Denver Public Works (DPW) is implementing multiple programs to improve pedestrian mobility in the City. In doing so, DPW has received and performed research related to the existing portion of public sidewalk that is made of sandstone (flagstone). Current DPW standards require both concrete and sandstone to have equal thickness when used for sidewalk in the public right-of-way. The results of the research indicate that the compressive strength of primary source of sandstone utilized in the City for public sidewalk exceeds the minimum that is required by DPW (4,000 psi). This means that similar performance may be achieved using thinner sandstone pieces than is currently authorized.
It is therefore determined that DPW's Public Works Transportation Standards and Details for the Engineering Division (PWES-001.5), Curb & Gutter and Detached Sidewalk (Std. Dwg 5.0), Note 4, subsection b), enacted April 1, 2017 shall be waived and replaced with the following statement:
Sandstone must be at least 2-1/2" thick by 5' long (minimum) by 2' wide (minimum). Driving surfaces should be at least 4" thick.
The waiver shall take effect immediately.