Experimental Study on Composite Beam of Steel Truss and Concrete
|Keywords||composite truss experimental study finite element analysis flexural rigidity moment capacity|
In the recent years, the development of structural engineering has been broughtabout a lot of challenges by the designs of variety structures such as super high-rise,large span, and special demanded-shapes. With innovation and energy savings, acomposite truss is one type of new structures developed from a composite beam.Comparing with composite beam, the composite truss possesses more steel materialsavings and economical benefits, etc. The thesis is mainly focused on tests, theoreticalanalysis, and finite element analysis. The results of theoretical analysis are verified bythe tests. In this thesis, the main completed tasks and conclusions are as the followings:1. Completed static loading tests on3sets of steel trusses and3sets of compositetrusses,2trusses per set. Through the tests, the steel trusses and composite trusses arecompared in mechanic performance, rigidity, deformation, and moment capacity, etc.By comparing, the conclusions are drawn that: after using steel truss and concrete slabacting together as a composite truss, the mechanic performance of its chords and webs,and structural stability are greatly improved, and its rigidity and moment capacity areincreased. So, the composite truss is more economical for engineering application.2. Used FEM to simulate and analyze the test. By FEM, conducted the parameteranalysis affecting on its mechanic performance, and analyze main factors impactingflange effective width for composite truss. The analyzed data of flange effective widthis compared with composite beam Code. The analyzed results showed that: the stiffnessof composite truss is most affected by its bottom chord cross-section, slightly affectedby its web cross-section, and mostly unaffected by its top chord cross-section; thestiffness is not obviously affected by concrete strength, but more impacted by flangethickness and width-span ratio; it is also showed that as the degree of shear connector isdropped down, the stiffness and moment capacity of composite truss is decreased, butnot obviously; as in symmetric and line loads, the flange effective width of compositetruss can be calculated by using composite beam Code, but it is unsafe in case ofconcentrated loads.3. Combined with the method of reduction rigidity in consideration of slip effect,proposed the short-term stiffness and deflection formulas for composite truss, which are verified by FEM and test results.4. By considering slip effect, proposed the elastic moment capacity formula, andmethods for calculating the ultimate moment capacity for composite truss.