Simulation-Based Reliability Assessment of Timber Structures

Lokaj, Antonín; Marek, P.

doi:10.4203/ccp.91.148

Cited by 10 publications

(5 citation statements)

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“…Due to the relatively high carrying capacity dispersion of the round timber and the bolted joints with the slotted -in plates it is reasonable to consider using some of the fully probabilistic methods e.g. [6,7,8] for the reliable and safe design and assessment of this type of structures and joints.…”

Section: Discussionmentioning

confidence: 99%

Selected Problems in Using Round Timber in Building Structures

Lokaj

Klajmonová

2014

AEF

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Section: Discussionmentioning

confidence: 99%

Selected Problems in Using Round Timber in Building Structures

Lokaj

Klajmonová

2014

AEF

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“…The load, material and geometrical properties of a structure which determine the performance function of the system are treated as random quantities with assumed practical probability distributions. This approach was employ because, there is need for a fully probabilistic approach to the safety assessment of structural timber decks, due to many factors, such as climate, material composition and degradation of structural timber, occurrence of natural disasters and impacts of man-made technology which control the existence of human beings and the quality of the surrounding environment of bridge decks [13]. Many of these quantities cannot be represented adequately by deterministic values or relationships, thus, the variability in these quantities need be included in models of both nature and the built environment [13,14].…”

Section: Methodsmentioning

confidence: 99%

“…This approach was employ because, there is need for a fully probabilistic approach to the safety assessment of structural timber decks, due to many factors, such as climate, material composition and degradation of structural timber, occurrence of natural disasters and impacts of man-made technology which control the existence of human beings and the quality of the surrounding environment of bridge decks [13]. Many of these quantities cannot be represented adequately by deterministic values or relationships, thus, the variability in these quantities need be included in models of both nature and the built environment [13,14]. With adequate Probability Density Functions (PDF) to represent the possible variability of each individual random variable, the combined effect of these variables on the performance function of a bridge can be used to study the safety or possibility inherent with using specific ranges of stringers spacing of Nigerian timbers for bridge decks.…”

Section: Methodsmentioning

confidence: 99%

Reliability Assessment of Stringers Spacings in Bridges as Function of Timber Properties

2016

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This presentation accounts for established functions of stringer spacing of major Nigerian woods when used as bridge decks. It entails stochastic evaluation of bridge wood decks with absolute regards to the spacing of supporting stringers. A timber bridge deck is modelled on timber stringers in accordance with current specifications as outline in AASHTO LRFD (2010), to represent real life experiment in order to depict the structural behaviour of Nigerian timbers when used for bridge decks. This model is then subjected to some degree of entropy using Advance Second Moment Reliability Assessment (ASMRA) method, which is subsequently analysed using JAVA library with the help of Flanagan polynomial. The concept of ASMRA with Flanagan polynomial returns optimum output values for any input array of data along the input normal distribution curve. Taking Lophira alata (EKKI), Afzelia bipindensis (APA),Chlorophora exceisa (IROKO) and Mitragyna ciliate (ABURA) to represent N1, N2, N3, and N4 classes of Nigerian timber suitable for bridge decks, convincingly, it was established that, stringer spacing, strength classes, timber thicknesses and width are some of the major factors among others influencing the structural behaviour of Nigerian timber species used for bridge decks. These data are treated as random variables to generate relative optimum values which, are used to predict the relationship between stringer spacing as a dependent variable on other variables using Analysis of Variance (ANOVA) and multiple Regression line analysis. For the considered timber species, it was observed that large percentages, (R 2 ≌ 1 that is 100% for EKKI, APA, IROKO and ABURA of the variation in the dependent variable (stringer spacing) is explained by the independent variables (strength classes, timber thicknesses, timber width, plank deck unit weight, unit weight of surfacing material, lane load, thickness of surfacing material and reliability indices) which are all good fit. Also all the predicted regression lines are reliable and statistically significant as the significance F, (3.59709E-05 for EKKI, 5.58768E-05 for APA, 3.59709E-05 for IROKO and 8.55563E-05 for ABURA) are all less than 0.05. Thus, these established relationships will help in future forecast of stringer spacing for bridge deck design and analysis within acceptable structural reliability indices which are statistically significant (and are all within acceptable values ≤0.05).

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“…STUDY STUDY STUDY METHODOLOGY METHODOLOGY METHODOLOGY METHODOLOGY The concept of Advance Second Moment Reliability Assessment (ASMRA) method is used herein to evaluate the structural safety of various Nigerian timber species for bridge decks. This is because, there is need for a fully probabilistic approach to the safety assessment of structural timber decks, due tomany factors, such as climate, material composition and degradation of structural timber, occurrence of natural disasters and impacts of man-made technology control the existence of human beings and the quality of the surrounding environment of bridge decks [8]. Many of these quantities cannot be represented adequately by deterministic values or relationships, thus, the variability in these quantities need be included in models of both nature and the built environment [8,9].…”

Section: Studymentioning

confidence: 99%

“…This is because, there is need for a fully probabilistic approach to the safety assessment of structural timber decks, due tomany factors, such as climate, material composition and degradation of structural timber, occurrence of natural disasters and impacts of man-made technology control the existence of human beings and the quality of the surrounding environment of bridge decks [8]. Many of these quantities cannot be represented adequately by deterministic values or relationships, thus, the variability in these quantities need be included in models of both nature and the built environment [8,9]. With adequate Probability Density Functions (PDF) to represent the possible variability of each individual random variable, the combined effect of these variables on the performance function of a bridge can be used to study the safety or possibility of using Nigerian timbers for bridge decks.…”

Section: Studymentioning

confidence: 99%