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SurveyingSurveying is a technique in by which measurements are taken on the surface of the earth and presented on the maps or stored in the digital format and vice versa. There are following types surveying, 1. Plane surveyingIt is meant for small areas where the surface of the earth is taken to be plane surface, i.e. curvature of the earth is ignored. e.g. for survey inside a city. 2. Geodetic surveyingIn this curvature of the earth is taken into consideration. e.g. National surveys, Basic triangulation network of a country. Geodesy is termed as actual shape of the earth. Surveying mapsThere are following types of surveying maps: 1. Topographic mapsIt shows natural and artificial features on the surface of the earth. Surveying done for this purpose is called topographic surveying. 2. Engineering mapsThes maps shows the detail of engineering projects, e.g. roads, bridges, dams. Surveying done for this purpose is called engineering surveying. 3. Geographic mapsThese are about the political boundaries of the country and used by general public. Surveying done of these purposes are undertaken by the state agency. e.g. in Pakistan state agency is "Survey of Pakistan" 4. Cadastral mapsThese shows ownership rights of individual or communities. Surveying done for this purpose is called cadastral surveying.

PhotogrammetryPhotogrammetry is the branch of surveying in which measurements are made from photographs. MeritsThis is a very quick and accurate method of surveying in which the ground observations are almost totally eliminated. This is very accurate method if true interpretations of photographs are made. It also provides means to develop a Contour map. DemeritsThis method requires fair weather conditions. The instrument is very expensive, and staff should be highly qualified and experienced to make full use of this method. Types of PhotogrammetryThere are Two main Types of photogrammetry - aerial photogrammetry and terrestrial photogrammetry. 1. Aerial photogrammetryIn these photographs are taken from specially manufactured plane. The characteristics of this procedure are following: The plane is made to fly along the center of longitudinal strips marked with the help of clearly visible ground monuments. The speed of aircraft being known the camera speed is adjusted accordingly to provide the requisite transverse and longitudinal overlap between successive photographs. The speed of the aircraft, its height and specification of the camera are already known. The photographs are then developed in laboratory with each photograph being placed in its proper position and by cutting the overlapped edges. This will provide a base map on the basis of actual photographs which can be processed further for particular requirements. The scale of photographs can be established by distances on the ground between two points and this dimension on the graph. The contours can be drawn by putting the photographs under the stereo plotter. Stereo plotter is an optical device which gives three-dimensional view of plane photographs. 2. Terrestrial photogrammetryIn this type, the photographs are taken from elevated ground stations. Further development of these photographs will take into account the elevations of camera and tilt of the axis of photograph. This method is very similar to previous one except that the camera is in stationary position. The camera used in this method is called photo-theodolite as it will require the same features as theodolite. This type of photogrammetry is much cheaper and can be carried out by individual surveying firms also.

By deflection angle methodBearing of the first line AB is measured with the help of prismatic compass or by any other method. Setup the theodolite and point B and with horizontal circle reading bisect point A. Transit the telescope and rotate it in the direction of next station point C and note the angle, this will be θ1 R and is called deflection angle at B. Repeat this procedure for the remaining points of traverse measuring the deflection angle and writing with them letter "L" or "R". For calculation of bearing we have to simply add the deflection angles right ® to bearing of previous line to find out the bearing of next line and subtract the deflection angle left (L) from the bearing of previous line to find out the bearing of next line. Examplelet θ1 = 35°, θ2 = 55°, θ3 = 45°, Bearing of AB = 65° 00′ 00″ Add 35° R = 35° 00′ 00″ Bearing of BC = 100° 00′ 00″ Subtract 55° L = 55° 00′ 00″ Bearing of CD = 45° 00′ 00″ By direct Bearing method Bearing of first line AB is determined by any method. Setup the instrument at point B. Set the horizontal circle reading at the Back Bearing of AB and bisect the back station A. Rotate the instrument in clockwise direction and bisect the next point C. The circle reading will give directly bearing of line BC. Repeat the procedure for remaining lines.

For open traversing Following procedure is adopted in case of open traversing with the help of prismatic compass, We will setup the compass at point A, B, C and so on and note the Fore Bearing and back Bearing of lines. The length of lines or legs are measured by chain twice and mean lengths are calculated. During taking measurements in the field, the method used angular measurement, and linear measurement should be of same standard of accuracy, i.e. either combination of Prismatic compass and Chain or combination of theodolite and metallic tape. For closed traversingIn case of closed Traversing while using Prismatic compass, the interior angles can be calculated by comparing the bearings of adjacent lines. The above rule also applied in case of closed Traverse with Theodolite. Check for closed traverse∑ Interior angles = (2N - 4) × 90°, where N is no of sides of closed traverse.

