I-405 - Renton - Slide Repair and Culvert Replacement - Photos

On Oct. 31, crews redirected Thunder Hills Creek through the new culvert. The stream is back running underneath I-405 just in time for winter weather.


Crews finished installing the new culver in October, after being delayed by problems with the tunnel boring machine this summer.




Crews see the light at the end of the tunnel as they work through 120 feet of loose dirt under I-405. The boring machine they were using veered off course in July. They had to come in from the other side with a six-foot diameter pipe and hand dig their way to the wayward boring machine. It's exhausting work. They plan to meet the boring machine by mid-October and then it's full steam ahead.



Crews for Northwest Boring plow through 120 feet of loose dirt to get to the off-course boring machine which sits half way under I-405.




A crane hoists one of the 20-foot-long culvert sections into the boring machine frame


Crews working for our contractor set up the frame for the equipment that will tunnel underneath I-405 to install the new culvert.


The emergency pumping system has two main components:  1) a set of pumps that pulls water from the smaller pipes and moves the water to the north into a storm drain along the I-405 shoulder.  The smaller pipes over the white sandbags are part of this component. 2) The second component consists of 15 pumps (the silver cylinders) that move water into three 24-inch-wide pipes.  These pipes carry the water 2000 feet around I-405 and then disperse it into a wetland on the other side of the freeway.


The orange generators power the sump pumps that help divert Thunder Hills Creek away from the damaged culvert.  Five pumps connect to a manifold that distributes the water into one of three 24-inch wide pipes.


These pumps and pipes move water from Thunder Hills creek into a storm drain along the I-405 shoulder to the north of the project area.


Crews stabilized the sinkhole with crushed rock.  The sinkhole formed on top of the portion of the culvert that collapsed in the Dec. 3 storm.


Project Engineer Lisa Hodgson talks to reporters about the project and upcoming closures


WSDOT staff examine the sinkhole adjacent to southbound I-405



Another view of the sinkhole


This image from inside the culvert shows the blockage caused by the collapse.