Load and Resistance Factors for Progressive Collapse Resistance Design of Reinforced Concrete Building Structures

2011 ◽  
Vol 255-260 ◽  
pp. 338-344 ◽  
Author(s):  
Ying Wang ◽  
Feng Lin ◽  
Xiang Lin Gu
Keyword(s):  
Reinforced Concrete ◽  
Progressive Collapse ◽  
Building Structures ◽  
Safety Factors ◽  
Ultimate State ◽  
Resistance Factors ◽  
Collapse Resistance ◽  
Load And Resistance Factors ◽  
Load Effects ◽  
Partial Safety Factors

Due to the absence of provision for the load and resistance factors in design codes in China, designers often quote the provisions which are given in criterion or guidance of other countries such as USA. However, the partial safety factors of the load are various in different criterions. Based on the reliability theory, the load and resistance factors for progressive collapse resistance design of building structures were determined in this study. Firstly the simplified format of design expression in the ultimate state was obtained according to the expression in routine structural design. Then the failure probability of a structure during design reference period was taken as the sum of the probability of all incompatible failure events in this period, and the objective reliability index of the structure could be obtained. Finally using trial-and-error procedure and JC method, reliability analysis was performed for structural members to obtain the partial safety factors of load effects and resistance and the coefficient for combination value of load effects in design expression in the ultimate state. In this paper the load and resistance factors for progressive collapse resistance design of reinforced concrete structures subjected to blast was calculated as an example, and the recommendation values were given for the application at last.

A LRFD Code Format for Accounting Long-Term Variation of Multiple Load Effects

2002 ◽  
Author(s):  
Paulo Mauricio Videiro ◽  
Luis Volnei Sudati Sagrilo ◽  
Edison Castro Prates de Lima
Keyword(s):  
Extreme Value ◽  
Structural Components ◽  
Short Term ◽  
Resistance Factors ◽  
Term Variation ◽  
Load And Resistance Factors ◽  
Load Effects ◽  
Code Format ◽  
Multiple Load

This paper proposes a Load and Resistance Factors Design (LRFD) code format for structural components of offshore structures under multiple load effects. This code format accounts for the long-term variation of seastate and the actual correlation between dynamic load effects due to environmental actions. Ultimate limit states are formulated in terms of an Interaction Ratio (IR) random variable, such that the long-term extreme value of IR greater than unity means component failure. The long-term distribution of IR is obtained by combining the distribution of each short-term seastate. The short-term response of the generally nonlinear IR is determined by time domain simulation, taking into account partial load and resistance factors. The IR short-term distribution may be fitted, for instance, by using Rayleigh or Weibull distribution. The main advantages of the proposed code format are: • This code format accounts implicitly and correctly for the actual correlation among all dynamic environmental load processes. • Structural designers have used interaction ratios for a long time. Hence, it is straightforward to evolve from a deterministic stage of looking for IR < 1, as in old Working Stress Design codes, to a code format where the aim is to design structural components with long term IR extreme value < 1. The feasibility of the proposed code format is demonstrated by calibrating partial factors for beam-column cylindrical members based on components of a Floating Production System Semi-submersible hull.

Safety factors and limit states analysis in geotechnical engineering

1984 ◽  
Vol 21 (1) ◽  
pp. 1-7 ◽  
Author(s):  
G. G. Meyerhof
Keyword(s):  
Geotechnical Engineering ◽  
Stability Conditions ◽  
Safety Factors ◽  
Limit States ◽  
Resistance Factors ◽  
Performance Factors ◽  
Load Factors ◽  
Partial Safety Factors ◽  
And Performance ◽  
Earth Retaining Structures

This paper outlines the ultimate and serviceability limit states in geotechnical engineering analyses. The magnitude of customary total and suggested partial safety factors in earthworks, earth retaining structures, excavations, and foundations is discussed. On the basis of comparisons between these safety factors and using recommended load factors on various types of loading, including water pressures, common resistance factors on cohesion and friction of soils and performance factors can be established together with some additional modification factors for particular stability conditions. The serviceability limit states of foundations and structures are briefly discussed.

Calibration of the Ontario Highway Bridge Design Code 1991 edition

1994 ◽  
Vol 21 (1) ◽  
pp. 25-35 ◽  
Author(s):  
Andrzej S. Nowak ◽  
Hid N. Grouni
Keyword(s):  
Reinforced Concrete ◽  
Reliability Analysis ◽  
Prestressed Concrete ◽  
Highway Bridge ◽  
Live Load ◽  
Design Code ◽  
Reliability Indices ◽  
Resistance Factors ◽  
Load And Resistance Factors ◽  
Selection Of

The paper describes the calculation of load and resistance factors for the Ontario Highway Bridge Design Code (OHBDC) 1991 edition. The work involved the development of load and resistance models, the selection of the reliability analysis method, and the calculation of the reliability indices. The statistical models for load and resistance are reviewed. The considered load components include dead load, live load, and dynamic load. Resistance models are developed for girder bridges (steel, reinforced concrete, and prestressed concrete). A reliability analysis is performed for selected representative structures. Reliability indices are calculated using an iterative procedure. The calculations are performed for bridge girders designed using OHBDC 1983 edition. The resulting reliability indices are between 3 and 4 for steel girders and reinforced concrete T-beams, and between 3.5 and 5 for prestressed concrete girders. Lower values are observed for shorter spans (up to 30–40 m). The acceptance criterion in the selection of load and resistance factors is closeness to the target reliability level. The analysis confirmed the need to increase the design live load for shorter spans. Partial resistance factors are considered for steel and concrete. The criteria for the evaluation of existing bridges are based on the reliability analysis and economic considerations. Key words: bridge code, calibration, load factor, resistance factor, reliability index.

Sign in / Sign up

Export Citation Format

Share Document