Measurements of Displacements and Deformations and Reliability Analysis of Base Transceiver Station (BTS) Made of Steel

2017 ◽  
Author(s):  
Izabela Skrzypczak ◽  
Grzegorz Oleniacz ◽  
Przemysław Leń ◽  
Monika Mika
Keyword(s):  
Mobile Communications ◽  
Reliability Index ◽  
Design Stage ◽  
Building Structures ◽  
Reliability Method ◽  
Safety And Reliability ◽  
The Stability ◽  
Index Value ◽  
Building Standards ◽  
Steel Trusses

Safety and reliability of BaseTransceiver Station (BTS) in Global System for Mobile Communications (GSM) should be provided not only at the design stage and construction work, but also during the service. The technical conditions and safety of building structures is also dependent on the determination of geometric deviation of the entire structure and its individual components. This should be referred to the recommendations of code limits. The geodetic measurements of displacements and deformations of objects are extremely important to evaluate the stability and security of the structure and its maintenance. Steel trusses or concrete columns must meet the requirements of building standards and instructions as well as the standard requirements for the deviation limits during the construction phase and operational work. The primary and overarching objective of inventory of BTS is to ensure that the safety of the service and the users is fulfilled. The investigation of the reliability of BTS towers by determining the reliability index value using First Order Reliability Method (FORM) recommended in Eurocode 0 will be perfomed. The values of reliability index will be defined for the serviceability limit.

scholarly journals ANALISIS KEANDALAN DAN SUSUT DAYA PENYULANG TABANAN SETELAH REKONFIGURASI

2018 ◽  
Vol 5 (2) ◽  
pp. 139
Author(s):  
Salman Al Farisi ◽  
Rukmi Sari Hartati ◽  
I Wayan Sukerayasa
Keyword(s):  
Reliability Analysis ◽  
System Reliability ◽  
Reliability Index ◽  
Power Loss ◽  
Electrical System ◽  
Reliable System ◽  
Global Era ◽  
System Reliability Analysis ◽  
Interference Frequency ◽  
Index Value

The need for electricity in this global era is increasing, so that a more reliable electrical system is needed. A reliable system cannot be separated from interference, so there needs to be a system reliability analysis and power loss to the feeder by configuring the network. This research was conducted to find the reliability index value in the form of interference frequency and duration of interference (SAIFI and SAIDI). In one Tabanan feeder the results obtained exceed the standard so reconfiguration is performed Based on the analysis obtained before reconfiguration, the reliability index for SAIFI is 6,7456 (failure / year) and SAIDI is 11,4767 (hour / year) and power loss by 6,27 %. After reconfiguration of Tabanan feeder, the reliability index was better, for SAIFI is 5.2475 (disturbance / year) and SAIDI is 9,8798 (hour / year), the power loss was 2.82%. Sanggulan feeder is a new feeder reconfiguration result from Tabanan feeder, where the analysis was carried out to find out the reliability index of Sanggulan feeder, it was obtained the SAIFI value of 4.5753 (disturbance / year) and SAIDI of 9.5297 (hour / year) and power loss of 4,80%.

Some Important Issues on First-Order Reliability Analysis With Nonprobabilistic Convex Models

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
C. Jiang ◽  
G. Y. Lu ◽  
X. Han ◽  
R. G. Bi
Keyword(s):  
Reliability Analysis ◽  
Reliability Index ◽  
Probability Model ◽  
Mean Value ◽  
Convex Model ◽  
First Order ◽  
Reliability Method ◽  
Complex Engineering ◽  
Mean Value Method ◽  
Form Type

Compared with the probability model, the convex model approach only requires the bound information on the uncertainty, and can make it possible to conduct the reliability analysis for many complex engineering problems with limited samples. Presently, by introducing the well-established techniques in probability-based reliability analysis, some methods have been successfully developed for convex model reliability. This paper aims to reveal some different phenomena and furthermore some severe paradoxes when extending the widely used first-order reliability method (FORM) into the convex model problems, and whereby provide some useful suggestions and guidelines for convex-model-based reliability analysis. Two FORM-type approximations, namely, the mean-value method and the design-point method, are formulated to efficiently compute the nonprobabilistic reliability index. A comparison is then conducted between these two methods, and some important phenomena different from the traditional FORMs are summarized. The nonprobabilistic reliability index is also extended to treat the system reliability, and some unexpected paradoxes are found through two numerical examples.