Vertical angleIt is the angle in the vertical plane between horizontal line passing through the intersection of cross hairs and inclined line joining intersection of cross hairs and the point being observed. Circle reading in case of vertical angleDuring Face left vertical angle will be computed in the following manner, When angle of elevation, vertical angle = 90° - Circle reading. When angle of depression, vertical angle = Circle reading - 90°. Now, during Face right vertical angle will be computed in th following manner, When angle of elevation, vertical angle = Circle reading - 270°. When angle of depression, vertical angle = 270° - Circle reading. Example for method of bookingAngle Face Circle reading (° ′ ″) Angle value (° ′ ″) Mean (° ′ ″) Remarks * L 69 58 30 20 01 30 20 01 45(+ve) Elevation R 290 02 00 20 02 00 In case of angle of elevation value of vertical angle will be +ve while in case of depression it will be -ve.

IntroductionSometimes it needs to approximate the distance between two points. One can do it without using any distance measuring instrument. But firstly, you need to compute your own pace length, then you can use your pace length to approximate the actual distance. However, it is not accurate enough to use into the calculations or computations. Procedureopen a chain and let it fly in straight position along the piece of ground. Walk along the chain and count the number of steps. The distance being known personal pace length will be equal to length of the chain divided by number of steps. Repeat the observation for two or three times. ExampleLength of chain No of Paces Pace Length 30m 44 0.68 30m 43 0.69 ApplicationNow, you just need to multiply the number of steps you walked between two points to your pace Average pace length. Approximate Distance = Pace length × No of steps walked Useful Conversions1 feet = 12 inch. 1 m = 3.28 feet. 1 inch = 2.5 cm. 3 inch = 0.25 feet.

1. PacingPermissible error ≤ 1 feet in 20 feet. 2. ChainPermissible error ≤ 1 in 1000. 3. Metallic tapePermissible error ≤ 1 in 1000. 4. Steel tapeThis tape is made of steel alloy of very small co-efficient of thermal expansion. Permissible error ≤ 1 in 1000. 5. Invar tapeThis tape is made of very expensive steel alloy of almost negligible co-efficient of thermal expansion and is used for very precise linear measurements. Permissible error ≤ 1 in 50,000. 6. TachometryPermissible error ≤ 1 in 50,000. 7. Electronic distance meterPermissible error ≤ 1 in 100,000.

LevelingIt is the branch of Surveying in which relative elevations of points are determined. There are following Types of Leveling 1. Ordinary levelingIt is general purpose Leveling and unless otherwise stated all types of Leveling will come into this category. 2. Reciprocal levelingThis is done when a site is unusually long, i.e. crossing the river. Sights are taken from the two banks by placing the staff on the opposite bank almost simultaneously and finding the average of apparent difference of level. This method eliminates the error due to curvature and refraction. 3. Precise levelingThis is a special type of Leveling using very precise level fitted with parallel plate micrometer and using precise staff with invar strip This is used for establishing new bench marks and therefore is undertaken by state agencies. 4. Barometric levelingThis type of leveling is used in higher surfaces of earth like mountains. Application of levelingLongitudinal Sections (L-Sections): It is done to determine the levels at given intervals along the center of level road. Cross Sections (X-Sections): These are the levels at a given cross section of a road or any engineering work Contouring Invert levels for sewers Head rooms from bridges: Staff is used in inverted position from the zero-end touching the ceiling of the bridge, the reading is entered as -ve and R.L of that position is calculated in usual manner.

1. TripodIt should be of a rigid type capable of fixing the position of the instrument with a small lateral movement on its top when required. 2. Foot screwsThese are provided for leveling the instruments. 3. Plate levelProvided for checking the level of the instrument. 4. Horizontal clampProvided to clamp the movement in horizontal plane. 5. Vertical clampFor clamping movement in vertical plane. 6. Slow motion screwsThese screws are used to move Theodolite either vertically or horizontally in small fractions. 7. TelescopeIn a telescope vertical hair is used for horizontal angle measurement while horizontal hair is used for vertical angle measurement. Focusing arrangement for the object glass is usually provided in the body of the telescope. Collimator is provided to bring the object in the field of view. 8. Vertical axisIt is the axis around which the telescope rotates in horizontal plane. 9. Horizontal axisIt is the axis around which telescope rotates in vertical plane. 10. Optical plummetIt is provided for centering the instrument over a ground station. 11. Angle reading arrangementIn screen display you can note angle measurements taken with Theodolite.

