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<?xml-stylesheet type="text/xsl" href="https://communities.bentley.com/cfs-file/__key/system/syndication/rss.xsl" media="screen"?><rss version="2.0" xmlns:dc="http://purl.org/dc/elements/1.1/"><channel><title>RM Bridge: Elastic compression loss results in structural elements</title><link>https://communities.bentley.com/products/bridge_design___engineering/w/bridge_design_and_engineering__wiki/7765/rm-bridge-elastic-compression-loss-results-in-structural-elements</link><description /><dc:language>en-US</dc:language><generator>Telligent Community 12</generator><item><title>RM Bridge: Elastic compression loss results in structural elements</title><link>https://communities.bentley.com/products/bridge_design___engineering/w/bridge_design_and_engineering__wiki/7765/rm-bridge-elastic-compression-loss-results-in-structural-elements</link><pubDate>Mon, 29 May 2023 17:26:42 GMT</pubDate><guid isPermaLink="false">6dad98f5-dbc9-4c4d-a9ba-e9da8dc6aa8e:69fc7e26-04c1-4a9e-962b-8ce6988000a2</guid><dc:creator>Ana Carla Peres</dc:creator><comments>https://communities.bentley.com/products/bridge_design___engineering/w/bridge_design_and_engineering__wiki/7765/rm-bridge-elastic-compression-loss-results-in-structural-elements#comments</comments><description>Current Revision posted to LARS | LEAP | OpenBridge | OpenTunnel | RM Wiki by Ana Carla Peres on 5/29/2023 5:26:42 PM&lt;br /&gt;
&lt;h1&gt;Question&lt;/h1&gt;
&lt;p&gt;Why does elastic compression loss (e.g. loss of pre-stressing in previously grouted tendons due to stressing of further tendons)&amp;nbsp;not appear in internal force results of structural elements?&lt;/p&gt;
&lt;h1&gt;Answer&lt;/h1&gt;
&lt;p&gt;The influence of prestressing losses in previously grouted tendons on the internal forces of the respective structural element is just pretended but in reality not existent when differences between the relevant cross-sections (concrete sections, composite sections) are properly considered. Let us show the relationship on behalf of a concentrically in 2 steps pre-stressed beam (the general validity also for bending, shear, multi-stage stressing is obvious):&lt;/p&gt;
&lt;p&gt;Let us denote:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;N&lt;sub&gt;conc&lt;/sub&gt;&amp;nbsp;&amp;nbsp; Prestressing force first applied on the net concrete section A&lt;sub&gt;conc&lt;/sub&gt;&lt;/li&gt;
&lt;li&gt;N&lt;sub&gt;comp&lt;/sub&gt;&amp;nbsp; Prestressing force later applied on the grouted section A&lt;sub&gt;comp&lt;/sub&gt;&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;In principle, the two forces are related to 2 different cross-section areas and adding them is not allowed. However, in proof checking procedures we generally want to work with summation values applied to one relevant cross-section, normally the relevant composite section after grouting all tendons. I.e. for working with the final composite section A&lt;sub&gt;comp&lt;/sub&gt; we must adjust N1 accordingly.&lt;/p&gt;
&lt;p&gt;Let us look at the concrete stresses after the two steps: &amp;sigma;&lt;sub&gt;c&lt;/sub&gt; = N1/A1 + N&lt;sub&gt;comp&lt;/sub&gt;/A&lt;sub&gt;comp&lt;/sub&gt;. For working with the summation value N = N1+N&lt;sub&gt;comp&lt;/sub&gt; and the composite section A&lt;sub&gt;comp&lt;/sub&gt; we must relate the value N1 to the composite section by N1&lt;sup&gt;*&lt;/sup&gt; = N1*(A&lt;sub&gt;comp&lt;/sub&gt;/A1).&amp;nbsp;&lt;/p&gt;
&lt;h4&gt;See Also&lt;/h4&gt;
&lt;p&gt;&lt;a title="Elastic compression losses of tendons" href="/products/bridge_design___engineering/w/bridge_design_and_engineering__wiki/elastic-compression-losses-of-tendons.aspx"&gt;Elastic compression losses of tendons&lt;/a&gt;&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;

&lt;div style="font-size: 90%;"&gt;Tags: tendon losses, Prestressed Concrete, Elastic shortening, Elastic compression&lt;/div&gt;
