2.1 GDE Methodology

Using the GDE methodology, the elements inspected were divided into groups of Pillars (P); Beams (V); Slabs (L); Stairs (E); Upper reservoir (R); Lower reservoir (R), and Expansion joints (J).

After this division, intensity factors (F_i) and weighting factors (F_p) were assigned for each manifestation present in the element, according to the tables present in the work by ^{Fonseca (2007}). Thus, it was possible to calculate the degree of damage, according to equations (1) and (2).

D=0,8. Fp. Fi To  Fi≤2,0 (1)

D=(12. Fi-28) Fp To  Fi≥3,0 (2)

Where:

D - Degree of damage

F_i - Intensity factor

F_p - Weighting factor

With the degree of damage (D) of each manifestation, the degree of deterioration of the element (G_de) is calculated according to equation (3).

Gde=Dmáx1+∑    i=1n  Di-Dmáx∑    i=1n  Di (3)

Where:

G_de - Degree of deterioration of the element;

D_i - Degree of damage “i”;

D_max - Highest degree of damage to the element;

n - Element damage numbers.

A level of deterioration is related to the value of the element's degree of deterioration and thus we obtain recommendations for actions to be taken. This relation can be seen in Table 1.

To determine the degree of deterioration of elements divided into similar groups, the degree of deterioration of the family (G_df) is calculated, which is a function of the degree of deterioration of the element (G_de) through equation (4).

Gdf=Gde,máx1+∑    i=1n  Gde,i-Gde,máx∑    i=1n  Gde,i (4)

Where:

Gde,máx - Highest degree of element deterioration

Gde, i - Degree of element deterioration “i” (≥ 15)

m - Number of elements with Gde ≥15

Finally, by obtaining the degree of deterioration of each family (G_df), the degree of deterioration of the structure (G_d) is calculated. The equation used for this calculation is expressed below, equation (5).

Gd=∑    i=1k   Fr,i.Gdf, i∑    i=1k   Fr,i (5)

Where:

k - Number of families in the structure;

Fr,i - Structural relevance factor of the family “i”;

Gdf, i - Degree of family deterioration “i”.

Thus, for the degree of deterioration of the structure, similarly to the degree of deterioration of the element (G_de), an association can be made to a level of deterioration and consequently measures that can be taken in this situation can be obtained. The table applied for this analysis is Table 1, p. 05.

2.2 GUT Methodology

The GUT methodology originated in the 1980s through the work of Kepner and Tregoe with the aim of creating a strategic planning tool to assist in decision-making (^{Fáveri; Silva, 2016}). In civil construction, the work of ^{Verzola, Marchiori, and Aragon (2014}) proposed changes in the methodology in order to allow its application in building inspections and reduce the possibility of errors through subjectivity. The methodology uses the variables Severity (G), Urgency (U), and Tendency (T), in which weights ranging from 1 to 10 are assigned, with 1 being assigned to the least severe and 10 to the most severe. Thus, through the product of the variables (GxUxT), a classification is made according to how critical each situation is (Verzola; Marchiori; Aragon, 2014).

Some researchers such as ^{Santana et al. (2019)}, ^{Moura and Cavalheiros (2019}), and ^{Braga et al. (2019}) applied the GUT methodology in their research to carry out inspections and identify the most critical points of the building, proving it to be practical and making it possible to define priority for decision-making. According to ^{Verzola, Marchiori, and Aragon (2014}), tables 2, 3, and 4 determine the grades to be assigned for each grade according to the variable.

The grade corresponds to the value assigned to each pathological manifestation according to the associated degree, that is, in total degree, a grade of 10 is assigned, a high degree is grade 8, an average degree gets a grade of 6, a low degree is grade 3 and no degree gets a grade of 1. Thus, the grade is assigned for each variable of the manifestation, and using the product of these values, it is possible to list the problems that have higher priority. Those with greater value deserve special attention, as they are the most serious, and urgent and tend to get worse (^{Periard, 2011}).

3.1 Pathological manifestations

Mapping was carried out on each inspected floor to facilitate the identification of the elements. Furthermore, the evaluated elements were divided into families as proposed by the GDE methodology (2007). Then, the pathological manifestations identified were presented according to this division.

In the column family, only one element, P01, was identified, and it was possible to notice a great exposure of the reinforcements in the process of corrosion, identifying stains along the reinforcements and detachment of the concrete due to the expansion of the reinforcement, as can be seen in Figure 1.

Figure 1 Detachment of concrete and corrosion of reinforcement in element P01 

In the slabs family, elements L01 to L08 were identified, as shown in Figure 2, in which stands out the constant presence of moisture, generating dark spots in element L01, detachment of the paint in element L02, formation of calcium carbonate stalactites, due to efflorescence in element L04, small stains and cracks in elements L05 and L08 and wear of waterproofing in element L03. There are also cracks in elements L06 and L07 due to additional loads applied by a telephone antenna over the roof.

Figure 2 Pathological manifestations identified in the slabs. (1) Dark spots on element L01. (2) Detachment of the ping in element L02. (3) Wear of waterproofing on element L03. (4) Efflorescence with formation of stalactites in element L04. (5) Small moisture spots on the L05 element. (6) and (7) Cracks due to additional loading on the cover, on elements L06 and L07. (8) Dark spots of moisture on element L08. 