Fore bearingIt is the bearing of line when the first letter of line say AB is taken as origin. This is to be written as Fore Bearing (F.B). Back bearingIt is the bearing of line when second letter of line say AB is taken as origin and this is to be written as Back Bearing (B.B). Theoretical difference between Fore Bearing (F.B) and Back Bearing (B.B) should be 180°. Local attractionIf the difference between magnetic Fore Bearing and Back Bearing of a line is not exactly 180°, it may be due to presence of local attraction at one of both stations. If this difference is exactly 180° then both stations are free from local attraction. Local attraction may be due to following reasons. Overhead electrical wires Magnetic materials in the vicinity Practice problemIn the following table observed Bearings are given, we will compute the corrected bearings and Internal Angles. Line Observed Correction Corrected F.B B.B F.B B.B AB 70° 00′ 251° 00′ A= +30′ , B= -30′ 70° 30′ 250° 30′ BC 328° 00′ 145° 00′ - 327° 30′ 147° 00′ CD 225° 00′ 71° 00′ - 257° 30′ 77° 30′ DA 139° 00′ 316° 00′ - 136° 30′ 316° 30′ By observing the table, it may be noted that no line has a difference of exactly 180° between Fore Bearing and Back Bearing. In such a case, a line where the difference is closest to 180° is selected. Such a line is called line of least disagreement, for this line correction is assign to each of the two stations of that line with opposite sign. In the above table line AB is selected for error distribution. Now, we will compute internal angles from these corrected Bearings. A = (360° - 316° 30′) + 70° 30′ = 114° 00′ B = 327° 30′ - 250° 30′ = 77° 00′ C = 257° 30′ - 147° 30′ = 110° 00′ D = 136° 30′ - 77° 30′ = 59° 00′ Before computation of internal angles, you need to draw a rough sketch of scheme based on corrected bearings so that you can judge which angle is lying in which quadrant.

Latitude and DepartureIn order to do start with Theodolite Traversing you should be familiar with the Latitude and Departure which are discussed briefly below, OA is the line with whole circle bearing equal to θ. OC = Latitude = lCosθ OB = Departure = lSinθ By using the above formulae for Latitude and Departure with whole circle bearing, calculator will be giving algebraic sign automatically for Latitude and Departure. For a closed Traverse ∑ of all Latitude is equal to zero and ∑ of Departure is also equal to zero. Consecutive co-ordinatesWhen the Latitude and Departure are calculated at second point of a given line taking first point as a origin then it is called consecutive co-ordinates. Independent co-ordinatesIndependent co-ordinates are the Latitude and Departure of points of a traverse with respect to a common origin, so that all the values are +ve. These are used for plotting purposes. Bowdich RuleThis rule is used to apply the correction in Latitude and Departure which states that correction in Latitude/Departure is equal to Length of Line multiply by Total correction in Latitude/Departure and then dividing by the perimeter. Traverse TableFor the following traverse ABCD, I have applied the correction in Latitude and Departure using Bowdich rule. Line L (m) Bearing (° ′ ″) Latd. Depr. Corrections applied Consecutive co-ord. Independent co-ord. Latd. Depr. Latd. Depr. Latd. Depd. AB 148 115 30 -63.27 133.58 -0.26 - -63.98 133.58 500 500 BC 172 42 25 126.98 116.02 -0.30 - 126.68 116.02 628.68 616.02 CD 201 205 30 -181.42 -86.53 -0.36 - -181.7 -86.53 444.90 529.49 DA 202 306 15 119.44 -162.9 -0.36 - 119.08 -162.9 563.98 366.59 ∑ 723 +1.28 +0.17 -1.28 0 +0.17 As you can see, correction was not applied in Departure as the error was too small to be neglected. Using Bowdich rule we can apply correction in Latitude and Departure for respective line

The following points should be kept in mind while selecting pipe for a certain water supply system, Carrying capacity. Durability. Fire cost. Maintenance cost. Type of water to be conveyed. 1. Cast iron pipes (C.I)Most widely used for the city water supplies. Average life is 100 years. Corrosion my reduce its capacity by 70%. Must be lined with cement or bitumen. C = 130 for new pipe. C = 100 for old pipe (Selected for Design). "C" is the Hazen Williams Coefficient known as HWC. It is the important term used in the design of water distribution system. 2. Steel pipesContains less carbon than Cast Iron pipes. Frequently used for trunk mains. Difficult to make connections hence seldom used for water distribution systems. Much Stronger and lighter than Cast Iron pipes. Cheaper than Cast Iron pipes. Cannot withstand vacuum, hence collapse. Highly susceptible to corrosion, hence high maintenance charges are required. 3. Ductile pipesSimilar to Cast Iron pipes except increased ductility. Ductile iron is produced by adding a controlled amount of Mg into molten iron of low sulphur and phosphorous content. Stronger, tougher and elastic than Cast Iron pipes. More expensive than Cast Iron pipes. 4. Galvanized iron (G.I) pipesManufactured by dipping Cast Iron pipe in molten zinc. Resistant to corrosion. Mainly used for plumbing. 5. Concrete pipesUsual size of Reinforced Cement Concrete pipe is 400mm dia. and above. Not subjected to corrosion. Manufactured at or near site. Average life is 75 years. C = 138 to 152. 6. Asbestos cement pipes (A.C)Sizes are 100mm to 600mm dia. Average life is 30 years. Immune to actions of acids, salts, soil and corrosion. Less cost for laying and jointing. Less plumbing cost due to less friction. C = 140. Asbestos Cement pipes are economical and are generally preferred to use in the design of water supply systems. 7. Poly vinyl chloride pipes (PVC)Mainly used for domestic plumbing. Easy to install and easy to handle. Cheaper in material cost Weak to sustain load. Only available 350mm dia size. Expected life is 25 years.

