The Study On The Mechanical Behavior Of Beam With Large Round Hole And The Reinforcement Method Of Steel Pipe

With the rapid development of science and technology and the growing population,there are more and more high-rise buildings and even super high-rise buildings.With the increasing use function of buildings,the intelligent facilities are becoming very enormous and complex.At present,the pipelines are mostly set under the structural beams,occupying 1/6-1/5 of the floor height.And the floor net height and pipeline reservation space,according to the requirements of building function and pipeline specifications,are usually not reduced.If holes are opened in structural beams,pipelines can pass through the holes of beams with holes,which can reduce floor height.When the height of a building is limited,the application of beams with holes can effectively increase the number of layers of the building and improve the economic and social benefits of the building.In the Manual of Concrete Structure Construction(Fourth Edition),the size and position of the reserved holes and the arrangement and calculation methods of the reinforcement steel bar are specified.However,in the actual engineering,the size of the holes in the beam has not met the requirements of the Manual of Concrete Structure Construction(Fourth Edition).In order to meet actual engineering needs,it is necessary to study the mechanical behavior of beams with large round holes.The opening of holes and especially large holes in the abdomen of beams reduces the effective force sections of beams at the position of holes,the strength and capacity of beams,meanwhile,brings problems such as the arrangement of steel bars.If the problems are not handled properly,it is easy to cause engineering accidents.Therefore,it is necessary to study the reinforcement methods of steel pipes for beams with large round holes.In this paper,the Abaqus finite element software is used to simulate reinforced concrete beams with large round holes,which studies the mechanical behavior of beams with large round holes and the reinforcement methods of steel pipes.This paper mainly analyzes the mechanical behavior of beams with large round holes under different parameters,and extracts the corresponding capacity-middle vertical displacement curves and the capacity change curves under different parameters.This paper analyzes the influence of the mechanical behavior of beams with large round holes under different parameters,such as hole diameter size,vertical position of hole,horizontal position of hole,outer diameter size of steel pipe,vertical position of steel pipe,horizontal position of steel pipe,wall thickness of steel pipe,steel pipe and assembly method of reinforcement steel bar,distance between double holes,distance between double steel pipes,double steel pipes and assembly method of reinforcement steel bar.In comparison,hole parameters and the reinforcement methods of steel pipe which are beneficial to the mechanical behavior of beams with large round holes are obtained,which provides practical suggestions for the design and steel pipe reinforcement of beams with large round holes.Through comparison and analysis,the following conclusions are drawn:(1)Steel pipe reinforcement is an effective reinforcement method for beams with large round holes.(2)In the actual project,it is advisable to open a large hole in the beam under the condition that the region where hole is located has a large bending moment and a small shearing force,the hole diameter size is appropriate and the vertical position should be biased towards the tension region.(3)When opening a large hole in a region where the bending moment is large and the shearing force is small,we need to choose the appropriate steel pipe wall thickness and do not need to use reinforcing steel bars,and use the reinforcement method of steel pipe to improve the flexural capacity of beam with large round hole,which can make it close to the flexural capacity value of beam without hole.When opening a large hole in a region where the shearing force is large and the bending moment is small,the reinforcement method of steel pipe can be used to improve the shear capacity of beam with large round hole.In particular,the combination of steel pipe and inclined steel bars is the best method for reinforcement.(4)In the actual project,when two large round holes are opened in the region where the bending moment is large and the shearing force is small,and under the condition that the hole diameter sizes are appropriate and the vertical positions are middle,the mechanical principle is the same as that of single-hole beam,the distance between double holes has almost no effect for the flexural capacity of beam,and other mechanical situations are similar to single-hole beam.