{"id":33737,"date":"2026-04-27T13:00:39","date_gmt":"2026-04-27T13:00:39","guid":{"rendered":"https:\/\/protasoftware.com\/technical-manuals\/structural-modelling\/working-with-flat-slabs\/"},"modified":"2026-06-19T12:37:44","modified_gmt":"2026-06-19T12:37:44","slug":"working-with-flat-slabs","status":"publish","type":"wiki","link":"https:\/\/protasoftware.com\/wiki\/working-with-flat-slabs\/","title":{"rendered":"Working With Flat Slabs"},"content":{"rendered":"<h1 class=\"toc_anchors\" id=\"Flat_Slab_Guidelines\" style=\"line-height: 60px;margin: 20px 0px 10px;font-size: 24px;font-weight: 500\"><span class=\"colour\">Flat Slab Guidelines<\/span><br \/><\/h1>\n<p style=\"margin: 0px 0px 10px;line-height: 20px\"><span style=\"font-size: 14px\" class=\"size\"><span style=\"font-size: 16px\" class=\"size\"><span class=\"colour\">The modelling, analysis and design of flat slab is described in detail here :<\/span><\/span><\/span><\/p>\n<ol>\n<li class=\" align-left\" style=\"list-style-type: disc;text-align: left\"><span class=\"font\"><span style=\"font-size: 16px\" class=\"size\"><span class=\"highlight\"><span class=\"colour\">For ProtaStructure 2022\/ ProtaStructure 2024:<\/span><span class=\"colour\">&nbsp;<a target=\"_blank\" href=\"https:\/\/support.protasoftware.com\/portal\/en\/kb\/articles\/flat-slab-modelling-analysis-and-design\" rel=\"noopener noreferrer\">Flat Slab Modelling, Analysis and Design<\/a><\/span><\/span><\/span><\/span><\/li>\n<li class=\" align-left\" style=\"list-style-type: disc;text-align: left\"><span class=\"colour\">For Flat Slab and Raft Design with Slab Patch Panel:&nbsp;<\/span><a target=\"_blank\" href=\"https:\/\/support.protasoftware.com\/portal\/en\/kb\/articles\/flat-slab-and-raft-design-with-slab-patch-panels\" rel=\"noopener noreferrer\">Flat Slab and Raft Design with Slab Patch Panels&nbsp;<\/a><\/li>\n<\/ol>\n<p style=\"margin: 0px 0px 10px;line-height: 20px\"><span style=\"font-size: 14px\" class=\"size\"><span style=\"font-size: 16px\" class=\"size\"><span class=\"colour\">The following are additional topics of interest related to flat slab.<\/span><\/span><\/span><\/p>\n<h3 style=\"line-height: 32px;font-weight: 500;margin-top: 20px;margin-bottom: 10px;font-size: 20px\" class=\"toc_anchors\" id=\"Flat_Slab_Insertion_methods\"><span style=\"font-size: 16px\" class=\"size\"><b><span class=\"colour\">Flat Slab Insertion methods<\/span><\/b><\/span><\/h3>\n<ul style=\"margin-top: 0px;margin-bottom: 10px;padding-top: 6px;padding-bottom: 6px;font-size: 14px\">\n<li style=\"padding-top: 6px;padding-bottom: 6px\"><span style=\"font-size: 16px\" class=\"size\"><span class=\"colour\">For the flat slab, it is unlikely that your slab would be fully bounded\/surrounded by beams, hence the more appropriate method would be \u201cAxis Region\u201d or \u201cPick Axis\u201d.<\/span><\/span><\/li>\n<li style=\"padding-top: 6px;padding-bottom: 6px\"><span style=\"font-size: 16px\" class=\"size\"><span class=\"colour\">For Axis Region, you simply click on any point bounded by axis and a slab will be automatically with those axes as insertion axis. You can combine them by holding down the CTRL key while clicking successively locations and a single slab panel will be created after you release the key.<\/span><\/span><\/li>\n<li style=\"padding-top: 6px;padding-bottom: 6px\"><span style=\"font-size: 16px\" class=\"size\"><span class=\"colour\">For Pick Axis method, simply picking on the axes that bound the slab in any order (clockwise or anti-clockwise), starting from any axis and finally re-select the first axis you have shown to end the insertion action. &nbsp;For more information, please refer to<\/span>&nbsp;<\/span><span style=\"background-color: transparent\" class=\"highlight\"><span class=\"colour\"><span style=\"font-size: 16px\" class=\"size\"><a target=\"_blank\" href=\"https:\/\/support.protasoftware.com\/portal\/en\/kb\/articles\/working-with-slabs#Pick_Axis\" rel=\"noopener noreferrer\">Working with Slabs &#8211; Pick Axis<\/a><\/span><\/span><\/span><span style=\"font-size: 16px\" class=\"size\">&nbsp;<span class=\"colour\">section.