Papers by Keyword: Column

Abstract: This paper refers to behaviour and capacity of axially loaded columns strengthened under load using welded steel plates. This method of strengthening is fast, simple and widely used but no universal and reliable analytical solution has been presented yet. In the paper, focus is put on flexural buckling. The approach using cross-section properties of strengthened member and the modified buckling reduction factor was used to calculate the ultimate resistance. In buckling theory, the resistance of column subjected to compression load is reached when the most stressed fibres start to yield. However, some researchers allow certain amount of yielding for base material of columns strengthened under load. In the paper, the new modified buckling reduction factor based on Eurocodes is derived. Two types of column strengthening under various preload magnitudes are investigated using finite element study in ANSYS code and transient analysis type. Birth and death of elements is used to simulate strengthening welded plates. The results are compared with analytical solutions.

Abstract: This article describes the effect of inclination of columns on the change of stiffness of high-rise buildings with circular floor plan. Analysis was made for the building loaded by forces induced by wind and seismic loads. Various high-rise buildings with columns with different inclinations and buildings with vertical columns were analyzed from the viewpoint of horizontal displacements. The results were compared. The comparison was made with horizontal displacements of the building, where columns were inclined.

Abstract: Experimental tests have been conducted to investigate the performance of Concrete Filled Carbon Fiber Reinforced Polymer Sheet Tube (CFCST) columns. The main variables of this experimental program were the number and wrapping angles of CFRP sheets. In the first stage, stress versus strain characteristic of CFCST specimens was investigated by uni-axial tests. In the second stage, six full-scaled CFCST columns subjected to quasi-static lateral loading, as well as constant axial compression, were tested. The test results showed that the response of CFCST was seriously influenced by these two variables. This test results could be utilized for establishing the analytical models.

Abstract: The main objective of this study is to parametrically investigate the effect of pre-and post-corrosion and loading damage on concrete-jacketed reinforced concrete (RC) columns under uni-axial loading. A model capable of evaluating the squash load of un-jacketed or jacketed RC columns with and without corrosion damage was induced. The parametric studies based on this model are meant to investigate the effect of rebar corrosion on the axial compression capacity of jacketed RC column. It was concluded that the longitudinal rebar corrosion has more distinct effect on the peak load than that of web rebar. The jacketing rebar corrosion has more distinct effect on the peak load than that of substrate rebar.

Abstract: The column of heavy double turret five-axis horizontal milling complex machining center is taken as the object of study. Solidworks is used to establish three-dimensional model of milling machining center column, the established modal is be imported into ANSYS Workbench for static and dynamic characteristics analysis. First, by comparing the column deformation, the stress and strain under no-load and load conditions, which is concluded that column design is too conservative and be optimized. Secondly, the modal analysis was carried out on the column, which provides a theoretical basis for the optimization of the column by getting the first six natural frequencies and mode shapes of cloud.

Abstract: According to Rankkine method, it finds a simple method to calculate the ultimate bearing capacity of reinforced concrete columns subjected to four-faced heating. This method is based on the study results by Dotreppe. And the concrete structure design Specification (GB50010-2002). Sixty-four columns from three different laboratories have been calculated by this method, and safe and correct results are got. An example using the simplified formulation has been presented. It can find that the method is simple and convenient, so it is fit for Chinese engineers.

Abstract: A reliability analysis was conducted on high-strength concrete (HSC) columns during a fire. The influences of fire’s randomness and explosive spalling of concrete were investigated. The fire resistance for axial loading capacity of HSC columns was in terms of steel yield strength and concrete compressive strength with considering the effect of elevated temperatures. The load random variables included dead load and sustained live load. The JC method was applied to calculate the reliability index of the fire resistance of axially loaded HSC columns. It was found that the randomness of fire and explosive spalling of concrete had a significant influence on reliability of HSC columns.

Abstract: This paper presents a review of research progress in fire performance of concrete-filled steel tubular (CFST) columns. Experimental results of CFST columns in fire are reviewed with influence parameters, such as heights, cross-sectional dimension, section types, concrete types, concrete strengths, load ratio, load eccentricity, fire exposed sides and so on. Some conclusions of CFST columns under fire conditions are summarized. Deficiencies in the fire performance experiments of CFST columns are identified, which provide the focus for future research in the field.

Abstract: A kind of online or portable online odor detector is needed for continuously monitoring the concentration and tracing the source of the odor which is one of the atmosphere pollution. Combining gas chromatograph (GC) and micro-fluidic chip technology, we present a kind of odor detecting system which using micro-fluidic chip for gas separator and photo ionization detector (PID) for sensor. The 115×60×6mm micro-fluidic chip, etched a micro channel of 1mm diameter and 1.8m length inside, is filled by polyethylene glycol as stationary phase according to the type and character of odor. Respectively using micro-fluidic chip and stainless steel packed columns, the acetone detecting experiments prove that corresponding values of the theoretical plates numbers are 2156 and 1250, in addition, the values of their tailing factor are 1.20 and 1.33. The separation experiment between acetone and ethyl alcohol in the chip illustrate the degree of separation is 3.1.

Abstract: Through the experimental test, influences of axial compression ratio on seismic ductility of SRC columns are analyzed. The limit values of axial compression ratio of the columns are obtained, corresponding to different stirrup ratios at a certain level of displacement ductility.