Improved structural design code

Load combination of permanent and variable loads

“…The uncorrelated combination distribution GQ(x) can be obtained by using dedicated algorithms [2,3,7], the Monte Carlo simulation with two seed numbers, or by using the convolution equation [4,5,6] given by the integral…”

“…Formula (1) can be written in many alternative ways with the same result. If the partial distributions are normal, the uncorrelated combination distribution GQi (x;GQ, GQ) is also normal and the following simple formula can be applied [4,6]:…”

“…The uncorrelated load combination is illustrated in Figure 1. Due to the boundary condition, formulas (5) and (6) are omitted here, so the total combined load is approximately 10 % less than the sum of the actual loads, i.e., a part of the load vanishes.…”

“…This combination may also be called a 'non-simultaneous combination', as the design load values are non-simultaneous and either one or both loads are multiplied with a reduction factor before adding the loads together. The authors have called this combination independent combination in the earlier papers [5,6]  Correlated load combination: In this approach, the two design load values are added together assuming that they occur simultaneously, the Monte Carlo simulation is conducted using one seed number, i.e., the same seed number for both loads. This combination can be characterized as a full combination, as there is no reduction or vanishing.…”

“…This combination can be characterized as a full combination, as there is no reduction or vanishing. The authors have called this combination dependent combination in the earlier papers [5,6] In this paper we propose that, for the appropriate results in the standardized load combination estimation, the permanent load and the main variable load should be combined correlated. In support of this proposal we present and justify the following three arguments.…”