By: Javier Encinas, PE | May 21, 2019
ASDIP CONCRETE is a structural engineering software for design of concrete members. It includes the design of continuous beams based on the latest ACI 318 provisions.
Beam deflections are sometimes overlooked during the design process, affecting the serviceability of the structure. The calculation of deflections involves the consideration of the cracked properties of the section, and the influence of the reinforcing steel. The design process may become time-consuming, since also the long-term deflection effects should be accounted for. This document is a design overview of the deflections calculation of a typical continuous beam using ASDIP CONCRETE.
As an example, consider the concrete continuous beam shown below. It is a two-span beam subject to uniform and concentrated loads. Calculate the deflections and check in what conditions of use it may be acceptable per the ACI.
1.- Enter the geometric dimensions of the beam, as shown above.
2.- Enter the material properties f'c and fy.
3.- Enter the applied loads. In this case the beam supports uniform and concentrated loads. The image below shows that 30% of LL is continuously applied, which affects the long-term deflection calculation. The Detailed tab shows the step-by-step calculations with exposed formulas and references to the ACI code.
Click to enlarge
ASDIP CONCRETE performs the detailed calculation of deflections per load case. The properties of the transformed section include the influence of the reinforcing steel. The long-term deflections are calculated accurately for the specified sustained live load. According to the ACI provisions, this beam is not adequate if it is attached to elements likely to be damaged.
ASDIP CONCRETE includes the design of continuous beams, with multiple options to optimize the design easily. The deflections are calculated accurately, including the long-term deflections due to sustained loads. This example shows that the design can be completed and optimized within minutes.
Javier Encinas, PE
ASDIP Structural Software