</description></item><item><title>RM Bridge: Elastic compression loss results in structural elements</title><link>https://communities.bentley.com/products/bridge_design___engineering/w/bridge_design_and_engineering__wiki/7765/rm-bridge-elastic-compression-loss-results-in-structural-elements/revision/11</link><pubDate>Wed, 01 Jun 2022 15:45:24 GMT</pubDate><guid isPermaLink="false">6dad98f5-dbc9-4c4d-a9ba-e9da8dc6aa8e:69fc7e26-04c1-4a9e-962b-8ce6988000a2</guid><dc:creator>MarcosBeier</dc:creator><comments>https://communities.bentley.com/products/bridge_design___engineering/w/bridge_design_and_engineering__wiki/7765/rm-bridge-elastic-compression-loss-results-in-structural-elements#comments</comments><description>Revision 11 posted to LARS | LEAP | OpenBridge | OpenTunnel | RM Wiki by MarcosBeier on 6/1/2022 3:45:24 PM&lt;br /&gt;
&lt;h1&gt;Question&lt;/h1&gt;
&lt;p&gt;Why does elastic compression loss (e.g. loss of pre-stressing in previously grouted tendons due to stressing of further tendons)&amp;nbsp;not appear in internal force results of structural elements?&lt;/p&gt;
&lt;h1&gt;Answer&lt;/h1&gt;
&lt;p&gt;The influence of prestressing losses in previously grouted tendons on the internal forces of the respective structural element is just pretended but in reality not existent when differences between the relevant cross-sections (concrete sections, composite sections) are properly considered. Let us show the relationship on behalf of a concentrically in 2 steps pre-stressed beam (the general validity also for bending, shear, multi-stage stressing is obvious):&lt;/p&gt;
&lt;p&gt;Let us denote:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;N&lt;sub&gt;conc&lt;/sub&gt;&amp;nbsp;&amp;nbsp; Prestressing force first applied on the net concrete section A&lt;sub&gt;conc&lt;/sub&gt;&lt;/li&gt;
&lt;li&gt;N&lt;sub&gt;comp&lt;/sub&gt;&amp;nbsp; Prestressing force later applied on the grouted section A&lt;sub&gt;comp&lt;/sub&gt;&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;In principle, the two forces are related to 2 different cross-section areas and adding them is not allowed. However, in proof checking procedures we generally want to work with summation values applied to one relevant cross-section, normally the relevant composite section after grouting all tendons. I.e. for working with the final composite section A&lt;sub&gt;comp&lt;/sub&gt; we must adjust N1 accordingly.&lt;/p&gt;
&lt;p&gt;Let us look at the concrete stresses after the two steps: &amp;sigma;&lt;sub&gt;c&lt;/sub&gt; = N1/A1 + N&lt;sub&gt;comp&lt;/sub&gt;/A&lt;sub&gt;comp&lt;/sub&gt;. For working with the summation value N = N1+N&lt;sub&gt;comp&lt;/sub&gt; and the composite section A&lt;sub&gt;comp&lt;/sub&gt; we must relate the value N1 to the composite section by N1&lt;sup&gt;*&lt;/sup&gt; = N1*(A&lt;sub&gt;comp&lt;/sub&gt;/A1).&amp;nbsp;&lt;/p&gt;
&lt;h4&gt;See Also&lt;/h4&gt;
&lt;p&gt;&lt;a title="Elastic compression losses of tendons" href="/products/bridge_design___engineering/w/bridge_design_and_engineering__wiki/elastic-compression-losses-of-tendons.aspx"&gt;Elastic compression losses of tendons&lt;/a&gt;&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;

&lt;div style="font-size: 90%;"&gt;Tags: tendon losses, Prestressed Concrete, Elastic shortening, Elastic compression&lt;/div&gt;
</description></item><item><title>RM Bridge: Elastic compression loss results in structural elements</title><link>https://communities.bentley.com/products/bridge_design___engineering/w/bridge_design_and_engineering__wiki/7765/rm-bridge-elastic-compression-loss-results-in-structural-elements/revision/10</link><pubDate>Mon, 15 Nov 2021 19:29:48 GMT</pubDate><guid isPermaLink="false">6dad98f5-dbc9-4c4d-a9ba-e9da8dc6aa8e:69fc7e26-04c1-4a9e-962b-8ce6988000a2</guid><dc:creator>Ana Carla Peres</dc:creator><comments>https://communities.bentley.com/products/bridge_design___engineering/w/bridge_design_and_engineering__wiki/7765/rm-bridge-elastic-compression-loss-results-in-structural-elements#comments</comments><description>Revision 10 posted to LARS | LEAP | OpenBridge | OpenTunnel | RM Wiki by Ana Carla Peres on 11/15/2021 7:29:48 PM&lt;br /&gt;
