# Ground-Borne Vibration Due to Construction Works with Respect to Brownfield Areas
## 3 Experimental Setup and Results of SEISMIC Measurements
### Interpretation of the Measured Data with Respect to Historical and Decaying or Dilapidated Objects  
The standard in [26] was used for the theoretical study of possible seismic loading of historical and decaying or dilapidated buildings. The assessment of the technical seismicity, with the exception of the blasting response, is carried out according to the table entitled \"Effective velocity limit values v\({}_{\text{eff}}\) (mm\(\cdot\)s\({}^{-1}\)) of the given standard\" [35]. An effective value is the statistical value that determines the magnitude of the variable, that is, the velocity of the oscillation. We calculate it as the ratio of the maximum measured vibration amplitudes and the square root of the two. The response to the technical seismicity load is generally judged by the value of the effective oscillation velocity at the reference station, i.e., at the lowest floor of the building or its base/foundations. If values less than those according to [35] are measured at the reference station, it is not necessary to further assess the design for damage in terms of load capability. For assessment based on a given standard, a building object must be classified into the class of importance and the class of resistance (durability). According to the class meanings [35], the objects are divided into four classes, namely U, L, II, and III. Class U (v\({}_{\text{eff}}\) from 0.2 to 1.5 mm\(\cdot\)s\({}^{-1}\)) is designated as objects of an exceptional economic nature and/or social significance, Class I (v\({}_{\text{eff}}\) from 0.4 to 3 mm\(\cdot\)s\({}^{-1}\)) is of great importance, Class II (v\({}_{\text{eff}}\) from 0.7 to 4 mm\(\cdot\)s\({}^{-1}\)) is of medium importance, and Class III (v\({}_{\text{eff}}\) from 1.1 to 5 mm\(\cdot\)s\({}^{-1}\)) is designated as objects of limited importance. According to the classes of resistance, the objects are divided into 6 classes: (A) objects most prone to damage, which do not correspond to today's building regulations, e.g., historical monuments; (B) ordinary brick structures; (C) large brick and breezeblock buildings, stone bridges, stone tiling of underground structures; (D) buildings with steel or wooden skeletons/frames, stone bridge supports, brick and breezeblock pavements, cast iron pipes; (E) steel reinforced concrete and steel structures, steel reinforced concrete engineering networks, concrete monolithic structures of underground structures, coil and coaxial communication cables; (F) the most resilient objects, steel reinforced concrete and steel lining of tunnels, shelters for civil defense, and steel pipelines. The individual classes of resistance are further subdivided into four subgroups (residential, civil, industrial and agricultural objects; engineering objects; underground structures; and underground engineering networks and cables). From the above list, objects located in brownfield areas can be classified into resistance classes A, B, C or D. With respect to the class of significance of these objects, we can consider all classes, starting with the U class (0.2 for class of resistance A, 0.4 for B, 0.7 for C and 0.9 mm\(\cdot\)s\({}^{-1}\) for D) for objects that are already included in the list of protected monuments and ending in class III (1.1; 1.8; 2.8; \begin{table}
\begin{tabular}{c c c} \hline
**Vibration Source** & **Dominant Component (Hz)** & **Bandwidth (Hz)** \\ \hline Vibrated gravel piles & 48 & 40–60 \\ Sheet piles & 15 & 9–19 \\ First stage of compaction & 21 & 16–28 \\ Second stage of compaction & 28 & 18–38 \\ \hline \end{tabular}
\end{table} 
Table 1: Summary of the obtained frequencies from the presented sources of vibration. 3.5 mm\(\cdot\)s\({}^{-1}\)), which can be, for example, objects destined or intended for controlled demolition. This range of effective velocity limit values is displayed in Figure 13.  
In the Czech standard [35], the vibrations with the character of a longer-lasting impact load or steady periodic load are judged by their effective values.