Experimental Study On The Effects Of Spacing In Multipoint Anchoring Ways For Flexural Behavior Of Concrete Beams Strengthened By The WSGG Anchor Systems

The anchoring and prestressed tensioning technology, which is based on WGSS(wave-shaped-gear-grip) anchor for CFRP (Carbon Fiber Reinforced Polymer) has greatconvenience in construction and tremendous flexibility in manipulation. In the series ofprevious experimental study, the high level of prestressing force and excellent anchoringperformance has been proved. However, the effects of spacing of anchors on theflexural behavior of beams are studied inadequately and more experiments andtheoretical analysis need to be carried out and added.Two strengthened reinforced concrete T beams of different spacing of anchors aretested and compared. CFRP in TL1is anchored by three WSGG anchors, spacing ofanchoring are both set by1600mm. CFRP in TL2is anchored by four WSGG anchors,spacing of anchoring near two supports are both set by1200mm, and spacing ofanchoring near mid-span is set by1000mm. Strain of concrete, steel bars and CFRPsheets, deflection, development of cracks, failure mode and ultimate bearing capacity ofbeams are observed and recorded in the experimentation. Through the results, someconclusions will be drawn.①Profited from the matching of the spacing of CFRP’smid-span and the location of beam’s plastic zone, the increasing of curvature of TL2canbe further achieved, meanwhile, the deformability can be enhanced and the ultimatelode is over44%more than TL1’s.②The mid-span of CFRP is given the biggest stressin TL2, the ultimate tensile stress of CFRP can be nearly approached and CFRP is tornin ultimate status. Focused on the key section of beam, the maximum rate of ultilizationof CFRP is reflected in the mid-span of TL2.③After tensioning of CFRP sheets,through the observation of the loss of prestressing force in short time, TL2has beentestified less loss and better anchoring performance.Based on the study of tests, four approximate calculation methods are compared inthe calculation of ultimate bending capacity. Through the contrastive analysis of eachresult and deviation, a suggestive amendatory calculation method is put forward so thatthe calculative rationality and accuracy of ultimate bending capacity can be improvedfor this experiment.