Analysis of Restrained Composite Perforated Beams during Fire Using a Hybrid Simulation Approach

This paper is concerned with the behavior of restrained perforated beams acting compositely with a profiled slab during a fire. These members are increasingly popular in the construction of long-span floor systems because they provide a structurally and materially efficient design solution and provide space for placement of building services. However, their response during a fire has received little attention from the research community until recently. In the current work, a hybrid simulation-type numerical approach is adopted using a combination of the OpenSEES, ABAQUS, and OpenFresco software. The accuracy of the model is validated using available fire test data whereby the temperatures measured during the experiments are directly applied in the numerical model at various locations. The effect of axial and rotational restraint due to the connections between the beams and columns is also investigated following validation of the model. Furthermore, the hybrid simulation approach is employed to study a number of salient parameters, including load ratios, material grade, and the location of the openings. The variation in axial force during the fire is also examined. Various failure modes were observed during the analysis, including flexural and shear failure, failure of the web-post, concrete crushing, and also a Vierendeel mechanism. The fire resistance of the analyzed beams is compared with the values obtained from the most common design codes. Because of the consideration of restraint forces, which are not included in the design codes, the resistances predicted by the finite-element simulations were more favorable. It was found that the location of the openings along the span and also the boundary conditions had a considerable effect on the time-displacement behavior, axial reactions, and web-post buckling behavior, as well as the fire performance of the perforated beam

Analysis of restrained composite beams exposed to fire using a hybrid simulation approach

Obtaining an accurate simulation of the boundary conditions is very challenging but it is essential in order to represent the true behaviour of the whole structure in fire. In recent years, hybrid simulation has been emerging as an efficient and economical method for simulating realistic boundary conditions in the field of earthquake engineering. This technique can be used to study the load redistribution that may occur in a structural system as a result of locally elevated temperatures. In this paper, the fire-exposed element will be modelled in one analysis (a 3D model) and the rest of the structure in another analysis (a 2D model). This kind of sub-structuring enables the behaviour of the structural system as a whole to be studied. A hybrid simulation (HS) approach is presented and successfully implemented using the OpenFresco and OpenSees software. This approach enables the simulation of the correct restraint provided by the cold structure to the fire affected structural element. The HS analysis of a composite beam is compared with an unrestrained or simply supported version to highlight the difference in behaviour. Finally, the Cardington restrained beam test is modelled to demonstrate the potential of HS technique. Good agreement with the test results highlights that HS approach can be an effective method for studying the behaviour of the whole structural system

Analysis of restrained composite perforated beams during fire using a hybrid simulation approach

202311 bckwAccepted ManuscriptSelf-fundedPublishe

Response of restrained stainless steel corrugated web beams at elevated temperature

This paper is focused on the fire behaviour of axially restrained corrugated web beams made from stainless steel. A finite element (FE) model is developed and validated against available fire test results on restrained flat web carbon steel beams, unrestrained stainless steel cellular beams and numerical studies conducted on carbon steel corrugated web beams in fire. The verified FE model is then employed to conduct an extensive parametric study to assess the relative influence of key properties on the response. The behaviour of stainless steel corrugated web beams (SSCWBs) is compared to that of stainless steel flat web beams (SSFWBs) during exposure to a standard fire under axially restrained support conditions. The axial compression developed in an SSCWB is shown to be significantly lower than that of a comparable SSFWB due to the reduced axial stiffness. A number of parameters are examined including the grade of steel, load ratio, presence of axial restraint as well as thicknesses of the flange and web. It is shown that the overall behaviour of SSCWBs is quite similar compared with equivalent carbon steel corrugated web beams (CSCWBs). However, the stainless steel beams also show much improved performance in terms of survival time due to better retention of mechanical properties at elevated temperature compared with carbon steel. An analytical model for predicting the critical parameters related to the axial force-temperature response of SSCWBs is also presented and verified against the results obtained from the FE models