MAX, MIN, and ALL are output for a specific Load Combination. – MIDAS Support

Question

MAX, MIN, and ALL are output for a specific Load Combination.

Answer

MAX, MIN, ALL are output when the type of Load Combination is 'Envelope Type'.

In load combination type there are four different types.

[Results] tab > [Combination] group > [Load Combination]

The combination methods for each type are as follows:

1. Add Type : Linear combination of analysis results
→ L1 + L2 + ... + M1 + M2 + ... + S1 + S2 + ...+ R1 + R2 + ... + T + LCB1 + LCB2 + ... + ENV1 + ENV2 + ...

2. Envelope Type : The maximum (max), minimum (min), and maximum absolute values for each analysis result. Those are applicable only in the General tab.
→ CBmax : Max(L1, L2, ..., M1, M2, ..., S1, S2, ...,R1, R2, ..., T, LCB1, LCB2, ..., ENV1, ENV2, ...)
→ CBmin : Min(L1, L2, ..., M1, M2, ..., S1, S2, ...,R1, R2, ..., T, LCB1, LCB2, ..., ENV1, ENV2, ...)
→ CBall : Max(|L1|, |L2|, ..., |M1|, |M2|, ..., |S1|, |S2|, ..., |R1|, |R2|, ..., |T|, |LCB1|, |LCB2|, ..., |ENV1|, |ENV2|, ...)

3. ABS Type : The sum of the absolute values of analysis results
→ |L1| +| L2|+ ... + |M1| + |M2| + ... + |S1| + |S2| + ...+ |R1| + |R2| + ...+ |LCB1| + |LCB2| + ... + |ENV1| + |ENV2| + ...

4. SRSS Type : SRSS(Square Root of Sum. of the Squares) combination of analysis results
→ (L12 +L22 +...+M12 +M22 +...+S12 +S22 +...+R12 +R22 +...+T2 +LCB12 +LCB22 +...+ ENV12 +ENV22 +...)1/2

Where,
L : Analysis results for static unit load condition × load factor
M : Analysis results for moving load condition × load factor
S : Analysis results for settlement condition × load factor
R : Analysis results for Response Spectrum condition × load factor
T : Analysis results for time history analysis condition × load factor
LCB : Analysis results for pre-defined load combination condition × load factor
ENV : The analysis result for the pre-defined Envelope condition × load factor

To understand the 'Envelope Type' more easily, let's compare it with the 'Add Type'. Simply, the 'Add Type' linearly combines Load Cases as shown on the left side of the image below, resulting in a single value at a specific point. On the other hand, the 'Envelope Type', shown on the right side of the image below, overlaps the graphs of each Load Case to obtain the maximum value (MAX), minimum value (MIN), and maximum absolute value (ALL) at a specific point.

Therefore, only the 'Envelope Type' among the four load combination types outputs MAX, MIN, and ALL values. However, if a load combination includes an Envelope Type Load Combination as one of the load combinations in it, it outputs MAX, MIN, and ALL values.

In addition, if moving load, settlement, or time history analysis, which consider various cases, are included within the Load Combination, the MAX, MIN, and ALL values will be outputted even if they are not of Envelope Type. This is because these analyses already calculate the Envelope results.