Sidewall Plates Research Articles

Experimental and numerical investigations on damage evolution of concrete under sulfate attack and freeze-thaw cycles

The macro-microstructure tests of concrete under the alternating action of salt freezing (ASF) were conducted to investigate the macro-mechanical properties and microstructure pore evolution patterns of concrete. Combined with CT scanning and 3D pore model reconstructing technologies, we present the evolution equation of concrete porosity and the quantitative relation between the fractal dimension of concrete pores and the macroscopic strength under the ASF. Then, a macro-microscopic damage evolution model of concrete was proposed to study the structural performance evaluation of an aqueduct. The results show that the compressive strength (fc), splitting tensile strength (ft), and relative dynamic modulus (Erd) of concrete specimens under the ASF show a decreasing trend as a whole, and the mechanical properties of concrete gradually decrease with the increase of sulfate solution concentration. With the increase of the cycles of salt freezing alternation, the pore fractal dimension of the concrete gradually decreases and the porosity gradually increases. After the cycle of 8 times, the pore fractal dimension decreases by 6.06%, and the porosity increases by 7.30% compared with the initial state. The porosity of concrete is negatively correlated with the strength, while the fractal dimension of the pore structure is positively correlated with the strength. When the ASF reaches 8 times, the maximum compressive stress and tensile stress of the groove body are 9.48 MPa and 3.13 MPa, respectively, which appear at the ends of the lower chord. The displacements of the bottom and side wall plates are 0.384 mm and 3.289 mm, respectively. The penetrating cracks appear at the junction, and the structure severely deteriorates.

Comparison of strengthening methods for tubular T joint corresponding to each static failure mode

This paper is aimed to determine the optimal strengthening method for hollow section T-joint under compression based on the comparison of the increase on strength, self-weight, constructability and aesthetic. Numerical research is carried out to compare each type of strengthening method from its strength efficiency. Increase of strengthened joint self-weight is calculated as the self-weight of the strengthening. It affects the overall weight of the structure and the economy. Possibility of strengthening in time, welding difficulty and visual sensibility are the analyzed parameters in the constructability and aesthetic analysis. For the chord face failure mode, method mainly consists on strengthening the chord flange with material. Four types are proposed in which the collar plate strengthening is the optimal type with ponderation equal to 11.75 for all the criteria combined. The brace failure mode is reduced or avoided through adding material to link the chord and the brace member or to weld the brace together with the chord member. The collar plate strengthening is the optimal among the four types proposed for β≤0.8 and the integral joint for β=1 which is the most frequent in bridge. The sidewall plate is the only type of strengthening to avoid or reduce the sidewall failure.

ASSESSMENT OF SHS TUBULAR T JOINTS SUBJECTED TO CHORD AXIAL FORCES

AbstractThis paper aims to investigate the behaviour of T‐type welded joints consisting of cold‐formed steel square hollow sections (SHS), with β equal to 1.0, with and without sidewall plate reinforcement. A particular focus is on the preload effect in the chord, which is subjected to different levels of tension and compressive axial forces. For this purpose, a finite element numerical study was developed in ANSYS software, based on the development of calibrated models with experimental results. The results were compared with analytical formulations prescribed by standards and in the literature.

Corrigendum to “Experimental and numerical investigation of SHS truss T-joints reinforced with sidewall plates” [Thin-Walled Struct. 145 (2019) 1–16

Corrigendum to “Experimental and numerical investigation of SHS truss T-joints reinforced with sidewall plates” [Thin-Walled Struct. 145 (2019) 1–16

Experimental and numerical investigation of SHS truss T-joints reinforced with sidewall plates

