their influence and application to railway structures has not been thoroughly investigated. This study has thus placed a particular emphasis on the application of blind bolts on the Sydney Harbour Bridge as a feasible alternative constituent of railway track upgrading. Finite element modeling has been used to simulate the behaviours of the precast steel-concrete panels with common types of bolt connection using commercially available package, ABAQUS. The steel-concrete composite track slabs have been designed in accordance with Australian Standards AS5100. These precast steel-concrete panels are then numerically retrofitted by three types of most practical bold connections: head studded shear connector, Ajax blind bolt and Lindapter hollow bolt. The influences of bolt connections on load and stress transfers and structural behaviour of the composite track slabs are highlighted in this paper. The numerical results exhibit that all three bolts can distribute stresses effectively and can be installed on the bridge girder. However, it is also found that Lindapter hollow bolts are superior in minimising structural responses of the composite track slabs to train loading.