ROBUSTNESS OF BUILDING STRUCTURES - Recent developments and adopted strategy

in Eurosteel 2011 - 6th European Conference on Steel and Composite Structures - Proceedings (2011, September)

Recent events such as natural catastrophes or terrorism attacks have highlighted the necessity to ensure the structural integrity of buildings under an exceptional event. According to the Eurocodes and ... [more ▼]

Recent events such as natural catastrophes or terrorism attacks have highlighted the necessity to ensure the structural integrity of buildings under an exceptional event. According to the Eurocodes and some different other national design codes, the structural integrity of civil engineering structures should be ensured through appropriate measures but, in most cases, no precise practical guidelines on how to achieve this goal are provided. At the University of Liège, the robustness of building frames is investigated following the so-called “alternative load path method”, with the final objective to propose design requirements to mitigate the risk of progressive collapse considering the conventional scenario “loss of a column” further to an unspecified event. In particular, a complete analytical procedure has been developed for the verification of the robustness of steel or composite plane frames. For sake of simplicity, these first works have been based on the assumption that the dynamic effects linked to the column loss were limited and could therefore be neglected. More recently, complementary works have been carried out with the objective to address the dynamic effects. Besides, the extension of the static procedure to actual 3D frames is under investigation in Liège. The present paper gives a global overview of the ongoing researches in the field of robustness at the University of Liège and, in particular, the global strategy aiming at deriving design requirements is detailed. [less ▲]

Robustness of car parks against localised fire - Deliverable II: Experimental tests and development of sophisticated behavioural models

Report (2012)

Grant Agreement Number RFSR-CT-2008-00036

Robustness of car parks against localised fire - Deliverable IV: Development of FEM model for car parks under localised fire

Report (2012)

Research Programme of the Research Fund for Coal and Steel - Steel RTD Project carried out with a financial grant of the Research Programme of the Research Fund for Coal and Steel - Grant Agreement Number ... [more ▼]

Research Programme of the Research Fund for Coal and Steel - Steel RTD Project carried out with a financial grant of the Research Programme of the Research Fund for Coal and Steel - Grant Agreement Number RFSR‐CT‐2008‐00036 [less ▲]

Robustness of car parks against localised fire - Deliverable VI: Development of design recommendations, critical appraisal and application to a study case

Report (2012)

Grant Agreement Number RFSR‐CT‐2008‐00036

Robustness of optimal design of fMRI experiments with application of a genetic algorithm.

in NeuroImage (2010), 49(3), 2433-2443

In this paper we apply the genetic algorithm developed by Kao et al. (2009) to find designs which are robust against misspecification of the error autocorrelation. Two common optimality criteria, the A ... [more ▼]

In this paper we apply the genetic algorithm developed by Kao et al. (2009) to find designs which are robust against misspecification of the error autocorrelation. Two common optimality criteria, the A-optimality criterion and the D-optimality criterion, based upon a general linear model are employed to obtain locally optimal designs for a given value of the autocorrelation. The maximin criterion is then used to obtain designs which are robust against misspecification of the autocorrelation. Furthermore, robustness depending on the choice of optimality criterion is evaluated. We show analytically and empirically that the A- and D-optimality criterion will result in different optimal designs, e.g. with different stimulus frequencies. Optimal stimulus frequency for the A-optimality criterion has been derived by Liu et al. (2004) whereas we derive here the optimal stimulus frequency for the D-optimality criterion. Conclusions about the robustness of an optimal design against misspecification of model parameters and choice of optimality criterion are drawn based upon our results. [less ▲]

The robustness of self-organized criticality against extinctions in a tree-like model of evolution

in Europhysics Letters [=EPL] (1995), 32(7), 613-618

We investigate a so-called punctuated-equilibrium model of tree-like evolution containing extinctions for the weakest species with respect to a strength parameter r. Without extinctions (for r = 0), the ... [more ▼]

We investigate a so-called punctuated-equilibrium model of tree-like evolution containing extinctions for the weakest species with respect to a strength parameter r. Without extinctions (for r = 0), the model leads to self-organized criticality. For r not equal 0, a transition from growing trees to finite ones takes place at some critical r(c) = 0.48 +/- 0.01 value. For 0 less than or equal to r less than or similar to r(c), self-organized criticality is thus robust against extinctions of the weakest species. The size distribution of avalanches follows a power law behaviour with an exponent 3/2 which seems to be independent of the parameter r. The growing trees are found to be self-similar with a non-universal fractal dimension D-f non-trivially ranging from 2 to 1 depending on the parameter r. This constraint model opens up the field of description of various possible physical events for such an evolution model. [less ▲]

