STRENGTHENING OF REINFORCED CONCRETE BEAM STRUCTURES USING EXTERNAL REINFORCEMENT. EFFICIENCY RESEARCH

Repair of reinforced concrete beam with externally bonded steel plate or fibre reinforced polymer (FRP) laminate is becoming both environmentally and economically preferable rather than replacement of deficient beam. The well known advantages of external reinforcement over other methods include; low cost, ease of maintenance and the ability to strengthen part of the structure while it is still in use. The disadvantage of this method, however, is the premature debonding of the externally bonded strips which is brittle and undesired mode of failure. It is also known that debonding of the externally bonded steel plates prevents the reinforced concrete (RC) beam from reaching its full strengthening capacity. The aim of this study was to increase the scientific understanding on the behaviour of damaged reinforced concrete beams strengthened and/or retrofitted for shear using vertical steel plate fixed with adhesive and steel connectors to eliminate or delay debonding failure. Four reinforced concrete beam specimens were prepared to investigate the effects of connectors in preventing or delaying premature debonding of shear strips to restore the capacities of fully damaged beams. Three damaged beams have been repaired and strengthened with steel plates and loaded monotonically up to the maximum load capacities in order to define load–deflection relationship. It is concluded that the repairing of severely shear-damaged RC beams with steel plates by using steel and adhesive connectors can fully restore the original shear capacities of the beams.

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Crack formation and crack propagation into the compression zone on reinforced concrete beam structures

International Journal of Computational Methods and Experimental Measurements ◽

10.2495/cmem-v5-n2-116-124 ◽

2017 ◽

Vol 5 (2) ◽

pp. 116-124

Author(s):

Samdar Kakay ◽

Daniel BÅrdsen ◽

Ove T. Gudmestad

Keyword(s):

Reinforced Concrete ◽

Crack Propagation ◽

Concrete Beam ◽

Crack Formation ◽

Reinforced Concrete Beam ◽

Compression Zone ◽

Beam Structures

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Prediction of Creep for a Reinforced Concrete Beam Strengthened with an External Reinforcement System Using the Stepped Isothermal Method

Lecture Notes in Civil Engineering - Proceedings of STCCE 2021 ◽

10.1007/978-3-030-80103-8_12 ◽

2021 ◽

pp. 113-121

Author(s):

Almaz Shakirov ◽

Alfred Sulejmanov

Keyword(s):

Reinforced Concrete ◽

Concrete Beam ◽

Reinforced Concrete Beam ◽

Isothermal Method ◽

Reinforcement System ◽

External Reinforcement

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Evolutionary Optimization Of Normally Operated Reinforced Concrete Beam Structures Taking Into Account The Risk Of Accidents

Promyshlennoe i Grazhdanskoe Stroitel stvo ◽

10.33622/0869-7019.2019.09.45-50 ◽

2019 ◽

pp. 45-50

Keyword(s):

Reinforced Concrete ◽

Cross Sections ◽

Concrete Beam ◽

Reinforced Concrete Beam ◽

Operating Conditions ◽

Evolutionary Modeling ◽

Beam Structures ◽

Variable Parameters ◽

Evolutionary Operators ◽

Random Change

An algorithm for search optimizing reinforced concrete beam systems using the theory of evolutionary modeling has been developed. The search for this solution is performed on the formed areas of permissible values of the variable parameters represented by discrete sets of values. These parameters are dimensions of the cross sections of an element, a concrete class, a class and diameters of steel reinforcement. One of the main active constraints is the value of cost expression of the material losses risk in case of possible structure failure. The main difference between the proposed algorithm and classical evolutionary methods is the use of a new controlled random change operator to find the solution in the iterative process. Herewith other evolutionary operators are not used. To assess the productivity of the proposed algorithm, an example of a two-span beam designing is given. The presented developments make it possible to obtain design solutions for reinforced concrete beam structures taking into account the optimal ratio of costs for the structure manufacturing and the risks costs of its failure under normal operating conditions.

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