scholarly journals Story Stability of a Structure- A Literature Review

2021 ◽  
Vol 1197 (1) ◽  
pp. 012074
Author(s):  
Mohammad Abdul Sai Sohail ◽  
Sreenivasa Prasad Joshi

Abstract Column is a slender beam, which carries load. Failure pattern of a column varies with different parameters such as buckling, compression, shear and tension. The initial imperfections in a column increases deflection and reduction in load carrying capacity. To accomplish stability, the key engineering elements such as connection and rigidity governs the effective length and width of the members. The researchers, covering the key engineering elements with different loading patterns, established numerous comprehensive studies. Further, advancement in the research were carried out to determine lateral stiffness, inter-story displacement and deflected beam shape under various loading patterns. The present study focuses on various literatures on effective length and governing factors, which determine the stability of the structure.

2014 ◽  
Vol 610 ◽  
pp. 88-93 ◽  
Author(s):  
Yao Zheng ◽  
Dong Hua Zhou ◽  
Zhi Lun Ouyang ◽  
Jing Lin Zhu ◽  
Chun Xiu Han

In this paper the elastic load-carrying capacity of the stability columns, which provide lateral support to leaning columns, is investigated. The solution to the effective length of the columns is obtained by using of differential equations. The influences of the leaning columns on the stabilizing columns are studied and the nomo-graphs for determining effective length of the supporting columns are made for practical using. The effective length of columns can be quickly determined by using the nomo-graph, which shows intuitively the trends of the curves in the nomo-graph owing to some relevant parameters.


Author(s):  
D. Rudland ◽  
R. Lukes ◽  
P. Scott ◽  
R. Olson ◽  
A. Cox ◽  
...  

Typically in flaw evaluation procedures, idealized crack shapes are assumed for both subcritical and critical crack analyses. Past NRC-sponsored research have developed estimation schemes for predicting the load-carrying capacity of idealized cracks in nuclear grade piping and similar metal welds at the operating conditions of nuclear power reactors. However, recent analyses have shown that growth of primary water stress corrosion cracks (PWSCC) in dissimilar metal (DM) welds is not ideal; in fact, very unusual complex crack shapes may form, i.e., a very long surface crack that has a finite length through-wall crack in the same plane. Even though some experimental data on base metals exists to demonstrate that complex shaped cracks in high toughness materials fail under limit load conditions, other experiments demonstrate that the tearing resistance is significantly reduced. At this point, no experimental data exists for complex cracks in DM welds. In addition, it is unclear whether the idealized estimation schemes developed can be used to predict the load-carrying capacity of these complex-shaped cracks, even though they have been used in past analyses by the nuclear industry. Finally, it is unclear what material strength data should be used to assess the stability of a crack in a DM weld. The NRC Office of Nuclear Regulatory Research, with their contractor Battelle Memorial Institute, has concluded an experimental program to confirm the stability behavior of complex shaped circumferential cracks in DM welds. A combination of full-scale pipe experiments and a variety of laboratory experiments were conducted. A description of the pipe test experimental results is given in a companion paper. This paper describes the ongoing analyses of those results, and the prediction of the load-carrying capacity of the circumferential cracked pipe using a variety of J-estimation scheme procedures. Discussions include the effects of constraint, appropriate base metal material properties, effects of crack location relative to the dissimilar base metals, and the limitations of the currently available J-estimation scheme procedures. This paper concludes with plans for further development of J-estimation scheme procedures for circumferential complex cracks in DM welds.