&lt;h1&gt;Question&lt;/h1&gt;
&lt;p&gt;Why does elastic compression loss (e.g. loss of pre-stressing in previously grouted tendons due to stressing of further tendons)&amp;nbsp;not appear in internal force results of structural elements?&lt;/p&gt;
&lt;h1&gt;Answer&lt;/h1&gt;
&lt;p&gt;The influence of prestressing losses in previously grouted tendons on the internal forces of the respective structural element is just pretended but in reality not existent when differences between the relevant cross-sections (concrete sections, composite sections) are properly considered. Let us show the relationship on behalf of a concentrically in 2 steps pre-stressed beam (the general validity also for bending, shear, multi-stage stressing is obvious):&lt;/p&gt;
&lt;p&gt;Let us denote:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;N&lt;sub&gt;conc&lt;/sub&gt;&amp;nbsp;&amp;nbsp; Prestressing force first applied on the net concrete section A&lt;sub&gt;conc&lt;/sub&gt;&lt;/li&gt;
&lt;li&gt;N&lt;sub&gt;comp&lt;/sub&gt;&amp;nbsp; Prestressing force later applied on the grouted section A&lt;sub&gt;comp&lt;/sub&gt;&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;In principle, the two forces are related to 2 different cross-section areas and adding them is not allowed. However, in proof checking procedures we generally want to work with summation values applied to one relevant cross-section, normally the relevant composite section after grouting all tendons. I.e. for working with the final composite section A&lt;sub&gt;comp&lt;/sub&gt; we must adjust N1 accordingly.&lt;/p&gt;
&lt;p&gt;Let us look at the concrete stresses after the two steps: &amp;sigma;&lt;sub&gt;c&lt;/sub&gt; = N1/A1 + N&lt;sub&gt;comp&lt;/sub&gt;/A&lt;sub&gt;comp&lt;/sub&gt;. For working with the summation value N = N1+N&lt;sub&gt;comp&lt;/sub&gt; and the composite section A&lt;sub&gt;comp&lt;/sub&gt; we must relate the value N1 to the composite section by N1&lt;sup&gt;*&lt;/sup&gt; = N1*(A&lt;sub&gt;comp&lt;/sub&gt;/A1).&amp;nbsp;&lt;/p&gt;
&lt;h4&gt;See Also&lt;/h4&gt;
&lt;p&gt;&lt;a title="Elastic compression losses of tendons" href="/products/bridge_design___engineering/w/bridge_design_and_engineering__wiki/elastic-compression-losses-of-tendons.aspx"&gt;Elastic compression losses of tendons&lt;/a&gt;&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;

&lt;div style="font-size: 90%;"&gt;Tags: tendon losses, Prestressed Concrete, Elastic shortening, Elastic compression&lt;/div&gt;
</description></item><item><title>RM Bridge: Elastic compression loss results in structural elements</title><link>https://communities.bentley.com/products/bridge_design___engineering/w/bridge_design_and_engineering__wiki/7765/rm-bridge-elastic-compression-loss-results-in-structural-elements/revision/9</link><pubDate>Thu, 22 Jul 2021 15:26:41 GMT</pubDate><guid isPermaLink="false">6dad98f5-dbc9-4c4d-a9ba-e9da8dc6aa8e:69fc7e26-04c1-4a9e-962b-8ce6988000a2</guid><dc:creator>MarcosBeier</dc:creator><comments>https://communities.bentley.com/products/bridge_design___engineering/w/bridge_design_and_engineering__wiki/7765/rm-bridge-elastic-compression-loss-results-in-structural-elements#comments</comments><description>Revision 9 posted to LARS | LEAP | OpenBridge | OpenTunnel | RM Wiki by MarcosBeier on 7/22/2021 3:26:41 PM&lt;br /&gt;
&lt;h1&gt;Question&lt;/h1&gt;
&lt;p&gt;Why does elastic compression loss (e.g. loss of pre-stressing in previously grouted tendons due to stressing of further tendons)&amp;nbsp;not appear in internal force results of structural elements?&lt;/p&gt;
