# Comparison of Condition Rating Systems for Bridges in Three European Countries
## 3 Slovakia
### The Load-Carrying Capacity of Road Bridges (LCC)  
Load-carrying capacity (\(LCC\)) is one of the most important parameters of bridge reliability. The load-carrying capacity of the bridge on highways and roads of categories I, II. and III. and local roads are defined by the heaviest possible weight of one vehicle that can be allowed to pass the bridge under the conditions specified in the [18]. The \(LCC\) is determined as the lowest value of the \(LCC\) for the crucial element of the superstructure and substructure of the bridge. It should be provided exclusively by a detailed structural analysis. But for concrete and composite bridges (steel, concrete) it is possible to use an alternative combined structural analysis. It is indicated in the \(LCC\) analysis according to the applied method as follows:  
* V--load-carrying capacity determined by detailed structural analysis;
* K--load-carrying capacity determined by a combined procedure, i.e., by a detailed structural analysis based on the standard rules provided by the original standards (codes from the date of design). The \(V\) method is dominantly preferred for all types of structures. However, in the case of insufficient data from the inspection or diagnostic survey, the \(K\) method can be applied. In Slovakia, three categories of the \(LCC\) are used depending on the load types as follows:  
* Normal \(LCC\)--\(V_{n}\);
* Exclusive \(LCC\)--\(V_{r}\);
* Exceptional \(LCC\)--\(V_{e}\). \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Class** & **State** & **Description** & **LCC Factor** \\ \hline I. & Flawless & Without any hidden or obvious defects. & 1.00 \\ II. & Very good & The occurrence of only appearance defects that do not affect the load-carrying capacity & 1.00 \\ III. & Good & The occurrence of larger faults that do not affect the load-carrying capacity of the bridge. & 1.00 \\ IV. & Satisfactory & The occurrence of faults that do not have an immediate effect on the load-carrying & 0.80 \\ V. & Bad & The occurrence of faults that have an adverse effect on the load-carrying capacity of the bridge, but can be removed without replacing the faulty parts. & 0.60 \\ VI. & Very bad & The occurrence of faults that affect the load-carrying capacity and cannot be removed & 0.40 \\ VII. & Emergency & The occurrence of faults that affect the load-carrying capacity of the bridge to such an extent that require immediate remedial action to avert impending disaster. & 0.20 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Slovak condition rating system for road bridges based on the extent of the failures [16]. Exceptional \(LCC\) has been defined only for the selected highways and roads of higher categories. Each of the \(LCC\) categories is the function of \(F_{z}\), which is the load factor, that can be determined as follows:  
\[F_{z}=\left(R_{d}\ -\sum_{i=1}^{n-1}E_{rs,Ed,i}\right)\bigg{/}E_{n,(r),(e),Ed}\ [ \text{dimensionless}] \tag{1}\]  
where: \(Rd\) is the design resistance of the element; \(E_{n,(r),(e),Ed}\) is the design value of the live load vertical effects, represented by the appropriate load category for \(V_{n}\), \(V_{r}\) and \(V_{e}\); \(\sum_{i=1}^{n-1}E_{rs,Ed,i}\) are the design, combination, or group values of the other permanent load effects, which are simultaneously acting with the vertical live load effect. For the Normal \(LCC\), the load model LM1 according to the _STN EN 1991-2_[19] is applied as a value of \(E_{n,Ed}\). In the case of the Exclusive \(LCC\), the special load model of the heavy vehicle (900/150 kN) multiplied by the dynamic factor (\(\varphi=1.40\ -L/500\); \(\varphi\geq 1.0\); \(L\) is affected length in [m]) according to the _STN EN 1991-2_ (see Figure 3) is used as a value of \(E_{r,Ed}\), whereas for the Exceptional \(LCC\), the load model LM3 (3000/240 kN) in compliance with _STN EN 1991-2_ is employed as a value of \(E_{e,Ed}\). The load factor \(Fz\) corresponds with the \(LCC\) factor.