Research On The Being Bent Composite Beams Of Hot-Rolled H Steel And Larch

The prefabricated composite steel-wood beam is a new kind of composite component.It is applied to construction members of framed buildings by using "steel"and "wood",which are combined by high-strength big hexagon bolts and epoxy resin adhesive.Hot-Rolled H steel is used as the main framework of buildings;wood is used to work as concrete.It is fastened on the surface of upper and lower flange from steel.On one hand,wood can prevent steel from rusting by touching less air,on the other hand,wood is also used to bear load with steel.Therefore,the character of energy-saving materials from wood can be applied,and it accords closely with the environmental-friendly demands in our contemporary society.Recent years,lots of researches have been finished to single steel structure buildings and wood structure buildings by scholars at home and abroad,and numerous achievements in scientific research have also been gained.However,there are few relevant research to composite steel-wood beams,and more researches are about individual members of connection methods,and the individual members are mainly about wood structure,and steel is used as junction.This study is supported by National Science Foundation of China under Grant No.51578544.In this paper,composite beams are the main target being studied,and the primary contents can be seen as follows:(1)two glulam beams and eight composite beams have been manufactured,and the ten beams were loaded in same loading method by controlling variable method with same span length;deflection and strain value at different position have been tested.(2)Bending mechanical property about glulam beams and composite beams have been compared and analyzed.Being compared with glulam beams,ultimate bearing capacity of composite beams are much greater than glulam beams’,but the deflection of mid-span from composite beams is smaller than glulam beams’;during the period of experiment,there are three variables about them:width of wood,section sizes of steel and linking methods,and the section sizes of steel is the most important factors for ultimate capacity,deflection and strain.When the section sizes of steel is greater,the ultimate capacity of composite beams is greater,and deflection and strain is smaller,but the influence of other two variables is not so obvious.(3)test points were established between the interfaces of steel and wood from six composite beams,and strain gauges were pasted to test slip strain and analyze elastic-plastic mechanical properties of composite beams considering slip effect.According to calculation and organizing data,we find that yield bending moment from section of composite beams is related to interface slip by transformation-section method,and if slip strain is smaller,section stiffness reduction factor will be greater,and yield bending moment will be smaller.