Use of Optical Fibers to Investigate Strength Limit States for Pressure Pipe Liners

2019 ◽  
Author(s):  
Titilope Adebola ◽  
Ian Moore ◽  
Neil Hoult
Keyword(s):  
Optical Fibers ◽  
Limit States ◽  
Strength Limit ◽  
Pressure Pipe

Reliability analysis of wood I-joists

1993 ◽  
Vol 20 (4) ◽  
pp. 564-573 ◽  
Author(s):  
R. O. Foschi ◽  
F. Z. Yao
Keyword(s):  
Reliability Analysis ◽  
Carrying Capacity ◽  
Failure Modes ◽  
Limit State ◽  
Load Carrying Capacity ◽  
Limit States ◽  
Element Analysis ◽  
Strength Limit ◽  
Reliability Method ◽  
Load Carrying

This paper presents a reliability analysis of wood I-joists for both strength and serviceability limit states. Results are obtained from a finite element analysis coupled with a first-order reliability method. For the strength limit state of load-carrying capacity, multiple failure modes are considered, each involving the interaction of several random variables. Good agreement is achieved between the test results and the theoretical prediction of variability in load-carrying capacity. Finally, a procedure is given to obtain load-sharing adjustment factors applicable to repetitive member systems such as floors and flat roofs. Key words: reliability, limit state design, wood composites, I-joist, structural analysis.

Case Study for Bolted T-Stub Connection Design

2013 ◽  
Vol 716 ◽  
pp. 626-631
Author(s):  
Wan Hu Jong ◽  
Myung Jang Hee
Keyword(s):  
Design Methodology ◽  
High Strength ◽  
Ideal Strength ◽  
Limit States ◽  
Strength Limit ◽  
Moment Connection ◽  
Plastic Strength ◽  
Connection Design

This paper is mainly performed to investigate T-stub connection that is described on the basis of ideal strength limit states. The determination of T-stub based on the full plastic strength of the steel beam in accordance with 2005 AISC Seismic Provisions. The T-stub connections considered herein were performed to include the T-stub component of bolted moment connection frames. Therefore, the proposed T-stub models will be evaluated by comparing the required factored bar strength. T-stub components using ten high strength bolts with wider gages are demonstrated in this design. In addition, equations for connection design will be described in this paper. Finally, new design methodology is applied to T-stub connections suggested in this study.

scholarly journals Seismic Performance Evaluation of Boil-Off Gas Compressor in LNG Terminal

2015 ◽  
Vol 9 (1) ◽  
pp. 557-569 ◽  
Author(s):  
Hyo-Sang Park ◽  
Tae-Hyung Lee
Keyword(s):  
Performance Evaluation ◽  
Seismic Performance ◽  
Fragility Curves ◽  
Time History ◽  
Likelihood Estimation ◽  
Integrated System ◽  
Limit States ◽  
Seismic Performance Evaluation ◽  
Strength Limit ◽  
Anchor Bolts

Liquefied natural gas (LNG) terminals, one of the lifeline facilities, need to be protected by a proper seismic design against extreme earthquakes. An LNG terminal consists of a series of process facilities that are connected by pipelines of various sizes. Boil-off gas (BOG) compressor is one of the critical process facilities whose failure will cause the functional failure of the LNG terminal. Process facilities, including BOG compressor, other than LNG storage tanks and pipes, have not been a major concern in terms of the seismic performance evaluation. In this study, the seismic performance of a BOG compressor is evaluated and the seismic fragility functions are presented. An integrated system of a BOG compressor is modeled by a 3 dimensional finite element modeling scheme. A series of time history analyses are conducted to monitor the behavior of anchor bolts, one of the most critical elements in the BOG compressor. To develop fragility curves, a set of 20 ground motions are selected from a database of the historic earthquake accelerations. Fragility curves are developed based on the maximum likelihood estimation approach with respect to the strength limit states. When an earthquake load is applied to the BOG compressor, the main motor is likely to overturn and the flywheel is likely to slide, and, consequently, anchor bolts will be subjected to tension and shear force, respectively. It is concluded that the BOG compressor is safe against the design level earthquake