Leveling equipmenta) LevelThere are different types of Levels as follows, 1. Dumpy levelIt is the type of Level in which whole body of level is cast in one unit. 2. Tilting levelStill being used, Level can be tilted in vertical plane with the help of tilting drum. 3. Automatic levelIn this type, the line of sight becomes horizontal when the Level is within certain limits. This system provides the works on the principal of gravitation. b) StaffIt is the graduated rod of maximum 5m length usually available in telescopic form. The gradations are both in feets and meters. Smallest graduation in feet is 0.01 ft or 1/100 ft and smallest division in meters is .005m. Technical terms in leveling1 - SightsA reading taken from a level on staff is called sight. 2 - Back sight (B.S)It is the first sight taken after setting of the instrument. 3 - Fore sight (F.S)It is the last sight taken before shifting the instrument. 4 - Intermediate sight (I.S)These are sights taken between F.S and B.S. 5 - Line of collimationIt is the straight line joining the intersection of cross hairs and optical center of object glass. 6 - Level lineIt is the curved line equidistant from the center of earth at all points. 7 - Horizontal lineIt is the straight line tangent to observer position. The of collimation obtained by a carefully leveled instrument is a horizontal line. 8 - Reduced level (R.L)It is the level of a point with respect to a certain datum whose level is taken as zero. 9 - DatumIt is a certain reference level to which levels of all other points are referred i.e in Pakistan Datum is mean sea level (MSL) at Karachi. 10 - Change point (C.P)It is the last position of staff after which the instrument was shifted.

A tunnel is an elongated, narrow essentially linear underground opening with a length greatly exceeding its width or height. Most tunnels are nearly or exactly horizontal but for special purposes, tunnels may be driven at angles up to 30 degrees from the earth's surface. The one which is greater than 30 degrees from horizontal are designed as shafts. When rocks in tunnels are highly in-competent, especially when underground water is present, tunneling becomes a very costly and hazardous operation, and excavation and containment of such rocks present a challenge that requires maximum use of highly technical skills and ingenuity. History of tunnelingThere is abundant archaeological evidence that in Europe stone age man sank shafts and drove tunnels to recover flint for the fabrication of sharp-edged implements such as knives, axes etc. later as an elementary knowledge of metallurgy was acquired by premature people, possibly for the first time central Asia, underground excavation became necessary to supply the increasing demands for metals and alloys. Very early underground excavations for metal-bearing have been identified in Caucasia, between the Black and Caspian Sea, and date back to approximately 3500 BC. Many tunnels were built in ancient times by the Babylonians, Indians, Persia and Egypt in search for precious metals. Stone-age man used very primitive tools in underground excavation. Particularly useful to him were picks made of deer antlers, flint axes and hammers and wedges made of bone and wood. The production of metals and alloys provided materials for increasingly efficient rock excavation. Later on, explosives were used in the seventeenth century. For hundreds and perhaps thousands of years underground working in hard rocks, especially those containing few fractures and fissures, were advanced by building fires against rock faces to cause expansion and spalling. In some operations spalling of the heated rock was accelerated by dowsing it with water. The fractured rock was than separated from the working face with picks, gads and wedges. With the increasing use of explosives first the black powder later nitroglycerin, steel temping techniques were perfected and permitted efficient and economical hand drilling of holes for explosives. Tunneling machines have been used to excavated tunneling with diameters of about 6 ft to more than 36 ft. Rate of excavation of over 400 ft per day have been recorded in soft ground. In hard rocks it can be less as 100 ft per day. It includes a rotating cutter head and provision for controlling forward thrust and alignment. In the hardest of rocks, near the middle of the nineteenth century steam powered piston drills and later percussion drills, powered by compressed air, made their appearance and at the same time several tunneling machines such as moles were invented. Tunnels have been driven in a variety of natural materials ranging from unconsolidated water-soaked clay, sand and gravel to dry very hard un-fractured rocks. It is one of the costliest and at the same time one of the most hazardous of all engineering under-takings. In case of long tunnels in area of geological complexity, all types of uncertainties arise, including design and construction techniques and including estimate of cost. The location of a tunnel like the site of bridge often does not allow much freedom of choice. It becomes necessary at given place to maintain an alignment. Before designing and planning a tunnel the undesirable underground conditions must be anticipated. Tunnels through massive un-fractured granite or through horizontally layered sandstones that are well cemented and un-joint present no special problems in design and preparation of cost estimation, whereas in geological complex areas it is an art and intelligent guess work. Purpose of tunnelingTunnels have been constructed for great variety of purpose, and they are classified as follows: Tunnels driven to gain access to economic mineral deposits and to provide haul-ways for extracted minerals. In some mining operations tunnels are driven to provide adequate circulation of air in underground workings. Transportation Tunnels, including pedestrian highness navigational and railroad tunnels. These are among the largest and at time the most difficult of all tunnels to excavate. Water or Sewage Tunnels: These tunnels may or may not be constructed so as to transport liquid under pressure, and a distinction is made between gravity flow tunnels and pressure tunnels. The latter are designed to contain without leakage water under hydrostatic pressure or force-pressure head. Military Tunnels: These tunnels are driven in connection with underground military operations. Tunnels to provide protection from atomic explosion. Utility Tunnels. Built to contain power and communication transmission line, gas line, etc.

