Dennis Lam

Parametric study on composite steel beams with precast concrete hollow core floor slabs

Abstract This paper describes the finite element modelling of steel beams acting compositely with proprietary precast hollow core slabs. A companion paper (Lam D, Elliott KS, Nethercot DA. Experiments on composite steel beams with precast hollow core floor slabs. Proceedings of the Institution of Civil Engineers: Structures and Buildings 1999; in press [1] ) reports results of full scale bending tests and compression slab tests. The finite element package ABAQUS was used to extend the scope of the experimental work, by first demonstrating that a 2-dimensional plane stress analysis is sufficiently accurate, providing that the correct material input data and shear stud characteristics obtained from isolated push-off tests are used. The FE results are within 5% of the experimental results. An extensive parametric study was carried out to investigate the flexural behaviour of composite beams with variations in transverse reinforcement ratio, stud spacing and steel UB section.

Finite Element Analysis of Steel-Concrete Composite Girders

Finite element models for the analysis of solid slabs and precast hollow core slabs composite girders are presented. For both models, 8-node three-dimensional solid elements are used in the analysis. The material non-linearity of all components of the composite girders is taken into consideration. The non-linear load-slip characteristics of the headed shear stud connectors are included in the models. The models predict load – deflection behaviour and stress distribution along the length of the beam. Good agreement is obtained between the models and results previously published.

Behaviour of Axially Loaded Concrete Filled Stainless Steel Elliptical Stub Columns

This paper presents the details of an experimental investigation on the behaviour of axially loaded concrete-filled stainless steel elliptical hollow sections. The experimental investigation was conducted using normal and high strength concrete of 30 and 100 MPa. The current study is based on stub column tests and is therefore limited to cross-section capacity. Based on the equations proposed by the authors on concrete-filled stainless steel circular columns, a new set of equations for the stainless steel concrete-filled elliptical hollow sections were proposed. From the limited data currently available, the equation provides an accurate and consistent prediction of the axial capacity of the composite concrete-filled stainless steel elliptical hollow sections.

Finite Element Modelling of Headed Stud Shear Connectors in Steel-Concrete Composite Beam

Publisher Summary In steel–concrete composite construction, headed stud shear connectors are commonly used to transfer longitudinal shear forces across the steel–concrete interface. Present knowledge of the load–slip behavior of the shear stud in composite beam is limited to data obtained from the experimental push-off tests. A finite element model to simulate the structural behavior of headed stud shear connector in steel–concrete composite beam is described in the chapter. The model is based on finite element method and takes into account linear and nonlinear behavior of the materials. The model has been validated against test results and compared with data given in the current Code of Practices, for which both demonstrate the accuracy of the model used. Parametric studies using the model to investigate variations in concrete strength and shear stud diameter are also discussed in the chapter. The model takes into account the linear and nonlinear material properties of the concrete and shear stud. The FE results compare well with the experimental push-off test results and specified data from the codes. The FE model accurately predicts the mode of failure.

Behaviour of Headed Shear Stud in Composite Beams with Profiled Metal Decking

This paper presents a numerical investigation into the behaviour of headed shear stud in composite beams with profiled metal decking. A three-dimensional finite element model was developed using general purpose finite element program ABAQUS to study the behaviour of through-deck welded shear stud in the composite slabs with trapezoidal deck ribs oriented perpendicular to the beam. Both static and dynamic procedures were investigated using Drucker Prager model and Concrete Damaged Plasticity model respectively. In the dynamic procedure using ABAQUS/Explicit, the push test specimens were loaded slowly to eliminate significant inertia effects to obtain a static solution. The capacity of shear connector, load-slip behaviour and failure modes were predicted and validated against experimental results. The delamination of the profiled decking from concrete slab was captured in the numerical analysis which was observed in the experiments. ABAQUS/Explicit was found to be particularly suitable for modelling post-failure behaviour and the contact interaction between profiled decking and concrete slabs. It is concluded that this model represents the true behaviour of the headed shear stud in composite beams with profiled decking in terms of the shear connection capacity, load-slip behaviour and failure modes.