&lt;h1&gt;Answer&lt;/h1&gt;
&lt;p&gt;The influence of prestressing losses in previously grouted tendons on the internal forces of the respective structural element is just pretended but in reality not existent when differences between the relevant cross-sections (concrete sections, composite sections) are properly considered. Let us show the relationship on behalf of a concentrically in 2 steps pre-stressed beam (the general validity also for bending, shear, multi-stage stressing is obvious):&lt;/p&gt;
&lt;p&gt;Let us denote:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;N&lt;sub&gt;conc&lt;/sub&gt;&amp;nbsp;&amp;nbsp; Prestressing force first applied on the net concrete section A&lt;sub&gt;conc&lt;/sub&gt;&lt;/li&gt;
&lt;li&gt;N&lt;sub&gt;comp&lt;/sub&gt;&amp;nbsp; Prestressing force later applied on the grouted section A&lt;sub&gt;comp&lt;/sub&gt;&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;In principle, the two forces are related to 2 different cross-section areas and adding them is not allowed. However, in proof checking procedures we generally want to work with summation values applied to one relevant cross-section, normally the relevant composite section after grouting all tendons. I.e. for working with the final composite section A&lt;sub&gt;comp&lt;/sub&gt; we must adjust N1 accordingly.&lt;/p&gt;
&lt;p&gt;Let us look at the concrete stresses after the two steps: &amp;sigma;&lt;sub&gt;c&lt;/sub&gt; = N1/A1 + N&lt;sub&gt;comp&lt;/sub&gt;/A&lt;sub&gt;comp&lt;/sub&gt;. For working with the summation value N = N1+N&lt;sub&gt;comp&lt;/sub&gt; and the composite section A&lt;sub&gt;comp&lt;/sub&gt; we must relate the value N1 to the composite section by N1&lt;sup&gt;*&lt;/sup&gt; = N1*(A&lt;sub&gt;comp&lt;/sub&gt;/A1).&amp;nbsp;&lt;/p&gt;
&lt;h4&gt;See Also&lt;/h4&gt;
&lt;p&gt;&lt;a title="Elastic compression losses of tendons" href="/products/bridge_design___engineering/w/bridge_design_and_engineering__wiki/elastic-compression-losses-of-tendons.aspx"&gt;Elastic compression losses of tendons&lt;/a&gt;&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;

&lt;div style="font-size: 90%;"&gt;Tags: tendon losses, Prestressed Concrete, Elastic shortening, Elastic compression&lt;/div&gt;
</description></item><item><title>RM Bridge: Elastic compression loss results in structural elements</title><link>https://communities.bentley.com/products/bridge_design___engineering/w/bridge_design_and_engineering__wiki/7765/rm-bridge-elastic-compression-loss-results-in-structural-elements/revision/8</link><pubDate>Tue, 02 Feb 2021 18:39:32 GMT</pubDate><guid isPermaLink="false">6dad98f5-dbc9-4c4d-a9ba-e9da8dc6aa8e:69fc7e26-04c1-4a9e-962b-8ce6988000a2</guid><dc:creator>Ana Carla Peres</dc:creator><comments>https://communities.bentley.com/products/bridge_design___engineering/w/bridge_design_and_engineering__wiki/7765/rm-bridge-elastic-compression-loss-results-in-structural-elements#comments</comments><description>Revision 8 posted to LARS | LEAP | OpenBridge | OpenTunnel | RM Wiki by Ana Carla Peres on 2/2/2021 6:39:32 PM&lt;br /&gt;
&lt;h1&gt;Question&lt;/h1&gt;
&lt;p&gt;Why does elastic compression loss (e.g. loss of pre-stressing in previously grouted tendons due to stressing of further tendons)&amp;nbsp;not appear in internal force results of structural elements?&lt;/p&gt;
&lt;h1&gt;Answer&lt;/h1&gt;
&lt;p&gt;The influence of prestressing losses in previously grouted tendons on the internal forces of the respective structural element is just pretended but in reality not existent when differences between the relevant cross-sections (concrete sections, composite sections) are properly considered. Let us show the relationship on behalf of a concentrically in 2 steps pre-stressed beam (the general validity also for bending, shear, multi-stage stressing is obvious):&lt;/p&gt;