Barrier Function Method in Reliability Based Design Optimization

2005 ◽  
Vol 297-300 ◽  
pp. 1882-1887
Author(s):  
Tae Hee Lee ◽  
Jung Hun Yoo
Keyword(s):  
Design Optimization ◽  
Barrier Function ◽  
Reliability Index ◽  
Feasible Solution ◽  
Reliability Based Design Optimization ◽  
User Requirement ◽  
Mean Values ◽  
Reliability Based Design ◽  
Design Variables ◽  
Reliability Method

In practical design applications, most design variables such as thickness, diameter and material properties are not deterministic but stochastic numbers that can be represented by their mean values with variances because of various uncertainties. When the uncertainties related with design variables and manufacturing process are considered in engineering design, the specified reliability of the design can be achieved by using the so-called reliability based design optimization. Reliability based design optimization takes into account the uncertainties in the design in order to meet the user requirement of the specified reliability while seeking optimal solution. Reliability based design optimization of a real system becomes now an emerging technique to achieve reliability, robustness and safety of the design. It is, however, well known that reliability based design optimization can often have so multiple local optima that it cannot converge into the specified reliability. To overcome this difficulty, barrier function approach in reliability based design optimization is proposed in this research and feasible solution with specified reliability index is always provided if a feasible solution is available. To illustrate the proposed formulation, reliability based design optimization of a bracket design is performed. Advanced mean value method and first order reliability method are employed for reliability analysis and their optimization results are compared with reliability index approach based on the accuracy and efficiency.

A time-varying reliability-based robust design method considering overall efficiency of axial piston pump

2021 ◽  
pp. 1748006X2110661
Author(s):  
Zunling Du ◽  
Yimin Zhang
Keyword(s):  
Energy Conversion ◽  
Robust Design ◽  
Design Method ◽  
Design Stage ◽  
Structure Parameters ◽  
Time Varying ◽  
Design Variables ◽  
Reliability Method ◽  
Overall Efficiency ◽  
Axial Piston

Axial piston pumps (APPs) are the core energy conversion components in a hydraulic transmission system. Energy conversion efficiency is critically important for the performance and energy-saving of the pumps. In this paper, a time-varying reliability design method for the overall efficiency of APPs was established. The theoretical and practical instantaneous torque and flow rate of the whole APP were derived through comprehensive analysis of a single piston-slipper group. Moreover, as a case study, the developed model for the instantaneous overall efficiency was verified with a PPV103-10 pump from HYDAC. The time-variation of reliability for the pump was revealed by a fourth-order moment technique considering the randomness of working conditions and structure parameters, and the proposed reliability method was validated by Monte Carlo simulation. The effects of the mean values and variance sensitivity of random variables on the overall efficiency reliability were analyzed. Furthermore, the optimized time point and design variables were selected. The optimal structure parameters were obtained to meet the reliability requirement and the sensitivity of design variables was significantly reduced through the reliability-based robust design. The proposed method provides a theoretical basis for designers to improve the overall efficiency of APPs in the design stage.

Research on Characteristics of Fluid Exciting Force of Reactor Internals

2021 ◽  
Author(s):  
Zhipeng Feng ◽  
Liwen Deng ◽  
Xuan Huang ◽  
Pingchuan Shen ◽  
Shuai Liu ◽  
...  
Keyword(s):  
Pressure Fluctuation ◽  
Nuclear Reactor ◽  
Wide Band ◽  
Exciting Force ◽  
Design Stage ◽  
Response Analysis ◽  
Flow Induced Vibration ◽  
Analysis And Evaluation ◽  
Safety And Reliability ◽  
Force Characteristics

