Experimental Study On Normal Stress Of Reinforced Concerte Beams Strengthened With Quartz Sand And Bonded Steel

With the reform and opening up,the economic development is faster and faster,and the development of civil engineering is also developing rapidly.However,with the passage of time,more and more early-built buildings have entered or are about to enter the aging stage.From the perspective of economy and timeliness,combined with the natural and human environment around the building,many buildings are not suitable for overthrow and reconstruction.Therefore,the proportion of maintenance and reinforcement work in the civil construction industry is increasing year by year.In this paper,based on the existing construction technology,the traditional steel-bonded reinforcement technology is improved.Quartz sand is added to the adhesive layer in order to improve the performance of the adhesive layer,increase the stress transfer efficiency of the adhesive layer and enhance the effect of steel-bonded reinforcement.The main contents of this paper include:(1)Introduce the commonly used reinforcement methods of building structural members,and list the advantages and disadvantages of various reinforcement methods,introduce in detail the research status of steel-bonded reinforcement method at home and abroad,and expound the existing research results of steel-bonded reinforcement technology.(2)Understanding the reasons why building structural members need to be strengthened.At the same time,the excellent characteristics,application scope,general requirements,stress characteristics and failure modes of steel-bonded reinforcement technology are introduced in detail.(3)Five groups of data were selected for each of the three main factors: steel plate thickness,glue layer thickness and quartz sand thickness,and the most representative 25 combinations were selected by orthogonal test method.Therefore,25 specimens were prepared.(4)The existing literature calculation theory is introduced,and the stress calculation formula in the existing literature is brought into the test parameters to obtain the theoretical calculation stress data,which is compared with the experimental data.(5)Because the ratio of quartz sand to glue is too large,the bonding performance of the glue is greatly reduced after mixing,so the three groups are omitted.Through experiments,22 reinforced concrete beams under initial state were strengthened with bonded steel plates and loaded under symmetrical concentrated loads.Then the deflection,normal stress at the bottom of steel plate,normal stress at the bottom of concrete and shear stress between steel plate andrubber layer were analyzed according to the test data.The results show that adding quartz sand in the rubber layer is helpful to the interfacial stress.The effect transfer makes the steel plate give full play to its role,which proves the experimental assumption.Finally,some suggestions on the amount of quartz sand in practical engineering applications are put forward.