<\/span><\/span><\/li>\n<li style=\"padding-top: 6px;padding-bottom: 6px\"><span style=\"font-size: 16px\" class=\"size\"><span class=\"colour\">When inserting slabs for the flat slab, make sure that&nbsp;<\/span><\/span><span><span style=\"font-size: 16px\" class=\"size\"><span class=\"colour\">all columns and shear walls lie at the edges or corners of the slab<\/span><\/span><\/span><span style=\"font-size: 16px\" class=\"size\"><span class=\"colour\">.<\/span><\/span><\/li>\n<\/ul>\n<p style=\"margin: 0px 0px 10px;line-height: 20px\"><span style=\"font-size: 14px\" class=\"size\"><span style=\"font-size: 16px\" class=\"size\"><span class=\"colour\">In other words:<\/span><\/span><\/span><\/p>\n<p style=\"margin: 0px 0px 10px;line-height: 20px\"><span style=\"font-size: 14px\" class=\"size\"><span style=\"font-size: 16px\" class=\"size\"><span class=\"colour\">1. The slab boundary must coincide with the insertion axis of column\/wall. For example, if the insertion axis of the column is A\/1 then the slab boundary at the column must be either axis A or axis 1.<\/span><\/span><\/span><\/p>\n<p style=\"margin: 0px 0px 10px;line-height: 20px\"><span style=\"font-size: 14px\" class=\"size\"><span style=\"font-size: 16px\" class=\"size\"><span class=\"colour\">2. Try to keep your slab four-sided, i.e. rectangular or squarish.<\/span><\/span><\/span><\/p>\n<p style=\"margin: 0px 0px 10px;line-height: 20px\"><span style=\"font-size: 14px\" class=\"size\"><span style=\"font-size: 16px\" class=\"size\"><span class=\"colour\">3. For raft or flat slab, the slab type does not matter as it is only applicable for slabs designed using yield line, i.e. Analytical slab&nbsp;<\/span><\/span><span class=\"colour\">strip.<\/span><\/span><\/p>\n<h3 style=\"line-height: 32px;font-weight: 500;margin-top: 20px;margin-bottom: 10px;font-size: 20px\" class=\"toc_anchors\" id=\"Flat_Slab_Reinforcement_Design\"><b><span style=\"font-size: 16px\" class=\"size\"><span class=\"colour\">Flat Slab Reinforcement Design<\/span><\/span><\/b><\/h3>\n<ul style=\"margin-top: 0px;margin-bottom: 10px;padding-top: 6px;padding-bottom: 6px;font-size: 14px\">\n<li style=\"padding-top: 6px;padding-bottom: 6px\"><span style=\"font-size: 16px\" class=\"size\"><span class=\"colour\">The preferred method to show reinforcement for the flat slab is to \u201cUser Defined Contours\u201d or &quot;Threshold Contour&quot; as explained in the<\/span>&nbsp;<a style=\"font-size: 14px;background-color: transparent\" target=\"_blank\" href=\"https:\/\/support.protasoftware.com\/portal\/api\/kbArticles\/306520000054398600\/locale\/en\/attachments\/dc04n8f0660429cf84cbeae6ce2d405942558\/content?portalId=edbsneff51a3817fa93c6f82be8e7ba2af11e17e042278976e04371f7d6dc28158321&amp;inline=true\" rel=\"noopener noreferrer\"><span style=\"font-size: 16px\" class=\"size\">Flat Slab Training Manual<\/span><\/a>&nbsp;<span class=\"colour\">and<\/span>&nbsp;<span class=\"colour\"><a href=\"https:\/\/support.protasoftware.com\/portal\/en\/kb\/articles\/finite-elements-floor-analysis-ps2022\" target=\"_blank\" rel=\"noopener noreferrer\">Finite Elements Floor Analysis<\/a><\/span><\/span><\/li>\n<li style=\"padding-top: 6px;padding-bottom: 6px\"><span style=\"font-size: 16px\" class=\"size\"><span class=\"colour\">Alternatively, you can try to show rebars on the model plan view, but it is important that you define and cut the correct Finite Element Slab Strip \u2013 for you model that would be \u201cFixed Width Band strip\u201d. More details are available under Slab