# Bearing Capacity near Support Areas of Continuous Reinforced Concrete Beams and High Grillages
## 2 Materials and Methods  
In this regard, the Odessa State Academy of Civil Engineering and Architecture conducted systematic experimental studies [16; 34; 35] of the bearing capacity around the support sections of complexly loaded reinforced concrete structures, including continuous high beams. These structures symbolize the work, including monolithic reinforced concrete high grillages resting on the heads of piles, and from above, they are unfavorably loaded with concentrated forces (for example, columns). This work presents an engineering method for calculating the bearing capacity of the supporting sections of continuous monolithic reinforced concrete tape beams based on a punching scheme and includes the results of experimental studies from [16; 34]. To achieve this goal, a series of in-situ experiments with two-span continuous reinforced concrete beams were implemented on the relevant state budget topics. An analysis of the literature showed that researchers have not yet developed a unified idea; there are various interpretations about the influence of structural factors and external factors on the bearing capacity of the supporting sections of continuous reinforced concrete structures. From literary sources, it is known that the main performance parameters of reinforced concrete structures obey normal Gaussian distribution law. Because research factors can influence the exit function nonlinearly, it was advisable to approximate it by a polynomial of the second degree. Therefore, the experimental samples of this series (\(V\)) of experiments were made according to a five-factor three-level, similar in properties to the D-optimal, Ha5 plan [36]. This plan provided the same forecast accuracy of the output parameter in the region, which is described by a radius equal to 1 relative to the zero point. The following factors were selected as research and changed at three levels:  
\(x_{1}\)--is the relative run of the slice, \(\alpha/I_{0}=1\), 2, 3 with \(I_{0}=d=155\) mm;  
\(x_{2}\)--class of concrete C, MPa, C12/15, C20/25, C30/35;  
\(x_{3}\)--coefficient of transverse reinforcement \(\rho_{\rm w}(B_{p}I)=0.0018\); 0.0032 0.0050 (\(2Q3\), 4, 5 \(B_{p}I\), S = 77,5 mm);\(x_{4}\)--coefficient of lower longitudinal reinforcement \(\rho_{l,b}\)(A500 C) = 0.0101; 0.0146; 0.0199 (2010, 12, 14 A500 C);  
\(x_{5}\)--coefficient of supreme longitudinal reinforcement \(\rho_{l,t}\)(A500 C) = 0.0101; 0.0146; 0.0199 (2010, 12, 14 A500 C). Each experiment within the full-scale experiment was provided with two specimen beams with six supporting sections. A total of 54 primary and 3 auxiliary seminatural beams were tested. The spans of the samples were 8 \(h_{0}\) + 8 \(h_{0}\) = 1240 mm + 1240 mm. They were reinforced (Figure 1) with two flat-welded frames. For the manufacture of the above beams, heavy concrete of the above classes was used on granite-crushed stone of fractions 5-10 mm and quartz sand with a particle size of 1.5. As a binder, ordinary 400 Portland cement (without additives) was used. To reduce the water-to-cement ratio, improve the easy-to-find concrete mix, and shorten the time required for concrete to gain strength in all experiments, we used the complex additive Relaxax--Super M (ISO 9001 No. 04.156.26) in the amount of 1% of the cement weight in terms of dry substance. To test prototype beams, special power plants were designed and manufactured (Figure 2). Following the recommendations of regulatory documents, the prototypes were loaded with a hydraulic jack DG-50 and a distribution beam--traverse with two steps concentrated by short-term forces--until the first normal and inclined cracks appeared along (0.04... 0.6)\(F_{ult}\), then by (0.08... 0.120)\(F_{ult}\) to the development of maximum permissible deflections, and finally, by (0.04... 0.06)\(F_{ult}\) to destruction. The load exposure at each stage was 15 min, with all measurements at the beginning and the end of each degree of load. Figure 1: Design and reinforcement of continuous reinforced concrete beams (\(V\) series). _I_—experience number.