Study On Large-diameter Pestressed SSWM-M In The Fexural Srengthening Of RC Grder Bridge

The pre-stressed stainless steel wire mesh–mortar as a pre-stressedlaminate or shell structure that is composed by high strength stainless steel wiremesh and mortar is suitable for structural strengthening and rehabilitation. And itis difficult to pre-stress the stainless steel wire mesh in the engineeringapplication. To reduce the practical difficulty and provide a uniform and effectiveprestress, a jogged anchor is proposed for anchoring large diameter stainless steelwire mesh. In order to verify the applicability of the new construction technology,the following studies were carried.Firstly, the flexural performances of five damaged RC beams strengthenedwith different diameter pre-stressed stainless steel wire mesh–mortar and onereferential RC beam were tested. Through the curves of load-midspan deflection,load-reinforced strain, load-strand strain and crack condition, this paperanalyzes the flexural strengthening performance of the pre-stressed stainless steelwire mesh–mortar and the effects of the different diameters. The experimentalresults indicate the bearing capacity and stiffness of the strengthened beamsincreased significantly. And the test results also indicate that the large diameterpre-stressed stainless steel wire mesh–mortar has a better performance incontrolling the crack growth, restoring the flexural capacity and stiffness etc. thanthe small diameter pre-stressed stainless steel wire mesh. By monitoring theelongation of stainless steel wire, this article proposes a prestress loss formula,which is suitable for jogged anchor tensioning system, and calculation resultswith the experimental results can be good agreement.Secondly, based on existing research, this paper analyzes the calculationmethod of the resultant force of concrete compression zone and the advancedstrain, and then proposes the flexural capacity formulae for large diameterpre-stressed stainless steel wire mesh–mortar is established for rehabilitationdesign. The results of the proposed formulae are in good agreement with theexperimental observation, which validates the effectiveness and correctness of theproposed formulae. Thirdly, a further reforcement test is conducted on a griger bridge–Huangge Bridge, which was strengthened with large diameter pre-stressedstainless steel wire mesh–mortar. Through the contrast of load test, it was foundthat: in the same load condition, the reinforced Huangge Bridge restored theflexural capacity and stiffness. The prestress loss formula was modified by theconstruction conditions, which is suitable for engineering application.