*7.3. Web (Stage III)*

The third stage of research on the bridge object was carried out in March, when the average ambient temperature was the lowest of the considered cases and it was around 4 ◦C. The average wind speed was equal in this period 13 km/h = 3.61 m/s [39]. The initial temperature of the concrete mix delivered to the construction site reached the value of 14.8 ◦C. The maximum temperature of the concrete web was equal 34.3 ◦C (in point p6, p8) and it was 23.5 ◦C lower than the maximum temperature recorded for the same element during the second stage of testing. The lowest temperature (32.5 ◦C) occurred in the middle of the web height (point p7).

As before, it was assumed, that throughout the analyzed time, the web was insulated by the formwork layer. Thermophysical parameters were adopted according to Tables 2 and 8. The temperature measurements in the web was made along its height, therefore the least-exposed point, located in the middle of the web height (p7) was chosen. The results of numerical simulations correspond very well to the measured values (Figure 29). Based on Figure 29b, the relative error of extreme concrete temperature was equal to 1.0% and the time occurrence of peak 6.3%.


12.0·10<sup>6</sup> 4.3 <sup>1</sup>·10–4 14.8 4.4 5.6

**Table 8.** Thermophysical parameters—web, 40 cm thick, stage III.

**Figure 29.** The concrete temperature of web, 40 cm thick (stage III): (**a**) Constant ambient temperature and (**b**) variable, measured ambient temperature.
