I-225 in South Denver

I 225

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Erosion Controls of Colorado has completed most contract work. The remaining work recently completed was related to the slope stabilization of a severely eroded slope above the ground nail wall in the northwest quadrant of I-225 and Mississippi.

This slope has been stabilized via the installation of soil retention blankets, anchors and Turf Reinforcement Mat (TRM). As of June 1, 2016, approximately two days of work remains related to grading and installation of TRM on the roadway ditch. This work will be complete as soon as the respective area dries from recent rain. The only impacts to I-225 will be shoulder closures.

Damage Overview

I-225 is a six lane interstate providing major north-south access within the Denver metro area.  In many areas, the roadway is lower compared to the surrounding area, with relatively steep slopes leading away from the shoulders.  At several locations north of Mississippi Avenue on southbound I-225, the slopes became saturated from the rains, causing the soil to slide down the slopes and into the ditch below.  There were multiple areas in the section from 6th Avenue to Smith Road where the joint filler in the concrete pavement had been pushed up and out of the joints from pressure caused by the rain.

Emergency (Temporary) Repairs

The slide material from the slopes came to rest in the ditch and was determined not to be a danger to the travelling public, so no Emergency Repair  work was performed to remove the slide material.  During water pumping operations, an erosion hole formed at the outlet of the pumping hose.  CDOT filled the hole with concrete to protect the embankment and roadway from being undermined during water removal operations.

I 225jointdamage2015Permanent (Long-Term) Repairs

Long-term repairs will include removal of the slide material from ditches and placing it back into the slide areas with turf reinforcement mats and seeding for new vegetation.  The expansion joints that were damaged will be cleaned out and replaced.    

Estimated Timeline

  • Est. Design Start:  Summer 2014
  • Est. Construction Start: Summer 2015

Estimated Budget

  • $1 million


One of the goals in the repair process is to introduce certain betterments to roadway facilities that were damaged and make them more resilient to similar storm events in the future.  Based on analysis of  the damage caused during the flood event, certain design elements will be incorporated in an effort to prevent or lessen the severe damage that significant flood events can cause.  At the I-225/I-70 flooding site, the turf reinforcement mats will improve the stability of the slope and prevent similar damage in future storm events.  

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