&lt;p&gt;Let us denote:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;N&lt;sub&gt;conc&lt;/sub&gt;&amp;nbsp;&amp;nbsp; Prestressing force first applied on the net concrete section A&lt;sub&gt;conc&lt;/sub&gt;&lt;/li&gt;
&lt;li&gt;N&lt;sub&gt;comp&lt;/sub&gt;&amp;nbsp; Prestressing force later applied on the grouted section A&lt;sub&gt;comp&lt;/sub&gt;&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;In principle, the two forces are related to 2 different cross-section areas and adding them is not allowed. However, in proof checking procedures we generally want to work with summation values applied to one relevant cross-section, normally the relevant composite section after grouting all tendons. I.e. for working with the final composite section A&lt;sub&gt;comp&lt;/sub&gt; we must adjust N1 accordingly.&lt;/p&gt;
&lt;p&gt;Let us look at the concrete stresses after the two steps: &amp;sigma;&lt;sub&gt;c&lt;/sub&gt; = N1/A1 + N&lt;sub&gt;comp&lt;/sub&gt;/A&lt;sub&gt;comp&lt;/sub&gt;. For working with the summation value N = N1+N&lt;sub&gt;comp&lt;/sub&gt; and the composite section A&lt;sub&gt;comp&lt;/sub&gt; we must relate the value N1 to the composite section by N1&lt;sup&gt;*&lt;/sup&gt; = N1*(A&lt;sub&gt;comp&lt;/sub&gt;/A1).&amp;nbsp;&lt;/p&gt;
&lt;h4&gt;See Also&lt;/h4&gt;
&lt;p&gt;&lt;a title="Elastic compression losses of tendons" href="/products/bridge_design___engineering/w/bridge_design_and_engineering__wiki/elastic-compression-losses-of-tendons.aspx"&gt;Elastic compression losses of tendons&lt;/a&gt;&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;

&lt;div style="font-size: 90%;"&gt;Tags: tendon losses, Prestressed Concrete, Elastic shortening, Elastic compression&lt;/div&gt;
</description></item><item><title>RM Bridge: Elastic compression loss results in structural elements</title><link>https://communities.bentley.com/products/bridge_design___engineering/w/bridge_design_and_engineering__wiki/7765/rm-bridge-elastic-compression-loss-results-in-structural-elements/revision/7</link><pubDate>Tue, 15 Sep 2020 14:55:49 GMT</pubDate><guid isPermaLink="false">6dad98f5-dbc9-4c4d-a9ba-e9da8dc6aa8e:69fc7e26-04c1-4a9e-962b-8ce6988000a2</guid><dc:creator>MarcosBeier</dc:creator><comments>https://communities.bentley.com/products/bridge_design___engineering/w/bridge_design_and_engineering__wiki/7765/rm-bridge-elastic-compression-loss-results-in-structural-elements#comments</comments><description>Revision 7 posted to LARS | LEAP | OpenBridge | OpenTunnel | RM Wiki by MarcosBeier on 9/15/2020 2:55:49 PM&lt;br /&gt;
&lt;h1&gt;Question&lt;/h1&gt;
&lt;p&gt;Why does elastic compression loss (e.g. loss of pre-stressing in previously grouted tendons due to stressing of further tendons)&amp;nbsp;not appear in internal force results of structural elements?&lt;/p&gt;
&lt;h1&gt;Answer&lt;/h1&gt;
&lt;p&gt;The influence of prestressing losses in previously grouted tendons on the internal forces of the respective structural element is just pretended but in reality not existent when differences between the relevant cross-sections (concrete sections, composite sections) are properly considered. Let us show the relationship on behalf of a concentrically in 2 steps pre-stressed beam (the general validity also for bending, shear, multi-stage stressing is obvious):&lt;/p&gt;
&lt;p&gt;Let us denote:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;N&lt;sub&gt;conc&lt;/sub&gt;&amp;nbsp;&amp;nbsp; Prestressing force first applied on the net concrete section A&lt;sub&gt;conc&lt;/sub&gt;&lt;/li&gt;
&lt;li&gt;N&lt;sub&gt;comp&lt;/sub&gt;&amp;nbsp; Prestressing force later applied on the grouted section A&lt;sub&gt;comp&lt;/sub&gt;&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;In principle, the two forces are related to 2 different cross-section areas and adding them is not allowed. However, in proof checking procedures we generally want to work with summation values applied to one relevant cross-section, normally the relevant composite section after grouting all tendons. I.e. for working with the final composite section A&lt;sub&gt;comp&lt;/sub&gt; we must adjust N1 accordingly.&lt;/p&gt;
