6TH International Congress on Technology - Engineering - Kuala Lumpur3 - Malaysia (2018-07-19)

Influence Of Double Idealized Shear Flow Zones On The Torsional Resistance In Uhpfrc Beams

The influence of double idealized shear flow zones on the torsional resistance for under-reinforced ultra-high performance fiber reinforced concrete beams subjected to pure torsion was investigated. The concrete beams section was reinforced with two layers of transverse and longitudinal reinforcements, which located in the idealized shear flow and tension zones. To study the influence of double reinforcements on the torsional resistance of under-reinforced ultra-high performance fiber reinforced concrete beams, four beams were cast and tested under pure torsion. The beams designed in accordance with the American Concrete Institute. The main transverse and longitudinal reinforcements in the shear flow zone are kept constant in the beams while the transverse reinforcement in the idealized tension zone was covered different percentage of this zone. The test results were confirmed that the torsional resistance at peak loads was improved up to 25.14%, due to covering 85.4% of the idealized core zone area by reinforcement. In addition, the twisting angle at peak loads decreased up to 34.09% due to enhancement in stiffness of the beam’s section up to 82.45%. The value of shear strain was reduced up to 49.86% due to the enhancement of the strain in longitudinal reinforcement while the strain in transverse reinforcement was reduced at peak load. The spacing between spiral cracks and their inclination angle were increased due to the inclusion of reinforcement in the core zone area. The space truss model was modified to cover the influence of reinforcement in the idealized tension zone. The proposed modification model was shown that it has a good agreement with the test results.
Ferhad Rahim Karim, Badorul Abu Bakar, Choong Kok Keong, Omer Q. Aziz