Steel-concrete composite slab

Fig. 13.21. Robinson-type of steel-concrete composite slab.

A steel-conerete composite slab is newly available in construetion, of which concrete is placed in a steel mold that eonsists of steel side plates, top reinforcing bars and transverse ribs, and stud-planted bottom steel plates. Configuration of one t) e slab is shown Fig. 13.21. Compared with a reinforced concrete slab, this slab is expeeted to bear a large load- capacity and to have good enduranee. Although these eharacteristics are favorable for bridge construction, visual inspection is very difficult in particular, for concrete and its interfaee with steel plate. As a result, effective inspee-tion techniques for steel-concrete eomposite slabs are in demand and under development. 

A Robinson-type steel-concrete composite floor slab was of dimensions of 1540 mm x 159 mm x 1500 mm, which is shown in Fig. 13.22. To withstand deflections due to concrete casting, transverse ribs are arranged at the center and on both sides. The loading position was set at the top center of the specimen. A plate of dimensions 200 mm x 125 mm was installed as a loading plate. Load of 100 kN was first applied 2 million times at a frequency of 3 Hz, then 250 kN was applied 0.5 milhon times at 2 Hz, and finally 300 kN was applied 0.5 million times at 1 Hz. 

Itoh T, Shigeishi M, Ohtsu M (2002) Acoustic emission in fatigue process of steel plate-concrete composite slab. Progress in Acoustic Emission 11 132-137... 

Spacone El-Tawil 2004). The behaviour of composite beams (made of two components connected through shear connectors to form an interacting unit) is significantly influenced by the type of connection between the steel beam and the concrete slab. Flexible shear connectors allow the development of partial composite action. Thus, for accurate analytical response prediction, structural models of composite structures must account for the interlayer slip between the steel and concrete components. A composite beam finite element able to capture the interface slip is therefore an essential tool for model-based response simulation of steel-concrete composite structures. 

Seismic Analysis of Steel-Concrete Composite concrete slab in compression (component 1), (c) krnemat-Buildings Numerical Modeling, Fig. 13 Component ics of the concrete slab in tension (component 5), and (d) model (a) overall joint model, (b) kinematics of the overall exterior joint model... 

A potential structural application of epoxy resin adhesives in bridge construction is to use them to form the necessary shear connection between steel girders and the concrete deck slab in composite bridges, in place of conventional welded mechanical fasteners. There are three ways in which bonded shear connections between steel and concrete might be achieved. 

Holomek, J. and Bajer, M., 2012. Experimental and Numerical Investigation of Composite Action of Steel Concrete Slab. Procedia Engineering. 2012(40), 143-147, ISSN 1877-7058, DOI 10.1016/j.proeng.2012.07.070. 

The effective width of the concrete slab is chosen using the recommendations of C.P. 110 Part 1 1972 The Structural Use of Concrete and is the smaller of the beam spacing or 20% of the span which is 1.8 m. The stage 1 or construction loads to be taken by the steel beam alone are due to the weight of the wet concrete slab and the self weight of the steel beam. (It is assumed for the purposes of the example that the weight of falsework etc., is included in the slab dead load.) The stage 2 loads include all the loads to be taken by the composite section and consist in this case of all finishes and imposed load. 

In the particular case of the apphcation of glass-fibre reinforced vinylester composites as internal reinforcement for concrete bridge deck slabs, the results showed their superior fatigue performance and longer fatigue life when compared with the steel-reinforced ones (El-Ragaby et al., 2007). 

The distinction between composite materials and composite structures is not sharp and laminated composites form a group that may be logically considered for different purposes either as materials or as structures. Composite materials are used to build up composite structures, but homogeneous ones may also be used. It is usual to consider concrete and fibre-reinforced concrete as composite materials. A concrete beam reinforced with steel bars or a set of steel beams connected together with a concrete steel-reinforced slab to create... 

Orthotropic steel decks are represented in a similar way. For composite bridges with concrete decks, the cross section of the relevant beam element is composed of the transverse girder and the effective width of the concrete slab. 

The present subchapter presents a simplified (new) modeling approach based on the work of Zhao et al. (2012) for the nonlinear analysis of SCC beams and composite frames with deformable shear connections (based on the distributed plasticity approach) using line elements to simulate the stmctural beam and column members, layered fiber section to simulate the reinforced concrete slabs, and nonlinear spring elements for the simulation of the interface between the stmctural steel beams and the reinforced concrete slab. Vertical interactions between the slab and steel beams are not expected to be significant, therefore are not accounted into the analysis. The geometry of the model, along with a simple set of details, is outlined below. The assembled model is shown in Fig. 1. 

The degree of composite action and interaction between the steel beam and the concrete slab is a fundamental mechanism that needs to be... 

The gradual plastification of a composite cross section can be described using the concept of fiber section model, similarly to the modeling of the concrete slabs in section Introduction. The fiber model is presented in Fig. 24. The concept behind this model is rather simple the cross-sectional area of the SCC element is subdivided into fibers represented by their area, Ai, and coordinate location (yi Zi - with origin the centroid of the section). Different material properties (e.g., concrete confined and unconfined, steel, reinforced steel) can be assigned to each of the fibers. Based on the relevant constitutive material... 

The second development is that most floors in steel structures have become composite ones, with the use of shear studs to connect floor beams and girders to concrete slab cast in metal deck (Viest et al. 1997). The use of the metal deck as both formwork and reinforcement, the... 

Eurocode 8 (EC8) follows three general design concepts based on the ductiUty requirements and capacity design considerations of steel buildings the concept of the low-dissipative structural behavior of DCL structures, the concept of dissipative stmctural behavior of DCM and DCH stmctures satisfying the ductility and capacity design requirement, and the concept of dissipative structural behavior with steel dissipative-controUed zones. In the latter case, when composite action may be considered from Eurocode 4 (EC4) in the presence of the steel and concrete (slab) interaction, specific measures have been stipulated to prevent the contribution of concrete under seismic conditions, hence apply general rules for steel frames. 

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