Tunnel sectionsTunnels range in dimensions of cross-sections from those of small galleries driven by miners working with hand tools, to tunnels large enough to accommodate railroad trains, double lane of highway traffic, or to transport very large volume of water as in diversion structures in dams. A minimum size of tunnel is 9 ft high and 4 ft wide at the working face. Designed shapes or sizes of tunnels in x-section conform to a planned uses to tunnel and some extent to the nature of the material that is anticipated will be encountered during excavation, x-sectional shapes vary from square or rectangular as for example in mining operations in strongly bedded sediment rocks, to circular. A common type of x-section is horseshoe shaped to provide maximum stability in the roof portion of the tunnel. Geological explorationThe geological conditions that are likely to meet in any given work of construction must be predicted. The line of the tunnel and the neighboring ground is geologically surveyed and sub-surface data obtained by exploratory boring. Careful control of such trial boring operations is necessary in order to extract the maximum amount of information from the ground. The cost of tunneling in general is least where construction is carried out in sound rock, and in one kind of rock throughout. Straight forward geological conditions such as simply dipping strata allow cost to be estimate easily; more uncertainties arise in connection with folded and faulted beds. Geological structures such as faults and joints should be mapped along the line of a tunnel. Strongly developed joints systems are potential channels for underground circulation and should be recorded. Badly fractured ground is to be avoided if possible. If unavoidable it may require special timbering or other treatment, and a prediction of where faults are likely to meet underground is therefore of greater importance. Hard rocks where excavated may stand with little support (some tunnels are unlined throughout) because they are strong enough to withstand the lateral pressure exerted by surrounding rocks but if soft bands are present there may be a tendency to slipping on these weaker layers and suitable support for the walls of the excavation will be necessary. Inter- bedded hard and soft rocks, such as sand-stones and shales may give rise to many difficulties. Ground-water percolating through the sand-stones soaks into the shales and softens them and hence the slipping is promoted.

Hi Everyone I’m working on an L-shaped RC building where a movement joint is required, primarily to accommodate thermal and shrinkage movements in RC flat slab. The two wings meet at a re-entrant corner, with the left wing skewed relative to the right wing by approx. 54°.The proposed solution is to provide a movement joint through the slabs, with Ancon ESDQ (available in the UK; lateral, rotational and longitudinal movement allowed)dowels across the joint. The design intent is: Transfer vertical shear only across the joint No transfer of in-plane axial force, shear, or moment Allow longitudinal, lateral, and rotational movement across the joint Dowels generally perpendicular to the joint line With respect to wind-induced differential deflection between the two wings: Is the correct design approach to: determine the maximum relative horizontal displacement between the two structures at the joint (from SLS wind combinations), combine this with thermal, shrinkage, and construction tolerances, and then specify a required movement capacity for the dowels (axial/lateral, as applicable) to ensure the system does not bind or lock up? Many thanks

