Company:
County of Orange and Rancho Mission Viejo
Status:
Awarded
Awarded:
Project of the Year
Additional Files



Additional Information

Cow Camp Road Bridge over Gobernadora Canyon

Project Location:

Unincorporated South Orange County, CA

Project Description:

Cow Camp Road is a new four-lane arterial roadway located east of San Juan Capistrano. It serves as a vital east–west link between Antonio Parkway and Ortega Highway, providing access and all backbone infrastructure to a new development of the Rancho Mission Viejo property where 14,000 homes are planned along with 5.2 million square feet of non-residential uses over 6,000 acres.

The Cow Camp Road Bridge over Gobernadora Canyon is 1,340-feet-long and 79-feet-wide and accommodates vehicle, pedestrian and bicycle traffic over a 60-foot-deep natural canyon and major regional drainage facility. When construction is complete, this will be one of the largest bridges in Orange County. Critical infrastructure utilities, including water, electrical, gas and communications are supported within the structure, providing connections to various phases of the new development. This massive, yet elegant, structure is constructed of post-tensioned concrete supported on seven-foot diameter columns and 12-foot diameter shaft foundations in the canyon to a depth of 130 feet.

Project Justification:

There were unique challenges, solutions and features associated with the design and construction of this bridge project that are worthy of recognition.

Michael Baker International’s multi-discipline team worked closely with the Rancho Mission Viejo (RMV) team to gain concurrence from numerous public agencies during the planning, engineering and construction phases of Cow Camp Road over the last seven years.

Flooding, High Ground Water and Scour | Gobernadora Canyon is a major drainage area subject to major flood flows and potential scour of bridge foundations. This threat was mitigated with deep, large diameter drilled shaft foundations for the bridge within the canyon to accommodate scour depths of 12 feet. This foundation type was selected to mitigate scour effects while minimizing excavation associated with deep pile supported foundations beneath the high ground water elevations – making bridge construction more economical. This design approach was a direct result of lessons learned from construction difficulties associated with other nearby bridges.

Local Seismicity and Geotechnical Concerns | The unique site geotechnical conditions included high seismicity, lateral soil spreading, liquefaction and high ground water. Michael Baker and GMU Geotechnical Engineering worked together to address these issues by coordinating with Caltrans, the County of Orange and TCA to address the latest requirements of all seismic design criteria, including checks proving the structure remains elastic (undamaged) during lower level earthquakes.

Innovation | In the spirit of improving upon similar bridge designs in the area, the project team invested a significant amount of time and research investigating the hinge details normally associated with concrete bridges longer than 700 feet. The typical hinge detail consists of costly and complex girder bearings and congested reinforced steel in the hinge area. The team’s research and design calculations indicated that this hinge could be avoided by constructing the bridge in three stages, prestressing the bridge at each stage and using closure pours with special detailing to complete the full length of the structure. This phased approach eliminated the need to use the expensive hinge detail, which will ultimately provide a structure that will be more predictable during lateral seismic movements. These detail refinements were approved by all reviewing agencies and resulted in $1.5 million in cost savings for the bridge construction.

Special Circumstances:

During construction of the foundation at Bent 5, the Contractor encountered difficulties placing concrete in one of the large 12-foot diameter drilled shafts in the deepest portion of the canyon where some soil caving occurred in the hole, causing large voids in the concrete at three critical sections of the pile foundation. After extensive inspection of the concrete, including cross-hole sonic testing, the pile was rejected, requiring these anomalies to be repaired or replaced with a new foundation system at the bent. Michael Baker and GMU worked with the Contractor to develop an emergency remedial repair program for the pile mitigation, including an alternative foundation design in case the pile mitigation was not successful. These two alternatives were evaluated simultaneously with agency reviewers. The pile mitigation plan consisted of drilling a series of holes surrounding the entire existing pile, creating a grout jacket to contain new concrete to fill the voids in the pile – all in accordance with Caltrans specification requirements. The alternative plan involved drilling four new seven-foot diameter CIDH “sister piles” alongside the existing damaged pile.

