## 2 Materials and Methods
### Database of Buildings
#### 2.2.3 Building Technical Condition Indicators
The partial least squares regression (PLSR) approach from data mining presented in Section 2 was used to update the generalized damage index formula \(w_{u}\). Taking into account the specificity of the studied buildings, it was found that the description of the generalized damage index \(w_{u}\) for the studied groups of buildings are linear combinations (Table 2) of the damage indices of structural and finishing elements \(w_{ui}\) with the general form of the formula:  
\[\mathbf{w_{u}}=a_{1}w_{u1}+\ldots+a_{n}w_{un} \tag{4}\]  
The formula calculated for large-block buildings does not take into account the values of indicators \(w_{u9}\), \(w_{u20}\), \(w_{u22}\), as contrary to large-panel buildings, they turned out to be insignificant in this group. The \(w_{u}\) values determined for particular buildings fall within the categories of insignificant and moderate. The average rate of technical wear presented in Table 3 and Figure 3 indicates a very similar rate of wear growth between 2002 and 2007 in the group of large-block (by 4.3% over five years) and large-panel buildings (by 4.1% over five years). Between 2007 and 2012, an increase in the rate of consumption growth was recorded in the group of large-block (up to 5.0% over five years) and a decrease in the group of large-panel buildings (down to 3.2% over five years). This situation may be caused by differences in the quality of maintenance of buildings. In the group of large-block buildings, between 2002 and 2007 there was a much higher number of renovations carried out than between 2007 and 2012. This is particularly true for public utility buildings (including schools), which are exposed to accelerated wear due to their operating conditions. In 2002, the average values of the damage intensity index in the compared groups of buildings were similar at the level of \(5.9\div 6.0\%\) (Figure 4). In the group of large-block buildings, a similar rate of increase of the damage index was observed between 2002 and 2012, at the level of \(0.6\div 0.7\%\), while among the large-panel buildings an increase of the index by 1.4% until 2007 and by 0.6% until 2012 was observed. \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline
**Group of Buildings** & \multicolumn{3}{c}{**Large-Block**} & \multicolumn{3}{c}{**Large-Panel**} \\ \hline
**Inventory Year** & **2002** & **2007** & **2012** & **2002** & **2007** & **2012** \\ \hline Average age & 27.8 & 32.8 & 37.8 & 18.6 & 23.6 & 28.6 \\ \hline Average degree of technical wear \(s_{2}\) [\%] & 27.4 & 31.7 & 36.7 & 17.8 & 21.9 & 25.1 \\ \hline Average building damage intensity index \(w_{u}\) [\%] & 6.0 & 6.7 & 7.3 & 5.9 & 7.3 & 7.9 \\ \hline Damage contribution in technical wear(\(w_{u}/s_{2}\)) [\%] & 22\% & 21\% & 20\% & 33\% & 33\% & 31\% \\ \hline Increase in average damage intensity index \(w_{u}\) & - & 0.7 & 0.6 & - & 1.4 & 0.6 \\ between consecutive inventories [\%] & & & & & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Characteristics of the technical condition of the studied groups of buildings. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline
**Group of Buildings** & \multicolumn{3}{c}{**Large-Block**} & \multicolumn{3}{c}{**Large-Panel**} \\ \hline
**Inventory Year** & **2002** & **2007** & **2012** & **2002** & **2007** & **2012** \\ \hline Average age & 27.8 & 32.8 & 37.8 & 18.6 & 23.6 & 28.6 \\ \hline Average degree of technical wear \(s_{2}\) [\%] & 27.4 & 31.7 & 36.7 & 17.8 & 21.9 & 25.1 \\ \hline Average building damage intensity index \(w_{u}\) [\%] & 6.0 & 6.7 & 7  
In case of evaluation of the safety of the structures, the horizontal component of vibration acceleration \(PGA_{H}\) (horizontal peak ground acceleration) or its velocity \(PGV_{H}\) (horizontal peak ground velocity) is generally taken as the basic indicator for evaluating the risk of mining tremors. Therefore, the multiplicity of tremors acting on the building is not taken into account. Such a procedure does not allow evaluation of the influence of tremors on technical wear of a building.