Rock support for tunnels and underground cavern design is a demanding and very complex task. In principle, the problem can be approached from two directions: The first way is to define the relationship between geo-mechanical properties of the rock mass and the support methods used. This is mostly based on the utilization of statistical and empirical data gathered in similar conditions. The second way is to estimate the deformation characteristics of the rock structure, and then the related effect on supporting structures. This method typically requires very good rock property and rock mass property data. The most important factors affecting rock reinforcement method and design are: Geological factors, such as rock mass structure. Dimensions and geometry of excavated space. Location and direction of caverns in the rock mass. Excavation method. Use and expected lifetime of space. Common support methods in underground construction work are: Bolting. Sprayed Concrete. Steel Arches. Concrete Lining. Grouting. 1. BOLTINGRock bolting is one of the most common methods of rock reinforcement. The main principle of bolting is to reinforce loose rock or fractured in-situ rock to precent caving or spalling, and to assist the rock mass to form its own self-supporting structure. Bolts can be divided into three categories according to the way they behave in the rock, for example, grouted bolts, mechanically anchored bolts and friction bolts. 1.1. Cement-grouted boltsCement-grouted rebar is still the most inexpensive and widely used rock bolt, because it is simple and quick to install and can be used with or without mechanized equipment. Correctly installed, a cement-grouted bolt gives rock support for years. The grout cement provides protection from corrosion. Special galvanized and/or epoxy coated bolts can be used in extremely severe conditions. The major disadvantages of the cement-grouted bolt is its relatively long hardening period. The grout takes between 15-25 hours to harden; therefore, it does not provide immediate support. When immediate support and/or pre-tensioning is needed, a grouted wedge-type or expansion-shell bolt can be used. Mixing additives in the grout can reduce the hardening time, but it also increases bolting cost. The water/cement ratio considerably affects the quality of installed bolts. The best water/cement ratio is 0.3 (w/c). This grout density can be easily used and maintained when using mechanized bolting equipment. 1.2. Resin-grouted boltsResin-grouted bolts give the required support relatively quick due to a short hardening time. When correctly installed with full-length grouting, the resin-grouted bolt is considered to give permanent support with a life span of 20 to 30 years. By using resins with two different hardening times, with faster one at the bottom of the hole and another that is slower at the stem, the bolts can be pre-tensioned. The same can be done for short-time support by only bottom-grouting the bolt. 1.3. Cable boltsCable or steel strained bolts are used to bind and secure large volumes of rock around large caverns. Cable bolts can be used both before and after excavation, and also used for preventing rockslides in mountain slopes and quarries. The anchor itself is a steel strand, typically two strands of 15.2 mm in diameter, with typical bolt length being between 10-25 meters. Today, with mechanizes equipment, the installation and grouting of cable bolts of any length is fast and efficient, and the cable bolt's bearing capacity clearly exceeds capacity of rebar steel bolts. Its lack of efficient protection against corrosion limits its extensive use in permanent rock support. 1.4. Mechanically anchored boltsMechanically anchored bolts are usually wedge or expansion-shell bolts that are point-anchored at the bottom of the hole. The bolt has an expanding anchor at its end. After insertion, the bolt is either rotated or pressed/hammered against the bottom of the hole. This expands the wedged end and anchors the bolt firmly to the end sides of the hole. To install anchored bolts successfully, the hole size must be accurate, and the rock must be relatively solid. Wedge or expansion-shell bolts are typically meant for temporary rock support. Together with cement grouting, it provides both immediate and long-term support. 1.5. Friction-type boltsTypical examples of friction-type bolts are the split-set and Swellex bolts. Both are quick and easy to install and give instantaneous support. They cannot, however, be used for long-term reinforcement. The split-set bolts is hammered into the hole, which has a slightly smaller diameter than bolt. Using the correct hole size for a specific bolt diameter is essential for successful installation. Split set bolts are very suitable for layered formations. The Split-set bolts provide immediate support but only for fairly short period of time. A disadvantage is that the split-set cannot be effectively protected against corrosion. The life span can somewhat be extended by using cement grouting. The Swellex bolt has a longer life span than the Split-set. It is installed by applying high-pressure water to bolt after inserting it to the hole. The high pressure expands the bolt to its final dimensions in the hole, therefore enabling it to utilize the roughness and fractures in the bolt hole surface. As with the Split-set bolt, poor corrosion protection limits this bolt. 1.6. Equipment for bolt installationDevelopment of mechanized equipment began as early as the 1970s. Today there is a wide selection of fully mechanized equipment, and a wide variety of different methods for bolt installation. The main factors affecting the choice of method are usually tunnel size, number of bolts to be installed and work cycle arrangement at this site. Manual operation, the hand-held drilling and installation of bolts, is typically used in small drifts and tunnels where drilling is also performed by hand-held equipment, and there is a limited amount of bolting work. Semi-mechanized installation is still typical at tunneling work sites. The drilling jumbo is used for drilling bolt holes, and bolt installation is performed from the jumbo's basket boom or from a separate utility carrier or truck. With today's full mechanized equipment, one operator can handle the entire bolting process from drilling to grouting and bolt installation. The operator is positioned away from the unbolted area under a safety canopy that protects him from failing rock. Although safety is a major reason for the development of mechanized bolting equipment, the superior installation technique of mechanized bolting rigs also produces consistently higher bolting quality. Thanks to powerful cement mixers, pumps and effective grouting methods, the bolts are securely fixed and grouted to their full length, providing a sound reinforcement structure, even with long bolts. 2. SCREENINGScreening, which is the installation of wire mesh, is most typically used in underground mining, but also construction sites together with bolting and/or sprayed concrete. Screening is primarily performed manually by applying the wire mesh together with bolting of the tunnel. It can also be done by mechanized equipment, such as by having a screen manipulator on the bolting or shotcreting unit, or on a dedicated screening machine. 3. SPRAYED CONCRETESprayed concrete, otherwise called shotcreting, is widely used support method in construction. It is used for temporary or long-term support, lining and backfilling. Usually, shotcrete is used together with bolting to obtain the best support or reinforcement. Shotcrete can be reinforced by adding steel fiber to the concrete. The most common forms of shotcreting are dry-mix and wet-mix methods. In the dry-mix method the aggregate, cement and accelerators are mixed together and propelled by compressed air. Water is added last through a control valve on spray nozzle. The dry method is suitable for manual shotcreting because the required equipment is usually inexpensive and small. On the other hand, dry method can pose a health hazards as it creates considerably more dust and rebound than the wet method. The quality also depends heavily on the shotcreting crew and may vary widely. In the wet mix method, aggregate, cement, additives and water are measured and mixed before transport. Today, wet mix is more widely used because it is easy to mechanize and the capacity can easily out-do the dry method. Rebound rate is low and the quality procedure is even. Critical factors in shotcreting are: Water/cement ratio. Grain size distribution of aggregate. Rebound ratio. Grain size distribution. Mix design. Nozzle design. Nozzle distance and angle. Layer thickness. Manual shotcreting has been largely replaced by mechanized shotcreting machines. With mechanized equipment, multiple capacities per hour can be reached, together with consistent and even quality of the concrete layer. Safety, ergonomic and environmental conditions are other important aspects of shotcreting. These factors are efficiently improved with mechanized shotcreting units. 4. STEEL ARCHESSteel arches are common permanent support method for weak rock formations. These are usually installed in the tunnel immediately after each round, at the same time as rock bolting. Steel arches are also commonly installed during shotcreting to give temporary support before final concrete lining of e.g. traffic tunnels. 5. GROUTINGGrouting is the method in which a solidifying liquid is pressure-injected into the rock mass. The main purpose of grouting is to prevent ground water leakage into the tunnel, and to increase overall rock mass strength. In grouting, a chemical agent or cement mass is pressure-pumped into the drill-hole to penetrate fractured and fill cavities. In drill and blast tunneling, grouting is typically performed before (pre-grouting) or after (post-grouting) excavation. 5.1 Pre-groutingPre-grouting means that rock mass is grouted before excavation begins. Usually, pre-grouting is done from the tunnel, but in situations with low overburden it is also possible to do it from the surface. Probe holes are drilled to map possible fractures and register water flow. This helps to analyze the need for grouting. Later, grout holes are drilled in conical-fan shape in front of the tunnel face. Typical grouting fan length is 15-25 meters. After drilling, the grouting agent is pumped into the hole until leakage has reached an acceptable level. Tunnel excavation can begin once the grouting mass has settled. Grouting fans overlap each other so that in 15-meter-long grout holes, grouting is performed every second or every third round depending on the round length. 5.2 Grouting after excavation (post-grouting)When grouting is done after excavation, grouting holes are drilled from the tunnel in a radial form. In good rock conditions with small water leakage, post-grouting is often adequate. Post-grouting enables better rock mass structure evaluation. On the other hand, water leakage blockage is more difficult because the water flow tends to flush away the grouting agent before it hardens. 5.3. Grouting agentsThe grouting agents can be divided into two categories: Suspension and Chemical. Cement water or bentonite water suspension is the most typical in rock grouting because both are cost-effective and environmentally safe. The drawback is, however, a relatively large maximum grain size, which leads to poor penetration in small cracks. Penetration characteristics can, however, be improved by adding additives. Silicate-based chemicals are also used to speed up the hardening time. Chemical agents are silicate-based, resin polymers, polyurethane-based or lignin-based chemicals that typically penetrate very s cracks and have adjustable hardening times.

