Concrete filled tube

The aim of this study is to show the enormous potential of composite bridges which is not yet fully exploited after more than one century since its first appearance. It concentrates on the field of railway bridges. After a brief overview of the historical evolution of composite bridges from Melan patent to widespread usage, it gives a summation about the Hungarian railway bridges compared with the European average regarding span, age and type. The second part of this paper gives an extensive description about the innovative steel-concrete composite railway bridges. These are mainly beam bridges which solve the problems of hogging area of continuous structures. Bridge types which are introduced by this study:
– Concrete filled (CF) hollow section girder
– CF steel pipe
– CF narrow-width steel box
– CF I girder
– Rolled
– Welded
– Double composite section
– External longitudinal post-tensioning
– Preflex girder
At the end it gives an overview about the composite arch bridges regarding the construction methods.

This paper presents a finite-element (FE) analysis of hybrid fiber-reinforced polymer (FRP)-concrete-steel double-skin tube (FSDT) in the form of columns. The FSDT columns that were examined consisted of a concrete wall sandwiched between an outer FRP tube and an inner steel tube. A FE software was used to develop a pushover analysis of three-dimensional FSDT models to simulate seismic loading. The FE models were validated against the experimental results gathered from seven FSDT columns tested under cyclic loading. The FE analysis results were in good agreement with the experimental backbone curves. The maximum error was 9% in predicting the bending strengths of the columns. Aparametric study evaluated the effect of axial load level, concrete wall thickness, concrete strength, diameter-to-thickness ratio (D=t) of the steel tube, and number of FRP layers on the FSDT columns’ behavior. This study revealed that the behavior of FSDT columns is quite complex. It also revealed that this behavior is controlled by the interactions that occur among the steel tube’s stiffness, the concrete wall’s stiffness, and the FRP hoop’s stiffness. Local buckling occurred in all of the specimens examined. This buckling caused the FSDT system to rupture. Two modes of failure were defined as follows: (1) steel/concrete compression failure, and (2) FRP rupture. Compression failure was relatively gradual whereas failure due to FRP rupture was quite abrupt. Finally, the bending strength increased as the applied axial load, concrete compressive strength, and number of FRP layers increased. The bending strength also increased as both the concrete wall’s thickness and the D=t decreased.

... Seismic Multi-Axial Behavior of Concrete-Filled Steel Tube Beam-Columns Tiziano Perea Roberto T. Leon Georgia Institute of Technology Atlanta, Georgia August 14, 2009 Page 2. Introduction • NEESR-II: System Behavior Factors for Composite and Mixed Structural Systems ...