Ultimately, the Contractor successfully implemented the pile mitigation plan, which kept the project on the schedule approved by all agencies. The overall response to this emergency demonstrates the true collaboration among the Owner, Contractor and Design Team.

Project Attachments:

This project exemplifies the successful collaboration among the Owner, Contractor, Design Team and all Agencies to deliver a major infrastructure project in Orange County.

Award Citation::

The Cow Camp Road Bridge over Gobernadora Canyon is 1,340-feet-long and 79-feet-wide and accommodates vehicle, pedestrian and bicycle traffic over a 60-foot-deep natural canyon and major regional drainage facility. When construction is complete, this will be one of the largest bridges in Orange County. Critical infrastructure utilities, including water, electrical, gas and communications are supported within the structure, providing connections to various phases of the new development.

Suggested Award Summary:

Cow Camp Road is a new four-lane arterial roadway located east of San Juan Capistrano. It serves as a vital east–west link between Antonio Parkway and Ortega Highway, providing access and all backbone infrastructure to a new development of the Rancho Mission Viejo property where 14,000 homes are planned along with 5.2 million square feet of non-residential uses over 6,000 acres.

The Cow Camp Road Bridge over Gobernadora Canyon is 1,340-feet-long and 79-feet-wide and accommodates vehicle, pedestrian and bicycle traffic over a 60-foot-deep natural canyon and major regional drainage facility. When construction is complete, this will be one of the largest bridges in Orange County. Critical infrastructure utilities, including water, electrical, gas and communications are supported within the structure, providing connections to various phases of the new development. This massive, yet elegant, structure is constructed of post-tensioned concrete supported on seven-foot diameter columns and 12-foot diameter shaft foundations in the canyon to a depth of 130 feet.

The multi-discipline project team worked closely with Rancho Mission Viejo (RMV) to gain concurrence from numerous public agencies during the planning, engineering and construction phases of Cow Camp Road over the last seven years.

Flooding, High Ground Water and Scour | Gobernadora Canyon is a major drainage area subject to major flood flows and potential scour of bridge foundations. This threat was mitigated with deep, large diameter drilled shaft foundations for the bridge within the canyon to accommodate scour depths of 12 feet.

Local Seismicity and Geotechnical Concerns | Unique site geotechnical conditions included high seismicity, lateral soil spreading, liquefaction and high ground water. The team worked together to address these issues by coordinating with Caltrans, the County of Orange and TCA to address the latest requirements of all seismic design criteria, including checks proving the structure remains elastic (undamaged) during lower level earthquakes.

Innovation | In the spirit of improving upon similar bridge designs in the area, the project team invested a significant amount of time and research investigating the hinge details normally associated with concrete bridges longer than 700 feet. The team’s research and design calculations indicated that this hinge could be avoided by constructing the bridge in three stages, prestressing the bridge at each stage and using closure pours with special detailing to complete the full length of the structure. This phased approach eliminated the need to use the expensive hinge detail, which will ultimately provide a structure that will be more predictable during lateral seismic movements. These detail refinements resulted in $1.5 million in cost savings.

CEC {banner_alt}

Contact Us


Please contact the Executive Board of Directors at .(JavaScript must be enabled to view this email address) if you would like to speak with an ASCE OC Branch representative, or the webmaster if you have any questions or comments about this web-site.

ASCE OC Branch

360 E. 1st St., #992
Tustin, CA 92780

(714) 258-8306

Website

ASCE Los Angeles Section

(714) 258-8306

Website

ASCE National Society

1801 Alexander Bell Drive
Reston, VA 20191

1-800-548-ASCE

Website

Stay Connected


Copyright © 2024 ASCE Orange County, California Branch. All Rights Reserved.

Designed and developed by Jub Jub Interactive.