Investigation of buried full-scale SFRC pipes under live loads: Fid-Bau Portal

Investigation of buried full-scale SFRC pipes under live loads

Nehdi, Moncef L. / Mohamed, Nedal / Soliman, Ahmed M.

Highlights • Full-scale SFRC pipes buried in soil and subjected to live loads were explored. • The earth pressure around the pipe and pipe diametrical deformations were quantified. • ASTM C76 recommendations for Type C wall were found to be overly conservative. • SIDD provided reasonable estimation of vertical stresses at un-cracked pipe’s invert. • Pipes with 40kg/m³ of long fibres showed lower deformations than that of RC pipes.

Abstract Several studies investigated the mechanical performance of steel fibre-reinforced concrete (SFRC) pipes under the Three-Edge Bearing Test (TEBT). However, the field performance of buried full-scale SFRC pipes is yet to be duly investigated. This study is an exploratory investigation providing first time data on the behaviour of buried full-scale 600-mm diameter SFRC pipes under actual and simulated live loads. The first phase of this study monitored the behaviour of SFRC pipes under standard CL 625 truckloads. In the second phase, the post-cracking behaviour of SFRC pipes under artificial live loads was examined. Results showed that the current design recommendations for the pipe wall thickness in ASTM C76 for Type C wall are overly conservative. In addition, it was found that the SIDD method overestimates the vertical soil stress at the pipe crown and underestimates the horizontal soil stress at pipe spring-lines by 73% and 272%, respectively. Cracked SFRC pipes incorporating a relatively high fibre dosage exhibited less deformation than that of cracked regularly reinforced concrete pipes. Moreover, the post-cracking behaviour of SFRC pipes was more sensitive to the type of bedding installation rather than the type of steel fibres.