Angle measurementFor angle measurement with theodolite vertical hair is used. Basically, there are two methods horizontal angle measurement, Repetition method (For single angle) Reiteration method (For more than one angle) 1. By Repetition methodLet suppose it is desire to measure the angle A from the following figure. We will use repetition method for this purpose. ProcedureSetup the theodolite at station A. Bisect the point B with vertical hair of theodolite and move telescope in clockwise and direction to bisect at point C. Note this circle reading in the book and fix this circle reading, then again bisect the point B by keeping the circle reading fixed. Now, release the circle reading and rotate the telescope again in clockwise direction till it bisect again point C. Similarly get 3rd and 4th repetition and note the circle reading after 4th repetition in the book. Change the face of telescope and repeat the above steps, an example and method of booking observations have given below, Inst. Station Angle Face Repetition Circle Reading (° ′ ″) Angle value (° ′ ″) Mean of faces (° ′ ″) A BAC L 1 25 20 00 25 20 10 25 20 9.5 4 101 20 40 R 1 25 20 03 25 20 09 4 101 20 36 2. By Reiteration methodThis method is used if there are more than one angles to be measure from a certain station point. Consider the following figure, we will measure angles AOB and BOC using this method. ProcedureSetup the theodolite at station O, bisect the point A with a certain circle reading with face left. Rotate the instrument in clockwise direction and bisect B, note the circle reading. Then rotate and the telescope till it bisect the point C, note this circle reading also. All these reading will book into face left position. Transit the telescope and rotate the instrument through 180°, this time bisect the point C firstly and then rotate telescope in anticlockwise direction towards B and then ultimately towards A. Put these readings in face right position. You can do more than one sets of measurements for the accurate results, I have done one set and booking method is as follows, Inst. Station Stn. Sighted Face Circle reading (° ′ ″) Mean of faces (′ ″) Angle value (° ′ ″) O A L 10 20 05 20 06 AOB 37 10 05 R 190 20 07 B L 47 30 10 30 11 R 227 30 12 BOC 41 10 14 C L 88 40 20 40 25 R 268 40 30 One should start observation with some initial circle reading say 25°, if we start our observation with zero circle reading our calculations for computing mean will be little bit difficult.