The upper reservoir family and the lower reservoir family showed possible flaws in their waterproofing, identified by the characteristic appearance of light efflorescence stains on elements R01 and R02.

Figure 3 Efflorescence spots in the reservoir. (1) R01. (2) R02. 

It is noted that the beam family did not present any element that demonstrated the development of pathological manifestations.

The elements of the family of stairs and expansion joints were E01 for the stairs and J01 and J02 for the expansion joints, as can be seen in Figure 4. In it, it is noted that the element E01 showed only wear on its steps due to the weather over the years and in elements J01 and J02, the constant presence of humidity resulted in the dark spots identified.

Figure 4 Efflorescence spots in the reservoir. (1) Wear of stair treads on element E01. (2) and (3) Stains due to humidity in elements J01 and J02. 

3.2 Application of methodologies and analysis of results

First, it was observed that the family that has the largest number of elements that present pathological manifestations is the slab family, with 57.14% of the identified anomalies, as can be seen in Figure 5.

Figure 5 Graph of the frequency of pathological manifestations by family of elements. 

Through the mapping of the pathological manifestations that affect the building, it was noticed that in the 14 structural elements inspected, 35.29% of the pathological manifestations are originated due to the infiltration of humidity as we can see in Figure 6. In addition, other pathological manifestations such as efflorescence (17.65%) and dark spots (11.76%) also have a similar cause.

Figure 6 Graph of the frequency of pathological manifestations in the elements. 

Regarding the GDE/UnB (2007) methodology, it is possible to raise some analysis based on the graphic model used by ^{Medeiros et al. (2020}). In the slab family, elements L06 and L07 are the ones that most influence the calculation of the degree of deterioration of the family, as can be seen in figure 7. In addition, it is worth noting that element L05 is not taken into account for the G_df calculation for presenting G_de less than 15.

Figure 7 Degree of deterioration of the slabs. 

The beam families have a null degree of deterioration, as no pathological manifestation was identified in the elements that compose them, in the family of stairs, the only identified element has G_de less than 15. Thus, for both, G_df equal to zero was calculated. As for the families of columns and upper and lower reservoirs, it is observed that they are composed of only one element, so the value of the degree of deterioration of the family corresponds to the value of the degree of deterioration of the element itself, this can be seen, respectively, in figures 8, 9 and 10.

Figure 8 Degree of deterioration of the pillars. 

Figure 9 Degree of deterioration of the upper reservoir. 

Figure 10 Degree of deterioration of the lower reservoir. 

In addition, in the expansion joints, the presence of two elements that present the same degree of deterioration was found, but the degree of deterioration of the family is higher than the value obtained for the elements individually. Thus, by the mathematical formulations, it is possible to observe that the influence of the repetition of elements that have the same degree of deterioration does not represent such a significant increase since it has the maximum value as a reference, this value is multiplied by the result of the root that involves the sum and the maximum value. Figure 11 shows the value of G_df and the values of G_de for each element.

Figure 11 Degree of deterioration of expansion joints. 

Thus, when evaluating the degree of deterioration of the families and the degree of deterioration of the structure, it is noted that the slabs are the ones that represent the greatest influence for the structure to be at an average deterioration level,15 to 50, and therefore it needs intervention within a maximum period of 2 (two) years. Figure 12 shows the values ​​of G_df of each family in comparison to the global value of the structure, G_d.

Figure 12 Degree of deterioration of the structure. 

The application of the methodologies makes it possible to define which element or pathological manifestation needs priority within the global scenario, which can be decisive for assertive and efficient work. By the GDE methodology (2007) it is defined that the elements L07 and L06 need special attention, given that they present a poor and high level of deterioration, respectively, which implies a need for intervention within a maximum period of 6 (six) months for element L07 and 1 year for element L06. On the other hand, elements E02 and L05 have a low level of deterioration, requiring only preventive maintenance. The other elements are classified at a medium level of deterioration, with interventions being suggested within a maximum period of 2 (two) years. In addition, the structure has a G_d equal to 35.99, classifying it as an average level of deterioration, which requires a maximum intervention period of 2 (two) years. The list of maintenance priorities is presented in table 5(1).

By the GUT methodology (2014), it is possible to evaluate only the pathological manifestations separately. Thus, based on the scale of values ​​defined by the methodology, in tables 2, 3, and 4, where from 81% to 100% is defined as a total degree, it was considered that the attribution of grades 10 for the three parameters, or that is, grade 1000 represents 100% and consequently, the percentage of the other values ​​can be easily obtained and thus assign a classification to the pathological manifestations. Having defined this, in table 5 (2) the pathological manifestations were listed in order of priority, that is, from the highest to the lowest score.

It is noted that by the GUT methodology (2014) there is a certain repetition of values, which makes it difficult to determine priority. In addition, most of the pathological manifestations are of a low or no degree, in terms of severity, urgency, and tendency, diverging from the GDE methodology (2007). However, for both methodologies, it is possible to define that elements L07 and L06 need maintenance priority.