Strip Type (<\/span><\/span><a style=\"background-color: transparent\" target=\"_blank\" href=\"https:\/\/support.protasoftware.com\/portal\/en\/kb\/articles\/working-with-slab-strips-ps-2022\" rel=\"noopener noreferrer\"><span style=\"font-size: 16px\" class=\"size\">Working with Slab Strips<\/span><\/a><span style=\"font-size: 16px\" class=\"size\">&nbsp;<span class=\"colour\">and<\/span>&nbsp;<span class=\"colour\"><a href=\"https:\/\/support.protasoftware.com\/portal\/en\/kb\/articles\/working-with-slab-strips-ps-2022#Analysis_Results_Source_FE_Strip\" target=\"_blank\" rel=\"noopener noreferrer\">FE Strip-Fixed Band Strip<\/a><\/span>&nbsp;<span class=\"colour\">sections)<\/span><\/span><\/li>\n<li style=\"padding-top: 6px;padding-bottom: 6px\"><span style=\"font-size: 16px\" class=\"size\"><span class=\"colour\">\u201cFixed band strip\u201d, will take a single max positive and negative moment to design for the entire length and width of a strip. Hence you only get one top and bot reinforcement, with may lead to some over design if the width of the strip is too large. Hence, you need to examine or evaluate how wide and how many fixed width band strip you want to cut as that has an influence on how efficient the steel design is.<\/span><\/span><\/li>\n<li style=\"padding-top: 6px;padding-bottom: 6px\"><span style=\"font-size: 16px\" class=\"size\"><span class=\"colour\">In the FE tab of the FE slab strip, there is an option to use &quot;integral&quot;.&nbsp;&nbsp; As the name implies, the moments across the width of the strip is \u201caveraged out\u201d or \u201cspread out\u201d by integration so that a lower maximum moment is obtained. This assumes that the slab is sufficient stiff so that the load tend to \u201cdistribute itself\u201d across a certain width. With \u201cintegral\u201d unchecked, ProtaStructure scans for a single max moment to design across the span and support region.<\/span><\/span><\/li>\n<div><span style=\"margin: 10px 0px;position: relative;padding: 10px 10px 10px 40px\" class=\"KB_New_Editor_Highlights\"><img decoding=\"async\" src=\"https:\/\/protasoftware.com\/wp-content\/uploads\/2026\/04\/prota-doc-1e7791280a202d1a6c7f4c2237e5018e.png\" data-type=\"non-resize\" style=\"position: absolute;left: 12px;top: 14px;width: 15px;max-width: 100%\" data-image=\"contentStyle\" alt=\"Alert\"><span><span class=\"colour\"><span style=\"font-size: 16px\" class=\"size\">The FE fixed band strip can only be used if cut across slabs with the same thickness.&nbsp; The reason is the design will only detect the slab thickness nearest to the first end of the strip. If you have many slabs with different thicknesses, then do not use the FE Slab Strip.&nbsp; Use the other method of design using the As required contours as outlined in the Flat Slab training manual<\/span><\/span><\/span><\/span><\/div>\n<li style=\"padding-top: 6px;padding-bottom: 6px\"><span style=\"font-size: 16px\" class=\"size\"><span class=\"colour\">Please be aware that cutting strips may not be able to give you a full solution, you will still need to combine or supplement it by investigating the steel contours.<\/span><\/span><\/li>\n<\/ul>\n<p style=\"margin: 0px 0px 10px;line-height: 20px\"><span style=\"font-size: 14px\" class=\"size\"><span style=\"font-size: 16px\" class=\"size\"><span class=\"colour\">In a nutshell, if you wish to use FE Slab Strip, the procedure is as follows:<\/span><\/span><span class=\"colour\"><br \/><\/span><\/span><\/p>\n<p style=\"margin: 0px 0px 10px;line-height: 20px\"><span style=\"font-size: 14px\" class=\"size\"><span style=\"font-size: 16px\" class=\"size\"><span class=\"colour\">a)&nbsp;<\/span><\/span><span style=\"background-color: transparent\" class=\"highlight\"><span style=\"font-size: 16px\" class=\"size\"><span class=\"colour\">Model\/define