&lt;p&gt;Let us look at the concrete stresses after the two steps: &amp;sigma;&lt;sub&gt;c&lt;/sub&gt; = N1/A1 + N&lt;sub&gt;comp&lt;/sub&gt;/A&lt;sub&gt;comp&lt;/sub&gt;. For working with the summation value N = N1+N&lt;sub&gt;comp&lt;/sub&gt; and the composite section A&lt;sub&gt;comp&lt;/sub&gt; we must relate the value N1 to the composite section by N1&lt;sup&gt;*&lt;/sup&gt; = N1*(A&lt;sub&gt;comp&lt;/sub&gt;/A1).&amp;nbsp;&lt;/p&gt;
&lt;h4&gt;See Also&lt;/h4&gt;
&lt;p&gt;&lt;a title="Elastic compression losses of tendons" href="/products/bridge_design___engineering/w/bridge_design_and_engineering__wiki/elastic-compression-losses-of-tendons.aspx"&gt;Elastic compression losses of tendons&lt;/a&gt;&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;

&lt;div style="font-size: 90%;"&gt;Tags: tendon losses, Prestressed Concrete, Elastic shortening, Elastic compression&lt;/div&gt;
</description></item><item><title>Elastic compression loss results in structural elements</title><link>https://communities.bentley.com/products/bridge_design___engineering/w/bridge_design_and_engineering__wiki/7765/rm-bridge-elastic-compression-loss-results-in-structural-elements/revision/6</link><pubDate>Mon, 14 Sep 2020 17:12:50 GMT</pubDate><guid isPermaLink="false">6dad98f5-dbc9-4c4d-a9ba-e9da8dc6aa8e:69fc7e26-04c1-4a9e-962b-8ce6988000a2</guid><dc:creator>MarcosBeier</dc:creator><comments>https://communities.bentley.com/products/bridge_design___engineering/w/bridge_design_and_engineering__wiki/7765/rm-bridge-elastic-compression-loss-results-in-structural-elements#comments</comments><description>Revision 6 posted to LARS | LEAP | OpenBridge | OpenTunnel | RM Wiki by MarcosBeier on 9/14/2020 5:12:50 PM&lt;br /&gt;
&lt;h1&gt;Question&lt;/h1&gt;
&lt;p&gt;Why does elastic compression loss (e.g. loss of pre-stressing in previously grouted tendons due to stressing of further tendons)&amp;nbsp;not appear in internal force results of structural elements?&lt;/p&gt;
&lt;h1&gt;Answer&lt;/h1&gt;
&lt;p&gt;The influence of prestressing losses in previously grouted tendons on the internal forces of the respective structural element is just pretended but in reality not existent when differences between the relevant cross-sections (concrete sections, composite sections) are properly considered. Let us show the relationship on behalf of a concentrically in 2 steps pre-stressed beam (the general validity also for bending, shear, multi-stage stressing is obvious):&lt;/p&gt;
&lt;p&gt;Let us denote:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;N&lt;sub&gt;conc&lt;/sub&gt;&amp;nbsp;&amp;nbsp; Prestressing force first applied on the net concrete section A&lt;sub&gt;conc&lt;/sub&gt;&lt;/li&gt;
&lt;li&gt;N&lt;sub&gt;comp&lt;/sub&gt;&amp;nbsp; Prestressing force later applied on the grouted section A&lt;sub&gt;comp&lt;/sub&gt;&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;In principle, the two forces are related to 2 different cross-section areas and adding them is not allowed. However, in proof checking procedures we generally want to work with summation values applied to one relevant cross-section, normally the relevant composite section after grouting all tendons. I.e. for working with the final composite section A&lt;sub&gt;comp&lt;/sub&gt; we must adjust N1 accordingly.&lt;/p&gt;
&lt;p&gt;Let us look at the concrete stresses after the two steps: &amp;sigma;&lt;sub&gt;c&lt;/sub&gt; = N1/A1 + N&lt;sub&gt;comp&lt;/sub&gt;/A&lt;sub&gt;comp&lt;/sub&gt;. For working with the summation value N = N1+N&lt;sub&gt;comp&lt;/sub&gt; and the composite section A&lt;sub&gt;comp&lt;/sub&gt; we must relate the value N1 to the composite section by N1&lt;sup&gt;*&lt;/sup&gt; = N1*(A&lt;sub&gt;comp&lt;/sub&gt;/A1).&amp;nbsp;&lt;/p&gt;
