Experimental Study on Flexural Behavior of Post-Tensioning Bonded Partially Prestressed Ultra-High Strength Concrete Beams

Jinqing Jia,Gang Meng

(Institute of Structural Engineering, Dalian University of Technology, Dalian 116023, China)



Abstract:

This paper presents the results of four partially prestressed ultra-high strength concrete beams in flexure. The test results are used to evaluate the effects of prestressing tendon depth and area on flexure behavior of specimen beams. The test results indicate that: the cracking load, yielding load, peak load and stiffness post-cracking of specimen beams are enhanced by reducing prestressing tendon depth or increasing prestressing tendon area, and the flexural ductility is improved by increasing prestressing tendon depth or reducing prestressing tendon area. The effect of complex reinforcement index considering the strength of the equivalence principle and the reinforcement position on loading levels under serviceability limit state, flexural strength and displacement ductility factor are studied. The influence coefficient of prestressing tendon kp is introduced in the complex reinforcement index. As the complex reinforcement index increases, the loading levels under serviceability limit state and flexural strength increases linearly, and the displacement ductility factor decreases linearly. The test results also verify the conventional beam flexural theory based on the plane cross-section assumption for predicting ultimate flexural strength of partially prestressed ultra-high strength concrete beams is valid. After the introduction of the coefficient kp, the calculation method of cracks in code for design of concrete structure in china are appropriated for the specimen beams.

Key words:  partially prestressed  ultra-high strength concrete  flexural behavior  ductility  serviceability limit state

DOI：10.11916/j.issn.1005-9113.2015.02.014

Clc Number:TU378.2

Fund: