Experimental study on thermal performance of improved open-web roofs with induced ventilation

The double layer open-web roof structure is a type of heat preservation and insulation roof structures, in particular suitable for medium and large span roof structures. However, the construction procedures for traditional open-web roof structures are rather complicated because of the built-in molds in the cavity. On the other hand, passive ventilation is an effective route to enhance the thermal performance of the building envelope. In this paper, an improved open-web roof structure is presented. The steel tube shear connectors are employed to replace the tubby reinforced concrete shear connectors. The adopted shear connectors have small holes in the middle part of their heights. This improvement not only simplifies the construction procedures, but also enhances the thermal performance for open-web roof structures. In order to verify the effectiveness of proposed new open-web roofs, experiments with temperature measurements were performed for a real roof structure. The measured results show that nearly half of the heat flow is drawn out from the cavity due to the induced ventilation. The proposed new open-web roofs have significant improvement and effectiveness on thermal performances, when comparing with traditional open-web roof structures.