Page 55

2015FallShotcreteEMag

Goin’ Underground (a) (b) Fig. 3: Overhead load applied to the tunnel Fig. 5: Mockup of ring girder shoot Fig. 4: Waterproofing and ring girders being Fig. 6: Shooting the mockup installed three times we had to divert to an alternate pump. thicknesses during a follow-on mobilization Because the pumps were inline, the conversion (refer to Fig. 5(a) and (b) and 6). was accomplished with minimal down time. Another challenge, which was proven at the Temporary support of the overhead structures, mockup stage, was the encapsulation of the No. 11 which had a pile foundation that would be inter- (#36M) reinforcing bar splices, which were rupted by the tunnel, would eventually be lapped, leaving us only a 3.5 in. (90 mm) opening replaced by steel tube ring girders installed to to shoot through. permanently carry the load of the overhead The next challenge was shooting a 36 in. structures once the transfer occurred. The shot- (0.9 m) thick structural liner from spring line to crete encapsulation of the ring girders was the spring line, mostly in the overhead position and first issue and we proved our methods were finishing the project in less than 5 days. We accurately represented during the mockup for attacked the project by working two crews per the project. Due to the size of the girders, we shift and two long shifts per day, with a cleanup used a layering method and encapsulated the and maintenance shift in between, with the wall backs of ring girders ahead of the reinforcement segments being installed first, then moving to being installed. We then shot the remaining shooting the overhead areas. Due to the thickness Shotcrete • Fall 2015 53


2015FallShotcreteEMag
To see the actual publication please follow the link above