• Explosives and Blasting
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• v.26 no.2
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• pp.52-63
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• 2008

Recently the demand of demolition for the unnecessary cylindrical silo structure is increasing due to deterioration and unsatisfactory functional conditions and the issue of demolition is becoming a major highlight. This case study introduced the explosive demolition of the cylindrical silo structure by felling method. The results of explosive demolition conducted on cylindrical silo structure using the felling method show, A silo had collapsed precisely according to estimated direction but in case of B silo there was a minor difference. The lower colunms and ring girder support was designed to the hinge line but in reality the lower colunms of the silo did not do its structural support role and only the ring girder support did its role successfully. As for the impact vibration, most of the measurements were within the estimated range.

• Structural Engineering and Mechanics
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• v.53 no.1
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• pp.159-172
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• 2015

This paper is concerned with effects of the wall flexibility on the seismic behavior of ground-supported cylindrical silos. It is a well-known fact that almost all analytical approximations in the literature to determine the dynamic pressure stemming from the bulk material assume silo structure as rigid. However, it is expected that the horizontal dynamic material pressures can be modified due to varying horizontal extensional stiffness of the bulk material which depends on the wall stiffness. In this study, finite element analyses were performed for six different slenderness ratios according to both rigid and flexible wall approximations. A three dimensional numerical model, taking into account bulk material-silo wall interaction, constituted by ANSYS commercial program was used. The findings obtained from the numerical analyses were discussed comparatively for rigid and flexible wall approximations in terms of the dynamic material pressure, equivalent base shear and bending moment. The numerical results clearly show that the wall flexibility may significantly affects the characteristics behavior of the reinforced concrete (RC) cylindrical silos and magnitudes of the responses under strong ground motions.

• Explosives and Blasting
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• v.27 no.2
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• pp.12-18
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• 2009

Recently, several cases of destruction of old cylindrical silos by explosive demolition method have been reported. This study deals with the subject concerning the pre-weakening of a cylindrical concrete silo for the application of overturning explosive demolition method. In the past, the pre-weakening operation of structure in explosive demolition has been done by use of some empirical methods. These empirical approaches, however, have possibilities of unexpected accidents. In order to provide a guideline for the pre-weakening of cylindrical silos and similar structures, this paper shows the result of a case study, in which the instability of a silo due to pre-weakening is investigated by a numerical structural analysis before actually conducting pre-weakening and demolition operations.

• Explosives and Blasting
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• v.26 no.1
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• pp.7-14
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• 2008

In order to complete successfully the demolition of a silo structure by means of felling method, structural properties and the geometric design of blast mouth have to be considered. In this study, a commercial software, 3-dimensional applied element analysis (3D AEM), was used to investigate the effect of the geometrical parameters of blast mouth on the collapse behavior of the silo structure.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.35 no.3
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• pp.183-190
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• 2022

The construction of an underground silo structure was the first stage of erecting the Gyeongju low-and-intermediate-level radioactive waste disposal facility. The facility, completed in 2014, has a scale of 100 000 drums and is currently in operation. The underground silo structure, 25 and 50 m in diameter and height, respectively, consists of cylindrical (for storing waste packages) and dome parts. The dome is divided into lower (connected to the operation tunnel) and upper parts. The wall of the underground silo structure is an approximately 1-m-thick reinforced concrete liner. In this study, finite element analysis was performed for each phase of the construction sequence and operation of the underground silo structure. Two-dimensional axial symmetric finite element analysis was implemented using the SMAP-3D program. Three-dimensional finite element analysis was also performed to examine the reliability of the two-dimensional axial symmetric finite element model. The structural behavior of the underground silo structure was predicted, and its structural safety was examined.

• Explosives and Blasting
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• v.26 no.1
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• pp.1-5
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• 2008

In this study, the structural behavior accorded by pre-weakening before demolishing a cylindrical structure was investigated to ensure structural stability using 3 dimensional applied element method (3D AEM). An opening angle of crushed area for the pre-weakening was changed to examine the displacement behavior of the cylindrical structure. This study shows that the crushing range for pre-weakness must be below 40% to void the collapse of the cylindrical silo structure.

