Study on residual strength of concrete filled steel tube after exposure to explosing impact
The residual bearing mechanism of concrete filled steel tubular beams with different casing hoop steel coefficients after exposure to explosing impact were experimentally investigated. The experiments were carried out on the reaction frame for loading, and the pressure and the residual deformation modes were recorded. The results show that the concrete filled steel tubular beams have good anti-explosion ability and the casing hoop steel coefficient is an important factor to the value of residual strength.
Hollow and concrete filled steel hollow sections under transverse impact loads
Abstract Steel hollow sections are used extensively in the construction, offshore, mining and security industries. In many applications these sections are concrete filled in order to gain strength advantages under axial compression loads. These sections may be subjected to transverse impact loads from accidental or intentional impacts or explosive events. This paper reports an experimental and analytical investigation of hollow and concrete filled steel square hollow (SHS) section beams subjected to low velocity, large mass transverse impacts at the beam mid-span. Three different section sizes were tested as fully clamped beams, where the impact energy was sufficiently large so as to cause complete failure of the beam by tensile tearing. It is shown that non-compact hollow sections undergo local deformations beneath the impactor, and when concrete filled these sections can sustain greater transverse impact loads as the local deformations are restricted from forming. The effect is shown to be less pronounced for compact sections. An elastic–plastic theoretical method is developed to establish the force–displacement and energy absorption relationships for hollow and concrete filled sections, and is shown to compare well with the experimental results. The local reduction of the section at the point of load application is explicitly included. A design procedure is developed whereby the analyst may use a deflection, force or energy limit to design hollow and concrete filled steel SHS members for transverse impact loads.
Evaluation of buckling load and dynamic performance of steel shear wall retrofitted with strips made of shape memory alloy
One of the most imperfections of the steel shear wall is out of plane displacements that cause severe damage in both structural and non-structural elements. In this paper, the effects of shape-memory alloys on steel shear walls are investigated. First, a numerical analysis using the finite element method in ABAQUS software has been carried out according to an experimental test. The results of the numerical analysis have been verified with experimental results. Next, shape-memory alloy fibers have been added vertically and horizontally to various parts of the steel shear wall. The results show that retrofitting with the shape-memory alloy reduces the out-of-plane displacement of the steel shear wall under both cyclic and seismic loadings. Besides, the buckling load in the steel shear wall increases when it is retrofitted with the shape-memory alloy. Also, the total out-of-plane movement (accumulated absolute displacements) of the steel shear wall and non-structural damage are controlled by the characteristic of a shape-memory alloy material called “super-elastic”.