Author(s):  
D. Rudland ◽  
P. Scott ◽  
R. Olson ◽  
A. Cox

Typically in flaw evaluation procedures, idealized flaw shapes are assumed for both subcritical crack growth and critical crack stability analyses. Past NRC-sponsored research have developed estimation schemes for predicting the load-carrying capacity of idealized flaws in nuclear grade piping and similar metal welds at the operating conditions of nuclear power reactors. However, recent analyses have shown that growth of primary water stress corrosion cracks (PWSCC) in dissimilar metal (DM) welds is not ideal; in fact, very unusual complex crack shapes may form, i.e., a very long surface crack that has a finite length through-wall crack in the same plane. Even though some experimental data on base metal cracks exist to demonstrate that complex shaped cracks in high toughness materials fail under limit load conditions, other experiments demonstrate that the tearing resistance is significantly reduced. At this point, no experimental data exists for complex cracks in DM welds. In addition, it is unclear whether the idealized estimation schemes developed can be used to predict the load carrying capacity of these complex-shaped flaws, even though they have been used in past analyses by the nuclear industry. Finally, it is unclear what material strength data should be used to assess the stability of a crack in a DM weld. The NRC Office of Nuclear Regulatory Research (RES), with their contractor Battelle Memorial Institute, has begun an experimental program to confirm the stability behavior of these complex shaped flaws in DM welds. A combination of thirteen full-scale pipe experiments and a variety of laboratory experiments are planned. This paper will summarize the past base metal complex-cracked pipe experiments, and the current idealized flaw load carrying capacity estimation schemes. In addition, the DM weld complex cracked pipe experimental test matrix will be presented. Finally, plans for using these results to confirm the applicability of idealized flaw stability procedures are discussed.


2012 ◽  
Vol 18 (1) ◽  
pp. 81-90 ◽  
Author(s):  
Zdeněk Kala

The random load carrying capacity of steel plane frames with bracing stiffness is studied. The load carrying capacity is evaluated using the geometrically non-linear FEM analysis. The incremental stiffness matrix of a slightly curved element utilized in the non-linear incremental analysis is listed. Initial imperfections are considered as random variables. Statistical analysis and Sobol sensitivity analysis are performed using the Latin Hypercube Sampling method. The effect of initial random imperfections on the load carrying capacity is studied, whilst assuming constant slenderness of the columns. The evaluation parameters are the pair of non-random values of elastic bracing stiffness, and system length of the columns. The paper illustrates that the load carrying capacity is very sensitive to initial crookedness of the columns in the event that the non-sway (symmetric) and sway (anti-symmetric) buckling modes coincide. In this case, the design load carrying capacity obtained from statistical analysis according to the EN 1990 (2002) standard is relatively very small (of low safety). Results show that the reliability of design of a steel frame according to EUROCODE 3 (1993) is significantly misaligned. The significance of the first and the second buckling forces as indicators of sensitivity of the load carrying capacity to the imperfections is discussed. Santrauka Tiriama plieninio plokščio rėmo su standžiaisiais ryšiais laikomoji galia. Ji vertinama atliekant geometriškai netiesinę BEM analizę. Aptariama šiek tiek išlinkusio elemento laipsniškai didėjanti standumo matrica, atliekant netiesinį iteracinį skaičiavimą. Atsitiktiniu dydžiu laikomas pradinis defektas. Statistinė ir Sobolio (Sobol) jautrumo analizė atliekama pritaikant LHS metodą (Latin Hypercube Sampling Method). Nagrinėjamas pradinio atsitiktinio defekto poveikis laikomajai galiai darant prielaidą, kad pastovus dydis yra liauna kolona. Vertinimo kriterijus yra ne atsitiktinių didžių pora, t. y. tampriai standus ryšiai ir konstrukcijos kolonų aukštis. Straipsnyje aptariama kolonos pradinio kreivio įtaka laikomajai galiai, atsižvelgiant į klupumo formas, kai nelinksta (simetrinė apkrova) ir linksta (nesimetrinė apkrova). Laikomosios galios projektavimo apkrovos, šiuo atveju gautos iš statistinės analizės pagal EN 1990 (2002) standartą, yra palyginti nedidelės. Gauti rezultatai rodo, kad plieninio rėmo patikimumas pagal Eurocode 3 (1993) labai nesutampa. Nagrinėjama defektų įtaka laikomajai galiai atsižvelgiant į pirmą ir antrą klupimo jėgą.