Abstract This paper presents a study on the behaviour of cold-formed SHS truss T-joints reinforced with a pair of sidewall plates. This type of reinforcement may be used in tubular joints where the chord and the brace have the same width and is very efficient particularly for failure modes involving the chord sidewall. An experimental programme and a numerical study are presented and discussed, while the research covered reinforced joints with a pair of sidewall plates and their unreinforced counterparts, the braces being subjected to axial compressive forces. The geometry of the reinforcement plates varied in thickness and in length. The results from the experimental tests were thoroughly discussed, and in a second step were used to calibrate a numerical study that was the basis to a parametric analysis involving the most relevant parameters affecting the joint behaviour. The joint resistances obtained were compared with those forecasted by Eurocode 3 - part 1.8, ABNT NBR 16239, and analytical solutions available in the literature. These comparisons indicated that the available methods for the design of these joints lead to scattered predictions: for the unreinforced joints, the results were very conservative, mainly for increasing chord sidewall slenderness values. On the other hand, the analytical and codes proposals for reinforced joints with sidewall plates with similar thickness of the chord overestimate the observed values in the majority of cases. Finally, this paper proposes two alternative design equations for the studied joints that are more accurate in predicting their resistance when compared to the presented experimental and numerical results.

Earthquake Damages and Disaster Prevention of Aboveground Storage Tanks

Severe damages in aboveground storage tanks (AST) have been often experienced due to earthquakes in Japan. In this paper, earthquake damages of ASTs which occurred for the last several decades are reviewed. These are damages in the 1964 Niigata Earthquake, the 1978 Miyagi Earthquake, the 1983 Sea of Japan Earthquake, the 1995 Kobe Earthquake, the 2003 Hokkaido Earthquake and the 2011 Great East Japan Earthquake. The damages of ASTs can be classified into 3 types in accordance with the characteristics of earthquake. These are the impulsive motion due to a high frequency earthquake, the sloshing motion due to a low frequency earthquake and the tsunami attack. In the impulsive motion, buckling of sidewall plates and uplift of sidewall-to-bottom joints occurred. In the sloshing motion, sinking of floating roofs into liquid and buckling of sidewall-to-roof joints occurred. In the tsunami attack, ASTs moved and overturned to leak oil.

Automatic Generation of the Word in Tire Mold Side Plate Based on Font Vectorization

This paper introduces vectorization technology fromTrueType font for the text on the sidewall plate of the tire mold. TrueTypefont processing technology is the extraction of Windows functions and datatypes of the font outline. Call the API function to process the text in orderto achieve the CNC Machining of the text. It completes the tire mold word-processingsoftware on this basis. The software enables a variety of functions includingtext layout, font zoom, font spacing adjustment, font choice. It also providesa rapid tool for the quickly arranged and CNC machining of the text on thesidewall plate of the tire mold.

442 抵抗板による円筒容器スロッシングの制振

Sloshing suppression effects of vertical baffle plates installed inside a cylindrical tank are tested through computational fluid dynamics. Frequency responses and seismic responses by 2003 Off-shore Tokachi Earthquake are simulated about two distribution patterns, plates stuck out on the side wall and that interrupting the free surface. Frequency responses show both patterns increase the damping and free surface plates reduce the participation factor. Free surface plates have an advantage over side wall plates and reduce the maximum seismic response by about the half of the original, factors of which are explained by modal parameters obtained by the frequency response.

Viscous boundary layers at the sidewall of a convection cell

Profiles of both the mean value and the standard deviation of the local fluctuating velocity were directly measured near the sidewall of a cubic convection cell using water as the working fluid. Scaling laws with the Rayleigh number Ra for various boundary layer quantities have been established over the range of Ra from ${10}^{8}$--${10}^{10}$ and were found to be substantially different from those near the horizontal conducting plates where large temperature gradients exist. This in turn signifies the interplay between the temperature and the velocity fields at the horizontal plates. The length scale associated with the root-mean-square velocity is found to be analogous to the thickness of the wall layer, while the length associated with the mean velocity is analogous to the thickness of the boundary layer, in conventional wall-bounded shear flows. Our measurements also reveal that the large-scale circulation is quite uniform over a large region on the sidewall plate.

High temperature failures of heat resistant steel castings in waste incinerators

AbstractIn waste incinerators, heat resistant cast steel grates and side wall plates are exposed to uncontrollable temperatures up to approx. 1000°C and also to various corrosion attacks. Considerable temperature gradients may generate cracks, elevated Cl‐contents or S‐contents will produce high loss of wall thicknesses. Since failures may result from very different causes, all‐round recommendations as to material selection cannot be given.