Abstract Flow-induced vibration is an important issue related to the safety and reliability of nuclear reactor, which need to be analyzed and evaluated in the design stage. In order to obtain the input loads and key parameters used in the calculation of flow-induced vibration of reactor vessel internals (RVIs) that need to satisfy the engineering requirements. The typical RVIs are selected as the research object, and the fluid exciting force characteristics are studied based on the computational fluid dynamics methods. The results show that the fluid exciting force acting on the RVIs is a wide-band stochastic process. For upper internal, the largest pressure fluctuation occurs at the guide tubes and support columns located near the outlet. Therefore, it is necessary to pay more attention to these guide tubes and support columns in response analysis. As for core barrel, the root mean square value of the pressure fluctuation changes drastically at the inlet and outlet location. For lower internal, the lower flow field of RVIs is relatively disordered, and its pressure fluctuation possesses irregular characteristics. Each component of lower internal need to be considered in analysis and evaluation.

scholarly journals Energy transfer and influencing factors in soil during compaction

PLoS ONE ◽  
2020 ◽  
Vol 15 (11) ◽  
pp. e0242622
Author(s):  
Jie Li ◽  
Xiaohong Bai ◽  
Fuli Ma
Keyword(s):  
Energy Transfer ◽  
Test System ◽  
Building Structures ◽  
Bottom Pressure ◽  
Large Area ◽  
Compaction Characteristics ◽  
Consumption Ratio ◽  
Fill Soil ◽  
Compaction Curve ◽  
The Stability

In China, large-area excavation and filling engineering has increased rapidly with the expansion of construction land. The quality of filling engineering is the most important guarantee for the stability of building structures. Among all research on fill soil, the compaction characteristics are significant for indicating the strength and stability of filling engineering. In this paper, two layers of loess fill soil were compacted by a self-manufactured test system with three different compaction energies. Based on the variation in the soil bottom pressure obtained in the tests, the influence of the compaction parameters on the soil bottom pressure was investigated. The results show that the compaction curve can be used instead of the curve of the change in soil bottom pressure with water content; as the soil density increases, the soil bottom pressure increases to the maximum. The relation of the energy consumption ratio of the soil bottom (σ/σz) and the number of soil layers is exponential and reveals the stability of the soil skeleton formed during compaction. This paper describes the compaction characteristics of loess fill soil from the perspective of energy transfer, and the conclusions provide a theoretical basis for soil filling engineering.

scholarly journals Variable Weight Matter–Element Extension Model for the Stability Classification of Slope Rock Mass

Mathematics ◽  
2021 ◽  
Vol 9 (21) ◽  
pp. 2807
Author(s):  
Shan Yang ◽  
Zitong Xu ◽  
Kaijun Su
Keyword(s):  
Rock Mass ◽  
Classification Criteria ◽  
Evaluation Index ◽  
Open Pit ◽  
Constant Weight ◽  
Extension Model ◽  
Variable Weight ◽  
Slope Rock ◽  
The Stability ◽  
Index Value

The slope stability in an open-pit mine is closely related to the production safety and economic benefit of the mine. As a result of the increase in the number and scale of mine slopes, slope instability is frequently encountered in mines. Therefore, it is of scientific and social significance to strengthen the study of the stability of the slope rock mass. To accurately classify the stability of the slope rock mass in an open-pit mine, a new stability evaluation model of the slope rock mass was established based on variable weight and matter–element extension theory. First, based on the main evaluation indexes of geology, the environment, and engineering, the stability evaluation index system of the slope rock mass was constructed using the corresponding classification criteria of the evaluation index. Second, the constant weight of the evaluation index value was calculated using extremum entropy theory, and variable weight theory was used to optimize the constant weight to obtain the variable weight of the evaluation index value. Based on matter–element extension theory, the comprehensive correlation between the upper and lower limit indexes in the classification criteria and each classification was calculated, in addition to the comprehensive correlation between the rock mass indexes and the stability grade of each slope. Finally, the grade variable method was used to calculate the grade variable interval corresponding to the classification criteria of the evaluation index and the grade variable value of each slope rock mass, so as to determine the stability grade of the slope rock. The comparison results showed that the classification results of the proposed model are in line with engineering practice, and more accurate than those of the hierarchical-extension model and the multi-level unascertained measure-set pair analysis model.

scholarly journals Applying of green building standards for implementation of the city development strategies in Kyiv.