2019 ◽  
Vol 8 (3) ◽  
pp. 2606-2612

Due to the scarcity of land for the construction of industrial, commercial, and transportation structures for development in urban areas, it is very necessary to use the places which have weak strata. This has become very mandatory to use the land which has poor engineering properties due to the unavailability of land. In the recent years granular columns have come under the extensive use for increasing the load carrying capacity and reducing the settlement in the expansive soil and loose sand. Nowadays to increase the stability of the foundation, granular columns are being widely used. Traditional columns are driven into the weak expansive soil stratum and maintain its stability from lateral confinement, which is generally due to the reaction from the surrounding stiffened expansive soil. However, this is not so easy to support loose soil, an additional lateral support may have to be provided to stabilize it and reduce its settlements. This study aims to overcome this weakness in soil by wrapping the granular column in geotextile layer to enhance the lateral reinforcement. In the present paper the discussion is about the variation in load carrying capacity and settlement characteristics of granular column (made up of cement fly ash and sand in a definite proportion instead of aggregates and stones) and analyzing its effect on the expansive soil by comparing its results with geotextile encased columns. In this process the study investigates the improvement of load carrying capacity of a single granular column encased with geotextile through model test.


1994 ◽  
Vol 21 (3) ◽  
pp. 396-403 ◽  
Author(s):  
Murray C. Temple ◽  
Sherief S. S. Sakla

Angles used as web members in trusses are often welded to the chords with unbalanced welds. This is necessary because of space limitations. It is not known what effect such a weld has on the compressive load carrying capacity of an angle. The standards and specification examined allow an unbalanced weld for an angle. The justification for using such a weld is based on research conducted on angles in tension. For these members, it was concluded that an unbalanced weld does not affect the tensile load carrying capacity of the angle. Research results for angles with different weld patterns subjected to compressive loads are not available in the literature. Eighteen tests were conducted on angle compression members with various weld patterns. It was determined that an unbalanced weld is detrimental to the load carrying capacity of an intermediate length angle but is beneficial for a slender angle. Key words: angles, column (structural), compressive resistance, effective length, standards, welds.


1997 ◽  
Vol 119 (1) ◽  
pp. 76-84 ◽  
Author(s):  
E. Kim ◽  
A. Z. Szeri

We have demonstrated earlier that for laminar, isothermal flow of the lubricant in the non-cavitating film of long journal bearings, inertia has negligible effect on the load-carrying capacity and influences only the stability characteristics of the bearing. The question we pose in the present paper is: “will these conclusions remain valid for nonisothermal flow, or will lubricant inertia and dissipation interact and result in significant changes in bearing performance?” The results obtained here assert that the effect of lubricant inertia on load-carrying capacity remains negligible, irrespective of the rate of dissipation. The stability of the bearing is, however, affected by lubricant inertia. These results, although obtained here for long bearings and noncavitating films, are believed to be applicable to some practical bearing operations and suggest that for these, bearing load may be calculated from classical, i.e., noninertial theory.


2018 ◽  
Vol 7 (2.13) ◽  
pp. 372
Author(s):  
Darlina Tanjung ◽  
Jupriah Sarifah ◽  
Bangun Pasaribu ◽  
Marwan Lubis ◽  
Anisah Lukman ◽  
...  

Dynamics that occur in the city of Singkil impact on the development of the city both on socioeconomic aspects as well as in the physical manifestation of talud facilities, which can spur an increase in productivity of a region and the functioning of infrastructure of a city well and smooth. Effect of retaining wall against cliff reinforcement that can protect embankment or beach. By knowing the magnitude of the effect of the safety factor due to the slip, bolster, and the decrease due to the consolidation of the clay layer and the load of the embankment as well as the amount of time of the decline. The crumbling factor (FS guling = 14.97) is greater than the safety factor, for the stability of the slip where the maximum force, where the only force of thrust causing the active horizontal force component (Pa = 0.333) results in a FS (slip) greater than the safety factor of stability to the carrying capacity, the eccentricity value (e = - 0.081) more than 1/6 then the qmin value becomes positive, since the value of e <1/6, and the FS yield of soil bearing capacity (FS (carrying capacity) = 162.122) this value is greater than FS security means the talud safely holds load carrying capacity, safe against bolsters and slip. 


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