slabs<\/span><\/span><\/span><span class=\"colour\"><br \/><\/span><\/span><\/p>\n<p style=\"margin: 0px 0px 10px;line-height: 20px\"><span style=\"font-size: 14px\" class=\"size\"><span style=\"font-size: 16px\" class=\"size\"><span class=\"colour\">b) Cut&nbsp;<\/span><\/span><span style=\"background-color: transparent\" class=\"highlight\"><span style=\"font-size: 16px\" class=\"size\"><span class=\"colour\">FE&nbsp;Strip<\/span><\/span><\/span><span style=\"font-size: 16px\" class=\"size\"><span class=\"colour\">&nbsp;across of the appropriate type (refer to more notes below)<\/span><span class=\"colour\"><br \/>&nbsp; &nbsp; &nbsp;&nbsp;<img decoding=\"async\" src=\"https:\/\/protasoftware.com\/wp-content\/uploads\/2026\/04\/prota-doc-c42f4bcea5c89b9091d9a011e79c48ce.png\" style=\"padding: 0px;max-width: 100%;width: 914.412px;height: auto\" data-zdeskdocid=\"img_9129631784904644\" class=\"docsimage\" data-zdeskdocselectedclass=\"\"><\/span><\/span><\/span><\/p>\n<p style=\"margin: 0px 0px 10px 40px;line-height: 20px\"><span class=\"colour\"><span style=\"font-size: 14px\" class=\"size\"><br \/><\/span><\/span><\/p>\n<p style=\"margin: 0px 0px 10px 40px;line-height: 20px\"><span style=\"font-size: 14px\" class=\"size\"><span style=\"font-size: 16px\" class=\"size\"><span class=\"colour\">Above : Select FE Strip and choose fixed band strip in Slab Strip properties. Then select the Analysis result source and check \u201cIntegral Strip\u201d.<\/span><\/span><\/span><\/p>\n<div><span style=\"font-size: 14px\" class=\"size\"><span class=\"colour\"><br \/><\/span><\/span><\/div>\n<p style=\"margin: 0px 0px 10px 40px;line-height: 20px\"><span class=\"colour\"><span style=\"font-size: 14px\" class=\"size\"><img decoding=\"async\" src=\"https:\/\/protasoftware.com\/wp-content\/uploads\/2026\/04\/prota-doc-7ef209903fcc327f84cbb2327b19acd9.png\" style=\"padding: 0px;max-width: 100%;width: 893px;height: auto\" data-zdeskdocid=\"img_5092394925615478\" class=\"docsimage\" data-zdeskdocselectedclass=\"\"><br \/><\/span><\/span><\/p>\n<p style=\"margin: 0px 0px 10px 40px;line-height: 20px\"><span style=\"font-size: 14px\" class=\"size\"><span style=\"font-size: 16px\" class=\"size\"><span class=\"colour\">Above: Cut strip through the desire area. The scope of width can be adjusted by input value in corresponding cell and click &quot;Update&quot;.<\/span><\/span><\/span><\/p>\n<div><span style=\"font-size: 14px\" class=\"size\"><span class=\"colour\"><br \/><\/span><\/span><\/div>\n<p style=\"margin: 0px 0px 10px 40px;line-height: 20px\"><span class=\"colour\"><span style=\"font-size: 14px\" class=\"size\"><img decoding=\"async\" src=\"https:\/\/protasoftware.com\/wp-content\/uploads\/2026\/04\/prota-doc-e1d2d9d19903c0be1eee92d28e679dda.gif\" style=\"padding: 0px;max-width: 100%;width: 872px;height: auto\" data-zdeskdocid=\"img_8822668520491779\" class=\"docsimage\" data-zdeskdocselectedclass=\"\"><br \/><\/span><\/span><\/p>\n<p style=\"margin: 0px 0px 10px 40px;line-height: 20px\"><span style=\"font-size: 14px\" class=\"size\"><span style=\"font-size: 16px\" class=\"size\"><span class=\"colour\">Above: Scope of width also can be adjusted using <img decoding=\"async\" src=\"https:\/\/protasoftware.com\/wp-content\/uploads\/2026\/04\/prota-doc-24c60e35c809d3a0baf6c0ba990783b0.png\" style=\"padding: 0px;max-width: 100%\">&nbsp;and click &quot;Update&quot;<\/span><\/span><\/span><\/p>\n<div><\/div>\n<p style=\"margin: 0px 0px 10px;line-height: 20px\"><span style=\"font-size: 14px\" class=\"size\"><span style=\"font-size: 16px\" class=\"size\"><span class=\"colour\">c) Run Building Analysis or&nbsp;<\/span><\/span><span style=\"background-color: transparent\" class=\"highlight\"><span style=\"font-size: 16px\" class=\"size\"><span class=\"colour\">FE Floor Analysis and open Analytical Model (Analysis tab &gt; Analytical Model)<\/span><\/span><\/span><span class=\"colour\"><br \/><\/span><\/span><\/p>\n<p style=\"margin: 0px 0px 10px;line-height: 20px\"><span style=\"font-size: 14px\" class=\"size\"><span style=\"font-size: 16px\" class=\"size\"><span class=\"colour\">d) Without select any members,&nbsp;right click &gt; Arrange All Steel Bars&gt; Update All Steel Bars<\/span><\/span><\/span><\/p>\n<p style=\"margin: 0px 0px 10px;line-height: 20px\"><\/p>\n<div><span style=\"font-size: 14px\" class=\"size\"><span style=\"font-size: 16px\" class=\"size\"><span class=\"colour\">Make sure that everything is fine, i.e. mesh generated is reasonable by checking following in the Analytical Model:&nbsp;<\/span><\/span><span class=\"colour\"><br \/><\/span><\/span><\/div>\n<p style=\"margin: 0px 0px 10px;line-height: 20px\"><span style=\"font-size: 14px\" class=\"size\"><span style=\"font-size: 16px\" class=\"size\"><span class=\"colour\">a) If you have defined your slab edges correctly, you will notice that edges of shell elements coincide perfectly on the red dot represented by the column and shear walls.<\/span><\/span><span class=\"colour\"><br \/><\/span><\/span><\/p>\n<p style=\"margin: 0px 0px 10px;line-height: 20px\"><span style=\"font-size: 14px\" class=\"size\"><span style=\"font-size: 16px\" class=\"size\"><span class=\"colour\">b) The edges of shell element of one slab coincide perfectly with that of the adjacent slab.<\/span><\/span><\/span><\/p>\n<h3 class=\"toc_anchors\" id=\"Slab_Design_with_Slab_Patch_Panels\"><span style=\"font-size: 14px\" class=\"size\"><span style=\"font-size: 16px\" class=\"size\"><span class=\"colour\">Slab Design with Slab Patch Panels<\/span><\/span><\/span><br \/><\/h3>\n<div><span class=\"colour\">Slab Patch Panels allow you to use a Base Reinforcement throughout the entire floor and design additional top or bottom bars at column support region.&nbsp;<\/span><\/div>\n<div><\/div>\n<div><b><u>Recommended steps for Slab Patch Panels Usage<\/u><\/b><\/div>\n<ol>\n<li style=\"list-style-type: decimal\">(<i>Optional Step<\/i>) Perform an FE Floor Analysis or Building Analysis with slabs meshed and examine reinforcement contours to decide on the slab panel areas where you will put additional rebars.&nbsp;<\/li>\n<li style=\"list-style-type: decimal\">Insert FE Fixed Band Strips for based reinforcement calculation. Fixed band Strips allow you to decide and calculate the base reinforcement regions. Hence, it is important to first decide how many base reinforcement regions you will use.&nbsp;<\/li>\n<li style=\"list-style-type: decimal\">Insert Slab Patch Panels.&nbsp;Do not worry about the size of the patch panels yet. Ideally, they should cover the support moment contours. You can use an approximate size of 1.5&#215;15 m or 2&#215;2 m to start with. An FE Fixed Band strip should completely or partially cover slab patch panels in its tributary area.&nbsp;<\/li>\n<li style=\"list-style-type: decimal\">(<i>Optional Step<\/i>)&nbsp;View the FE Reinforcement Contours on the physical floor plan view (such as A<span style=\"font-size: 10px\" class=\"size\">sd1-top<\/span>, A<span style=\"font-size: 10px\" class=\"size\">sd2-top<\/span> for the upper floors, A<span style=\"font-size: 10px\" class=\"size\">sd1-bot<\/span>, and A<span style=\"font-size: 10px\" class=\"size\">sd2-bot<\/span> for raft foundations). This will help you understand whether the patch sizes are large enough to cover the negative support moment regions.&nbsp;<\/li>\n<li style=\"list-style-type: decimal\">Perform an FE Floor Analysis or Building Analysis with the slabs meshed.&nbsp;<\/li>\n<li style=\"list-style-type: decimal\">Design the slab reinforcements using <b><i>Design &gt; Slab<\/i><\/b> ribbon menu.