INVESTIGATION OF ELASTIC SHORT – TERM STABILITY OF RINFORCED AND COMPOSIT CONCRETE STRUTS BY MODIFIED NEWMARK METHOD

The aim of this Paper is to treat the elastic stability of reinforced and composite concrete struts. The object of this study is to verify the ability of the Modified Newmark Method to include geometric non-linearity in addition to the non-linearity due to cracking, and also to show the advantage of the established method to reconsider an ignored minor parameter in mathematical modelling, such as the effect of the cracking by extra geometric bending moment (Ny) on cross-section properties. The purpose of this investigation is not to present some new results for the instability of reinforced or composite concrete columns. Therefore, all kinds of non-linearities involved in the problem are not considered here. Only as mentioned, it is a part of the verification of the new established method to solve two kinds of non-linearities ( effect and cracking) together simultaneously. However, the Modified Newmark Method can be used to solve the non-linearity of materials and the time-dependent behaviour of concrete. But since it is out of the scope of this dissertation, it is not considered here, and the review given in the previous section was merely for the interest of the reader.

Keywords:

Stability , Buckling , Modified Newmark Method , Reinforced