**3. Nondestructive testing of bridges**

In the content of this chapter, 10 different bridges that have different type and carrier systems are selected as case studies:


#### **3.1. Historical masonry arch bridges**

Historical structures are identity of the communities. They are not only structures, which contain stone, timber, mortar, etc., they also contain the social culture and this is the biggest difference between the new structures. Almost every person is curious about the past and they want to learn some information of their ancestors. So the easiest way to learn about the past is to examine the historical data and structures. In the last century, people have given more attention to preserve the historical structures. A lot of studies have been carried out for

It is impossible to distinguish deterministic input *uk* from the noise terms *wk*, *vk* in Eq. (11). If the deterministic input term *uk* is modeled by the noise terms *wk*, *vk* the discrete‐time purely

Eq. (14) constitutes the basis for the time‐domain system identification through operational

The modal assurance criterion (MAC) is defined as a scalar constant relating the degree of consistency (linearity) between one modal and another reference modal vector [10] as follows:

> { } { } { }{ }{ }{ }

Æ ÆÆ Æ

where ∅ and ∅ are the modal vectors of *i*th and *j*th for different methods, respectively.

In the content of this chapter, 10 different bridges that have different type and carrier systems

Historical structures are identity of the communities. They are not only structures, which contain stone, timber, mortar, etc., they also contain the social culture and this is the biggest difference between the new structures. Almost every person is curious about the past and they want to learn some information of their ancestors. So the easiest way to learn about the past is

Æ Æ

*MAC*

**3. Nondestructive testing of bridges**

are selected as case studies:

**•** Steel bridges (Eynel)

**•** Base isolated bridge (Gülburnu)

**•** Old riveted bridges (Borçka)

**3.1. Historical masonry arch bridges**

**•** Footbridges (Ortahisar and Akçaabat)

=

**•** Historical masonry arch bridges (Osmanlı, Mikron, and Şenyuva)

**•** Long span concrete highway bridges (Kömürhan and Birecik)

<sup>2</sup> *<sup>T</sup> ai ej T T ai ai ej ej*

= + (14)

(15)

*k kk* 1 *k kk x Ax w y Cx v* <sup>+</sup> = +

stochastic state‐space model is obtained:

vibration measurements.

170 Structural Bridge Engineering

**2.3. Modal assurance criterion**

**Figure 1.** Views of the historical masonry arch bridges with relieve drawings. (a) Osmanlı Bridge, (b) Mikron Bridge, and (c) Şenyuva Bridge.

estimating behavior of these structures and reliable restoration could be made to preserve them for future.

Masonry arch bridges hold an important place in historical structures [11]. They are not complex structures. A stone arch bridge consists of stone blocks and mortar joints. Blocks have high strength in compression and low strength in tension while mortar has generally low strength. Historical masonry arch bridges are vital components of transportation systems in many countries worldwide, ensuring the ready access of goods and services to millions of people [12]. Many of those bridges, which were originally built for the passage of carts, are being used for road and rail vehicles. They demonstrate a surprisingly high load bearing capacity and good durability.

Osmanlı, Mikron, and Şenyuva historical masonry arch bridges constructed in Turkey are selected for example. The Osmanlı historical masonry arch bridge was built in the nineteenth

**Figure 2.** Accelerometer locations and views from the measurements. (a) Osmanlı Bridge, (b) Mikron Bridge, and (c) Şenyuva Bridge.

century. This two‐spanned arch bridge has a total length of 51.7 m. The span of each arch is 25.2 and 6 m, and the radius of each arch is 13 and 3m, respectively.

estimating behavior of these structures and reliable restoration could be made to preserve them

Masonry arch bridges hold an important place in historical structures [11]. They are not complex structures. A stone arch bridge consists of stone blocks and mortar joints. Blocks have high strength in compression and low strength in tension while mortar has generally low strength. Historical masonry arch bridges are vital components of transportation systems in many countries worldwide, ensuring the ready access of goods and services to millions of people [12]. Many of those bridges, which were originally built for the passage of carts, are being used for road and rail vehicles. They demonstrate a surprisingly high load bearing

Osmanlı, Mikron, and Şenyuva historical masonry arch bridges constructed in Turkey are selected for example. The Osmanlı historical masonry arch bridge was built in the nineteenth

**Figure 2.** Accelerometer locations and views from the measurements. (a) Osmanlı Bridge, (b) Mikron Bridge, and (c)

for future.