Robustness of steel and composite building structures

in 7th National conference on steel structures proceedings (2011, September)

Recent events such as natural catastrophes or terrorism attacks have highlighted the necessity to ensure the structural integrity of buildings under an exceptional event. According to the Eurocodes and ... [more ▼]

Recent events such as natural catastrophes or terrorism attacks have highlighted the necessity to ensure the structural integrity of buildings under an exceptional event. According to the Eurocodes and some different other national design codes, the structural integrity of civil engineering structures should be ensured through appropriate measures but, in most cases, no precise practical guidelines on how to achieve this goal are provided. At Liège University, the robustness of building frames is investigated with the final objective to propose design requirements to mitigate the risk of progressive collapse considering the conventional scenario “loss of a column” further to an unspecified event. In particular, a complete analytical procedure has been developed for the verification of the robustness of steel or composite plane frames. For sake of simplicity, these first works have been based on the assumption that the dynamic effects linked to the column loss were limited and could therefore be neglected. More recently, complementary works have been carried out with the objective to address the dynamic effects. Besides, the extension of the static procedure to actual 3D frames is under investigation in Liège. The present paper gives a global overview of the ongoing researches in the field of robustness at Liège University and, in particular, the global strategy aiming at deriving design requirements is detailed. [less ▲]

Robustness of steel and composite buildings under impact loading

in Batista, E.; Vellasco, P.; de Lima, L. (Eds.) Proceedings of the SDSS'Rio 2010 conference (2010, September)

In case of a vehicle impact against a building frame, one or more columns may be damaged or even fully destroyed. In such an exceptional event, the risk of progressive collapse of the whole structure has ... [more ▼]

In case of a vehicle impact against a building frame, one or more columns may be damaged or even fully destroyed. In such an exceptional event, the risk of progressive collapse of the whole structure has to be mitigated. Several approaches potentially exist to face this problem. In the present study, the so-called alternative load path method is followed. In two recent PhD studies at Liège University, a complete analytical procedure was developed permitting the prediction of the structural response of steel or composite plane frames further to the loss of a column. For sake of simplicity, these first works were based on the assumption of static behaviour. More recently, complementary research was carried out with the objective to address the dynamic effects. As a result, an original procedure for the appraisal of the structural robustness of plane building frames was proposed. The present paper presents this work. [less ▲]

Robustness of steel structures - Exercise SOLUTION: Application of different robustness approaches to a frame building structure

Learning material (2011)

The aim of this exercise is to investigate different ways of ensuring the robustness of a frame building structure considering a vehicle impact on a column of the ground floor. The building is located at ... [more ▼]

The aim of this exercise is to investigate different ways of ensuring the robustness of a frame building structure considering a vehicle impact on a column of the ground floor. The building is located at a corner of two roadways and thus the perimeter columns adjacent to these roads are likely to be impacted by a car or a lorry. Besides, the ground floor is a parking area (accessible to cars only) so that any internal column could also be damaged. The different approaches proposed in the Eurocodes will be applied and discussed. These methods consist for example in increasing the column resistance in such a way they can resist the impact or designing the structure so that it remains globally stable despite the loss of the damaged column. However, in such a case, a static removal of the column will be assumed (for sake of simplicity, no dynamic effect due to the failure of the column will be taken into account in this exercise). [less ▲]

Robustness of steel structures - Homework: Application of different robustness approaches to a frame building structure

Learning material (2011)

The aim of this exercise is to investigate different ways of ensuring the robustness of a frame building structure considering a vehicle impact on a column of the ground floor. The building is located at ... [more ▼]

The aim of this exercise is to investigate different ways of ensuring the robustness of a frame building structure considering a vehicle impact on a column of the ground floor. The building is located at a corner of two roadways and thus the perimeter columns adjacent to these roads are likely to be impacted by a car or a lorry. Besides, the ground floor is a parking area (accessible to cars only) so that any internal column could also be damaged. The different approaches proposed in the Eurocodes will be applied and discussed. These methods consist for example in increasing the column resistance in such a way they can resist the impact or designing the structure so that it remains globally stable despite the loss of the damaged column. However, in such a case, a static removal of the column will be assumed (for sake of simplicity, no dynamic effect due to the failure of the column will be taken into account in this exercise). [less ▲]