&lt;h4&gt;See Also&lt;/h4&gt;
&lt;p&gt;&lt;a title="Elastic compression losses of tendons" href="/products/bridge_design___engineering/w/bridge_design_and_engineering__wiki/elastic-compression-losses-of-tendons.aspx"&gt;Elastic compression losses of tendons&lt;/a&gt;&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;

&lt;div style="font-size: 90%;"&gt;Tags: tendon losses, Prestressed Concrete, Elastic shortening, Elastic compression&lt;/div&gt;
</description></item><item><title>Elastic compression loss results in structural elements</title><link>https://communities.bentley.com/products/bridge_design___engineering/w/bridge_design_and_engineering__wiki/7765/rm-bridge-elastic-compression-loss-results-in-structural-elements/revision/5</link><pubDate>Mon, 22 Sep 2014 11:42:29 GMT</pubDate><guid isPermaLink="false">6dad98f5-dbc9-4c4d-a9ba-e9da8dc6aa8e:69fc7e26-04c1-4a9e-962b-8ce6988000a2</guid><dc:creator>Diether</dc:creator><comments>https://communities.bentley.com/products/bridge_design___engineering/w/bridge_design_and_engineering__wiki/7765/rm-bridge-elastic-compression-loss-results-in-structural-elements#comments</comments><description>Revision 5 posted to LARS | LEAP | OpenBridge | OpenTunnel | RM Wiki by Diether on 9/22/2014 11:42:29 AM&lt;br /&gt;
&lt;h1&gt;Question&lt;/h1&gt;
&lt;p&gt;Why does elastic compression loss (e.g. loss of pre-stressing in previously grouted tendons due to stressing of further tendons)&amp;nbsp;not appear in internal force results of structural elements?&lt;/p&gt;
&lt;h1&gt;Answer&lt;/h1&gt;
&lt;p&gt;The influence of prestressing losses in previously grouted tendons on the internal forces of the respective structural element is just pretended but in reality not existent when differences between the relevant cross-sections (concrete sections, composite sections) are properly considered. Let us show the relationship on behalf of a concentrically in 2 steps pre-stressed beam (the general validity also for bending, shear, multi-stage stressing is obvious):&lt;/p&gt;
&lt;p&gt;Let us denote:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;N&lt;sub&gt;conc&lt;/sub&gt;&amp;nbsp;&amp;nbsp; Prestressing force first applied on the net concrete section A&lt;sub&gt;conc&lt;/sub&gt;&lt;/li&gt;
&lt;li&gt;N&lt;sub&gt;comp&lt;/sub&gt;&amp;nbsp; Prestressing force later applied on the grouted section A&lt;sub&gt;comp&lt;/sub&gt;&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;In principle, the two forces are related to 2 different cross-section areas and adding them is not allowed. However, in proof checking procedures we generally want to work with summation values applied to one relevant cross-section, normally the relevant composite section after grouting all tendons. I.e. for working with the final composite section A&lt;sub&gt;comp&lt;/sub&gt; we must adjust N1 accordingly.&lt;/p&gt;
&lt;p&gt;Let us look at the concrete stresses after the two steps: &amp;sigma;&lt;sub&gt;c&lt;/sub&gt; = N1/A1 + N&lt;sub&gt;comp&lt;/sub&gt;/A&lt;sub&gt;comp&lt;/sub&gt;. For working with the summation value N = N1+N&lt;sub&gt;comp&lt;/sub&gt; and the composite section A&lt;sub&gt;comp&lt;/sub&gt; we must relate the value N1 to the composite section by N1&lt;sup&gt;*&lt;/sup&gt; = N1*(A&lt;sub&gt;comp&lt;/sub&gt;/A1).&amp;nbsp;&lt;/p&gt;
&lt;h4&gt;See Also&lt;/h4&gt;
&lt;p&gt;&lt;a title="Elastic compression losses of tendons" href="/products/bridge_design___engineering/w/bridge_design_and_engineering__wiki/elastic-compression-losses-of-tendons.aspx"&gt;Elastic compression losses of tendons&lt;/a&gt;&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;

&lt;div style="font-size: 90%;"&gt;Tags: tendon losses, Prestressed Concrete, Elastic shortening, Elastic compression&lt;/div&gt;
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