scholarly journals OPTIMUM RELIABILITY OF A STEEL TAPERED PORTAL FRAME STRUCTURE EXPOSED TO FIRE

2016 ◽  
Author(s):  
Tamás Balogh ◽  
László Gergely Vigh
Keyword(s):  
Structural Reliability ◽  
Complex Form ◽  
Frame Structure ◽  
Passive Safety ◽  
Safety Measures ◽  
Reliability Indices ◽  
Reliability Method ◽  
Portal Frame ◽  
Portal Frame Structure ◽  
Fire Design

In this study, the optimum reliability of a tapered steel portal frame structure is presented for several cases. The aim of the research is to define target reliability indices for fire design situation since some research works (Balogh and Vigh, 2015a; 2015b) pointed that the achievable reliability (with using the prescriptive rules of Eurocode standards) is lower in extreme and seismic design situations than the suggested target value in (EN0, 2002). It seems that the target reliability indices of (JCSS, 2000) are preferable in these cases. In this paper, the optimum reliability is investigated as described in (Holickỳ, 2011), but total cost function is formulated with two decisive variables with respect to the amount of active and passive safety measures. The structural reliability is obtained with the help of a complex FORM (First Order Reliability Method) algorithm. The results of this investigation can help also to answer the question, whether active or passive safety measures are more effective tools to achieve optimal solutions in case of fire design of steel portal frames.

The Bayesian Compromise Decision Support Problem for Multilevel Design Involving Uncertainty

1994 ◽  
Vol 116 (2) ◽  
pp. 388-395 ◽  
Author(s):  
S. Vadde ◽  
J. K. Allen ◽  
F. Mistree
Keyword(s):  
Decision Support ◽  
Bayesian Statistics ◽  
Set Theory ◽  
Fuzzy Set Theory ◽  
Frame Structure ◽  
Bayesian Decision ◽  
Model Uncertainties ◽  
Research Issues ◽  
Portal Frame ◽  
Portal Frame Structure

In this paper we present an extension to the traditional compromise Decision Support Problem (DSP) formulation. In this formulation we use Bayesian statistics to model uncertainties associated with the information being used. In an earlier paper we have introduced a compromise DSP that accounts for uncertainty using fuzzy set theory. In this paper we describe the Bayesian Decision Support Problem. We use this formulation to design a portal frame structure. We discuss the results and compare them with those obtained using the fuzzy DSP. Finally, we discuss the efficacy of incorporating Bayesian statistics into the traditional compromise DSP formulation and describe some of the pending research issues.

scholarly journals DISCUSSION. STRAINS IN A STEEL PORTAL FRAME STRUCTURE.

1967 ◽  
Vol 38 (1) ◽  
pp. 143-146
Author(s):  
R SHEPHERD ◽  
W M EL DAKHAKHNI ◽  
E R BRYAN
Keyword(s):  
Frame Structure ◽  
Portal Frame ◽  
Portal Frame Structure

Study on Vertical Wind-Induced Vibration Response for Portal Frame Structures

2011 ◽  
Vol 71-78 ◽  
pp. 3605-3609
Author(s):  
De Zhi Liang ◽  
Min Huang
Keyword(s):  
Simulation Analysis ◽  
Vertical Wind ◽  
Wind Pressure ◽  
Frame Structure ◽  
Finite Element Software ◽  
Average Wind ◽  
Portal Frame ◽  
Wind Vibration ◽  
Portal Frame Structure ◽  
The Impact

In recent years, as the portal frame’s height toward higher and the span toward wider, the influence of wind vibration becomes more and more prominent among the portal frame structure. In the design of the portal frame, there are many different opinions on whether considering the impact of the vertical wind vibration to the portal frame. This paper taking a true engineering as an example, using finite element software to establish the solid model of the portal frame structure, selecting the junction of purlin and roof as a node of imposing vertical fluctuating wind load, we made numerical simulation analysis of vertical wind vibration. The simulation results will be compared with data of the internal forces and deformation under the average wind pressure. The results showed that: vertical wind vibration has a prominent effect to the portal frame and should be considered in the design.

scholarly journals Using passive control by a pendulum in a portal frame platform with piezoelectric energy harvesting

