4. Elevating grader

This machine consists principally of a disc plough which turns a strip of earth on to a conveyor belt which may be 4 ft. wide and 18-24 ft. long. The belt, running at right angles to the travel of the plough, delivers the earth into lorries which must travel in the same direction and at the same speed as the grader. The ground must therefore be suitable and sufficient space must be available.

Under favourable conditions these machines can dig and load 400 cu. yad. per hour at no greater cost than a stationary excavator. They are usually towed by caterpillar tractors and require a driver in addition to the driver of the tractor. This type of machine is only suitable for very large quantities of excavation and in circumstances where sufficient transport is available to remove the excavation, or where the excavation can be dumped in a window and left. For hard chalk or other rock which the plough will not cut, it is of course unsuitable and in wet sticky clay trouble is caused by clay sticking to the belt, etc.

5.Motor-grader d-144

The highly efficient model D-144 Motor Grader is particularly distinguished by versatility of performed operations, and due to this it is widely used for different branches of the building industry.

The model D-144 motor grader is successfully employed for road, railroad, industrial, municipal, airfield and hydrotechnical building operations.

The main working part of the motor-grader is the fully-swing blade provided with universal installation, which allows its up and down movement, shifting sidewise assymmetrically with reference to the main frame and setting at various angles in the horizontal plane. In limited space the full-swing blade allows to perform operation by the shuttle principle – without turning. Blade shifting is fully mechanized and can be easily effected without excessive effort of the grader operator.

6. Drag shovels or back-acting trenchers

Large construction work almost always calls for deep excavation unsuited to the skimmer for example a number of long trenches, some of these quite narrow ones perhaps only a couple of feet wide for water pipes, drains and so on.

For these, the equipment known as a Drag Shovel or Trencher is employed. The skimmer boom has to come off to be replaced by the one shown in the drawing. Here, the bucket which cuts backwards towards the navvy, is fastened to the dipper arm, hinged at the far end of the boom. Pulling on the rope running over the sheave at the top of the dipper arm moves the bucket away from the machine, pulling on the other one draws the cutting teeth along the ground, so making the cut.

This motion being carried on, the bucket is brought up close under the boom, the machine being slewed, the boom is lifted, and the hinged bottom opened by the tripping of the bucket latch. Alternatively, the bucket can be brought back to the position for commencing the cut, when the spoil falls out by the way it came in.

7. Driver, vehicle, and road

Transportation is a system consisting essentially of three components: driver, vehicle, and road. If any one of these components fails, the whole system would fail, and condition of hazards would be created on the road.To provide a safe and efficient transportation system, it is necessary that all of these three components should function in a well coordinated manner.

Driver. Studies have shown that 86% of the serious accidents are caused by drivers.

Vehicle. This components also plays a vital part in determining safety on roads. An unsafe vehicle is a source of constants danger in a road transportation system.

Road. To ensure maximum safety for the transportation system, it is necessary to plan and design highways on sound engineering techniques.

Modern roads. Modern roads should possess the following principal features. They should be designed according to the anticipated volume and speed of the traffic. Bends and gradients should always be slight. Visibility should not be hindered. They should be well lit. Hedge and tree planting on the road sides should provide a pleasant and interesting outlook to avoid monotony and boredom.

Road construction. In modern road construction, there is much greater recognition of the importance of the subsoil beneath a road. It is regarded as an integral part of the road. In case of mechanical stabilization granular or cohesive materials are added to the subsoil. In dry climates it is necessary to add substances helping to retain sufficient moisture.

Stabilization can be carried out by adding substances that harden the soil, and greatly increase its compressive strength. The constantly increasing volume of modern traffic involves the construction of numerous auxiliary structures, such as bridges, flyovers, tunnels, and underpasses. It is mainly these structures that will present problems for the engineers.

Road construction requires a great amount of versatile and powerful plants intended for carrying considerable amount of operations. Among them are the following:

Fig.1. Grader (motor grader)

1-scarifier (ripper, road ripper, rooter)-рыхлитель

2-grader leveling/leveling-выравнивающий нож грейдера (планировачный нож)

3-blade-slewing (slew turntable)-поворотный механизм ножа

.

Fig.2. road-metal spreading machine (macadam spreader, stone spreder)

1-tamping beam-трамбующая балка (рейка)

2-sole-plate-опора (опорная пята)

3-side stop-боковой ограничитель

4-side of storage bin-борт бункера расходного запаса материала

.

Fig.3. Surface finisher

1-side stop-боковой ограничитель

2-bin-бункер (расходного запаса материала)

Fig.4. Typical cross-section of a bituminous road

1-grass verge-обочина (травяная обочина) дороги

2-crossfall-поперечный уклон

3-asphalt surface (bituminous layer, bituminous coating)

4-base-щснова, основная (базовая) подложка

5-gravel sub-base course (hardcore sub-base course, Telford base),

an anti-frost layer-подложка гравия, морозостойкая подложка

6-sub-drainage-дренажный подслой (дренаж)

7-perforated cement pipe-перфорированная цементная труба

8-drainage ditch-дренажный сток (канава)

9-soil covering-грунтовое покрытие (насыпной грунт)

Fig.5. Three-wheeled rolled, a road roller

1-roller-каток, 2-all-weather roof – всепогодная