172 Structural Bridge Engineering

Şenyuva Bridge.

capacity and good durability.

The Mikron historic arch bridge, built in the mid‐nineteenth century during the Ottoman Empire, spans the Fırtına River in Rize, Turkey. Cut stone blocks composed the bridge's arches and parapets. In 1998, Turkey's General Directorate for Highways supervised repair of the main structural elements of the bridge (stone arches, side walls, and filler material). The bridge, with a total length of 33.80 m, has two stone, inner and outer semi‐circular arches, which have thicknesses of 0.50 and 0.15 m, respectively.

The Şenyuva historical arch bridge built in 1696 by the native population is located on Fırtına Stream in Çamlihemşin, Rize, Turkey. The bridge has a single arch. The total span of bridge is 52.4 m, the span of the bridge arch is 24.8 m, the height of the arch is 12.4 m, and the wide of the deck is 2.5 m. Height of the side walls at both side are 9.2 and 3.5 m, respectively. There are 60 cm × 30 cm dimensional parapets on both sides of the bridge deck. Some views of the bridges with relieve drawings are given in **Figure 1(a–c)**.

Ambient vibration tests were performed under existing environmental condition. B&K 8340 and B&K 3560 experimental measurement equipment were used. PULSE [13] and OMA [14] softwares were used to signal processing and parameter estimations. Accelerometer locations and views from the measurements for each bridge are shown in **Figure 2**.

**Figure 3.** The singular values of spectral density matrices for historical masonry arch bridges.

Accelerometer setups shown in **Figure 2** were used, and measurements were carried out for at least 30 min. The singular values of spectral density matrices are given in **Figure 3**. The dynamic characteristics are given in **Table 1** and **Figure 4**. The first four natural frequencies are obtained between 4 and 14 Hz. The mode shapes occurred as lateral and vertical forms.


**Table 1.** Experimentally identified natural frequencies and damping ratios.

**Figure 4.** The first four mode shapes of the historical masonry arch bridges.

#### **3.2. Long span concrete highway bridges**

Kömürhan and Birecik long span concrete highway bridges constructed in Turkey are selected for example. The bridge deck consists of a main span of 135 m and two side span of 76 m each. The total bridge length is 287 m and width of the bridge is 11.50 m. The structural system of Kömürhan Highway Bridge consists of deck, columns, side support, and expansion joint. The deck of the bridge was constructed with balanced cantilever and prestressed box beam method. There are two main columns of 59.50 m each. Foundation of the main column is concrete in mass having the dimension of 24 m × 13.5 m and 5 m depth. To combine deck cantilevers, an expansion joint is constituted in the main span of the bridge [16, 17].

Accelerometer setups shown in **Figure 2** were used, and measurements were carried out for at least 30 min. The singular values of spectral density matrices are given in **Figure 3**. The dynamic characteristics are given in **Table 1** and **Figure 4**. The first four natural frequencies are obtained between 4 and 14 Hz. The mode shapes occurred as lateral and vertical forms.

**1 2 3 4 1234**

Osmanlı 4.640 8.094 9.879 12.340 1.634 1.035 6.157 0.256 Mikron 6.063 9.563 9.906 13.590 1.945 0.967 0.835 0.258 Şenyuva 4.045 7.750 8.020 10.000 2.377 1.318 4.288 0.265

Osmanlı 4.642 8.325 9.735 11.910 1.634 1.035 6.157 0.256 Mikron 6.065 9.558 10.180 13.590 1.855 0.923 0.815 0.289 Şenyuva 4.066 7.960 8.044 10.100 2.377 1.318 4.288 0.265

Kömürhan and Birecik long span concrete highway bridges constructed in Turkey are selected for example. The bridge deck consists of a main span of 135 m and two side span of 76 m each.

**Bridges Natural frequencies (Hz) Damping ratio (%)**

EFDD method

174 Structural Bridge Engineering

SSI method

**Table 1.** Experimentally identified natural frequencies and damping ratios.

**Figure 4.** The first four mode shapes of the historical masonry arch bridges.

**3.2. Long span concrete highway bridges**

**Figure 5.** Some views of the long span concrete highway bridges with relieve drawings. (a) Kömürhan Bridge and (b) Birecik Bridge.

