{"id":15610,"date":"2004-09-01T15:25:08","date_gmt":"2004-09-01T15:25:08","guid":{"rendered":"http:\/\/www.newsteelconstruction.com\/wp\/?p=15610"},"modified":"2014-04-30T15:27:54","modified_gmt":"2014-04-30T15:27:54","slug":"ad-276-the-use-of-toggle-bolts","status":"publish","type":"post","link":"https:\/\/www.newsteelconstruction.com\/wp\/ad-276-the-use-of-toggle-bolts\/","title":{"rendered":"AD 276: The Use of \u2018Toggle Bolts\u2019"},"content":{"rendered":"
\"\"<\/a>

Fig. 1. Typical \u2018toggle bolt\u2019 for blind fixings<\/p><\/div>\n

It has come to our attention that increasing use is being made of \u2018toggle bolts\u2019 for blind fixing to hollow sections. A \u2018toggle bolt\u2019 (fig. 1) has a pivoted bar which lies within the bolt shank as it is inserted through a hole drilled in the section. Once the pivoted bar is through the section wall, the pivot bar turns through 90\u00ba under gravity and prevents the bolt being pulled back out of the hole.<\/p>\n

Some caution is required when using these bolts for the following reasons:<\/p>\n

\"\"<\/a>

Fig. 2. \u2018Toggle bolt\u2019 in fixed position<\/p><\/div>\n

Shear Resistance<\/strong>
\nQuoted shear resistance is often that appropriate to the threaded shank. However, given the small wall thickness of most hollow sections, the shear plane will almost always fall in the slotted zone of the bolt (fig. 2), where the resistance will be much reduced.<\/p>\n

Bearing Resistance<\/strong>
\nOne of the bearing interfaces will undoubtedly be the slotted portion of the bolt against the hollow section wall. It is not clear how the bearing resistance should be calculated, as the contact is not between a solid circular bolt in a circular hole. Furthermore, unlike the plies between a normal bolt head and nut, the material is not constrained all around the hole, but only locally by the toggle.<\/p>\n

Shear and Tension Resistance<\/strong>
\nThe behaviour of a \u2018toggle bolt\u2019 is obviously complex since the reaction against a tension force is not concentric to the bolt shank \u2013 the toggle only bears on one half of the bolt shank. The pivot does not transfer axial load. Tension will therefore induce some degree of bending, which must be carried across the slotted length of the bolt in combination with applied shear.<\/p>\n

Detailing Requirements<\/strong>
\nCare should be taken with detailing dimensions in hollow sections in order to ensure that the pivoted bar can fully rotate when the \u2018toggle bolt\u2019 has been inserted. Designers are reminded that the rules in BS 5950-1 are based on standard circular bolts, and it is doubtful if the strengths and design rules in the Standard can be directly applied to non-standard bolts. Designers using \u2018toggle bolts\u2019 should reassure themselves that the values quoted by manufacturers are appropriate for the application envisaged.<\/p>\n","protected":false},"excerpt":{"rendered":"

It has come to our attention that increasing use is being made of \u2018toggle bolts\u2019 for blind fixing to hollow sections. A \u2018toggle bolt\u2019 (fig. 1) has a pivoted bar which lies within the bolt shank as it is inserted through a hole drilled in the section. Once the pivoted bar is through the section […]<\/p>\n","protected":false},"author":1,"featured_media":15611,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[79,5],"tags":[82,529,1969],"class_list":["post-15610","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-ad","category-tech","tag-advisory-desk","tag-bolts","tag-toggle-bolts"],"jetpack_featured_media_url":"https:\/\/www.newsteelconstruction.com\/wp\/wp-content\/uploads\/2013\/02\/AD276.1.png","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p3WsLP-43M","_links":{"self":[{"href":"https:\/\/www.newsteelconstruction.com\/wp\/wp-json\/wp\/v2\/posts\/15610","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsteelconstruction.com\/wp\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsteelconstruction.com\/wp\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsteelconstruction.com\/wp\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsteelconstruction.com\/wp\/wp-json\/wp\/v2\/comments?post=15610"}],"version-history":[{"count":2,"href":"https:\/\/www.newsteelconstruction.com\/wp\/wp-json\/wp\/v2\/posts\/15610\/revisions"}],"predecessor-version":[{"id":15614,"href":"https:\/\/www.newsteelconstruction.com\/wp\/wp-json\/wp\/v2\/posts\/15610\/revisions\/15614"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsteelconstruction.com\/wp\/wp-json\/wp\/v2\/media\/15611"}],"wp:attachment":[{"href":"https:\/\/www.newsteelconstruction.com\/wp\/wp-json\/wp\/v2\/media?parent=15610"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsteelconstruction.com\/wp\/wp-json\/wp\/v2\/categories?post=15610"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsteelconstruction.com\/wp\/wp-json\/wp\/v2\/tags?post=15610"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}