This paper reports the results of a recent experimental study into the behavior of welded finplate connections to both hollow and concrete filled tubular (CFT) columns under shear. Experiments have been performed at both ambient and elevated temperatures with the aid of an electric kiln. The observed failure modes include fracture of the fin plate and tearing out of the tube around the welds. By considering the results of previously published research, the current design method for similar connections under purely tensile load, in CIDECT Guide 9, based on a deformation limit of 3% of the tube width is shown to be inadequate when evaluating the ultimate strength of such connections. By
comparing the results from the current test program which failed in the fin-plate with Eurocode guidance for failure of a fin-plate alone under shear and bending load it is shown that the column face
influences the overall connection strength regardless of failure mode. Concrete in-fill is observed to significantly increase the strength of connections over empty specimens, and circular column specimens were observed to exhibit greater strength than similarly proportioned square columns. A finite element (F.E.) model, developed using ABAQUS, is presented and validated against the experimental results in order that extensive parametric tests may be subsequently performed. When validating the model against elevated temperature tests it was found that using reduction factors suggested in published research for the specific steel grades improved results over applying the generic Eurocode elevated temperature steel strength reduction factors.
concrete filled tubes; fire resistance; joints; elevated temperature; fin plate; experiments;finite element modelling;
M.H. Jones and Y.C. Wang: University of Manchester, Manchester, UK
The Eurocode system provides limited information regarding the structural fire design of external steel structures. Eurocode 1 provides thermal action for external member but only in steady-state
conditions. On the other hand, Eurocode 3 provides a methodology to determine heat transfer to external steelwork, but there is no distinction in cross
section shapes and, in addition, the calculated temperature distribution is assumed to be uniform in the cross section. This paper presents the results of a research carried out to develop a new transient heat transfer model for external steel elements to improve the current approach of the Eurocodes. This research was carried out as part of the project EXFIRE development of design rules for the fire behaviour of external steel structures? funded by the European Research Programme of the Research Fund for Coal and Steel (RFCS).
fire safety design; external steel estructures,Eurocodes; thermal actions, thermal response, elevated temperatures; temperature distribution.
J.A. Chica and F. Morente : Construction Unit of the Research & Development Centre LABEIN-Tecnalia, Derio, Spain
The increasing use of performance-based approaches in structural fire engineering design of multi-storey composite buildings has prompted the development of various tools to help quantify the influence of tensile membrane action in composite slabs at elevated temperatures. One simplified method which has emerged is the Bailey-BRE membrane action method. This method predicts slab capacities in fire by analysing rectangular slab panels supported on edges which resist vertical deflection. The task of
providing the necessary vertical support, in
practice, requires protecting a panel\'s perimeter beams to achieve temperatures of no more than 620?C at the required fire resistance time. Hence, the integrity of this support becomes critical as the slab and the attached beams deflect, and large deflections of the perimeter beams may lead to a catastrophic failure of the structure. This paper presents a finite element investigation into the effects of vertical support along slab panel boundaries on the slab behaviour in fire. It examines the development of the membrane mechanism for various degrees of edge-beam protection, and makes comparisons with predictions of the membrane action design method and various acceptance criteria.
Anthony K. Abu , Ian W. Burgess : Department of Civil and Structural Engineering, University of Sheffield, Sheffield S1 3JD, UK
Roger J. Plank : School of Architectural Studies, University of Sheffield, Sheffield S10 2TN, UK
This paper presents results of fire tests on corrugated sheets used as load bearing structure of
roofs of industrial buildings. Additional tests of bolted sheet connections to the supporting structure at ambient and elevated temperatures are described. Three connection types were tested and their resistance, stiffness and deformation capacity was evaluated. Finite element simulations of the corrugated sheet based on the experimental observations are briefly described and design models are presented.
corrugated sheet; fire resistance; bolted connection; experiments.
Zden k Sokol, František Wald and Petra Kallerova : Faculty of Civil Engineering, Czech Technical University, Thakurova 7, 166 29 Prague,
This paper details a testing facility (?NATURAL FIRE FACILITY?) that allows closelycontrolled
experimental testing on full-scale sub-frames while reproducing the spatially transient temperature
conditions measured in real fires. Using this test facility, an experimental investigation of six steel sub-frames under a natural fire was carried out at the Department of Civil Engineering of the University of Coimbra. The main objective of these tests was to provide insight into the influence of these connection types on the behaviour of steel sub-structures under fire. The experimental layout is defined by two thermally insulated HEA300 columns and an unprotected IPE300 beam with 5.7 m span,supporting a composite concrete slab. Beam-to-column connections are representative of the most common joint type used on buildings: welded joints and extended, flush and partial depth plate. Finally, the available results are presented and discussed: evolution of the steel temperature; development of displacements and local deformations and failure modes on the joints zone.
structural engineering; steel and composite structures; fire behaviour; full-scale tests; structural integrity
Aldina Santiago, Luis Simoes da Silva : ISISE - Department of Civil Engineering, University of Coimbra, Coimbra, Portugal
Gilberto Vaz : Department of Mechanical Engineering, ISEC - Polytechnic Institute of Coimbra, Coimbra, Portugal
Paulo Vila Real : LABEST - Department of Civil Engineering, University of Aveiro, Aveiro, Portugal
Antonio Gameiro Lopes : Department of Mechanical Engineering, University of Coimbra, Coimbra, Portugal