International Journal of Advanced Structural Engineering
Volume:1 Issue: 2, Summer 2009

Nonlinear analyses allow simulating, in a more realistic way, the behaviour of structures subjected to several types of complex loading conditions such as earthquakes. However, it is recognized that these analyses normally generate a considerable amount of results, a factor that difficult its interpretation. Over the last years, considerable progresses have been made in structural nonlinear behaviour modeling, associated to the fast growing development of numerical algorithms and computer capacities. Therefore, a number of computational analysis tools have been developed to meet the analysis requirements from the behaviour viewpoint. However, a similar growth in the development of graphical results visualization tools has not been witnessed and the generalized use of such analysis programs is thus made difficult. To face this, a graphical processor called VISUALANL was developed for an existing nonlinear analysis program for plane frame structures. To observe the potentialities of such tool, an application example is presented illustrating both previously referred stages.

Nonlinear analyses allow simulating, in a more realistic way, the behaviour of structures subjected to several types of complex loading conditions such as earthquakes. However, it is recognized that these analyses normally generate a considerable amount of results, a factor that difficult its interpretation. Over the last years, considerable progresses have been made in structural nonlinear behaviour modeling, associated to the fast growing development of numerical algorithms and computer capacities. Therefore, a number of computational analysis tools have been developed to meet the analysis requirements from the behaviour viewpoint. However, a similar growth in the development of graphical results visualization tools has not been witnessed and the generalized use of such analysis programs is thus made difficult. To face this, a graphical processor called VISUALANL was developed for an existing nonlinear analysis program for plane frame structures. To observe the potentialities of such tool, an application example is presented illustrating both previously referred stages.

In the conventional design and analysis methods affecting parameters loads, material's strength, etc) are not set as probable variables. Safety factors in the current Codes and Standards are usually obtained on the basis of judgment and experience, which may be improper or uneconomical. In technical literature, a method based on nonlinear static analysis is suggested to set Reliability Index on strength of structural systems. In this paper, a method based on Nonlinear Dynamic analysis with rising acceleration (or Incremental Dynamic Analysis) is introduced, the results of which are compared with those of the previous (Static Pushover Analysis) method and two concepts namely Redundancy Strength and Redundancy Variations are proposed as an index to these impacts. The Redundancy Variation Factor and Redundancy Strength Factor indices for reinforced concrete frames with varying number of bays and stories and different ductility potentials are computed and ultimately, Reliability Index is determined using these two indices.

This paper describe the three dimensional finite element modeling and buckling analysis ofconventional pallet racking system with semi rigid connection. In this study threedimensional models of conventional pallet racking system were prepared using the finiteelement program ANSYS and finite element analysis carried out on conventional pallet racks with the 18 types of column sections developed along with semi-rigid connections. Aparametric study was carried out to compare the effective length approach and the finiteelement method for accuracy and appropriateness for cold-formed steel frame design.Numerous frame elastic buckling analyses were carried out to evaluate the alignment chartand the AISI torsional-flexural buckling provisions. The parameters that influence the valueof Kx for column flexural buckling were examined in this study. The alignment chart and theAISI torsional-flexural buckling provisions, used to obtain the effective lengths and elastic buckling load of members were also evaluated. Results showed that the elastic buckling load obtained from the AISI torsional-flexural buckling provisions is generally conservative compared to the results obtained from performing frame elastic buckling analysis. Results also showed that, the effective length approach is more conservative than the finite element approach.

The Baluarte do Cavaleiro is part of the stone masonry wall system existing in the city ofChaves of Portugal and it is a construction dated from the XVII century. The Baluarte doCavaleiro is formed by three walls (North-East, NE; South-East, SE; South-West, SW) andby two junction elements (designated here by cunhais). The SE wall has suffered twocollapses recently. The main objective of this research work is to describe the monitoringprocess adopted to control the stability of the Baluarte do Cavaleiro and the adjacentconstructions that could be affected during the last rebuilding process of this wall. Takinginto account that this rebuilding process included the total removal of this wall, it was alsopossible to identify the real geometry of the cross section of the wall, its building solution and the type of the sustained soil. It was also possible to contribute for a better understanding of the structural behaviour of this kind of stone masonry construction.