Evaluation Of Effective Width Research Articles

Effective width evaluation for HSS-UHPC composite beams with perfobond strip connectors

This paper investigates the design criteria for predicting the effective width in high strength steel (HSS)-to-Ultra-high performance concrete (UHPC) composite beams with perfobond strip connectors (PBLs). Twenty-eight HSS-UHPC composite beams with varying parameters of shear connection degree (C), span length (S), thickness (T) and width (W) of UHPC slab were numerically simulated and evaluated. The composite beams' strain distribution and shear lag effect were presented and analyzed. Results indicate that the shear lag of the HSS-UHPC composite beam under flexural loadings was significant, and the effective width coefficient (β) of the concrete slab was enlarged by the magnification of the C, T, and S. A comparison between the results obtained from the FE model and procedures for predicting the composite beams’ effective width was performed to assess the feasibility of design approaches. It reveals that existing codes provide good predictions for the HSS-UHPC composite beams with a W/S ratio below 0.3 but underestimate the effective width for those with W/S ratio beyond 0.3. Furthermore, an empirical model for predicting the effective width of HSS-UHPC composite beams, considering the shear lag and steel-to-UHPC interfacial slip, is derived and fitted by a data regression. The outcome of this study can provide a reference for HSS-UHPC composite beams in practical applications.

Numerical evaluation for the effective slab width of continuous composite beams

Basic beam bending theory and the effective width concept are commonly used in the design and analysis of steel–concrete composite beams to evaluate deflections, stresses, and strengths. The shear-lag effect is partially accountedfor by adopting a reduced “effective” slab width rather than the actual slab width. Besides the precise numerical values obtained via numerical analysis of a composite beam, Code provisions should provide a simplified practical techniquefor calculating effective slab width that is both simple and precise. Current design codes propose effective width values that are essentially a function of the beam span, ignoring the effects of other essential factors. Finite element analysis of continuous composite beams is a complex task, as large numbers of contacts and meshing elements are required to catch all the physical phenomena; this leads to potential convergence difficulties using a general static analysis. In this paper, several 3D numerical simulations of a composite continuous beam are conducted using the RIKS method available in ABAQUS. Comparisons to available experimental results are used to validate the proposed FE model. Then, the so-validated numerical model is utilized to perform a parametrical study to assess the effect of the longitudinal reinforcement at the hogging moment region and the influence of the concrete slab width on the effective width evaluation. Finally, the proposed finite element model and EC4 specification results are compared to draft a useable design guide.

Finite element study of effective width in steel-concrete composite beams under long-term service loads

Abstract In this work, a finite element-based approach is presented to study the effective width variation in non-pre-stressed steel-concrete beams under the serviceability stage, including time dependent effects such as concrete creep, shrinkage and cracking. For this purpose, the viscoelasticity theory in conjunction with a nonlinear cracking monitoring algorithm is used to trace the nonlinear viscoelastic response of the structure along time. The present numerical model is fully three-dimensional and permits the inclusion of partial interaction at the slab-beam interface. A comprehensive study is carried out on the long-term response of a composite girder bridge previously studied by other researches. Then, previous results are revised and extended herein. Potential shortcomings of some standard codes related to the effective width evaluation are also investigated. It is demonstrated that the slab effective width varies sharply along the beam axis in the short-term, while it approaches to the actual slab width in the long-term. For the studied example, the common assumption of using only the middle layer of the reinforced concrete (RC) slab for the effective width calculation is revised with a through-thickness integration procedure. The influence of some creep and shrinkage models as well as the ultimate tensile concrete strain on the effective width response is also assessed. Finally, a simple formula is proposed to evaluate the short-term slab effective width for the studied example.

A Fundamental Study on Effective Width Evaluation of Laminated Composite Box Girder

The domestic and foreign specifications presented the effective width based on flange length to width ratio only. The existing paper on the effective width grasped of the effect of span, load type and cross-section properties, but localized steel bridges. Recently, The studies are going on in progress for the application of fiber reinforced composite material in construction field. Therefore, it is required to optimum design that have a good grasp the deformation characteristic of the displacements and stresses distribution and predict variation of the effective width for serviceability loading. This research addresses the effective width of all composite material box girder bridges using the finite element method. The characteristics of the effective width of composite structures may vary according to several causes, e.g., change of fibers, aspect, etc. Parametric studies were conducted to determine the effective width on the stress elastic analysis of all composite materials box bridges, with interesting observations. The various results through numerical analysis will present an important document for construct all composite material bridges.

