How Do I Fix Development Length (ab) Error?

Under what conditions is a warning given?

1. Condition (a) is not satistified

Condition (a) usually occurs when the width of the wall and/or column on which the beam is supported is small.

Possible Solutions

• wall/column width can be increased

• the diameter of the longitudinal reinforcement can be smaller

• higher strength concrete can be used.

2. Condition (b) is not satistified

Condition (b) usually occurs on the top floor in a cassette floor system with low beam height

Possible Solutions

• beam height can be increased

• the diameter of the longitudinal reinforcement can be smaller

• higher strength concrete can be used.

The development length control is a control at the discretion of the user. When the "Article 7.4.3.1 control" option in the Beam Parameters window is activated, this control is performed for the beams and a warning is given in case of inadequacy.

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At the same time, with v10.82, insufficient clamping length (ab) error can also be seen in the reports.

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The following conditions are given in article 7.4.3.1 (b) of TBDY  .

In cases where the beams joining the column do not continue on the other side of the column, the upper and lower reinforcement on the beams shall be extended to the opposite surface of the core of the column surrounded by stirrups and bent 90 degrees from the inside of the stirrups. In this case, the total length of the horizontal part of the longitudinal reinforcement inside the column and the vertical part bent 90 degrees shall not be less than the straight clamping length lb stipulated in TS 500. The horizontal part of the 90 degree hook shall not be less than 0.4lb and the vertical part shall not be less than 12φ. In shear   walls and   columns with a straight clamping length of more than lb and 50φ, the clamping of the longitudinal reinforcement can be achieved straight without a 90 degree hook.

Possible Solutions

• In the above picture the total length of a + b should be increased. For this, the size of the column or shearwall can be increased in the relevant direction.

• The diameter of the longitudinal reinforcement can be reduced.

• Concrete grade can be upgraded. As the concrete strength increases, the clamping length will decrease.