ACI 2009 Concrete Projects Competition Winners

 

1st Place:
 Experiment Work and an Analytical Investigation on Shear Strength of High-Performance Concrete Beams with Web Reinforcement
Author:
 Jignesh I. Patel  
Faculty Advisor:
 Himat T. Solanki
Abstract:
 This paper presents theoretical investigation on the shear strength of high-performance concrete (HPC) beams with web reinforcement. This investigation involves a development of a theory based on the simplified shear design method by using the stress theory with a softened truss model. The study was carried out by considering several parameters, including concrete covers, web and longitudinal tensile steel ratios, overall beam depths, shear span-depth ratio, and concrete strength. The theoretical study was verified with the results of 133 beams previously published in the literature. A comparison of shear strength was made with the proposed theory and predictions by the shear design provisions outlined in IS 456:2000, ACI 318-05, and EC2 Part I. From comparison, it was found that the IS 456:2000 Code resulted in a more conservative prediction for HPC beams while in ACI 318-05 and EC2 Part I, the results were also conservative but may be adopted for the safe design of HPC beams.

To validate the proposed theory, four additional tests were conducted to examine the effect on the variation of longitudinal reinforcement ratio due to a two-point load. Concrete with a compressive strength of approximately 6810 and 7090 psi (47 and 49 MPa) was used in the beam specimen. Experimental results indicated that shear strength can be affected by the variation of the longitudinal reinforcement ratio. The shear span-depth ratio (a/d) of 1.51 and the shear reinforcement ratio (pt) of 0.20% were used in all beam specimens. The actual shear strength of each beam specimen was compared with the shear strength predicted using the provisions of ACI 318-05 and EC2 Part I. Based on experimental results, the shear strength increases with increases in longitudinal reinforcement ratio.
 
  
2nd Place:
 Marine Biofouling and its Implications on the Durability of Concrete Sea Defences  
Author:
 Peter Hughes
Faculty Advisor:
 Don Fairhurst
 
  
3rd Place:
 Human Hair-Reinforced Concrete  
Author:
 Yonathan Reches
Faculty Advisor:
 Dr. Thomas Kang