&nbsp;The designed rebars will also be automatically drawn on the physical floor plan view with the correct lap splices and extensions. The additional bars in the patch panels will be automatically extended outside the designated patch area by anchorage length.<\/li>\n<li style=\"list-style-type: decimal\">(<i>Optional Step<\/i>)&nbsp;Modify the size of slab patch panels if you need to. The most usual scenario would be to extend the patch panel region so that it covers more negative support moment contours. Optimizing the path panel size can further reduce the base reinforcement (not less than the minimum required, A<span style=\"font-size: 10px\" class=\"size\">smin<\/span>)<\/li>\n<li style=\"list-style-type: decimal\">(<i>Optional Step<\/i>) Redesign the reinforcement using <b><i>Design &gt; Slabs<\/i><\/b> ribbon menu.&nbsp;<\/li>\n<li style=\"list-style-type: decimal\">(<i>Optional Step<\/i>)&nbsp;Modify the base reinforcement and\/or additional reinforcements on the <b><i>Design &gt; Slabs<\/i><\/b> ribbon menu if you need to. If the edited reinforcement is not sufficient, ProtaStructure will issue a warning.<\/li>\n<\/ol>\n<div>\n<div><span style=\"margin: 10px 0px;position: relative;padding: 10px 10px 10px 40px\" class=\"KB_New_Editor_Highlights\"><img decoding=\"async\" src=\"https:\/\/protasoftware.com\/wp-content\/uploads\/2026\/04\/prota-doc-1e7791280a202d1a6c7f4c2237e5018e.png\" data-type=\"non-resize\" style=\"position: absolute;left: 12px;top: 14px;width: 15px\" data-image=\"contentStyle\" alt=\"Alert\"><\/p>\n<div><b>Important Remark<\/b><\/div>\n<div><u>Fixed band strips should completely or partially cover<\/u> the slab patch panels. Otherwise, the Fixed Band strips will continue to collect bending moment results from <b>column nodes<\/b>, which may yield an uneconomical design. If you think a column support region does not have a significant negative moment, you have the freedom not to insert a patch panel for that column.<\/div>\n<div>If you <u>choose not to insert patch panels<\/u> around a column, you <u>must cover<\/u> the column area with an FE Fixed Band. If you leave a particular column region uncovered by a Patch Panel or an FE Fixed Band Strip, the results in the column region will not be considered, and that particular column region will not be designed. <b>You may end up with an unsafe design<\/b>.<\/div>\n<p><\/span><\/div>\n<\/div>\n<h3 style=\"line-height: 32px;margin-top: 20px;margin-bottom: 10px;font-weight: 500;font-size: 20px\" class=\"toc_anchors\" id=\"Column_Punching_Shear_Design\"><span style=\"font-size: 16px\" class=\"size\"><b><span class=\"colour\">Column Punching Shear Design<\/span><\/b><\/span><span class=\"colour\"><br \/><\/span><\/h3>\n<ul style=\"margin-top: 0px;margin-bottom: 10px;padding-top: 6px;padding-bottom: 6px;font-size: 14px\">\n<li style=\"padding-top: 6px;padding-bottom: 6px\"><span style=\"font-size: 16px\" class=\"size\"><span class=\"colour\">Finally, do not forget to check for punching shear. Try not to run all the columns punching shear shear check altogether, as you need to define the correct type of column location (interior, edge, column).<\/span><\/span><span class=\"colour\"><br \/><\/span><\/li>\n<li style=\"padding-top: 6px;padding-bottom: 6px\"><span style=\"font-size: 16px\" class=\"size\"><span class=\"colour\">To do this, you can select a group of columns having the same type location by successively selecting each column while holding down the ctrl key.<\/span><\/span><span class=\"colour\"><br \/><\/span><\/li>\n<li style=\"padding-top: 6px;padding-bottom: 6px\"><span style=\"font-size: 16px\" class=\"size\"><span class=\"colour\">Then right click and choose &#8216;<\/span><\/span><a style=\"background-color: transparent\" target=\"_blank\" href=\"https:\/\/support.protasoftware.com\/portal\/en\/kb\/articles\/column-punching-check\" rel=\"noopener noreferrer\"><span style=\"font-size: 16px\" class=\"size\">Column Punching Check<\/span><\/a><span style=\"font-size: 16px\" class=\"size\"><span class=\"colour\">&#8216;.