DECISION MAKING TO IDENTIFY SECTION DIMENSIONS THAT PRODUCE ECONOMIC DESIGN FOR REINFORCED CONCRETE BEAMS

Abstract

In our life, it is on accepted fact that one of the most important human activities is decision making. It does not matter what field of activity one belongs to. Whether it is political, military, economic, or technological, decisions have a far-reaching influence on our lives. It also could be said that decision making plays an important role in structural design too. The very purpose of which is to find the best way so that a designer or a decision maker can derive a maximum benefit from the available resources.

In the work here, the aim is to find the dimensions of a rectangular beam which may give minimum cost. That was done by variation of rectangular beam height (h) from maximum height (h_max) –which it is here two or three times the beam width (b) – to the minimum beam height (h_min) which it is here indicated from the ACI-code 318-08 deflection minimum heights requirements tables. During this variation of (h), computer program calculates beam reinforcement and cost. Finally, the reader chooses the height (h) and width (b) that give the minimum cost. This search is restricted by ACI-code 318-08 beam design requirements.

          This work consists of five parts. The first part deals with the economic design of simply supported rectangular beams with different (b/h) ratios for spans ranging from 2.5m to 12.5m.

          The second part deals with the economic design of both fixed ends supported rectangular beams with different (b/h) ratios. The third part deals with the economic design of fixed-pinned ends supported rectangular beams with different (b/h) ratios. The fourth part deals with the economic design of continuous rectangular beams with different (b/h) ratios. The fifth part deals effect of changing the concrete cost Cc to reinforcement cost Cs ratio (i.e. Cs/Cc ratio) and the effect of changing the ratio (b/h) on design results