“…Many researches has been conducted recently on behavior of reinforced concrete in the application of many structure members like concrete beam without FRP (Mohammadhassani et al 2013, Mohammadhassani et al 2014a, Mohammadhassani et al 2014b, Mohammadhassani et al 2014c, Khorramian et al 2016, Khorami et al 2017b, Khorramian et al 2017, Mansouri et al 2017, Nasrollahi et al 2018, Nosrati et al 2018, Paknahad et al 2018, Sadeghipour Chahnasir et al 2018 and with FRP strengthening (Rahimi and Hutchinson 2001, Karimi et al 2011, Sinaei et al 2011, Ashour and Kara 2014, Moy 2018. From the recent researches on application of reinforced concrete in steel and composite beams, the non-strengthening beams' ultimate loads have Corresponding author, Ph.D. E-mail: phambinhgtvt@gmail.com been investigated (Kheyroddin 2008a, Shariati et al 2010, Shariati et al 2011a, Shariati et al 2011b, Shariati et al 2011c, Sinaei et al 2011, Shariati et al 2012a, Shariati et al 2012b, Shariati et al 2012c, Shariati et al 2012d, Shariati et al 2012e, Sinaei et al 2012, Mohammadhassani et al 2013, Mohammadhassani et al 2014a, Mohammadhassani et al 2014b, Mohammadhassani et al 2014c, Toghroli Ali et al 2014, Khorramian ...…”