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Annotated Dictionary of Construction Safety and Health
Published in Charles D. Reese, James V. Edison, Annotated Dictionary of Construction Safety and Health, 2018
Charles D. Reese, James V. Edison
Tractors must have seat belts. They are required for the operators when they are seated in the normal seating arrangement for tractor operation, even though back-hoes, breakers, or other similar attachments are used on these machines for excavating or other work which result in other than normal seating.
Mechanistic-based verification of a structural layer coefficient for high polymer-modified asphalt mixtures
Published in Road Materials and Pavement Design, 2021
Jhony Habbouche, Elie Y. Hajj, Peter E. Sebaaly, Murugaiyah Piratheepan
Two types of analysis were considered for each selected distress mode; static analysis representing a speed of 0 km/h (0 mph) and simulating traffic reaching a full-stop at an intersection, and dynamic analysis considering multiple speeds of 13, 24, and/or 72 km/h (8, 15, and/or 45 mph) with and without braking effect. The braking effect was introduced to simulate the actual loading conditions on pavements subjected to shoving, a dynamic mechanistic analysis was performed at a speed of 24 km/h (15 mph) and a temperature of 50°C (122°F) (which is the effective high analysis temperature for rutting and shoving) under braking conditions. The user needs to specify a braking friction coefficient (fBr) when specifying the axle/tire configuration. A braking friction coefficient (fBr) of 0.623 was calculated considering a tractor-semi trailer truck on a sloped pavement structure as illustrated in Figure 5 and based on the following assumptions (Siddharthan et al., 2015): The vehicle speed at brake initiation is 64 km/h (40 mph) and the stopping distance (SD) is 30.48 m (100 ft) with a pavement slope of 0 degree.The loading configuration consists of a tractor-semi trailer with a steering single tires, driving dual tires, and trailer dual tires axle.The tractor total weight, W1, is considered 71.2 kN (16,000 lbs) and the semitrailer total weight W2 is considered 284.7 kN (64,000 lbs) resulting in a gross weight of 355.9 kN (80,000 lbs). It should be mentioned that the same configuration of tandem axle/dual tires at the driving and trailer axle was considered as previously defined.