en Optimal design Optimal design پژوهشي Research <p><span style="font-size:11.5pt"><span new="" roman="" style="font-family:" times=""><m:omath><m:r><span cambria="" math="" style="font-family:"><span style="letter-spacing:-.2pt">In this study, the investigation of maximum inelastic displacement demands in steel moment- resisting (SMR) frames designed using the Performance-Based Plastic Design (PBPD) method is conducted under both near-fault and far-fault earthquake records. The PBPD method utilizes a target drift and predetermined yield mechanism as the functional limit state. To accomplish this, 6 steel moment frames having various heights were scaled using well-known</span></span></m:r></m:omath><m:omath><m:r><i><span cambria="" math="" style="font-family:"><span style="letter-spacing:-.2pt">&nbsp;sa</span></span></i></m:r><m:r><i><span cambria="" math="" style="font-family:"><span style="letter-spacing:-.2pt">(</span></span></i></m:r><m:ssub><m:ssubpr><span cambria="" math="" style="font-family:"><span style="letter-spacing:-.2pt"><m:ctrlpr></m:ctrlpr></span></span></m:ssubpr><m:e><m:r><i><span cambria="" math="" style="font-family:"><span style="letter-spacing:-.2pt">T</span></span></i></m:r></m:e><m:sub><m:r><i><span cambria="" math="" style="font-family:"><span style="letter-spacing:-.2pt">1</span></span></i></m:r></m:sub></m:ssub><m:r><i><span cambria="" math="" style="font-family:"><span style="letter-spacing:-.2pt">)</span></span></i></m:r></m:omath><span lang="IT" style="font-size:11.5pt"><span new="" roman="" style="font-family:" times=""><span style="position:relative"><span style="top:3.0pt"><span style="layout-grid-mode:line"> </span></span></span></span></span><span style="letter-spacing:-.2pt">&nbsp;method and, then, were analyzed by OPENSEES software. A total of 22 far-fault records and 90 near-fault records were compiled and employed for parametric nonlinear dynamic analysis. The near-fault records were classified into two categories: </span><m:omath><m:ssub><m:ssubpr><span cambria="" math="" style="font-family:"><span style="letter-spacing:-.2pt"><m:ctrlpr></m:ctrlpr></span></span></m:ssubpr><m:e><m:r><i><span cambria="" math="" style="font-family:"><span style="letter-spacing:-.2pt">T</span></span></i></m:r></m:e><m:sub><m:r><i><span cambria="" math="" style="font-family:"><span style="letter-spacing:-.2pt">1</span></span></i></m:r></m:sub></m:ssub><m:r><i><span cambria="" math="" style="font-family:"><span style="letter-spacing:-.2pt">/</span></span></i></m:r><m:ssub><m:ssubpr><span cambria="" math="" style="font-family:"><span style="letter-spacing:-.2pt"><m:ctrlpr></m:ctrlpr></span></span></m:ssubpr><m:e><m:r><i><span cambria="" math="" style="font-family:"><span style="letter-spacing:-.2pt">T</span></span></i></m:r></m:e><m:sub><m:r><i><span cambria="" math="" style="font-family:"><span style="letter-spacing:-.2pt">p</span></span></i></m:r></m:sub></m:ssub><m:r><i><span cambria="" math="" style="font-family:"><span style="letter-spacing:-.2pt">&ge;1</span></span></i></m:r></m:omath><span lang="IT" style="font-size:11.5pt"><span new="" roman="" style="font-family:" times=""><span style="position:relative"><span style="top:4.5pt"><span style="layout-grid-mode:line"> </span></span></span></span></span><span style="letter-spacing:-.2pt">&nbsp;and </span><m:omath><m:ssub><m:ssubpr><span cambria="" math="" style="font-family:"><span style="letter-spacing:-.2pt"><m:ctrlpr></m:ctrlpr></span></span></m:ssubpr><m:e><m:r><i><span cambria="" math="" style="font-family:"><span style="letter-spacing:-.2pt">T</span></span></i></m:r></m:e><m:sub><m:r><i><span cambria="" math="" style="font-family:"><span style="letter-spacing:-.2pt">1</span></span></i></m:r></m:sub></m:ssub><m:r><i><span cambria="" math="" style="font-family:"><span style="letter-spacing:-.2pt">/</span></span></i></m:r><m:ssub><m:ssubpr><span cambria="" math="" style="font-family:"><span style="letter-spacing:-.2pt"><m:ctrlpr></m:ctrlpr></span></span></m:ssubpr><m:e><m:r><i><span cambria="" math="" style="font-family:"><span style="letter-spacing:-.2pt">T</span></span></i></m:r></m:e><m:sub><m:r><i><span cambria="" math="" style="font-family:"><span style="letter-spacing:-.2pt">p</span></span></i></m:r></m:sub></m:ssub><m:r><i><span cambria="" math="" style="font-family:"><span style="letter-spacing:-.2pt"><1</span></span></i></m:r></m:omath><span lang="IT" style="font-size:11.5pt"><span new="" roman="" style="font-family:" times=""><span style="position:relative"><span style="top:4.5pt"><span style="layout-grid-mode:line"> </span></span></span></span></span><span style="letter-spacing:-.2pt">. The study aimed at investigate their impacts on the inter-story drift and the relative distribution of base shear along the