Study On Structural Properties Of The Boiler Frame With Wet-connected Envelop Angel Iron

In this paper, the boiler frame structure of the main factory in Pingdingshan Yaomeng Electric Power Group Company Limited is chosen to perform the research work on structural properties,reinforcement methodology,reinforcement scheme,stress history and bonding between concrete and outsourcing angle steels in details, with both theoretical analysis and finite element method(FEM) simulation, thus obtaining deformation characteristics, mechanical behaviors and bonding properties between concrete and outsourcing angle steels under different loading cases. Then, the overall performance of the structure and behaviors of the elements after reinforcement are discussed. Specified work is listed as following:(1) The site detection is carried out to demonstrate the reason, methodology and scheme of reinforcement in terms of necessity and rationality of the reinforcement.(2) The 3D model of the structure is established using FEM with beam element and combin element to carry out static analysis under self weight and wind load. The results show that the inter layer displacement angle of the dangerous part of the structure after reinforcement is 1/867, which meets the elastic deformation requirement(1/550) of concrete frame structure under serviceability state;The reinforcement works efficiently and the weak layer of the stiffness remains the same part of the structure;the bearing capacity of the reinforcement structure is improved.(3) Modal analysis is performed, whose results illustrate that after reinforcement, both frequencies of the first two vibration modes increase. However, there exists an apparent difference between the longitudinal and lateral stiffness of the structure and the torsion effect is obvious.(4) The author studies the seismic capacity of the structure using full method of transient analysis, whose results illustrate that in case of uncommon earthquakes, the weak layer of the strength remains the same part of the structure, and there is a great but not excessive promotion in ductility.(5) To study the bonding properties between concrete and outsourcing angle steels, the author uses the contact element to simulate the interaction between concrete and outsourcing angle steels. The results show that, the ultimate load of battened column is 7150 k N under loading progressively, which fulfills the requirement of bearing capacity limit states compared with the value 6815.9k N obtained from the static analysis with load effect combination. This demonstrates that the contact element works well in simulating the damage of structure and researching the shear force between concrete and outsourcing angle steels.