Influence of Beam Height-Column Width Ratio on Seismic Behavior of RC Moment Resisting Frames

Most reputable international design codes have included provisions for achieving ductile behavior and avoiding brittle and hazardous behavior in reinforced concrete frames. These provisions aim to achieve the concept of weak beam-strongcolumn, where plastic hinges during earthquake occur first in the beams. Analysis of frequent and repetitive failures in strong earthquakes in recent decades of reinforced concrete structures shows that the strong beam-weak column failuremode typically leads to severe damage in these structures. The frequent occurrence of this failure mode can be attributed to two main factors. Firstly, stiffer beams are often used against more flexible columns due to the absence of seismic provisions that limit the relation between beam height and column width results in column severe damage on column and finally collapse of them. Secondly, the effect of the cast-in-situ slab in increasing the negative flexural strength of the beam is often underestimated or ignored, leading to the flexural strength of the columns being less than that of the beams. To assess the impact of the ratio of beam height to column width on the seismic performance of MRFs, a series of computational models were created and analyzed in a parametric study. Prior to that, the FEA performance was validated by comparing its results with experimental data. The findings emphasize the urgent need for a new seismic provision that limits the beam height to column width ratio to a maximum of ۱.۲۵.

کلیدواژه ها:

Ratio of beam height to column width ، RC MRFs ، finite element analysis ، effective slab width