## 1 Introduction
### Two Major Objectives  
The Eurocodes, as well as several other codes, have two major deficiencies: complexity and inaccuracy regarding the target reliability. This proposal particularly addresses these two issues.  
Most current codes are partial safety factor codes with dissimilar load factors, \(\gamma_{G}\
eq\gamma_{Q}\), in the Eurocodes, \(\gamma_{G}=1.35\) and \(\gamma_{Q}=1.5\). This is a major reason for the complexity of the codes. The design value codes \(\gamma_{G}=\gamma_{Q}=1\) are the simplest, but it has not been proposed here, as the partial safety factor concept is widely implemented. This proposal is based on partial safety factor codes with equal load factors, \(\gamma_{G}=\gamma_{Q}\). It simplifies the codes and decreases the calculation work. The load tables of such codes are the same as the design value codes, and the codes with equal load factors, \(\gamma_{L}=\gamma_{G}=\gamma_{Q}\), can easily be converted into the design value codes, \(\gamma_{G}=\gamma_{Q}=1\), by altering the material safety factors (\(\gamma_{M}\)) as  
\[\gamma_{M}=\gamma_{L}\gamma_{M} \tag{2}\]  
where \(\gamma_{M}\) is the new material safety factor for the design value codes, i.e., it is the allowable stress and that \(\gamma_{L}\) is the load factor.  
In the Eurocodes, the load factors can be set as the same using the reasoning below:  
The basic design equation of the current Eurocodes [1] is  
\[1.35G+1.5Q\leq\frac{M}{\gamma_{M}} \tag{3}\]  
The variable load safety factor is multiplied and divided by 1.35.  
\[1.35G+1.35\frac{1.5}{1.35}Q\leq\frac{M}{\gamma_{M}} \tag{4}\]  
A new variable load \(Q_{u}\)  
\[Q_{u}=\frac{1.5}{1.35}Q \tag{5}\]is defined, i.e., it is 11% higher than the present one. Assuming Gumbel distribution and the coefficient of the variation \(V_{Q}=0.4\), the characteristic load of \(Q_{u}\) is the 103-year return load, while \(Q\) has a characteristic load of the 50-year return load.  
Thus, the new design equation with \(\gamma_{G}=\gamma_{Q}\) is obtained by replacing \(Q\) with \(Q_{u}\).  
\[1.35G+1.35Q_{u}\leq\frac{M}{\gamma_{M}} \tag{6}\]  
This equation always presents the same outcome as Equation (3) and can be simplified further by dividing by 1.35, with the same outcome as Equation (3) in most cases  
\[G+Q_{u}\leq\frac{M}{1.35\gamma_{M}}, \tag{7}\]  
when the design value equation is obtained. The reliability calculation of Equations (3), (6) and (7) are different. Thus, this subject is tackled in detail here.  
The codes proposed here are based on the partial safety factors. However, as the load factors are the same \(\gamma_{G}=\gamma_{Q}\), the codes can easily be changed to allowable stress codes.  
The Eurocodes may include considerable safe and unsafe design cases [14; 19] with a variability ratio of about 1.4. The inaccuracy arises mainly from four reasons.  
1. The characteristic load of the variable load is fixed; it is the 0.98-fractile of the one-year distribution, which induces excess safety for loads with low variation.
2. The loads are combined independently, which demands considerably different material safety factors in various permanent-variable load ratios.
3. The current safety factor setting procedure induces large variability, as constraints for big errors are missing.
4. The current safety factors are calculated indirectly using the reliability index as a reference, which induces extra error [18].  
The authors of [13] have explained that the loads should be combined dependently, which is applied here. The dependent load combination is safe regarding the independent combination as it results in about 10% higher safety factors.  
In this proposal, the characteristic load of the variable load is set as adaptable. It reduces the inaccuracy considerably, especially the excess safety and the material waste generated is reduced. This amendment does not increase the design work nor complicate the codes. The code writer only must do a little extra work in setting each variable load with its own characteristic load.