Reinforcement Optimization Of Simply Supported Deep Beams With Openings

With the diversification of construction,various forms of auxiliary equipmentpipelines are becoming more and more huge and complicated in the modernreinforced concrete structure,which results in the load acting on the structure beingincreasing.Deep beam as an important bearing component of structure often need toprovide openings through its webs to accommodate service ducts, which willeffectively reduce the height of floor.The load transfer mechanism in deep beams isbecoming more complicated because openings in the web area of deep beams reducethe structure’s ultimate load-carrying capacity and stiffness. The traditional designmethod may not reflect its structural behaviour. Therefore, scholars in the world havebeen studying it until now. Nowadays, the design principle of the two-dimensionalnon-truss component such as deep beam with openings was given in China codeGB50010-2010, but it still lacks definite mechanical concept of calculation modelsand design formulas, which make the deep beams with openings unsafe in practicalengineering. The strut-and-tie models have been adopted by many nations’ codebecause it reflects the real transfer mechanisms of deep beams and has the cleardesign ideas. Then the method became the typical method of designing complexmechanics structure. Based on the theory of the strut-and-tie models, the thesiscarried out a series of texts for designing the reinforcement of deep beams withopenings by using the optimizational approach. This study has a certain engineeringvalue and significance.For studying the behavior of deep beams with openings and proposing areasonable reinforcement design method, the thesis designed a series of specimensand completed the related experimental work by the strut-and-tie model in AppendixA of ACI318-08and the method in Appendix G of GB50010-2010. The strut-and-tiemodels of deep beams with openings, which constructed by a robust topologyoptimization method named the genetic evolutionary structural optimizationalgorithm (GESO), can effectively reflect the real transfer mechanisms of deep beams.The main work and research findings are as follows:1. In this paper,5group test specimens consisted of11simply supported deepbeams with openings and1simply supported deep beams subjected to two-point topconcentrated loads were tested to failure. The failure models of12reinforced concrete deep beams were comparative analysed.This paper investigated the factors that haveinfluence on the mechanical behavior of simply supported deep beams with openings.2. The strut-and-tie models of deep beams with openings which used the GESOto construct agree well with failure models of test specimens. Based on the theory(strut-and-tie models) mentioned above, the reinforcement design of deep beams withopenings will need fewer steels and be economical.3. The strut-and-tie model in ACI318-08conservative predict the ultimatebearing capacity.4. For deep beams with openings, the design method is not perfect and thecalculation formula cannot reflect the mechanical behavior of structure in GB50010-2010.So a reasonable design of mechanical model and calculation formulaneeds to be established.