| In the view of system reliability the behavior of progressive collapse-resistanceof reinforced concrete slab-column structures was investigated. The Monte-Carlomethod with continuous groups sample was used to analyze the reliability ofprogressive collapse of the slab-column structure. Based on the establishment ofslab-column structural performance function, the basic variables distributionsincluding punching resistance of the slab-column connection and loads and loadcombinations were introduced. By computing the failure probability of any oneslab-column connection under initial condition and the conditional failure probabilityof the other slab-column connection after first failure of the connection, theimportance of location of the slab-column connection on the progressive collapse-resistance of the slab-column structures and the robustness index in progressivecollapses-resistance were analyzed.The main destroying form is ensured by analysis the internal force distribution ofslab-column structure under vertical loads.The method to analysis the internal forceon the post-punching phase is proposed basing on the mechanism of the integrityreinforcement. By analyzing the effect of compression reinforcement capitals ininternal force redistribution after punching failure of structural, A more reasonablemethod is proposed to design the minimum demand area of compressionreinforcement.The ways of how to establish the performance function and to calculate thedistribution of random variables, the load effect combination rules is chose basing onthe characteristics of the actual structural reliability analysis. The results calculatedby mapping method and Monte Carlo method were compared. By combining theadvantages of the two methods, the sensitivity analysis of random variables is carried.An improved formula to calculate correlation coefficient is presented in the mappingmethod for system reliability calculation.Although the conditional probability is considered by using the correlation ofinternal unit in the traditional system reliability calculation, this correlation is basedon the initial structural internal force analysis. Actually, the order of failure unit notonly affected the conditional distribution but also the internal force. So a re-analyzefor structure and calculating for conditional failure reliability is demanded at the same time rather than separating it. Accordingly, a conditional probability theory andcalculating method is proposed.The Monte Carlo method of how to simulat the related variables and calculate theconditional failure probability is intruduced. An improved Monte Carlo method isproposed to make it possible to calculate all forms system probability. By applyingthis method to slab-column structure, we can calculate the failure probability of anyone slab-column connection under initial condition and the conditional failureprobability of the other slab-column connection after first failure of the connection.The influence of reliability calculation lives, correlation coefficient of resistance anddynamic coefficient for system failure probability are compared.The method to quantify the robustness for concrete structure is proposed byusing the physical meaning of second conditional failing probability. By using thisrobustness, the ability of resisting progressive collapse between different concretestructures can be evaluated. |
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