Shoulder

Unprotected areas adjacent to runways and overruns are susceptible to erosion caused by jet blast. Shoulders reduce the probability of serious damage to an aircraft to a minimum in the event that the aircraft runs off the runway pavement. The shoulder width, shown in Item 3 of Table 3-2, includes both paved and unpaved shoulders. Paved shoulders are required adjacent to all runways. The minimum paved shoulder width, shown in Table 3-2, allows the runway edge lights to be placed within the paved portion of the shoulder and to reduce foreign object damage (FOD) to aircraft. The unpaved shoulder should be graded to prevent water from ponding on the adjacent paved area (shoulder and runway). The drop-off next to the paved area prevents turf (which may build up over the years) from ponding water. For USAF, Army, Navy and Marine Corps airfields, manholes, hand holes, and drainage structures constructed within these areas should, at a minimum, be designed as provided in this section (NOTE: These requirements do not apply to projects already under design prior to the publication date of this manual.) Beyond the shoulders, grade structures are not designed to support aircraft wheel loads. The top surface of foundations, manhole covers, hand hole covers, and frames should be flush with the grade. Maintenance action is required if the drop-off at the top edge of the foundation exceeds 76 millimeters (mm) (3 inches (in)).

Paved Shoulder Areas
3-9.1.1 For structures with their shortest span equal to or less than 0.6 m (2 ft), design based on a wheel load of 34,000 kilograms (kg) (75,000 pounds (lb)) at a contact pressure of 1,724 kilopascals (kPa) (250 lb per square inch (psi)).

3-9.1.2 For structures with their shortest span greater than 0.6 m (2 ft), design based on the maximum number of wheels that can fit onto the span, considering the most critical assigned aircraft operating at its maximum gross weight. In no case, however, should the design be based on computed stress conditions less than those created by a wheel load of 34,000 kg (75,000 lb) at a contact pressure of 1,724 kPa (250 psi).

Unpaved Shoulder Areas
3-9.2.1 For structures with their shortest span equal to or less than 0.6 m (2 ft), design based on a wheel load of 22,667 kg (50,000 lb) at a contact pressure of 1,724 kPa (250 psi).

3-9.2.2 For structures with their shortest span greater than 0.6 m (2 ft), design based on the maximum number of wheels that can fit onto the span, considering the most critical assigned aircraft operating at its maximum gross weight. In no case, however, should the design be based on computed stress conditions less than those created by a wheel load of 22,667 kg (50,000 lb) at a contact pressure of 1,724 kPa (250 psi).