Axial Capacity of Concrete Filled Stainless Steel Columns

Concrete filled steel columns have been used widely in structures throughout the world in recent years especially in Australia and the Far East. This increase in use is due to the significant advantages that concrete filled steel columns offer in comparison to more traditional construction methods. Composite columns consist of a combination of concrete and steel and make use of these constituent material’s best properties. The use of composite columns can result in significant savings in column size, which ultimately can lead to significant economic savings. This reduction in column size can provide substantial benefits where floor space is at a premium such as in car parks and office blocks. The use of stainless steel column filled with concrete is new and innovative, not only provides the advantage mentioned above, but also durability associated with the stainless steel material. This paper concentrates on the axial capacity of the concrete filled stainless steel columns. A series of tests was performed to consider the behaviour of short composite stainless steel columns under axial compressive loading, covering austenitic stainless steels square hollow sections filled with normal and high strength concrete. Comparisons between Eurocode 4, ACI-318 and the Australian Standards with the findings of this research were made and comment.

The behaviour of composite steel beams with precast hollowcore slabs in hogging moment regions

Publisher Summary The chapter discusses the behavior of composite steel beams with precast hollow core slabs in hogging moment regions. Full-scale composite beams to column semi-rigid connections with precast hollow core slabs are tested in the chapter. The chapter presents a steelwork connection consists of a flush end plate bolted to column flanges. The main variables studied are shear studs spacing and degree of shear connection. Comprehensive instrumentations are used for all the tests, based on the experimental data, and equations to predict the rotation and the moment capacity for this type of composite connection are proposed in the chapter. A precast composite hollow core floor is a newly developed composite system for building that use precast hollow core slabs as the structural flooring. However, research on composite construction incorporating steel beams with precast hollow core slabs is still relatively new in comparison to the more traditional composite metal deck flooring.

Modelling of semi-rigid composite beam-column connections with precast hollowcore slabs

Publisher Summary The chapter describes the ongoing work on modeling the semi-rigid composite beam-column connections of composite beams with precast hollow core slabs. Using the finite element (FE) software ABAQUS, a three-dimensional (3D) model of a composite joint is set up. The technique of simulating bolt force, endplate, concrete elements, reinforcement, and shear connectors, and the interaction between slabs and steel beams is presented in the chapter. Preliminary results on the steel joint and simplify composite joint are also presented in the chapter. FE model for the bare steel joints and the simplified composite joints are presented, and the result of the simplified composite model showed good agreement with the experimental result but with lower joint stiffness. Further work on the full finite element model of composite joints is still going on.

EFFECTS OF TRANSVERSE REINFORCEMENT ON COMPOSITE BEAMS WITH PRECAST HOLLOW CORE SLABS

Transverse reinforcement is used to provide ties for the slabs and confined concrete from splitting. The ductility of the shear connector is directly affected by the amount of transverse reinforcement. Design equations presented in this paper for estimate of the shear capacity of the headed shear stud showed a good correlation with the push-off test results. For full shear connection design, pre-splitting shear capacity of the headed stud can be used for the composite design, while for partial shear connection design, post-splitting shear capacity of the headed stud should be used.

Steel — Concrete Composite Construction with Precast Concrete Hollow Core Floor

Publisher Summary Precast concrete hollow core floor units (hcu) are widely used in all types of multistorey steel framed buildings where they bear onto the top flanges of universal beams. The steel beam is normally designed in bending, in isolation from the concrete slab, and no account is taken of the composite beam action available with the precast units. A program of combined experimental and numerical studies was undertaken that aimed at deciding on a suitable approach for the design of composite steel beams that utilize precast concrete hollow core slabs. The results show that the precast slabs may be used compositely with the steel beams in order to increase both flexural strength and stiffness at virtually no extra cost, except for the headed shear studs. For typical geometry and serial sizes, the composite beams were found to be twice as strong and three times as stiff as the equivalent isolated steel beam. The failure mode was ductile, and may have been controlled by the correct use of small quantities of tie steel and insitu infill concrete placed between the precast units.