We know that at the intermediate support of a continuous beam, there will be hogging moment, and so, these three top bars will be in tension. We can see that, there are 3 bars at the top. This section shows the bars at the midspan region. Consider the continuous beam shown in the fig.14.54 below:Ĭonsider the sectional view XX. We will discuss about them with the help of an example. The sub clauses (1) and (2) give the guidelines for this increase. If the concrete cover is below certain specified values, an increase in lap length is required. But the bars which are near the exposed surfaces will be having only limited concrete (which we denote as the concrete cover) on the exposed side. The 'inner bars' of various members will have sufficient concrete all around.
So there must be sufficient 'mass of well compacted concrete' all around the bars. This can be explained as follows: We know that, for the lapped splice to work properly, sufficient bond should develop between steel and concrete. These sub clauses gives us the guidelines for 'increasing the lap length' when the concrete cover provided for the steel bars are below certain specified values. Now, this sub clause in turn, have two sub clauses.
It gives us the guidelines for calculating the lap length. The clause which we are discussing now is the sub clause (c) of 26.2.5.1. These requirements are clearly shown in the fig.14.53 So we have to simultaneously check two parameters and and ensure that they do not fall below required values. should not be less than the largest of.'Total contribution' = 'Straight length' + 8Ф.
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