Street Maintenance is a Priority
Recent citywide surveys of West Des Moines residents rate maintaining streets among the highest priorities and most important services provided by the City. The City of West Des Moines uses a Street Management System (SMS) to preserve and maintain the City’s public streets network. The ultimate goal of a SMS is to help achieve a very satisfactory roadway system for the least public dollar expenditure. The City also uses the SMS to determine the value of its public infrastructure for its annual financial report audits.
The City’s SMS is a computerized database system that is used to inventory street information, inspect pavement condition, predict future street needs and conditions, and determine repair needs and budgets. The City has used some form of a computerized SMS since 1991. The concept behind the SMS is to schedule timely proactive lower cost preventative maintenance activities that will extend pavement quality and reduce expensive pavement reconstruction. This results in substantial cost savings over the service life of the pavement. The concept is similar to having regular oil changes for a car to extend engine quality and life and save on expensive future repair and replacement costs.
As of November 1 2016, the City’s public street network consists of approximately 787 lane miles of roads. The replacement value of the City’s public street network is estimated at over $1.2 billion in today’s dollars. The City’s street network is probably the highest valued item owned by the taxpayers of West Des Moines.
In the past 10 years the City’s street network has grown at an average annual rate of 3.0 to 4.0 percent. With planned development, annexations and capital improvement projects; the City’s street network is anticipated to grow by at this percent annually in the foreseeable future.
The types of maintenance and repair use by the City’s SMS typically include asphalt overlays, patching, pavement sealing, and street reconstruction.
Annual rehabilitation activities include:
Asphalt Overlay - This activity involves resurfacing existing streets with two or three inches of hot mix asphalt (HMA). On streets with an existing asphalt surface, the existing surface is typically milled off to insure bonding with the new overlay. Asphalt overlays are used to restore ride and extend pavement life.
Patching - This activity involves removing a distressed portion of the pavement and replacing it with new concrete. Many times damaged intakes may be replaced as part of a patching project. Patching is used to improve pavement condition, preserve pavement quality and reduce future pavement damage.
Pavement Crack Sealing - This activity involves sealing existing pavement joints and cracks with an asphalt liquid to prevent water and debris from entering into the pavement. Excess water in the soil subgrade beneath the pavement is one of the primary causes of premature pavement failures. Pavement crack sealing is used to preserve pavement quality and reduce future pavement damage.
Street Reconstruction - This activity completely replaces a street with new pavement. Street reconstruction is only used on pavement sections in such a deteriorated condition that the pavement cannot be restored through other means. It is the most costly and time consuming rehabilitation activity and therefore is only used when all other methods will not provide a cost effective or long lasting repair. Reconstruction is used to restore a severely distressed street to a new condition.
Subdrain Retrofit - Subdrain retrofit is installing pipe along the sides of existing streets to drain excess ground water and saturated subgrade under pavement. Excess water beneath the pavement is one of the primary causes of premature failures. It is highly recommended to install subdrains anytime irrigation lines are placed along a street.
For the Summer and Fall of 2017 approximately $4.5 million dollars worth of street and pavement rehabilitation is proposed throughout the city. This includes the following:
· Patching - 8.6 lane miles
· Asphalt overlays - 9 lane miles
· Street Reconstruction - 0.6 lane miles
· ADA Compliant Sidewalk Ramp Replacements - 50-60
· City Parking Lot Repair - Fire Stations #17, #18, & #19
The following link is a map showing the locations of Street Maintenance projects that are proposed for 2016.
|2017 Proposed Street Rehab Construction|