Finite Element Analysis On Flexural Bearing Capacity Of Reinforced Concrete Beams With Openings

Due to the increasing number of urban population and nervous land,more and more tall buildings and even super tall buildings appear.The using function requirements of buildings are constantly improving,kinds of auxiliary facilities adapted to the intelligent are very large an complex.At present,the pipelins usually go through the building structure under the beam in the tall and super tall buildings which occupy1/6-1/5of the floor height. While the clear height of floors and pipeline room usually can not be changed due to the construction requirements and equipment constrains.Making all kinds of pipelines go through the abdomen of beams can avoid the space crowding under the beams which can decrease the total height and weight of the buildings in case of the layer number.It is good to resist wind load and earthquake effect,and it also can reduce the cost the engineering.Therefore,the reinforced concrete beams with openings has a braod application prospect.However,compared with the plain girder,the existence of the holes ruin the integrity and continuity of the beam section. Stiffness and bearing capacity of section are also affected by varying degrees.The crack width and deflection of the beam increase by the stress concentration produced around the opening parts,thus affects the normal use of the beam.There is no design method of reinforced concrete beams with openings in Code for Design of Concrete Structures in our country.Designers generally increase the structure reinforcement around the hole personnelly when the holes need to be opened in the beam in actural project,which is neither economic nor reasonable enough.The finite element software ABAQUS is using to make the nonlinear simulation experiments in the paper.The influence of parameter to the bearing capacity of beams with openings is the key point in the research,such as opening rate,shape of the hole,size of the hole,horizontal position and vertical position of the hole,the reinforcement around the holes.Moreover the correction formula of section flexural bearing capactiy of beams with openings is supposed and compared with the theoretical value to verify the reliability of the formula.lt has a vital significance to the practical application of the beams with openings.