**Figure 6.** Accelerometer location and views from the measurements.

Birecik Bridge is located 81 km of the Şanlıurfa‐Gaziantep state highway over Fırat River in Turkey. The construction of the bridge was started in June 1951 and the bridge was opened to the traffic in April 1956. The bridge consist of five arches, each arch has a 55 m main span. The total bridge length is 300 m and the width of the bridge is 10 m. The bridge arches have rigid connectivity at middle spans and side supports. But, right and left side of the middle points of slabs are constructed using joints. Columns, beams, arches, decks, and foundations were constructed as reinforced concrete [18]. Some views of the bridges with relieve drawings is given in **Figure 5**. **Figure 6** presents the accelerometer location and views from the measure‐ ment. The measurements were carried out for at least 60 min. The singular values of spectral density matrices obtained from vibration data are given in **Figure 7**.

**Figure 7.** The singular values of spectral density matrices for long span highway bridges.

The dynamic characteristics and related mode shapes are given in **Table 2** and **Figure 8**. The first four natural frequencies are obtained between 0.7 and 2.3 Hz for the Kömürhan Bridge and 2.4 and 4.6 Hz for the Birecik Bridge, respectively. The mode shapes occurred in lateral, vertical, and torsional forms.


**Table 2.** Experimentally identified natural frequencies and damping ratios.

**Figure 8.** The first four mode shapes of the long span highway bridges.

#### **3.3. Base isolated bridge**

the traffic in April 1956. The bridge consist of five arches, each arch has a 55 m main span. The total bridge length is 300 m and the width of the bridge is 10 m. The bridge arches have rigid connectivity at middle spans and side supports. But, right and left side of the middle points of slabs are constructed using joints. Columns, beams, arches, decks, and foundations were constructed as reinforced concrete [18]. Some views of the bridges with relieve drawings is given in **Figure 5**. **Figure 6** presents the accelerometer location and views from the measure‐ ment. The measurements were carried out for at least 60 min. The singular values of spectral

density matrices obtained from vibration data are given in **Figure 7**.

**Figure 7.** The singular values of spectral density matrices for long span highway bridges.

**Table 2.** Experimentally identified natural frequencies and damping ratios.

vertical, and torsional forms.

176 Structural Bridge Engineering

**Bridges EFDD method**

The dynamic characteristics and related mode shapes are given in **Table 2** and **Figure 8**. The first four natural frequencies are obtained between 0.7 and 2.3 Hz for the Kömürhan Bridge and 2.4 and 4.6 Hz for the Birecik Bridge, respectively. The mode shapes occurred in lateral,

**Natural frequencies (Hz) Damping ratio (%)**

Kömürhan 0.788 1.027 1.850 2.291 1.373 1.785 2.057 1.465 Birecik 2.496 3.115 3.378 4.545 4.358 0.899 0.863 0.118

**1 2 3 4 1234**

Base isolated Gülburnu Highway Bridge constructed in Turkey is selected for example. The construction of the bridge was started in November 2005 and the bridge was opened to the traffic in May 2009. The bridge is twin prestressed concrete box girder structures. The bridge

**Figure 9.** Some views of the base isolated bridge with relieve drawings.

deck consists of a main span of 165 m and two side span of 82.5 m each. The total bridge length is 330 m and the width of the bridge is 30 m. The structural system of the bridge consists of deck, piers, and side support. There are four piers and each has 4.50 m height and 9.00 m × 3.75 m cross‐section areas. All piers are footed on the two raft foundation with bored piles. Two abutments that allow longitudinal direction movement only support the superstructure at both sides [19, 20]. Some views of the bridge with relieve drawings is given in **Figure 9**.

Accelerometer locations are shown in **Figure 10**. The measurements were carried out for at least 60 min. The singular values of spectral density matrices obtained from the processing vibration data are given in **Figure 11**.

**Figure 10.** Accelerometer location and views taken from the measurements.

**Figure 11.** The singular values of spectral density matrices for base isolated bridge.


**Table 3.** Experimentally identified natural frequencies and damping ratios.

Natural frequencies, mode shapes, and damping ratios are given in **Table 3** and **Figure 12**. The first six natural frequencies are obtained between 0.9 and 4.5 Hz. The mode shapes occurred in vertical, torsional, longitudinal, and lateral forms.

**Figure 12.** The first six mode shapes of the base isolated bridge.
