L-shaped Cap Beam Spatial Analysis Of Small And Medium Span Bridge

Influenced by the terrain, geology and hydrology, different range of hole span arrangement (two adjacent cross-beam high often different) are often adopted in bridge design, for which have L-shaped cap beam become inevitable design elements. There is no corresponding information or technical studies to follow and designed with considerable arbitrariness when engineers design L-shaped cover for the regulation of beam, so in-depth study of this issue on the engineering design had practical application value.According to the study of bridge both home and abroad in recent years, that the ratio of bridge pier cap beam height l/h between 3 to 5 in majority, are in the range of deep beams' short beams, the mechanical characteristics of short beams no longer meet the plane section assumption, and their damage modes are different from common bending componenets. This paper analyzes three-dimensional finite element simulation of L-shaped cap beam with the appropriate analytic model and cell types, which based on the analysis of the pier cap beam highway models and calculation methods of current Reinforced Concrete and Pre-stressed Concrete Highway Bridge Design Code (JTG D62-2004), and combined with engineering examples and the use of large-scale finite element analysis Software ANSYS12.0. In finite element analysis method, the key point of analysis of L-shaped beam simulation is to select the right modules and materials, to determine the exact boundary conditions and simulation, and load loading methods, etc.The paper analyzed L-capping beams from the selected projects, and found the height ratio of the cover part and the lower common part of L-shaped cap beam (set to a/b) is 0.416 (about 0.4), and then assumed in the case of the load and reinforcement ratio in stillness, re-analyzing L-capping beam by changing the a/b value, and obtained the average displacement of L-shaped cap beam in the y (high degree) direction, the stress changes on the pier cap and beam cross-section along the y direction, on concrete unit in z (vertical direction) direction, and on longitudinal reinforcement steel and concrete cracking scope and cracking state, respectively. Then a comprehensive analysis of the L-shaped cap beam at different a/b value of these five changes of mechanical properties, and a comparative analysis on the higher part of the L-shaped cap beam involved in the size of the force. Important design recommendations are given:When the a/b> 0.8 the high side the cap beam force participation decreases, the amount of tension steel configuration should be reduced accordingly, and when the a/b≤0.8 when the high side of the part of the tensile reinforcement Configure amount should be roughly the same as the low side.