Mechanical Analysis Of Municipal Sewer Elevated Box Culvert Under Heavy Rain Caused Flood

The urban sewerage system is lifeline for the urban economy and citizens'life. It is prone to the risk of heavy rain caused flood. Especially in mountain city, the elevated box culvert of municipal drainage pipe will be subjected to the impact load due to flood and over-internal pressure of water which are always under-estimated during the process of design. Therefore, it is necessary to study on the mechanical behavior of municipal sewerage elevated box culvert due to heavy rain caused flood. The following research activities were carried out in this paper and the corresponding results were listed as follows:①Based on the classical theory of box beam, the paper focused on transverse force of box beam. The axial force equation was deduced for the simply supported rectangular box girder under uniformly distributed load. Taking the experimental beam as an example, the stress distributions of transverse bend and axial force were calculated. The influence of axial force to transverse bending was analyzed.②Flood load analysis of municipal sewerage elevated box culvert was carried out on a hypothesis that flood water buoyancy and dynamic impact load were static loads. Three resultant equations were obtained, including upstream maximal backwater height, horizontal and vertical applied force of flood acting on elevated box culvert.③Using the integral-type modeling method, the elevated box culvert of Chongqing sewerage system was simulated by the unit Solid65 in ANSYS. The sewerage pipe concrete might be eroded by many corrosive mediums, so the corrosive constitutive relation was adopted by the consideration of this strength degeneration. The displacement response and stress condition of elevated box culvert before cracking was primarily analyzed on the base of the analyzing results.④Two test models were designed according to two principles ("equal reinforcement ratio" and "similar reinforcement"). Then two static load tests were carried out in Structural Laboratory of Chongqing University in order to knowledge the stress response of a little deep simply supported box girder under uniformly distributed load. These results included longitudinal strain analysis, transverse strain analysis and shear zone strain analysis.⑤The test beam was modeled through a nonlinear finite-element software ABAQUS. The simulated results, which better agreed with the experimental data, betrayed that this analysis program was able to focus our attention in predicting stress response of concrete box beam.