Abstract
A numerical model is presented to simulate the mechanical behaviour of composite steel and concrete columns taking into account the interaction between the hollow steel section and the concrete core. The model, based on displacement finite element methods with an Updated Lagrangian formulation, allows for geometrical and material non linearities combined with heating over all or a part of the section and column length. Comparisons of numerical calculations made using the model with 33 fire resistance tests show that the model is able to predict the fire resistance, expressed in minutes of fire exposure, of composite columns with a good accuracy.
Key Words
composite column; hollow steel section; finite element; large displacements; slip; bond; fire situation; kinematic compatibility; plasticity; creep; iterative algorithm.
Address
Laboratory of Structural Mechanics, INSA-Rennes, 35043 FrancernLaboratory of Structural Mechanics, INSA-Rennes, 35043 FrancernFire Research and Engineering Section, CTICM, 78470 St R?y-l?-Chevreuse, France
Abstract
An experimental study was conducted to investigate the behavior of eccentric lightweight aggregate concrete-encased composite columns. This study aims at verifying the validity of such type of concrete in composite construction and checking the adequacy of the AISC-LRFD and the British Bridge Code BS 5400 specifications in predicting the column strength. Sixteen full-scale pin ended columns subjected to uniaxial bending about the major axis in symmetrical single curvature were tested.
Key Words
columns; composite columns; encased columns; lightweight concrete.
Abstract
The paper presents a model for analysing the shear-lag effect on the slab of twin-girder composite decks subjected to static actions, support settlements and concrete shrinkage, which are the main actions of interest in composite bridge design. The proposed model includes concrete creep behaviour and shear connection flexibility. The shear-lag in the slab is accounted for by means of a new warping function. The considered actions are then applied to a realistic bridge deck and their effects are discussed. The proposed method is utilised to determine the slab effective widths for three different width-length ratios of the deck. Finally, a comparison between the results obtained with the Eurocode EC4-2 and those obtained with the proposed model is performed.
Key Words
composite steel-concrete bridges; effective width; flexible shear connection; long term behaviour; shear-lag effect.
Address
Institute of Structural Engineering, University of Ancona, via Brecce Bianche, 60131, Ancona, Italy
Abstract
The importance of the research on moment-resistant properties of unstiffened tubular joints and the research background are introduced. The performed experimental research on the bending rigidity and capacity of the joints is reported. The emphasis is put on the discussion of the flexural behavior of the joints including sets of geometrical parameters of the joints and several loading combinations. Procedures and results of loading tests on four full size joints in planar KK and X configuration are described in details at first. Mechanical models are proposed to analyze the joint specimens. Three-dimensional nonlinear FE models are established and verified with the experimental results. By comparing the experimental data with the results of the analysis, it is reported reasonable to carry out the structural analysis under the assumption that the joint is fully rigidly connected, and their bending capacities can assure the strength of the members connected under certain limitation. Furthermore, a parametric formula for inplane bengding rigidity of T and Y type tubular joints is proposed on the basis of FE calculation and regression analysis. Compared with test results, it is shown that the parametric formula developed in this paper has good applicability.
Key Words
unstiffened tubular joint; flexural behavior; bending rigidity; loading test; non-linear FE analysis; joint rigidity evaluation.
Address
Department of Building Engineering, Tongji University, Shanghai 200092, China
Abstract
The ski jump in Innsbruck known for the famous annual New Year "Four-ski-jump-tournament" has been fully renewed. The original jumping tower (built for the 1976 Olympic winter games) was fully pulled down and a new landmark similar to a lighthouse has been erected located on a small hill at the border of the city. Zaha Hadid (London) won the international architectural competition for this significant building. The constructional realisation has been ordered from Aste Konstrucktion and has been finally honoured with the Austrian State award for consulting 2002. After a very strict rimetable the building was already handed over to the ownder for the jumping event in January 2002 and has been fully opened in September 2002 with a restaurant at the top.
Key Words
steel-concrete construction; mixed building technology; truss bridge; cantilevering platforms.
