• Steel and Composite Structures
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• 제21권3호
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• pp.589-604
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• 2016

Kenya has recently experienced worrying collapse of buildings during construction largely attributable to the poor quality of in-situ concrete and poor workmanship. The situation in the country is further compounded by rapid deterioration of infrastructure, hence necessitating the development of alternative structural systems such as concrete filled unplasticized poly vinyl chloride (UPVC) tubes as columns. The work herein adds on to the very limited and scanty work on use of UPVC tubes in construction. This study presents the findings of experimental and analytical work which investigated the structural response of composite concrete filled UPVC tubes under compressive load regime. UPVC pipes are cheaper than steel tubes and can be used as formwork during construction and thereafter as an integral part of column. Key variables in this study included the strength of infill concrete, the length to diameter ratio (L/D) of the plastic tube, as well as the diameter to thickness ratio (D/2t) of the plastic tube. Plastic tubes having varying diameters and heights were used to confine concrete of different strengths. Results obtained in the study clearly demonstrate the effectiveness of UPVC tubes as a confining medium for infill concrete, attributable to enhanced composite interaction between the UPVC tube and infill concrete medium. It was determined that compressive strength of the composite column specimens increased with increased concrete strength while the same decreased with increased column height, albeit by a small margin since all the columns considered were short columns. Most importantly, the experimental confined concrete strength increased significantly when compared to unconfined concrete strength; the strength increased between 1.18 to 3.65 times the unconfined strength. It was noted that lower strength infill concrete had the highest confined strength possibly due to enhanced composite interaction with the confining UPVC tube. The study further proposes an analytical model for the determination of confined strength of concrete.

• 복합신소재구조학회 논문집
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• 제5권4호
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• pp.52-57
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• 2014

Due to the advantageous mechanical properties of the fiber reinforced polymeric plastics(FRP), their application in the construction industries is ever increasing trend, as a substitute of structural steel which is highly vulnerable under hazardous environmental conditions (i.e., corrosion, humidity, etc.). In this study, hybrid FRP-concrete composite pile (HCFFT) connection is suggested. The HCFFT is consisted of pultruded FRP unit module, filament wound FRP which is in the outside of mandrel composed of circular shaped assembly of pultruded FRP unit modules, and concrete which is casted inside of the circular tube shaped hybrid FRP pile. Therefore, pultruded FRP can increase the flexural load carrying capacity, filament wound FRP and concrete filled inside can increase axial load carrying capacity. In the study, connection capacity of HCFFT(small and mid size) is investigated throughout experiments and finite element method. From the results of experiments, we suggested the connection methods about HCFFT pile connection.