STUDY ON SAFETY OF PULLING DOWN COLUMNS IN BUILDING DEMOLITION

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Hiroki Takahashi ◽  
Seiji Takanashi ◽  
Hori Tomohito ◽  
Ohdo Katsutoshi ◽  
Hino Yasumiti
Keyword(s):  
Numerical Analysis ◽  
Material Properties ◽  
Neutral Axis ◽  
Cutting Pattern ◽  
Building Demolition

When walls and columns are demolished during the demolition of buildings in Japan, the lower parts of the walls and columns are cut, after which they are pulled down. This method is called the fall-down method. However, the amount of cutting required is unknown. If a worker cuts the columns too deeply, the walls and columns will collapse and may crush the worker. In this study, the fall-down test of columns was carried out to assess the safety of cutting the lower part of columns. The parameters of the test included the pattern of cutting the lower part of columns and the material properties of the model. In addition, the position of the neutral axis was examined by numerical analysis. The results showed that the cutting pattern involving leaving the main reinforcement at the front of the fall-down and cutting the concrete near the neutral axis is safe at demolition sites. In contrast, the cutting pattern with one row of main reinforcement at the front was unsafe and could potentially lead to premature collapse. Columns at demolition sites should not be cut by this latter cutting pattern. The test and the analysis in this study reproduce the demolition site, and the results of these be widely applied in the actual demolition site.

Numerical analysis of damage zones in a bridge

2019 ◽  
Vol 11 (1) ◽  
pp. 1-12
Author(s):  
Mohammed Lamine Moussaoui ◽  
Mohamed Chabaat
Keyword(s):  
Numerical Analysis ◽  
Material Properties ◽  
Data File ◽  
Time Range ◽  
Bridge Structure ◽  
Time Step ◽  
Batch Mode ◽  
Content Type ◽  
Finite Element Software ◽  
Von Mises

Purpose The purpose of this paper is to present a numerical analysis of structural monitoring for damage zones detection. The study is performed with Ansys finite element software, which reads in batch mode programming a previously generated mesh data file and computes the transient dynamic solution for each time-step iteration within an analysis time range. Design/methodology/approach The approach itself is applied on a bridge structure which can be potentially subjected to damage zones due to severe loads cases and or earthquakes vibrations. The ideal Von Mises failure criterion ellipsoid envelope is applied for the detection of overstepped computed stresses and strains. Findings This numerical analysis allows computing, for each time-step iteration, the dynamic displacements at each degree of freedom and the corresponding stresses and strains inside the elements under the action of several times dependent loads cases. Practical implications Several simulations are considered to quantify the external loads. Originality/value The material properties of reinforced concrete RC are calculated for an existing specific bridge structure case. The RC strength is then introduced from the basic compounds material properties using the corresponding volumes fractions.

scholarly journals Reduction of Dynamic Impacts in Block Made of Concrete - Rubber Composites

2018 ◽  
Vol 14 (1) ◽  
pp. 61-68 ◽  
Author(s):  
Maciej Major ◽  
Izabela Major ◽  
Daniela Kuchárová ◽  
Krzysztof Kuliński
Keyword(s):  
Numerical Analysis ◽  
Dynamic Load ◽  
Material Properties ◽  
Material Model ◽  
Damping Factor ◽  
Rubber Composites ◽  
Elastic Deformations ◽  
Real Material ◽  
Additional Protection ◽  
Rubber Concrete

AbstractThe paper presents numerical analysis of block made of three layers: concrete with I-shape rubber pads, space filled with air and concrete with embedded cross rubber pads, respectively. The block is subjected to the dynamic load. To the analysis as rubber the hyperelastic incompressible Zahorski material model was assumed. This material well describes the real material properties in the range of large elastic deformations. Embedded rubber pads provide an additional protection against the transversal dynamic load. ADINA software was utilized to perform numerical analysis of determining the percentage damping factor of rubber-concrete composite in comparison with block made of concrete.

Numerical analysis of material properties in deformation of near hemispherical shells

2011 ◽  
Vol 16 (2) ◽  
pp. 209-213
Author(s):  
Xiao Zhao ◽  
Hui Chang ◽  
Bin Tang ◽  
Xu-hu Zhang ◽  
Hong-chao Kou ◽  
...  
Keyword(s):  
Numerical Analysis ◽  
Material Properties ◽  
Hemispherical Shells

Thermal Stress in Teeth

1978 ◽  
Vol 57 (4) ◽  
pp. 571-582 ◽  
Author(s):  
B.A. Lloyd ◽  
M.B. McGinley ◽  
W.S. Brown
Keyword(s):  
Thermal Stress ◽  
Numerical Analysis ◽  
Material Properties ◽  
Thermal Stresses ◽  
In Vivo Studies ◽  
Tooth Structure ◽  
Analysis Techniques ◽  
Tooth Type

Observations of crack damage in the tooth structure from in vivo studies and in vitro experimental thermal cycling studies were combined with numerical analysis techniques to identify and isolate the influence of thermal stresses an the creation and propagation of cracks in teeth. The factors considered in this study included: (a) variations in tooth type or geometry (molar, bicuspid, etc.), (b) tooth age, (c) material properties of the tooth, (d) the magnitude of the change in the temperature of the environment surrounding the tooth, and (e) the thermal resistance between the tooth and the medium surrounding the tooth.

scholarly journals Numerical Analysis of the Contact Behavior of a Polymer-Based Waterproof Membrane for Tunnel Lining

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2704
Author(s):  
Kicheol Lee ◽  
Dongwook Kim ◽  
Soon-Wook Choi ◽  
Soo-Ho Chang ◽  
Tae-Ho Kang ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Numerical Analysis ◽  
Material Properties ◽  
Interfacial Adhesion ◽  
Laboratory Experiments ◽  
Tunnel Lining ◽  
Contact Conditions ◽  
Contact Behavior ◽  
Initial Strength ◽  
Interface Parameters