2019 ◽  
Vol 3 (1) ◽  
pp. 16-30
Author(s):  
Dmytro Varavin ◽  
Tetiana Kryvomaz
Keyword(s):  
Environmental Protection ◽  
Public Space ◽  
Development Strategy ◽  
Negative Impact ◽  
Green Building ◽  
Building Structures ◽  
City Development ◽  
Land Relations ◽  
Building Standards ◽  
The City

The main tasks of the "Kyiv City Development Strategy until 2025" are in development and reconstruction of the city, improvement of its infrastructure and environmental protection, which perfectly correlates with the basic principles of green building. This is the modern practice in construction, reconstruction and the exploitation of buildings, in which they im-plement optimal architectural solutions, advanced engineering systems and materials for re-ducing of energy consumption and material resources, it is the process of improving the qual-ity of buildings and the comfort of their internal environment, improving of impact of build-ings on the health of people by minimizing the negative impact on the environment at all stag-es of life cycle of building structures. The practice of the tasks outlined in the Strategy will significantly contribute to the implementation of international environmental standards and to the application of constructive solutions of green building technologies. In particular it ap-peals to such urban development sectors as city development and land relations, housing and communal services, transport and urban mobility, environmental policy and environmental protection, public space, security and civil protection, historical and architectural heritage.

scholarly journals Options for solving the problem of parts of the Shelter object located outside the New Safe Confinement

2020 ◽  
Vol 19 (4) ◽  
pp. 57-65
Author(s):  
O. V. Balan ◽  
◽  
S. Gh. Brylka ◽  
V. V. Derengovskyi ◽  
V. V. Yehorov ◽  
...  
Keyword(s):  
Cost Effective ◽  
Radiation Condition ◽  
Design Stage ◽  
Final Decision ◽  
Building Structures ◽  
Short Term ◽  
Design Studies ◽  
Financial Costs ◽  
Work Area ◽  
Goals And Objectives

The parts of the Shelter object structures remained outside the New Safe Confinement (protruding parts) are considered in the article. The analysis of the building structures condition of the turbine hall and the deaerator stack protruding parts on the east and west sides is carried out and the necessity of works on strengthening and/or dismantling of bearing structures is confirmed. Possible variants of reconstruction of the Shelter object protruding parts are stated and the technological sequence of works is provided. The analysis of the possibilities of performing works in the conditions of functioning of the New Safe Confinement — Shelter object system proved that such activity is rather difficult task, which can cause significant physical and financial costs. As there is no guarantee of trouble-free operation of the building structures of the protruding parts during the entire service life of the New Safe Confinement, it is necessary to make every effort to solve this problem in the short term. The results of the analysis allow to choose the most advantageous solution to the goals and objectives for the safest and most cost/effective dismantling and/or strengthening of structures of protruding parts, taking into account a number of different criteria. These criteria may be different in nature, which allowed to build a generalized efficiency indicator for individual criteria with certain weights that determine the importance of each of the criteria for decision making. Based on the results of the analysis, these options can be considered equivalent. The final decision on the choice of the optimal variant for the Shelter object protruding parts reconstruction can be made after detailing the technological decisions at the design stage of protruding parts reconstruction and before the design studies of the radiation condition in the work area. The obtained information can be used as input data during the design of the reconstruction of the deaerator stack and the turbine hall parts of the Shelter object, which protrude beyond the New Safe Confinement.

Non-Probabilistic Structural Reliability Model Based on Ellipsoidal-Bound Model with Restricted Expansion

2011 ◽  
Vol 230-232 ◽  
pp. 920-924
Author(s):  
Kun Feng Li ◽  
Zi Chun Yang ◽  
Gui Feng Liu
Keyword(s):  
Reliability Index ◽  
Structural Reliability ◽  
Insufficient Data ◽  
Reliability Model ◽  
Gap Model ◽  
New Model ◽  
Model Based ◽  
Information Gap ◽  
Reliability Method

When insufficient data are available, probabilistic reliability method is invalid, but the non-probabilistic reliability method based on I-G (information-gap) model is a valid alternative. The most common I-G model, ellipsoidal-bound model, has been updated in this paper by acquiring information about span restrictions of uncertainty quantities and a corresponding non-probabilistic reliability index was proposed. The method for computing the reliability index was also given. The new model can reveal the influence of the span restriction of uncertainty quantities on structural reliability.

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