Calculation of failure probability of trusses with Monte Carlo simulation

• Grant number: 15/09380-6
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: August 01, 2015
• End date: July 31, 2016
• Field of knowledge: Engineering - Civil Engineering - Structural Engineering
• Principal Investigator: Dimas Betioli Ribeiro
• Grantee: Gabriel Sarmanho Castanho Savio
• Host Institution: Escola Politécnica (EP). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

The objective of this project is to develop a computer program for modelling tridimensional trusses including failure probability calculation with Monte Carlo simulations. Failure is defined here as the occurrence of any undesired behavior, being formulated using limit states. Matrix structural analysis is used to model the truss, defining three degrees of freedom for each node and only concentrated forces as external loads. This model is used to evaluate if the truss fails of not, considering all limit states to be avoided. The basic idea behind Monte Carlo simulations is to simulate the truss many times varying the input data and counting the cases for which fail occur. For a sufficient number of simulations, failure probability may be approximated by the division of the number of failure cases by the total number of simulations. It is intended that, by the end of the project, it will be possible to use the program to evaluate selected real engineering problems. Some possibilities to be studied are soccer stadium coverages and bridges. In such projects, it is common to use safety coefficients to improve structural efficiency by increasing solicitations above the predicted values and reducing material strength below expected. It is intended to discuss the efficiency of such approach in the examples, presenting scenarios in which there are different failure probabilities for the same safety coefficients.