height of the structure. The results revealed that the records with </span><m:omath><m:ssub><m:ssubpr><span cambria="" math="" style="font-family:"><span style="letter-spacing:-.2pt"><m:ctrlpr></m:ctrlpr></span></span></m:ssubpr><m:e><m:r><i><span cambria="" math="" style="font-family:"><span style="letter-spacing:-.2pt">T</span></span></i></m:r></m:e><m:sub><m:r><i><span cambria="" math="" style="font-family:"><span style="letter-spacing:-.2pt">1</span></span></i></m:r></m:sub></m:ssub><m:r><i><span cambria="" math="" style="font-family:"><span style="letter-spacing:-.2pt">/</span></span></i></m:r><m:ssub><m:ssubpr><span cambria="" math="" style="font-family:"><span style="letter-spacing:-.2pt"><m:ctrlpr></m:ctrlpr></span></span></m:ssubpr><m:e><m:r><i><span cambria="" math="" style="font-family:"><span style="letter-spacing:-.2pt">T</span></span></i></m:r></m:e><m:sub><m:r><i><span cambria="" math="" style="font-family:"><span style="letter-spacing:-.2pt">p</span></span></i></m:r></m:sub></m:ssub><m:r><i><span cambria="" math="" style="font-family:"><span style="letter-spacing:-.2pt">&ge;1</span></span></i></m:r></m:omath><span lang="IT" style="font-size:11.5pt"><span new="" roman="" style="font-family:" times=""><span style="position:relative"><span style="top:4.5pt"><span style="layout-grid-mode:line"> </span></span></span></span></span><span style="letter-spacing:-.2pt">&nbsp; exerted the greatest influence on the drift demands of upper stories in all frames. Conversely, the near-fault records with </span><m:omath><m:ssub><m:ssubpr><span cambria="" math="" style="font-family:"><span style="letter-spacing:-.2pt"><m:ctrlpr></m:ctrlpr></span></span></m:ssubpr><m:e><m:r><i><span cambria="" math="" style="font-family:"><span style="letter-spacing:-.2pt">T</span></span></i></m:r></m:e><m:sub><m:r><i><span cambria="" math="" style="font-family:"><span style="letter-spacing:-.2pt">1</span></span></i></m:r></m:sub></m:ssub><m:r><i><span cambria="" math="" style="font-family:"><span style="letter-spacing:-.2pt">/</span></span></i></m:r><m:ssub><m:ssubpr><span cambria="" math="" style="font-family:"><span style="letter-spacing:-.2pt"><m:ctrlpr></m:ctrlpr></span></span></m:ssubpr><m:e><m:r><i><span cambria="" math="" style="font-family:"><span style="letter-spacing:-.2pt">T</span></span></i></m:r></m:e><m:sub><m:r><i><span cambria="" math="" style="font-family:"><span style="letter-spacing:-.2pt">p</span></span></i></m:r></m:sub></m:ssub><m:r><i><span cambria="" math="" style="font-family:"><span style="letter-spacing:-.2pt"><1</span></span></i></m:r></m:omath><span lang="IT" style="font-size:11.5pt"><span new="" roman="" style="font-family:" times=""><span style="position:relative"><span style="top:4.5pt"><span style="layout-grid-mode:line"> </span></span></span></span></span><span style="letter-spacing:-.2pt">&nbsp;demonstrated the most significant impact on the lower stories of mid-rise frames. Additionally, the distribution of relative story shears was examined through genetic programming for optimum PBPD design of steel moment frame structures. As a result, a proposed relationship, denoted as b (seismic parameter for design lateral force distribution), was developed and optimized for both near-fault and far-fault records. This relationship depends on the fundamental period of vibration and the total height of the structure. The accuracy of the predicted model was assessed using </span><m:omath><m:ssup><m:ssuppr><span cambria="" math="" style="font-family:"><span style="letter-spacing:-.2pt"><m:ctrlpr></m:ctrlpr></span></span></m:ssuppr><m:e><m:r><i><span cambria="" math="" style="font-family:"><span style="letter-spacing:-.2pt">R</span></span></i></m:r></m:e><m:sup><m:r><i><span cambria="" math="" style="font-family:"><span style="letter-spacing:-.2pt">2</span></span></i></m:r></m:sup></m:ssup></m:omath><span lang="IT" style="font-size:11.5pt"><span new="" roman="" style="font-family:" times=""><span style="position:relative"><span style="top:3.0pt"><span style="layout-grid-mode:line"> </span></span></span></span></span><span style="letter-spacing:-.2pt">, which confirmed the reliability of the proposed relationship.</span><span style="letter-spacing:-.2pt"></span></span></span></p> &nbsp; Performance-Based Plastic Design (PBPD), Genetic Programming, Optimization, Seismic Parameter for Design Lateral Force Distribution. 37 60 http://ijoce.iust.ac.ir/browse.php?a_code=A-10-66-393&slc_lang=en&sid=1 A. Hadinejad 180031947532846002478 180031947532846002478 No Department of Civil Engineering, University of Mazandaran, Babolsar, Iran B. Ganjavi b.ganjavi@umz.ac.ir 180031947532846002479 180031947532846002479 Yes School of Civil Engineering, Collage of Engineering, University of Tehran, Tehran, Iran