The Java applet on this page is called Beam Strength. This applet is an analysis program for reinforced concrete beams. It can also be used as a tool for designing reinforced concrete sections. The program can calculate the nominal capacity Mn (capacity at failure) and design capacity Mu (capacity at failure times a reduction factor) of reinforced concrete rectangular, T, L and U beam. The sections can be singly or doubly reinforced (sections with only tensile reinforcement or sections with both tensile and compressive reinforcement). In practice most beams are designed with only tensile reinforcement (singly reinforced). However, in certain situations it might be necessary to design beams with both tensile and compression reinforcement (doubly reinforced). For example, when beam cross section is limited because of architectural or other considerations, it may happen that the concrete cannot develop the compression force required to resist the given bending moment. In some cases if a beam is designed with only tensile reinforcement, the section may become overreinforced, which is neither desirable nor acceptable by most codes of practice, in these situations the section must also be designed as doubly reinforced. There are situations in which compressive reinforcement is used for reasons other than strength. It has been found that inclusion of some compression reinforcement will reduce the long-term deflections of beams. In addition, in some cases, steel will be placed in the compression zone for minimum-moment loading or as stirrup-support bars continuous throughout the beam span. It is often desirable to account for the presence of such reinforcement in flexural design. In practice T, L, and U sections rarely need compression steel for strength reason, and often if this steel is present it is ignored in design. However, the Beam Strength applet is capable of evaluating the strength of T, L, U section with both tensile and compression steel.

Beam strength applet can be run in both US customary, and Metric units (SI units). This is to serve both International and US users.

WHY IS BEAM STRENGTH APPLET DEVELOPED?

Beam Strength applet is developed for the following reasons:

• As an analysis and design tool to aid Structural Engineering community on the Internet.
• As an instructional tool to aid instructors and students of Civil and Structural Engineering.
• As a tool to familiarize International Structural Engineers with the American Concrete Institute code and American concrete design practice.

ASSUMPTIONS

The following assumptions that are adopted by ACI (American Concrete Institute) are used in the analysis of the cross section strength of a beam:

• Ultimate compressive strain in concrete is equal to .003.
• Tensile strength of concrete is ignored.
• Strain varies linearly over the depth of the cross section.
• Steel stress varies linearly until yielding and remains constant beyond yielding.
• Compressive force in the concrete is determined from Whitney's equivalent stress block.