Experimental Researches On Flexural Properties Of Slotted Beam And Its Application In Frame Structure

Building energy consumption occupies more than thirty percent of total energyconsumption in China. Continuing to promote building energy conservation is a basicpolicy in our country. To structural eyes, a novel thermal self-insulation structuralcomponent i.e. slotted beam was advanced in this thesis. The slotted beams/lintels andsolid RC beams/lintels as reference were tested to study their flexural properties.Then the slotted beam was applied to the frame structure. The energy-efficient systemof frame structure with dual-beams was advanced and its principles were introduced.The thermal performance of the structure was also analyzed.Firstly, conventional solid reinforced concrete (RC) beams were modified toslotted beams for consideration as thermal self-insulation structural component. Theslotted beam consisted of an outer and an inner part with the slot located near themiddle of the beam along its width direction. Nine slotted beams and three solid RCbeams as reference were tested under four point bending. Flexural properties of thebeams were evaluated. The test results indicated that the outer part and the inner partof the slotted beam cooperated well under loading. The slotted beams can meet therequirement of normal usage. The existence of slot and the width ratio of inner part toouter part had negligible influence on crack width, failure pattern and ultimatestrength of the slotted beams. As the steel ratio increased, the crack width wasreduced while ultimate capacity increased accordingly. Concrete strength had noobvious effect on crack width. With the same steel ratio, the higher the concretestrength was, the greater the ultimate capacity would be.Secondly, the slotted lintel can be thermal self-insulation member through fillingthe slot with insulation materials which can cut the thermal bridge off. Two solidlintels and eight slotted lintels were tested to study their flexural properties. Testresults showed that the outer part and the inner part of the slotted lintels bothcooperated well with each other. The measured maximum crack width inserviceability limit state was smaller compared to the limit value in code, indicatingthat the slotted lintels can meet the requirement of normal usage. Generally, the slotand width ratio of the slotted lintels had little effect on initial crack load and failuremode. And the slot led to a slight decline of ultimate strength of the slotted lintelscompared with the solid lintels. The slotted lintels had a much better thermal performance than the solid lintels.Finally, the slotted beam was applied to the frame structure. The energy-efficientsystem of frame structure with dual-beams was advanced and its principles wereintroduced. The thermal performance of the beams and columns were also analyzedwith FLUENT software by building three-dimensional steady thermal conductionmodel. The results showed that this system was energy saving by59%compared withframe system. The heat flow of the beams and columns had been sharply reducedby79%, which indicated that this system had a distinct energy-saving effect. With thethermal bridges reduced and a great quantity of new wall materials used, there’s noneed to build outside or inside insulation, whose shortages were avoided. Because ofthese, this new system met the requirements of green ecological energy-efficientbuildings. This paper may provide the basis for the design and promotion of newenergy-efficient system.