# Research on the Safety Assessment of Corbel Beams of Reservoir Radial Gates Based on Real States
## 1 Introduction  
The radial gate is widely used in large and medium-sized hydraulic projects due to its advantages of light weight, small opening force, stable flow pattern through the gate, simple operation and maintenance, etc. It is characterized by the high pressure of support and the high positioning accuracy requirements of the support strut [1; 2; 3]. The commonly used supporting structure of the radial gate is the corbel, but as a typical cantilever structure, the corbel has many problems, such as many reinforcing bars, difficult construction, and difficulty to control the positioning accuracy of the support strut. In order to solve the above problems, many radial gates of large and medium-sized reservoirs adopt the corbel beam as their supporting structure, and it has performed well in operation for many years. However, with the progress of the reservoir danger removal and reinforcement, it has been discovered that there is no corresponding safety evaluation specification for the safety evaluation of the corbel beam of the radial gate. At present, _the Code for Design of Hydraulic Concrete Structures_ (SL191-2008) [4] is commonly used for the safety assessment of corbel beams, but due to the special spatial structure of corbel beams, which form a joint force with gate piers, their stress state is more complicated compared with that of the cantilever structure of the corbel, and their ability to bear loads and bending momentsis much greater than that of the corbel structure. Therefore, directly applying the safety assessment specification of the corbel to the corbel beam may lead to an incorrect judgment of insufficient bearing capacity, thereby impacting subsequent safety assessment, danger removal, and reinforcement processes [5; 6]. There are quite a few studies on the force analysis of the corbel and corbel beam structures of radial gates. [PERSON] et al. [7] used the SAP84 program with 8-node uncoordinated units to calculate the internal forces and bending moments of the corbel beam and the overall structure of the gate pier; [PERSON] et al. [8] used the HARMA three-dimensional structural analysis program to calculate the large differences in stress distribution inside the corbel beam and the corbel; [PERSON] et al. [9] used the method of structural mechanics to simplify the structural design of the corbel of radial gates; [PERSON] et al. [10] used theoretical mechanics to analyze and calculate the structure of the corbel beam; [PERSON] [11] et al. proposed a direct equation to quantify the load transfer law by studying the load transfer mechanism in deep beams and corbels; [PERSON] [12] et al. employed the shear friction method (SF) and strut and tie modeling (STM) to compare and analyze the effects of parameters such as _a/d_, width (_b_), compressive strength of concrete (_f'c_), yield strength of reinforcement (_fy_), and horizontal to vertical load ratio (_H/V_) on the shear capacity of a concrete cantilever beam. [PERSON] [13] et al. analyzed three damage cases and the ultimate load calculation of concrete cantilever beams in shear; [PERSON] [14] et al. used the shear friction (SF) method and strut and tie modeling (STM) to compare and calculate the ultimate load capacity of concrete cantilever beams with different shear span to effective depth ratios (_a/d_) for the ultimate load carrying capacity. However, the above studies mostly focus on the concrete cantilever structure, and there are no detailed analysis and research on the stress distribution of the joint force structure of the corbel beam and gate pier of the radial gate combined with engineering examples. In order to make an accurate safety assessment of the corbel beam, a finite element simulation of the joint force structure of the corbel beam and the gate pier (hereinafter referred to as the corbel beam structure) needs to be undertaken in conjunction with the real engineering properties [15; 16]. The real state of the corbel beam mainly includes the real material parameters and the force state.