<\/span><\/span><\/li>\n<li style=\"padding-top: 6px;padding-bottom: 6px\"><span style=\"font-size: 16px\" class=\"size\"><span class=\"colour\">Be reminded you must first run FE floor analysis and post processing, and click &#8216;merge column results with building analysis results&#8217; so that slab loads based on FE analysis are transferred to the columns.<\/span><\/span><span class=\"colour\"><br \/><\/span><\/li>\n<li style=\"padding-top: 6px;padding-bottom: 6px\"><span style=\"font-size: 16px\" class=\"size\"><span class=\"colour\">Otherwise, column punching will be based on building analysis (i.e yield line slab analysis) rather the FE floor analysis.<\/span><\/span><span class=\"colour\"><br \/><\/span><\/li>\n<li style=\"padding-top: 6px;padding-bottom: 6px\"><span style=\"font-size: 16px\" class=\"size\"><span class=\"colour\">You should not perform punching shear check for the columns connected to beam as you will need to design the beam to take the shear.<\/span><\/span><span class=\"colour\"><br \/><\/span><\/li>\n<li style=\"padding-top: 6px;padding-bottom: 6px\"><span style=\"font-size: 16px\" class=\"size\"><span class=\"colour\">ProtaStructure&nbsp;does not take into account any beam connected to a column for punching shear check.&nbsp;<\/span><\/span><\/li>\n<\/ul>\n<p style=\"margin: 0px 0px 10px;line-height: 20px\"><span style=\"font-size: 14px\" class=\"size\"><span style=\"font-size: 16px\" class=\"size\"><span class=\"colour\">Drop panels can be inserted added through the column properties &gt; Drop tab.<\/span><\/span><span class=\"colour\"><br \/><\/span><\/span><\/p>\n<p style=\"margin: 0px 0px 10px;line-height: 20px\"><span class=\"colour\"><span style=\"font-size: 14px\" class=\"size\"><\/span><\/span><\/p>\n<div><span style=\"margin: 10px 0px;position: relative;padding: 10px 10px 10px 40px\" class=\"KB_New_Editor_Highlights\"><img decoding=\"async\" src=\"https:\/\/protasoftware.com\/wp-content\/uploads\/2026\/04\/prota-doc-0d2d411042eecf6c4064e457319808eb.png\" data-type=\"non-resize\" style=\"position: absolute;left: 12px;top: 14px;width: 15px;max-width: 100%\" data-image=\"contentStyle\" alt=\"Alert\"> <\/p>\n<div><span class=\"colour\">The depth of the drop panel defined as <\/span><b><span class=\"colour\">h-Drop is inclusive of the slab thickness<\/span><\/b><span class=\"colour\">, NOT measured from soffit of the slab. (Example: slab is 150mm, drop panel is 200mm. Therefore the h-Drop is 350mm.) <\/span><span class=\"colour\"><br \/><\/span><\/div>\n<div><span class=\"colour\">Note that drop panels works best to improve punching shear capacity. They are less effective in reducing moment at the column as a thicker section may attract more moment, hence only model drop panel if punching shear is a problem.&nbsp;<\/span><\/div>\n<p><\/span><\/div>\n<\/p>\n<div><\/div>\n","protected":false},"excerpt":{"rendered":"<p>Flat Slab Guidelines The modelling, analysis and design of flat slab is described in detail here : For ProtaStructure 2022\/ ProtaStructure 2024:&nbsp;Flat Slab Modelling, Analysis&hellip;<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"template":"","meta":{"_whitepaper_youtube_videos":"","_whitepaper_youtube_url":"","_whitepaper_youtube_thumbnail":"","footnotes":""},"categories":[185],"whitepaper_topic":[],"whitepaper_product":[],"whitepaper_type":[],"class_list":["post-33737","wiki","type-wiki","status-publish","hentry","category-structural-modelling"],"yoast_head":"<!-- This site is optimized with the Yoast SEO Premium plugin v27.9 (Yoast SEO v27.9) - https:\/\/yoast.com\/product\/yoast-seo-premium-wordpress\/ -->\n<title>Working With Flat Slabs - 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