Waterproof membranes have higher initial strength, faster construction, and better waterproofing than conventional sheet membranes. In addition, their polymer constituents have much higher interfacial adhesion and tensile strength than those of conventional materials. However, despite their advantages, waterproof membranes are not widely used in civil construction. This study evaluates the material properties and interface parameters of a waterproof membrane by considering the results of laboratory experiments and numerical analysis. Since the contact behavior of a membrane at its interface with shotcrete is important for understanding the mechanism of the support it offers known as a shotcrete tunnel lining, modeling should adopt appropriate contact conditions. The numerical analysis identifies the suitability and contact conditions of the waterproof membrane in various conditions.

Crack Non-Circularity and Finite Erosion Effects on the 3D SIFs of a Bauschinger Modified Pressurized Thick-Walled Cylinder

2015 ◽  
Author(s):  
Qin Ma ◽  
Cesar Levy ◽  
Mordechai Perl
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Fatigue Life ◽  
Numerical Analysis ◽  
Material Properties ◽  
Thermal Loading ◽  
Circular Crack ◽  
Finite Element Package ◽  
Pressurized Cylinder ◽  
Walled Cylinder

Our previous studies have demonstrated that the 3D SIFs of a pressurized cylinder can be greatly affected by many factors. While an autofrettage process may introduce favorable residual stresses at the bore of the cylinder, other factors such as erosions and cracks, once introduced, may greatly reduce the effectiveness of the autofrettage results. In this study, we focus on how the non-circularity of cracks affects the 3D SIFs for a cylinder that contains finite erosions while keeping other conditions and material properties unchanged. Numerical analysis was performed using ANSYS, a standard commercially available finite element package. The residual stress due to any autofrettage process was simulated using the equivalent thermal loading. A closer look was given to problems with different crack configurations and how non-circularity of cracks affects the overall fatigue life of the cylinder when combined with other factors in comparison with circular crack only configurations.

Bend Allowance and Developed Length Calculation for Pressbrake Bending

1997 ◽  
Vol 119 (2) ◽  
pp. 227-237 ◽  
Author(s):  
F. Pourboghrat ◽  
K. A. Stelson
Keyword(s):  
Strain Hardening ◽  
Sheet Metal ◽  
Material Properties ◽  
Empirical Equation ◽  
Measured Data ◽  
Neutral Axis ◽  
Physically Based

Developed length refers to the length of the unstretched fiber measured over both bent and straight sections of a bent sheet. Bend allowance is a term coined by Sachs as a measure of the length of the unstretched fiber in the bent section. Sachs’ empirical equation for calculating bend allowance is not physically based and is independent of material and forming conditions. A physics-based model for calculating bend allowance and developed length for a strain hardening sheet metal formed by pressbrake bending is presented. Effects of material properties and tooling geometry on the calculation of these parameters are considered. It is shown that unlike Sachs’ assumption, it is the deformed shape and not the neutral axis shift or thinning that is important for calculating the developed length in pressbrake bending. It is also shown, by comparing calculated and measured data, that better accuracy can be obtained when the proposed method is used instead of Sachs’ empirical equation.

Bioreactor Development for Cultivating Tenocytes on Collagen Foils Supported by Constitutive Modelling

2013 ◽  
Author(s):  
Wolfgang Willenberg ◽  
Marcus Stoffel ◽  
Dieter Weichert
Keyword(s):  
Numerical Analysis ◽  
Mechanical Stimulation ◽  
Material Properties ◽  
Constitutive Modelling ◽  
Medical Applications ◽  
Physiological Conditions ◽  
Carrier Material ◽  
Tendon Cells ◽  
The Many ◽  
Material Tests

For medical applications, it is desirable to cultivate tendon cells. In addition to the many biochemical requirements for successful cultivation, mechanical stimulation also plays an important role. Especially, it is well known that tendon cells de-differentiate quickly if they are not put under physiological conditions. For this reason, a new bioreactor for the investigation and cultivation of tenocytes is developed, in which tenocytes are seeded on a carrier material. To be able to identify the real loads the tenocytes are subjected to, the material properties of the carrier material are found by performing material tests followed by a numerical analysis.

Numerical Analysis for Damage Characteristics Caused by Ice Collision on Side Structure

2016 ◽  
Author(s):  
Bo Cao ◽  
Dong-Myung Bae ◽  
Jung-Min Sohn ◽  
Aditya Rio Prabowo ◽  
Tuo Han Chen ◽  
...  
Keyword(s):  
Numerical Analysis ◽  
Low Temperature ◽  
Energy Method ◽  
Material Properties ◽  
The Other ◽  
Safe Distance ◽  
Damage Characteristics ◽  
The Difference ◽  
Temperature Damage

Ships operating in ice region have to meet more rigorous environment and more accidents occur such as hull-ice collision accidents or low temperature damage. The problem of hull-ice collision is a serious one about those. Compared with the other parts such as stern and stem, the side structure of a ship may be regarded as the weakest part in the collision accidents, due to its relative less safe distance. However, side structure has the biggest share among the whole structure, which means that it has the higher ratio to be collided with ice. It is worthy much to avoids the serious damages and improve the survivability of ship in the collision accident. This research simulated the collision between side structure and ice. It had analyzed the characteristics of damaged structure based on the energy method when the collision happened. And then it also discussed the importance of material properties especially for ice properties and compared the difference in the end. This paper can be taken as a period summary and were benefit to the research in next step. It was trying to find a way that can simulate the collision fast and accurately as well.

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