**3. Structural monitoring systems installed at L'Aquila**

Before the 2009 L'Aquila earthquake a strong network of seismic accelerometers were func‐ tioning close to the epicenter, mostly managed by the Italian Institute of Geophysics and Volcanology (INGV) [15], while very few structure were equipped by a permanent structural monitoring managed by Department of Civil Protection (DPC) [16] (see, also, Table 3). In particular, the response of the Pizzoli Town Hall during the main shock has been recorded and analyzed by DPC, giving special insights on the potentiality of these systems for immediate evaluation of the damaged occurred during an earthquake. The large amount of installed, temporally or permanently, devices of different type (accelerometers, smart wireless devices, displacement and velocity transducers, inclinometers, etc) reach a number of around three hundred (300) evidencing a large impact of this technology in the post-earthquake emergency phase, especially during the earthquake swarms. In particular several monitoring systems have been installed in the emergency phase, during the construction of temporary scaffolding, in order to verify the efficacy of the added structural system especially in the case of monu‐ mental building (see for example [17]). Because of this scope, in many cases, the permanent monitoring has worked only for a limited number of months (in the Table 3, the period is not always precisely known to the author and sometimes it should be considered indicative). In other cases, the monitoring system is permanently installed on the structure and it can be used also to determine the change that will occur in the structural behavior during the reconstruc‐ tion phase [8,9].

In several cases, the structural monitoring system uses only accelerometers, starting from very few measures (three channels in the minor case) to larger number of devices with different characteristics and sensitivity. Instead more complex monitoring systems are used in complex monumental churches and buildings where accelerometers are joined with crackmeters, inclinometers, and temperature measurement devices, etc.

coupling has been examined. Several studies have been devoted to optimize the dynamic performance of slender structures, such as skyscrapers or tall buildings, introducing dissipa‐ tion systems acting on the relative motion and aiming to reduce the maximum displacements at the higher floors. Different applications of similar concepts have been applied in the retrofitting of existing adjacent structures. The placements of viscous-type coupling devices into seismic joints have been proposed to dissipate energy and to avoid hammering phenom‐ ena [18-21]. In all cases "smart" coupling between adjacent structures has been exploited using passive, semi-active, and active control systems with different features and performances.

Forte Spagnolo Monumetal building UNIPAD/Town Council Masonry 5 months 8+6 8 monoaxial 0

concrete

building UNIVAQ/Town Council Masonry Currently

Pizzoli Town Hall Building DPC/Town Council Masonry Currently

**Building type Developer/Owner**

Building DPC/Town Council Reinforced

School: Auditorium DPC/Town Council Reinforced

DPC/Town Council Reinforced

Anime Sante Monumental church IUAV/Town Council Masonry 24 months 20+8 16 monoaxial +

Duomo Monumental church Private/Town Council Masonry daily 4+8 8 monoaxial 4 S. Biagio D'Amiterno Church Monumental church UNIPAD/Town Council Masonry 2 months 6+10 6 monoaxial 0 S. Marco Church Monumental church UNIPAD/Town Council Masonry 2 months 6+10 6 monoaxial 0 S. Agostino Church Monumental church UNIPAD/Town Council Masonry 2 months 16+10 16 monoaxial 0 S. Silvestro Church Monumental church UNIPAD/Town Council Masonry 24 months 11+8 8 monoaxial 0

**Prevalent structural material**

Advanced Applications in the Field of Structural Control and Health Monitoring After the 2009 L'Aquila Earthquake

building UNIVAQ/Town Council Masonry daily <sup>8</sup> 8 monoaxial 0

building UNIVAQ/UNIVAQ Masonry 12 months 2+2 2 triaxial 2

Currently

Navelli Town Hall Building DPC/Town Council Reinforced

Reiss-Romoli (AQ) Building DPC/Private Reinforced

(AQ) Building DPC/Town Council Reinforced

S. Maria di Collemaggio Monumental church UNIVAQ/Town Council Masonry Currently

New Building ANAS Public building ANAS Reinforced

**Table 3.** Examples of structural monitoring systems installed at L'Aquila

Finance Police School: Sport Palace

Pianola Sports Ground

Coppito (AQ) Finance Police

Palazzo Margherita Monumental

Palazzo Camponeschi Monumental

Scuola De Amicis Monumental

Coppito (AQ)

**MONITORED STRUCTURE**

School San Demetrio ne Vestini

working 17 17 monoaxial 0

**Number of Accelerometers**

http://dx.doi.org/10.5772/55438

**Number of wireless devices**

213

working 12+22 12 monoaxial 0

working 16+11 16 triaxial 27

working <sup>12</sup> 6 biaxial +

2 biaxial <sup>3</sup>

4 triaxial <sup>8</sup>

6 triaxial 0

concrete 2 months 4 4 triaxial 4

**Overall number of measurment devices**

**Monitoring time interval** 

concrete 2 months 1 1 triaxial 1

concrete 2 months 1 1 triaxial 1

concrete 2 months 1 1 triaxial 1

concrete 2 months 1 1 triaxial 1

concrete 2 months 3 1 triaxial +

Focusing the attention on the passive coupling of adjacent structures, different modelling approaches have been used. The synthetic description of the main problem features through a pair of simple oscillators interconnected by means of a springs and dashpot in series or parallel fashion has been proposed by many authors [22-25]. The use of a simple oscillator pair has been pursued by the research group of L'Aquila both for the proposal of a new design method [26-28] and the use of it at the preliminary stage of the design of the more complex