Evaluation of effective width of skin plate on box-type RC segment

Evaluation of effective width of skin plate on box-type RC segment

Discussion of “Long-term analysis of steel–concrete composite beams: FE modeling for effective width evaluation” [Engineering Structures 2006;28:1110–21

This paper presents a comprehensive work to evaluate the long-term influence of concrete on the shear-lag effect in steel–concrete composite beams, for which rather few tests and numerical studies have been reported. The FE study demonstrates that the effective width is greatly influenced by the analytic models: linear creep (CnSnC model) linear creep with shrinkage (CSnC model) creep with shrinkage and cracking (CSC model). Some numerical results were not well clarified, as discussed in the following.

Evaluation of Effective Width and Distribution Factors for GFRP Bridge Decks Supported on Steel Girders

Glass fiber-reinforced polymer (GFRP) bridge deck systems offer an attractive alternative to concrete decks, particularly for bridge rehabilitation projects. Current design practice treats GFRP deck systems in a manner similar to concrete decks, but the results of this study indicate that this approach may lead to nonconservative bridge girder designs. Results from a number of in situ load tests of three steel girder bridges having the same GFRP deck system are used to determine the degree of composite action that may be developed and the transverse distribution of wheel loads that may be assumed for such structures. Results from this work indicate that appropriately conservative design values may be found by assuming no composite action between a GFRP deck and steel girder and using the lever rule to determine transverse load distribution. Additionally, when used to replace an existing concrete deck, the lighter GFRP deck will likely result in lower total stresses in the supporting girders, although, due to the decreased effective width and increased distribution factors, the live-load-induced stress range is likely to be increased. Thus, existing fatigue-prone details may become a concern and require additional attention in design.

Long-term analysis of steel–concrete composite beams: FE modelling for effective width evaluation

This paper presents a finite element model suitable for long-term analysis of steel–concrete composite beams. The structure is modelled using one-dimensional beam elements for the steel profile and two-dimensional shell elements for the concrete slab, where the two types of element are interconnected by means of special-purpose link elements. In this way, the deformability of the connection system can be taken into account, along with the shear lag phenomenon in the concrete slab. Careful consideration is taken in modelling the concrete behaviour, for which both rheological phenomena, such as creep and shrinkage, and non-linear behaviour due to cracking are fully considered for a plane stress state. Some preliminary analyses carried out on a composite girder bridge subjected to long-term loading demonstrate the applicability of the proposed method for evaluating the influence of different and complex phenomena, such as the shrinkage and cracking of concrete, on the effective width evaluation. These analyses also highlight potential shortcomings in current design codes of practice, the validation of which necessitates further experimental and numerical work.

Experimental evaluation of effective width in steel–concrete composite beams

The paper deals with the evaluation of effective width for elastic and plastic analysis of steel–concrete composite beams. The study is performed through experimental tests performed at the University of Trieste on four specimens. Both cases of sagging and hogging bending moments are investigated, as well as the influence of the beam-to-column joint. It is shown that for all specimens the effective width increases with the load, approaching the width of the whole slab near the collapse. The presence of a beam-to-column joint does not affect this result. The comparison with the Eurocode 4 formulation demonstrates that such approach is adequate for elastic analyses, whereas it may be too restrictive for plastic analyses. A simple modification of the Eurocode 4 proposal is therefore presented for collapse analyses of composite beams under hogging bending moment.

Effective width evaluation for steel–concrete composite beams

In this paper the problems connected to the effective width evaluation for serviceability and ultimate analysis of steel–concrete composite beams are analyzed. By a parametric study carried out through the Abaqus code it is pointed out how the actual codes do not provide, in general appropriate results, for elastic and ultimate limit state checks. The most important parameters that influence the effective width are analyzed. Some preliminary criteria for an adequate design are presented.

Buckling and postbuckling investigations of imperfect curved stringer-stiffened composite shells. Part A: Experimental investigation and effective width evaluation

A box-like stringer-stiffened thin-walled CFRP structure was subjected to load cases well beyond the limits of local buckling. The development of the deflection pattern was recorded via optical means and analysed numerically. In addition, the structure was modelled and analysed using the MARC FE program in the nonlinear deflection range. The geometrical imperfections of the test structure were recorded by mechanical scanning and optical methods and introduced into the mathematical model. For the perfect (‘ideal’) and the geometrically imperfect (‘real’) structural model, the results of the FE analyses were compared and used to judge the effect of geometric imperfections on the postbuckling behaviour of the structure. The effective axial stiffness for the various postbuckling states was evaluated and related to analytical estimates of effective width values for orthotropic sheet-like panels.