Flexural strength of precast reinforced concrete beam extension

Abstract

This paper presents the performance analysis of the precast reinforced concrete beam extension, in order to solve the problem of constructing a long and big concrete beam. This beam size problem is one of the challenging problem in terms of setting it in the construction site. We discuss the flexural strength analysis for a joint mechanism in the middle of the beam element in order to ease the installation. The aim of the experiment is to evaluate the flexural strength on the concrete beam. Testing is conducted based on the ASTM C 78 standard, which is the concrete flexural strength test with two exposures due to the existence of a support which exist at the 1/3 of the area (third point loading). In this research we conduct experiment on a total of three samples. The first sample is a full beam with the size of 3000 mm x 250 mm x 350 mm. The second one is the beam with the concrete hollow by the size of 1300 mm x 250 mm x 350 mm. The third one is a beam with the steel sheet extension by the size of 1400 mm x 250 mm x 350 mm. The test result of the three samples shows that the maximum load which can be supported by the full beam is higher compared to other samples. Moreover, the maximum flexural strength which can be supported by the beam with the concrete hollow tube is lower compared to the beam with a steel sheet extension. The fracture pattern behaviour of the middle extension of the concrete beams can be identified.