2017 ◽  
Vol 24 (16) ◽  
pp. 3684-3697 ◽  
Author(s):  
Rodrigo T Rocha ◽  
Jose M Balthazar ◽  
Angelo M Tusset ◽  
Vinicius Piccirillo
Keyword(s):  
Energy Harvesting ◽  
Periodic Orbit ◽  
Internal Resonance ◽  
Passive Control ◽  
Dynamical Behavior ◽  
Frame Structure ◽  
Nonlinear Dynamical ◽  
Piezoelectric Energy ◽  
Portal Frame ◽  
Portal Frame Structure

This work presents a passive control strategy using a pendulum on a simple portal frame structure, with two-to-one internal resonance, with a piezoelectric material coupling as a means of energy harvesting. In addition, the system is externally base-excited by an electro-dynamical shaker with harmonic output. Due to internal resonance the system may present the phenomenon of saturation, which provides some nonlinear dynamical behavior to the system. A pendulum is coupled to control nonlinear behaviors, leading to a periodic orbit, which is necessary to maintain energy harvesting. The results show that the system presents, most of the time, as being quasiperiodic. However, it does not present as being chaotic. With the pendulum, it was possible to control most of these quasiperiodic behaviors, leading to a periodic orbit. Moreover, it is possible to eliminate the need for an active or semi-active control, which are usually more complex. In addition, the control provides a way to detune the energy captured to the desired operating frequency.

METAMODEL-BASED PROBABILISTIC DESIGN OPTIMIZATION OF STATIC SYSTEMS WITH AN EXTENSION TO DYNAMIC SYSTEMS

2011 ◽  
Vol 18 (04) ◽  
pp. 305-326 ◽  
Author(s):  
TURUNA S. SEECHARAN ◽  
GORDON J. SAVAGE
Keyword(s):  
Structural Reliability ◽  
Mechanistic Model ◽  
Complex Form ◽  
Probability Of Failure ◽  
Performance Measure ◽  
Surface Model ◽  
Probabilistic Design ◽  
Design Variables ◽  
Reliability Method ◽  
Distribution Parameters

In design, much research deals with cases where design variables are deterministic thus ignoring possible uncertainties present in manufacturing or environmental conditions. When uncertainty is considered, the design variables follow a particular distribution whose parameters are defined. Probabilistic design aims to reduce the probability of failure of a system by moving the distribution parameters of the design variables. The most popular method to estimate the probability of failure is a Monte Carlo Simulation where, using the distribution parameters, many runs are generated and the number of times the system does not meet specifications is counted. This method, however, can become time-consuming as the mechanistic model developed to model a physical system becomes increasingly complex. From structural reliability theory, the First Order Reliability Method (FORM) is an efficient method to estimate probability and efficiently moves the parameters to reduce failure probability. However, if the mechanistic model is too complex FORM becomes difficult to use. This paper presents a methodology to use approximating functions, called 'metamodels', with FORM to search for a design that minimizes the probability of failure. The method will be applied to three examples and the accuracy and speed of this metamodel-based probabilistic design method will be discussed. The speed and accuracy of three popular metamodels, the response surface model, the Radial Basis Function and the Kriging model are compared. Later, some theory will be presented on how the method can be applied to systems with a dynamic performance measure where the response lifetime is required to computer another performance measure.

Research of the Influence of Snow Load Distribution Factor on Mechanical Performance of Portal Frame

2014 ◽  
Vol 578-579 ◽  
pp. 846-849
Author(s):  
Yan Liu ◽  
Li Juan Guo ◽  
Hui Ling Wang ◽  
Fei Wang
Keyword(s):  
Mechanical Performance ◽  
Steel Structure ◽  
The United States ◽  
Frame Structure ◽  
Distribution Factor ◽  
Snow Load ◽  
Load Combination ◽  
Portal Frame ◽  
Deformation Features ◽  
Portal Frame Structure

The dissertation studies the force and deformation features of the portal frame structure under the snow load and load combination. The double cross gable portal frame model was established by 3d3s software in the paper, and analyzed under snow loading according to the regulations of China, Europe and the United States respectively. And some suggestions were put forward on the design of light-weight steel structure in China according to the comparison and analysis.

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