Identifying Common Sidewalk Distresses
Around the country, sidewalks have become major focus areas for infrastructure improvements. Like roadways, sidewalks can display a variety of distresses, from small cracks to severe faults, these distresses should be tracked and addressed by the city to improve public safety and ensure ADA compliance. Some of the most common sidewalk distresses are listed below:
Cracking is the most common sidewalk distress. In inches, a low severity crack will be less than 0.5 inches in width, while severe cracking is anything greater than 1 inch. Typically cracking does not impact the utility of a sidewalk to a degree which renders it inoperable, but severe cracking can be a precursor to more severe distresses, such as faulting. Cracks in sidewalks are not frequently addressed due to the nature of most concrete sidewalks. Rather than replacing an entire panel of concrete, municipalities generally wait until more severe distresses begin impacting the segment before repairs are issued. It is still helpful to know where sidewalk cracking has begun to form, so accurate budgeting and repair plans can be agreed on ahead of time
Faulting is what happens when severe cracks are left alone for too long. The sidewalk eventually breaks apart at the cracked seams and falls away to create large gaps. While a low severity fault can be as small as ½ an inch, high severity faults are anything larger than 1 full inch. Sidewalk faults can expand quickly and may even grow to the point of limiting pedestrian and ADA travel.
Shattered Slabs happen when a segment of sidewalk has been broken up so significantly that parts of the sidewalk are jostled out of place or missing completely. Segments displaying this form of distress severely restrict ADA travel and often present tripping hazards to pedestrian traffic. These segments must be dug out and replaced to return the sidewalk to full service.
Weeds/foliage tend to have significant impacts on neglected segments of sidewalk. Often this comes in conjunction with severe cracking and faulting, where the distressed areas have begun to grow foliage. This has an impact on travel, but it also accelerates the rate of deterioration on the segment. This type of distress is frequently considered an obstruction, rather than a sidewalk defect. In the example image below, the foliage was so invasive as to restrict travel on the segment of sidewalk, and prevent an accurate distress survey from being completed.
Obstructions are calculated and considered separately from the SWCI and should rank higher on the priority for the City to fix. There are two reasons for this. First is the consideration of ADA liability, where even a single obstruction on an overall Excellent SWCI-rated sidewalk will count the entire segment as a failure to comply with ADA regulations. Next is the cost consideration; a majority of obstructions are inexpensive and easily fixed problems. Foliage can be trimmed back, garbage and recycle receptacles can be repositioned so that they do not block the sidewalk and tripping hazards can often be smoothed over without spending a lot of capital.
IMS prioritizes sidewalk rehabs based on need, not worst-first. This methodology seeks to catch a sidewalk when it reaches the steepest point in its deterioration curve, and rehabilitate it to extend the overall lifespan of the sidewalk. Where a sidewalk falls on its deterioration curve is based on the sum of distress deducts gathered from an analysis of the survey recordings. Some distress, such as shattered slab, may impact the deterioration of a sidewalk far more than others. The analysis seeks to optimize rehabilitation funds by spending money in a manner that prolongs the lifespan of sidewalks while minimizing the rate that they fall into more expensive rehabilitation strategies, such as panel replacement.