en Structure-Concrete Structure- Concrete Research Paper Research Paper <p align="left"><i><font color="#231f20" face="TimesNewRomanPS-ItalicMT" size="2"><font color="#231f20" face="TimesNewRomanPS-ItalicMT" size="2"><font color="#231f20" face="TimesNewRomanPS-ItalicMT" size="2">Strut-and-Tie Model (STM) can be used to model the flow of compression within a concrete strut. Concrete struts are formed</font></font></font></i></p> <p align="left"><i><font color="#231f20" face="TimesNewRomanPS-ItalicMT" size="2"><font color="#231f20" face="TimesNewRomanPS-ItalicMT" size="2"><font color="#231f20" face="TimesNewRomanPS-ItalicMT" size="2">in various shapes such as prismatic or bottle-shaped. In order to study the behavior of concrete struts, a series of simple tests</font></font></font></i></p> <p align="left"><i><font color="#231f20" face="TimesNewRomanPS-ItalicMT" size="2"><font color="#231f20" face="TimesNewRomanPS-ItalicMT" size="2"><font color="#231f20" face="TimesNewRomanPS-ItalicMT" size="2">were performed. Eighteen reinforced concrete isolated struts with compressive strength of 65 MPa were tested up failure under</font></font></font></i></p> <p align="left"><i><font color="#231f20" face="TimesNewRomanPS-ItalicMT" size="2"><font color="#231f20" face="TimesNewRomanPS-ItalicMT" size="2"><font color="#231f20" face="TimesNewRomanPS-ItalicMT" size="2">point loading in the plane of specimens. The tested specimens were reinforced by various reinforcement layouts. The behavior</font></font></font></i></p> <p align="left"><i><font color="#231f20" face="TimesNewRomanPS-ItalicMT" size="2"><font color="#231f20" face="TimesNewRomanPS-ItalicMT" size="2"><font color="#231f20" face="TimesNewRomanPS-ItalicMT" size="2">of tested beams was investigated. Observations were made on transverse displacement, primary cracking and ultimate failure</font></font></font></i></p> <p align="left"><i><font color="#231f20" face="TimesNewRomanPS-ItalicMT" size="2"><font color="#231f20" face="TimesNewRomanPS-ItalicMT" size="2"><font color="#231f20" face="TimesNewRomanPS-ItalicMT" size="2">load and distribution of strain on the face of tested panels. Based on these observations, the geometry of the concrete struts was</font></font></font></i></p> <p align="left"><i><font color="#231f20" face="TimesNewRomanPS-ItalicMT" size="2"><font color="#231f20" face="TimesNewRomanPS-ItalicMT" size="2"><font color="#231f20" face="TimesNewRomanPS-ItalicMT" size="2">examined. a new model to analysis of concrete struts was proposed based on modified compression field theory (MCFT). A</font></font></font></i></p> <p align="left"><i><font color="#231f20" face="TimesNewRomanPS-ItalicMT" size="2"><font color="#231f20" face="TimesNewRomanPS-ItalicMT" size="2"><font color="#231f20" face="TimesNewRomanPS-ItalicMT" size="2">database of 44 tested specimens was compiled to evaluate the proposed model. The results indicate that using the ACI and CSA</font></font></font></i></p> <p align="left"><i><font color="#231f20" face="TimesNewRomanPS-ItalicMT" size="2"><font color="#231f20" face="TimesNewRomanPS-ItalicMT" size="2"><font color="#231f20" face="TimesNewRomanPS-ItalicMT" size="2">codes expressions regarding the amount of minimum required reinforcement in a strut produces conservative but erratic results</font></font></font></i></p> <p align="left"><i><font color="#231f20" face="TimesNewRomanPS-ItalicMT" size="2"><font color="#231f20" face="TimesNewRomanPS-ItalicMT" size="2"><font color="#231f20" face="TimesNewRomanPS-ItalicMT" size="2">when compared with the test data. Conversely, the new proposed model presents a more accurate prediction for the strength of</font></font></font></i></p> <p><i><font color="#231f20" face="TimesNewRomanPS-ItalicMT" size="2"><font color="#231f20" face="TimesNewRomanPS-ItalicMT" size="2"><font color="#231f20" face="TimesNewRomanPS-ItalicMT" size="2">44 tested struts.</font></font></font></i></p> Strut-and-tie, Transverse reinforcement, Strut, Efficiency factor 253 262 http://ijce.iust.ac.ir/browse.php?a_code=A-10-574-2&slc_lang=en&sid=1 A. Arabzadeh arabzade@modares.ac.ir 180031947532846009786 180031947532846009786 Yes Associate Professor, Structural Engineering Dept., Tarbiat Modarres University, Tehran, Iran R. Aghayari reza_agh@razi.ac.ir 180031947532846009787 180031947532846009787 No Assistant Professor, Civil Engineering Dept., Razi University,Kermanshah, Iran A. R. Rahai Rahai@aut.ac.ir 180031947532846009788 180031947532846009788 No Professor, Faculty of Civil Engineering, Amir Kabir University of Technology, Iran