• Magazine of the Korean Society of Agricultural Engineers
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• v.31 no.4
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• pp.58-71
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• 1989

This study aims to develop a computerized program for analysis of the ground-supported cylindrical shell structure with step varied section and to find out its mechanical characteri- stics through application of the developed program to the analysis of a ensiled farm silo as a model structure. The thickness of wall and bottom-plate of farm silo is assumed to be step-varied and its detailed structural dimensions are presented in Tab. 1 and 2. Several numerical case studies show that sectional stresses of the sample structures are largely reduced by adopting "varied section" design technique. And, other major results ob- tained from this study are summarize4 as follows ; 1. The variation of wall-thickness has a great influence on bending stresses of wall. Ho- wever, the larger the relative thickness of bottom-plate is, the smaller the influence is. 2. The magnitude of thickness of projecting toe of bottom-plate has negligible effect on sectional stresses 3. The conventional design methodology, which assumes the bottom edge of wall as clam- ped on ground, is proved to be discarded through the numerical analysis. 4. It is found that the "varied section" design technique should get similar effects as in the case of thick bott6m-plate having uniform thickness. 5. The variation of wall-thickness has a considerable effect on the bending stresses of bo- ttom-plate. Especially, this phenomenon is very remarkable in its projecting toe. In some cases. the negative bending moment may be acted on.

• Magazine of the Korean Society of Agricultural Engineers
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• v.29 no.2
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• pp.39-52
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• 1987

This study was to investigate the effects of soil-structure relative stiffness on the structural characteristics of the cylindrical tank supported by soil. A standard example model of the farm silo rested on the Winkler's subsoil model was used for the analysis of soil-structure coupled system. In this paper, Winkler's constants 4,15 and l00kg/cm$^2$/cm were considered and the bottom plate thicknesses of the farm silo 20, 30, 50,100 and 150cm were adopted. For the given model the effects of bottom plate thickness were the most conspicuous at weakest Winkler's constant 4kg/ cm$^2$/cm. While when Winkler's constant is l00kg/cm$^2$/cm, the effect of the bottom plate thickness is almost negligible. On the other hand, when the bottom plate thickness is more than 100cm, the effects of elastic foundation were aknost disappeared. In design practice, it is hoped that the thicknesses of bottom plate should be determined reasonably because of it's considerable effect on the structural characteristics as the lOOcm thickness of bottom plate will not be practical value in usual sites.

• Structural Engineering and Mechanics
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• v.62 no.4
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• pp.487-496
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• 2017

The focus of this study were to investigate patterns between wall pressures and stresses with grain moisture of soybean and rice varieties widespread cultivated in Turkey in order to determine needed designing parameters for structure analysis in silos at filling and discharge. In this study, the wall pressures and stresses were evaluated as a function of moisture contents in the range of 8-14% and 10-14% d.b. The pressures and von Mises stresses affected as significant by the change of grain moisture content. The main cause of pressure and stress drops is changed in bulk density. Therefore is extremely important bulk density and moisture content of the product at the structural design of the silos. 4 mm wall thickness, were determined to be safe for von Mises stresses in both soybean and rice silos is smaller than 188000 kPa.

• Magazine of the Korean Society of Agricultural Engineers
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• v.30 no.2
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• pp.44-54
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• 1988

This study was carried out to investigate the applicability of the conventional design method for ground supported circular cylindrical shell structures. For this purpose, the ensiled farm silo was adopted as a model structures. Herein, the conventional design method was based on the assumption that such structures are clamped at the bottom edges or the ground pressure is independent of the deflection at the surface. In the present paper, the applicability of above assumption was checked out by comparison with an exact method considering soil-structure interaction. Some results of numerical calculation show us ; When the ground is very hard, for example Winkler's constant k is larger than 100 kg / cm$^2$ / cm, or the bottom plate of structures has a infinitely stiffness, for example the bottom plate thickness is larger than 100 cm, the sectional forces, obtained from the conventional method at any wall of structures resting on an elastic foundation, can used for design purpose. Therefore, if the above condition is satisfied then the conventional assumptions can be justified for the design purpose. In this case, the assumption that such structures are fixed at the lower edges was more realistic than the assumption that the reaction pressure acting on structures is uniformly disributed since the accuracy of results of the analysis by the former assumption was higher than that obtained from the latter assumption. But the sectional forces in the bottom plate resting on ground directly could not be evaluate correctly by the conventional method.