Experimental Study And FEM Analysis On Torsional Strengthening For RC Beams By Steel Plates With Direct Shear Bolts

The main character of bolting steel plates with direct shear bolts lies in its ability tomake the contact between bolt and hole tight enough so that the group of bolts can workwith synergy and perform full advantage of the shear stiffness and bearing capacity. Theoverall performance of a RC member after strengthening is ensured due to thisimportant feature. Comparing with traditional strengthening methods，bolting steelplates with direct shear bolts is the most preferable one for it can completely avertdebonding problem which often occurs in bonding steel plates with adhesive and thefire-resistance significantly improves.This technique has wide ranges of application for RC members under tensile，compression，bending，shear and torsion. But in the field of torsional strengthening,thedesign code remains unclear. Therefore to investigate on the mechanism of thistechnique applied to RC beams under torsion shows remarkable value. For thispurpose，this thesis conducts both finite element method analysis and experimentalresearch on torsional strengthening for RC beams by steel plates with direct shear bolts.Specifically, the stress on the rebars and steel plates, the deformation of bolts, themechanism for anti-torque are investigated.The content of this thesis consists of：①Basic theories：Discourse on the varied angle space truss model for RC membersunder torsion. Description on shear performance of direct shear bolts based on theoryfor shear connectors in composite structures. Inference on the mechanism foranti-torque after strengthening.②FEM analysis：Applying finite element method inAbaqus to simulate the actionof the strengthened members under torsion in whole process. Investigates torque-twistangle curve, stress on rebars and steel plates, deformation of bolts.③Experimental research：A contrast destructive test is conducted to testify theeffectiveness of strengthening and a new measure for anchoring steel plates at end.Comparing experiment results with FEM conclusion. In the test, one part of thespecimen is strengthened while the other is not as contrast.④Conclusion：In the end of this thesis the final conclusion is given aftersummarizing and comparing all the research results comprehensively.