Market drivers Demand Demand for construction and civil engineering work can be divided in broad terms into public and private sectors. Public sector work is work for any public authority such as: • Government departments • Public utilities • Universities • The National Health Service, and • Local authorities. Private sector work is for a private owner or organisation or for a private client and includes: • Work carried out by fi rms on their own initiative • Work where the private sector carries out the majority of the risk/ gain. Increasingly, the distance between public and private sectors is disappearing with the introduction of strategies such as the Private Finance Initiative, which is included in Chapter 4. Demand for construction is infl uenced by the following factors: • The industry is vulnerable to economic infl uences as witnessed by the downturn in the UK housing sector in 2008. Figure 1.1 illustrates that the last 40 years have seen a number of periods of ‘ boom and bust’...
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Leveling instruments Older instruments: The wye level is the oldest and bulkiest of the older style optical instruments. A low-powered telescope is placed in a pair of clamp mounts, and the instrument then leveled using a spirit level, which is mounted parallel to the main telescope. The dumpy level was developed by English civil engineer William Gravatt, while surveying the route of a proposed railway line from London to Dover. More compact and hence both more robust and easier to transport, it is commonly believed that dumpy leveling is less accurate than other types of leveling, but such is not the case. Dumpy leveling requires shorter and therefore more numerous sights, but this fault is compensated by the practice of making foresights and back sights equal. Precise level designs were often used for large leveling projects where utmost accuracy was required. They differ from other levels in having a very precise spirit level tube and a micrometer adjustment to raise or low...
TYPES OF SURVEYING & LEVELLING Types of Surveying There are many types of disciplines in surveying and a surveyor during their career may decide to specialise in a particular discipline or may gain experience in all disciplines. The main disciplines of surveying are: Land surveying: Land surveying involves measuring and determining property boundaries, which are used as the basis for all property transactions including buying, selling, mortgaging and leasing. Due to the importance of having a secure and strong property market, in NSW a land surveyor needs to be registered to be able to carry out a land survey. Engineering surveying: Engineering surveyors are engaged in the construction industry and ensure construction works are built in the correct location and as per their design. They are generally found on construction sites setting out various types of works such as buildings, roads, bridges, tunnels and various other forms of infrastructure....
ESSENTIAL PARTS OF THE THEODOLITE The following are the essential parts of theodolite. 1. Trivet 2. Foot Screws 3. Tribrach 4. Leveling Head 5. Spindles 6. Lower Plate 7. Upper Plate 8. Plate Bubble 9. Standard of A-frame 10. Telescope 11. Vertical Circle 12. Index Bar or T-frame 13. Altitude Bubble 14. Compass TEMPORARY ADJUSTMENT OF THEODOLITE OR VTOTAL STATION 1. Setting the theodolite over the station 2. Approximate leveling by Tripod Stand 3. Centering 4. Leveling 5. Focusing the Eeyepiece 6. Focusing the Object glass 7. Setting the Vanier
DEFINITIONS OF FUNCTIONS 1. Centering: The setting of the Theodolite exactly overs a station mark by means of a plumb bob is known as centering 2. Transiting: The method of turning the telescope about its horizontal axis in a vertical plan through 180 degree is termed as transiting. 3. Face Left: ‘Face left’ means the vertical circle of the theodolite is on the left on the observer at the time taking reading. 4. Face Right: This refers to the situation when the vertical circle of the instrument is on the right side on the observer when the reading is taken. 5. Telescope Norm...
The Level: The surveyor uses a level to determine elevations. Levels fall into three broad categories: a "dumpy" level, a "Wye" (or 'Y') level, and "automatic" level. As with all tools of the surveyor, there are various degrees of accuracy within each category of level. A "dumpy" level has a telescope with cross hairs permanently mounted in a pair of arms. A "Wye level has a telescope with cross hairs that is removable from the arms. An "automatic" level is basically a dumpy level, but it has a built in compensator that automatically adjusts for minor errors in the setup of the instrument. In conjunction with a level, the surveyor will use a "level rod" to read an elevation up or down from the level of the telescope. From these obser...