{"id":1092,"date":"2017-06-12T14:03:51","date_gmt":"2017-06-12T14:03:51","guid":{"rendered":"http:\/\/buildsoftsupport.com\/?post_type=ht_kb&#038;p=1092"},"modified":"2023-04-21T06:54:33","modified_gmt":"2023-04-21T06:54:33","slug":"when-to-use-sj-or-sjini","status":"publish","type":"ht_kb","link":"https:\/\/support.buildsoft.eu\/nl\/knowledge-base\/when-to-use-sj-or-sjini\/","title":{"rendered":"When to use Sj or Sj,ini in global analysis"},"content":{"rendered":"<p>In case of a semi-rigid joint, the effects of the behaviour of the joints on the distribution of internal forces and moments within a structure, (and on the overall deformations), should be taken into account. When these effects are sufficiently small they may be neglected, this is the case when you have a pinned or rigid joint.<\/p>\n<p>Whether a joint is pinned, semi-rigid or rigid can be determined by comparing its initial rotational stiffness <em>S<sub>j,ini<\/sub><\/em> with the classification boundaries given in <strong>Eurocode\u00a01993-1-8<\/strong> <strong>\u00a75.2.2.5<\/strong>.<\/p>\n<p>The effect of the joint behaviour can be represented in a moment-rotation diagram or by a rotational stiffness value.<\/p>\n<h2>Possibilities to model the joint&#8217;s stiffness<\/h2>\n<h3>Moment rotation diagram<\/h3>\n<p><strong>Eurocode\u00a01993-1-8 \u00a75.1.1 (4)<\/strong> allows you to use any appropriate curve, including a linearised approximation, such as a bi-linear or tri-linear diagram. This last one is used in PowerConnect.\u00a0 If you are working with the Diamonds &lt;&gt; PowerConnect link, this tri-linear diagram is transferred to Diamonds automatically, ready to be used in the global analysis.<\/p>\n<figure id=\"attachment_1099\" aria-describedby=\"caption-attachment-1099\" style=\"width: 480px\" class=\"wp-caption aligncenter\"><img decoding=\"async\" loading=\"lazy\" class=\"wp-image-1099 size-full\" src=\"http:\/\/buildsoftsupport.com\/wp-content\/uploads\/2017\/06\/powerconnect_stiffnessdiagram.png\" alt=\"\" width=\"480\" height=\"260\" srcset=\"https:\/\/support.buildsoft.eu\/wp-content\/uploads\/2017\/06\/powerconnect_stiffnessdiagram.png 480w, https:\/\/support.buildsoft.eu\/wp-content\/uploads\/2017\/06\/powerconnect_stiffnessdiagram-300x163.png 300w, https:\/\/support.buildsoft.eu\/wp-content\/uploads\/2017\/06\/powerconnect_stiffnessdiagram-50x27.png 50w, https:\/\/support.buildsoft.eu\/wp-content\/uploads\/2017\/06\/powerconnect_stiffnessdiagram-60x33.png 60w, https:\/\/support.buildsoft.eu\/wp-content\/uploads\/2017\/06\/powerconnect_stiffnessdiagram-35x19.png 35w\" sizes=\"(max-width: 480px) 100vw, 480px\" \/><figcaption id=\"caption-attachment-1099\" class=\"wp-caption-text\">Example of the tri-linear moment-rotation diagram in PowerConnect<\/figcaption><\/figure>\n<h3>Rotational stiffness value Sj or Sj,ini<\/h3>\n<p>From <strong>Eurocode 1993-1-8 \u00a75.1.2 (3) and (4)\u00a0<\/strong>we learn that<\/p>\n<p><em>(3) In the case of a semi rigid joint, the rotational stiffness S<sub>j<\/sub> corresponding to the bending moment M<sub>j,Ed<\/sub> should generally be used in the analysis. If M<sub>j,Ed<\/sub> does not exceed 2\/3 M<sub>j,Rd<\/sub>, the initial rotational stiffness S<sub>j,ini<\/sub> may be taken in the global analysis.<\/em><\/p>\n<p><em>(4) As a simplification to (3), the rotational stiffness may be taken as S<sub>j,ini<\/sub>\/\u03b7 for the analysis for all values of M<sub>j,Ed<\/sub>, where \u03b7 is the stiffness modification coefficient. <\/em><\/p>\n<p>This means for the rotational stiffness:<\/p>\n<ul>\n<li>you should always use <em>S<sub>j<\/sub><\/em><\/li>\n<li>but if <em>M<sub>j_Ed<\/sub> &lt; 2\/3M<sub>j,Rd<\/sub><\/em>, you <em>may<\/em> use <em>S<sub>j,ini<\/sub><\/em><\/li>\n<\/ul>\n<p><script src=\"moz-extension:\/\/ccccaaeb-013b-4b99-be98-cffa5aa77072\/js\/app.js\" type=\"text\/javascript\"><\/script><\/p>\n<div id=\"ConnectiveDocSignExtentionInstalled\" data-extension-version=\"1.0.4\"><\/div>\n<p><script src=\"moz-extension:\/\/ccccaaeb-013b-4b99-be98-cffa5aa77072\/js\/app.js\" type=\"text\/javascript\"><\/script><\/p>\n","protected":false},"excerpt":{"rendered":"<p>In case of a semi-rigid joint, the effects of the behaviour of the joints on the distribution of internal forces and moments within a structure, (and on the overall deformations), should be taken into account. When these effects are sufficiently small they may be neglected, this is the case when&#8230;<\/p>\n","protected":false},"author":2,"comment_status":"open","ping_status":"closed","template":"","format":"standard","meta":[],"ht-kb-category":[1116,69],"ht-kb-tag":[],"_links":{"self":[{"href":"https:\/\/support.buildsoft.eu\/nl\/wp-json\/wp\/v2\/ht-kb\/1092"}],"collection":[{"href":"https:\/\/support.buildsoft.eu\/nl\/wp-json\/wp\/v2\/ht-kb"}],"about":[{"href":"https:\/\/support.buildsoft.eu\/nl\/wp-json\/wp\/v2\/types\/ht_kb"}],"author":[{"embeddable":true,"href":"https:\/\/support.buildsoft.eu\/nl\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/support.buildsoft.eu\/nl\/wp-json\/wp\/v2\/comments?post=1092"}],"version-history":[{"count":3,"href":"https:\/\/support.buildsoft.eu\/nl\/wp-json\/wp\/v2\/ht-kb\/1092\/revisions"}],"predecessor-version":[{"id":8965,"href":"https:\/\/support.buildsoft.eu\/nl\/wp-json\/wp\/v2\/ht-kb\/1092\/revisions\/8965"}],"wp:attachment":[{"href":"https:\/\/support.buildsoft.eu\/nl\/wp-json\/wp\/v2\/media?parent=1092"}],"wp:term":[{"taxonomy":"ht_kb_category","embeddable":true,"href":"https:\/\/support.buildsoft.eu\/nl\/wp-json\/wp\/v2\/ht-kb-category?post=1092"},{"taxonomy":"ht_kb_tag","embeddable":true,"href":"https:\/\/support.buildsoft.eu\/nl\/wp-json\/wp\/v2\/ht-kb-tag?post=1092"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}