Jl

c OEI

2EI/lo2N -1

In many cases it is reasonable to assume that the second order moment has a sine shaped distribution. This corresponds to C2 = n2, and M2 can then be written m2 =m 0

where Nb = nominal buckling load (based on nominal stiffness).

p = n2/co, parameter taking into account the distribution of first order moment

The total moment will be

which corresponds to equation (5.28) in 5.8.7.

5.8.7.2 Moment distribution

In some cases the value of Co is known, as in the examples mentioned in 5.8.7.3 (2).

The case of differing end moments will be examined more closely. A reference is made to 5.8.8.2 (2), with the well-known formula for an equivalent constant first order moment:

This is illustrated in figure 5.29.

Figure 5.29. Illustration of equivalent moments in case of differing end moments

Equivalent total moment

Equivalent 1st order moment

Figure 5.29. Illustration of equivalent moments in case of differing end moments

Equation (7-4) can be used with the equivalent first order moment according to (7-5) also. An example of the result is shown in figure 7-2, where two different 0 values were used: 8 and 10 respectively.

MnwfMn

0 0

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