interstate 680 is an important traffic corridor<\/a> located north of council bluffs, iowa<\/a>.\u00a0a key section of this interstate connects i-80 in nebraska with i-29 in iowa\u00a0and crosses the missouri river via the mormon bridge.\u00a0the route\u00a0carries approximately 17,400 vehicles per day and serves as a northern bypass of omaha, nebraska<\/a>, and council bluffs, iowa. it also provides critical access to the omaha airport.<\/p>\n
property and infrastructure damage plagued the area. the pavement on i-680 east of the mormon bridge was completely destroyed, and what remained showed signs of floodwater erosion<\/a>. eastbound lanes were higher than westbound lanes. ditches were left full of soil and flood debris. numerous washouts under the pavement left unknown voids. total roadway replacement was the only solution.<\/p>\n
emergency road repair of i-680 was essential to restore traffic, support regional recovery efforts, minimize the extent of damage, and protect what remained. the iowa dot and federal highway administration (fhwa) worked together to procure emergency relief funding for the project. under fhwa emergency relief rules, repairs must be done within 180 days after an emergency, further expediting the roadway repair process.<\/p>\n
floodwaters finally receded in september 2011, almost four months after flooding began. this left only two months to complete environmental permitting, survey, highway design, and reconstruction before the fhwa due date for emergency relief funding.<\/p>\n
rebuilding the road involved 2.6 miles of mainline reconstruction and .8 miles of interchange ramp reconstruction.<\/p>\n
the entire project was let by the iowa dot as a single lump sum to guide rapid completion. the prime contractor, peterson contractors, inc., entrusted snyder & associates to perform highway design<\/a> and construction staking while they rebuilt the flood-ravaged interstate highway.<\/p>\n
snyder & associates’ scope of work included limited topographic survey<\/a>, formulation of a stormwater<\/a> pollution prevention plan and npdes permitting, design, construction staking, and record drawings.<\/p>\n
the flood destroyed most of the existing pavement, so a\u00a0full topographic survey wasn\u2019t performed. however, a limited survey was obtained from the remaining pavement<\/a>. a field survey of remaining alignment monuments was also done to help establish the centerline.<\/p>\n
we reviewed the record drawing information provided by the dot and married it with available lidar modeling. the surface model was checked against vertical and horizontal information provided in the record drawings by focusing on known elevations such as culvert flowlines and pavement<\/a> profiles.<\/p>\n
working closely with the contractor contributed greatly to the project\u2019s success. the design of the roadway corridor was done in phases, beginning with the westbound subgrade, and driven by the contractor’s progress in the field. as the contractor worked around the clock, we adjusted our schedule to stay ahead of them.<\/p>\n
the project design was performed and delivered mainly through electronic files to the contractor. deliverables were patterned around contracting needs to avoid construction delays<\/a>. certain parts of the design were plotted for the construction team and dot inspection staff to convey the design intent. for example, the pavement jointing plans were delivered in this manner, but the bulk of the paper plans and record drawings were done after construction.<\/p>\n
a variety of technology was used to successfully complete the project including lidar surfacing, 3d modeling, gps-enabled construction equipment, and computer-aided design software.<\/p>\n
most notably, the construction team utilized computer software to perform the design and create 3d files for use in the field. using this technology allowed us to deliver the project more quickly. typically, it\u2019s the contractor\u2019s responsibility to convert paper plans into electronic designs. the close working relationship between us and the contractor eliminated any chance of error in converting the plans from paper to electronic.<\/p>\n
repair on an i-680 ramp that was severely damaged by flooding in spring 2011.<\/p><\/div>\n
the weather was a major concern, but due to unseasonably dry, warm fall weather, construction progressed smoothly. the road was rebuilt on the same footprint as the original road built in the 1960s to minimize environmental issues<\/a>.<\/p>\n
our project team was comprised entirely of subject matter experts, specializing in project-specific tasks. over the course of the project, this 12-member team of engineers<\/a>, technicians, and surveyors worked over 1,680 hours in 34 days. the majority of snyder\u2019s contribution was complete in 21 days, while construction staking carried through to 34 days.<\/p>\n
the road opened to traffic on november 2, 2011, following a ribbon-cutting ceremony. all but $2 million of the $19 million costs was eligible for emergency funding assistance<\/a> from the fhwa.<\/p>\n