ASDIP CONCRETE is a structural engineering software for design of concrete members. The new version 4 of this software was released recently. It includes a new feature called "Beam Design Manager". This post is a brief overview of how it works and how to use it to perform the design in less time and boost your productivity.
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Design of continuous beams
The design of continuous beams may be cumbersome and time-consuming. After defining the loads, it's necessary to perform the beam analysis in order to find the shears and moments along the beam, as well as the support reactions. This task by itself can be complex if done by hand. Once these internal forces are calculated, the next step is to design the reinforcement to provide the required strength. This is actually the design process, a mix of art and science, where the designer must select the bar sizes, lengths, and spacing, to make sure that enough capacity is provided.
Normally a continuous beam will have both positive and negative moments, therefore top and bottom rebars will be required. In addition, the shear requirements need to be checked along the beam, and if necessary, add stirrups wherever they are required. As part of the design, the development length of the rebars must be considered, as well as the spacing limitations established in the code. The image below shows a typical 3-span continuous beam subject to distributed and concentrated loads, and the corresponding shear and moment diagrams.
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Beam Design Manager
The Design Manager is a tool that performs the reinforcement design based on your preferred bar sizes and the generated shear and moment diagrams. The Design Manager will find the required number of bars and the required lengths along the continuous beam to make sure that the bending capacity ratio is less than 1.0. Likewise, it will find the required number of stirrups along the beam to satisfy the shear demand along the beam.
Of course the user could do this from scratch selecting the number of bars and lengths at each span, in a trial-and-error exercise, but this labor would be tedious and time consuming. Instead, the software calculates the required number of specified bars, and calculates the required length based of the moment diagram, and considering the bar development length. Then the designer can complete and fine tune the design easily, with minimum effort. The image below shows the beam capacity in blue after the Design Manager.
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ASDIP CONCRETE generates a beam elevation construction view, showing all rebars and stirrups calculated during the design. It should be noted that this view immediately reflects any change in the input values. The image below shows the rebars of the beam, corresponding to the capacity values shown above.
ASDIP CONCRETE includes the design of multi-span continuous beams. The design of such systems may be completed and optimized within minutes, which otherwise would be very cumbersome and time-consuming. The Beam Design Manager is a new tool that helps to optimize the reinforcement easily.
For engineering background, see the blog post Concrete Continuous Beams: A Structural Design Challenge. For our collection of blog posts about concrete design please visit Structural Concrete Design.
Javier Encinas, PE