7500 HARDESON RD 2021-06-09 - Laserfiche WebLink

A separation geotextile shall be placed under the spalls to prevent fine sediment from pumping up into the rock pad. The geotextile shall meet the following standards: Grab Tensile Strength (ASTM D4751) 200 psi min. Grab Tensile Elongation (ASTM D4632) 30% max. Mullen Burst Strength (ASTM D3786-80a)400 psi mina AOS (ASTM D4751) 20-45 (U.S. standard sieve size) . Consider early installation of the first lift of asphalt in areas that will paved; this can be used as a stabilized entrance,Also consider the installation of excess concrete as a stabilized entrance. During large concrete pours, excess concrete is often available for this purpose. . Fencing (see BMP C103: High Visibility Fence (p.269))shall be installed as neces- sary to restrict traffic to the construction entrance. . Whenever possible, the entrance shall be constructed on a firm, compacted sub- , grade. This can substantially increase the effectiveness of the pad and reduce the need for maintenance. 1 . Construction entrances should avoid crossing existing sidewalks and back of walk drains if at all possible. If a construction entrance must cross a sidewalk or back of walk drain, the full length of the sidewalk and back of walk drain must be covered 1 and protected from sediment leaving the site. Maintenance Standards Quarry spalls shall be added if the pad is no longer in accordance with the spe- cifications. If the entrance is not preventing sediment from being tracked onto pavement, then alternative measures to keep the streets free of sediment shall be used. This may I include replacement/cleaning of the existing quarry spalls, street sweeping, an increase in the dimensions of the entrance, or the installation of a wheel wash. . Any sediment that is tracked onto pavement shall be removed by shoveling or street sweeping. The sediment collected by sweeping shall be removed or sta- bilized on site. The pavement shall not be cleaned by washing down the street, except when high efficiency sweeping is ineffective and there is a threat to public safety. If it is necessary to wash the streets, the construction of a small sump to con- tain the wash water shall be considered. The sediment would then be washed into the sump where it can be controlled. . Perform street sweeping by hand or with a high efficiency sweeper. Do not use a non-high efficiency mechanical sweeper because this creates dust and throws soils into storm systems or conveyance ditches. 2014 Stormwater Management Manual for Western Washington Volume 11- Chapter 4 -Page 271