Reliability-based load and resistance factors for soil-nail walls

2011 ◽  
Vol 48 (6) ◽  
pp. 915-930 ◽  
Author(s):  
G.L. Sivakumar Babu ◽  
Vikas Pratap Singh
Keyword(s):  
Limit Equilibrium ◽  
Limit State ◽  
Input Parameter ◽  
Limit States ◽  
Soil Nail ◽  
Resistance Factors ◽  
Strength Limit ◽  
Load And Resistance Factors ◽  
Load And Resistance Factor ◽  
Parameter Values

Existing soil nailing design methodologies are essentially based on limit equilibrium principles that together with a lumped factor of safety or a set of partial factors on the material parameters and loads account for uncertainties in design input parameter values. Recent trends in the development of design procedures for earth retaining structures are towards load and resistance factor design (LRFD). In the present study, a methodology for the use of LRFD in the context of soil-nail walls is proposed and a procedure to determine reliability-based load and resistance factors is illustrated for important strength limit states with reference to a 10 m high soil-nail wall. The need for separate partial factors for each limit state is highlighted, and the proposed factors are compared with those existing in the literature.

RELIABILITY ANALYSIS OF STEEL BRACED REINFORCED CONCRETE FRAMES WITH SEMI-RIGID CONNECTIONS

2012 ◽  
Vol 12 (05) ◽  
pp. 1250037 ◽  
Author(s):  
H. B. BASAGA ◽  
M. E. KARTAL ◽  
A. BAYRAKTAR
Keyword(s):  
Finite Element ◽  
Reliability Analysis ◽  
Compression Strength ◽  
Limit State ◽  
Braced Frames ◽  
Limit States ◽  
Strength Limit ◽  
Steel Strength ◽  
Reliability Method ◽  
Story Drift

This paper presents the reliability analysis of the frame structures with semi-rigid connections. For this purpose, the SEMIFEM finite element program that is capable of dealing with the semi-rigid connections is coded in FORTRAN. Then, this program is connected to the reliability algorithm. The direct coupling method, which is a combination of the reliability method and finite element method, is utilized to determine the reliability indexes and probabilities of failure for the structure. The first order reliability method (FORM) is the one favored in the present reliability analysis. Two sets of steel framed structures are analyzed; each of four and eight stories, consisting of a portal frame and three types of concentrically braced frames. Concrete compression strength limit state in reinforced concrete (RC) columns, steel strength limit state in steel braces and inter-story drift limit state are considered in reliability evaluation. According to the limit states, X braced frames are determined as the safest structures, while the portal frames are regarded as the most unsafe structures. As the connection percentage increases, the safety of the structure increases in terms of inter-story drift and steel strength limit states, but decreases for concrete compression strength limit states.

High-voltage monitoring by the fiber-optic recirculating measuring system

2020 ◽  
pp. 38-44
Author(s):  
A. V. Polyakov ◽  
M. A. Ksenofontov
Keyword(s):  
Optical Fibers ◽  
High Voltage ◽  
Optical Sensors ◽  
Electromagnetic Interference ◽  
Fiber Optic ◽  
Electric Power Industry ◽  
Measuring System ◽  
Voltage Range ◽  
External Electromagnetic Fields ◽  
Optic Communication

Optical technologies for measuring electrical quantities attract great attention due to their unique properties and significant advantages over other technologies used in high-voltage electric power industry: the use of optical fibers ensures high stability of measuring equipment to electromagnetic interference and galvanic isolation of high-voltage sensors; external electromagnetic fields do not influence the data transmitted from optical sensors via fiber-optic communication lines; problems associated with ground loops are eliminated, there are no side electromagnetic radiation and crosstalk between the channels. The structure and operation principle of a quasi-distributed fiber-optic high-voltage monitoring system is presented. The sensitive element is a combination of a piezo-ceramic tube with an optical fiber wound around it. The device uses reverse transverse piezoelectric effect. The measurement principle is based on recording the change in the recirculation frequency under the applied voltage influence. When the measuring sections are arranged in ascending order of the measured effective voltages relative to the receiving-transmitting unit, a relative resolution of 0,3–0,45 % is achieved for the PZT-5H and 0,8–1,2 % for the PZT-4 in the voltage range 20–150 kV.

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