<story><title>The problem with reinforced concrete (2016)</title><url>https://theconversation.com/the-problem-with-reinforced-concrete-56078</url></story><parent_chain><item><author>nerdponx</author><text>&amp;gt; The present value of a building that lasts 50 years is not that much different that the same one that lasts 100 years.&lt;p&gt;That&amp;#x27;s a problem in and of itself, IMO. Construction is tremendously resource-intensive. We should not be building &amp;quot;throwaway&amp;quot; buildings.</text></item><item><author>idoh</author><text>I don&amp;#x27;t know if it is really a problem, more like a tradeoff. Reinforced concrete costs less and enables shapes that are impossible without it, with the downside that the buildings last 50 years instead of 100+ years. The present value of a building that lasts 50 years is not that much different that the same one that lasts 100 years.&lt;p&gt;With that in mind, it makes perfect sense to make an office building out of reinforced concrete.</text></item></parent_chain><comment><author>hackeraccount</author><text>That&amp;#x27;s a bit like the one horse shay.  It&amp;#x27;s not how long it  lasts but what are the costs associated with it lasting any given length of time.  Nothing lasts forever but say buildings lasted 500 years - Suddenly 500 years from now all buildings have to be replaced?  And what&amp;#x27;s the cost of this 500 year building?  Is it 10 times as much?  Or is it 5 times as much?&lt;p&gt;Saying we shouldn&amp;#x27;t have buildings that only last 50 years but rather they should last 500 is like saying they shouldn&amp;#x27;t last 50 years but instead 5.  Maybe.  Maybe 5 makes sense.&lt;p&gt;My assumption would be - shocker - it&amp;#x27;s probably a complicated trade off that&amp;#x27;s best adjudicated by the people with the most skin in the particular game.</text></comment>
<story><title>The problem with reinforced concrete (2016)</title><url>https://theconversation.com/the-problem-with-reinforced-concrete-56078</url></story><parent_chain><item><author>nerdponx</author><text>&amp;gt; The present value of a building that lasts 50 years is not that much different that the same one that lasts 100 years.&lt;p&gt;That&amp;#x27;s a problem in and of itself, IMO. Construction is tremendously resource-intensive. We should not be building &amp;quot;throwaway&amp;quot; buildings.</text></item><item><author>idoh</author><text>I don&amp;#x27;t know if it is really a problem, more like a tradeoff. Reinforced concrete costs less and enables shapes that are impossible without it, with the downside that the buildings last 50 years instead of 100+ years. The present value of a building that lasts 50 years is not that much different that the same one that lasts 100 years.&lt;p&gt;With that in mind, it makes perfect sense to make an office building out of reinforced concrete.</text></item></parent_chain><comment><author>idoh</author><text>A - The concept of present value isn&amp;#x27;t a problem, it&amp;#x27;s more like a fact, derived from the time value of money. It&amp;#x27;s like saying gravity is a problem.&lt;p&gt;B - Construction is resource intensive, no doubt about it. Without this technique the costs and resources would go up, double?, more? Many structures we take for granted, like freeway overpasses, would be impossibly expensive.</text></comment>