scholarly journals Ultimate Limit State Analysis of Ship Structures

2019 ◽  
Author(s):  
S Sathish Kumar
Keyword(s):  
Ultimate Load ◽  
Progressive Collapse ◽  
Limit State ◽  
Structural Response ◽  
Load Factor ◽  
Ultimate Limit State ◽  
Ship Structures ◽  
Limit State Analysis ◽  
Ultimate Limit ◽  
State Analysis

Subjective and objective uncertainties are imposed on ship structures due to the random nature of the loading environment, inadequate knowledge of physical phenomena associated with loads or deviations in material properties which make reliable predictions of structural response a difficult task. Strength criteria for ships can be established by ultimate strength studies of progressive collapse analysis of finite element models under different boundary conditions with combined geometric and material nonlinearities. Load-Displacement and/or Moment-Curvature curves can be generated and the ultimate load causing failure identified as a multiple of the design load. Ultimate limit state analysis can be carried out for various combinations of parameters to identify the ultimate load factor in each case.

An innovative methodology to determine the partial load factor for prestressing in cable supported bridges

2016 ◽  
Author(s):  
Alberto Carlucci ◽  
Mariona Pahisa ◽  
Kelvin Moneypenny
Keyword(s):  
Limit State ◽  
Load Factor ◽  
Ultimate Limit State ◽  
Force Response ◽  
Innovative Methodology ◽  
Partial Load ◽  
Definition Of ◽  
Partial Factor ◽  
State Factor ◽  
Ultimate Limit

<p>The design of cable supported bridges of short to medium spans requires the resolution of how to separate the load and effect of the major components of permanent loading: Gravity and Prestressing. <p>The Eurocode allows to use the same Ultimate Limit State factor for the Gravity “G” and the Prestressing “P” for flexible bridges and prescribes to use different factors for stiff bridges. <p>However, there is no clear definition in the Eurocode of when a bridge can be considered flexible. The paper introduces the concept of the Stay Force Response Index (SFRI) to define the degree of flexibility of the bridge and describes a method for the definition of the prestressing partial factor derived through a parametric analysis of concrete cable supported bridge. <p>This method, which is generally applicable beyond the Eurocode, would allow the designer to have the confidence in undertaking optimized hence, more economic and more sustainable designs.

scholarly journals Structural Phenomenon of Cement-Based Composite Elements in Ultimate Limit State

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
I. Iskhakov ◽  
Y. Ribakov
Keyword(s):  
Limit State ◽  
Structural Response ◽  
Minimax Principle ◽  
Ultimate Limit State ◽  
Spatial Structures ◽  
Design Concepts ◽  
Dynamic Loadings ◽  
Ultimate Limit ◽  
Additional Equation ◽  
Theoretical Results

Cement-based composite materials have minimum of two components, one of which has higher strength compared to the other. Such materials include concrete, reinforced concrete (RC), and ferrocement, applied in single- or two-layer RC elements. This paper discusses experimental and theoretical results, obtained by the authors in the recent three decades. The authors have payed attention to a structural phenomenon that many design features (parameters, properties, etc.) at ultimate limit state (ULS) of a structure are twice higher (or lower) than at initial loading state. This phenomenon is evident at material properties, structures (or their elements), and static and/or dynamic structural response. The phenomenon is based on two ideas that were developed by first author: quasi-isotropic state of a structure at ULS and minimax principle. This phenomenon is supported by experimental and theoretical results, obtained for various structures, like beams, frames, spatial structures, and structural joints under static or/and dynamic loadings. This study provides valuable indicators for experiments’ planning and estimation of structural state. The phenomenon provides additional equation(s) for calculating parameters that are usually obtained experimentally and can lead to developing design concepts and RC theory, in which the number of empirical design coefficients will be minimal.

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