SHOULDER CONSTRUCTION PRACTICES IN MICHIGAN

MICHIGAN USES TWO GENERAL TYPES OF SHOULDERS: ONE OF TURF-COVERED EARTH AND GRAVEL EIGHT FEET WIDE, AND A SECOND WITH A TWO-FEET STRIP OF OILED AGGREGATE WITH THE OUTER EIGHT FEET OF TURF-COVERED EARTH. THE FIRST TYPE OF SHOULDER IS PROVIDED WITH A FIFTEEN-INCH GRANULAR SUBGRADE, WHERE PLASTIC SOILS OCCUR. THE UPPER SIX INCHES OF EARTH SURFACE SOIL IS IN ALL CASES STABILIZED BY ADDITION OF BINDER SOIL TO BANK-RUN GRAVEL OR OTHER GRANULAR SOIL MATERIALS. THIS MECHANICALLY STABILIZED SHOULDER SOIL IS SEEDED. THE SECOND TYPE OF SHOULDER IS SIMILAR TO THE FIRST EXCEPT FOR THE TWO-FOOT STRIP OF OILED AGGREGATE ADJACENT TO THE TRAFFIC SURFACE. SEEDING OF TURF-COVERED SHOULDER AREAS IN BOTH TYPES OF SHOULDERS IS DONE DURING THE FIRST SPRING SEEDING SEASON (APRIL OR MAY) FOLLOWING CONSTRUCTION. THE SHOULDER IS HARROWED TO A DEPTH OF ABOUT 3/4 INCHES, OR DEEPER, FERTILIZER IS HARROWED IN AND MULCH IS WORKED INTO THE LOOSENED SHOULDER SURFACE. ABOUT 50 POUNDS OF MIXED SEED IS THEN APPLIED AND ROLLED OR COVERED BY USE OF A CHAIN DRAG. /AUTHOR/