TraversingIt is the method of establishing horizontal controls. TraverseTraverse is a series of connected lines forming or not forming a loop. In the first case it is called closed traverse (when the loop is formed) and in the second case it called open traverse (when loop is not formed). Vertical controlThat is the reference point in vertical plane, it includes series of benchmarks and points of known elevations. Horizontal controlIt is the series of points in the horizontal plane of known co-ordinates. Types of traversingTraversing can be further divided into two categories depending upon the type of instrument used, Compass Traversing Theodolite Traversing 1. Compass traversingWhen prismatic compass is used for determining the direction of line, the method is called compass traversing. 2. Theodolite traversingWhen theodolite is used for measurement of angles or directions, the method is called theodolite traversing. By direction of line, we mean the bearing of that line.

MeridiansMeridian is a reference direction with respect to which the direction of lines is mentioned. There are three types of meridians - True Meridian, Magnetic Meridian & Arbitrary Meridian 1. True MeridianIt is the reference direction of north pole of earth from a given station point. It is also called geographic meridian. 2. Magnetic MeridianIt is the direction of north pole indicated by magnetic needle. 3. Arbitrary MeridianThis is any assume direction to a well-defined object. It may be useful for small areas. e.g. A mosque is taken as reference and location of road will be mentioned with respect to this mosque. Direction of magnetic north with respect to true north is called magnetic direction. BearingsBearing is the angle which a certain line makes with a certain a certain meridian. Bearing with respect to true meridian is called true bearings while magnetic bearing is the angle which a line makes with respect to magnetic meridian. There are two ways to represent the bearings, Whole circle bearing (W.C.B) Reduced Bearing (R.B) 1. Whole Circle Bearing (W.C.B)It can be taken 0° to 360°. Quadrants are taken clock-wisely and angles are also determined in clockwise direction. 2. Reduced BearingReduced bearing or Quadrantal bearing is the angle which a line makes from North or South Pole whichever may be near. It is value is from 0° to 90°. Using the above figures, you can easily convert the Whole Circle Bearing into Reduced Bearing. Some Examples are given are below. Whole Circle Bearing (W.C.B) Reduced Bearing (R.B) 135° S45E 37° N37E 65° N65E 125° S55E 215° S35W 300° N60W

I encountered an issue with reinforcement installation on a construction site and there was a discussion regarding the following detail: In first drawing, the top reinforcement mesh is placed on top of the U bars, while in another drawing it is below the U bars, meaning the U bars hold both the top and bottom mesh. Is it critical how this detail is executed? Can the top mesh be placed on top of the U bars, or does it need to be under the U bars? Is it sufficient to ensure the proper overlap of bars only? The design standard being followed is Eurocode 2 (EC2).

Hi there I am not an engineer but looking for advice please. We live in a 1950s council house in Lincolnshire, and we're looking at mounting an aerial rig in our front room for our 8 year old daughter. She currently weighs approx. 26kg and will be doing aerial hoop and silks (like in this video https://www.youtube.com/watch?v=rsm3YNWAs9k) Our proposed solution is to put a 2630mm, 42.4mm galvanised steel tube wall-to-wall, secured with M6x75 concrete bolts, as shown in the image below. The blue wall is a supporting interior brick wall. My main concern is the other side, where the bay window is. My understanding is that this is steel reinforced concrete lintel. I am concerned that these are obviously designed to hold a static load, however obviously the aerial rig will have a lot of movement, and I am wondering whether it will be suitable to mount the steel bar in the brickwork above, or if we risk damaging the structural integrity of our house? Thanks you in advance Images can be found here of the room https://photos.app.goo.gl/aetVwKYPtDNSzSUT8

1. Using rise and fall methodIn this method booking is done in the following manner, B.S I.S F.S Rise Fall R.L Remarks 2.570 - - - - 100.00 A 3.750 - 1.200 1.370 - 101.37 C.P - - 3.750 - 0.70 100.67 B 5.620 - 4.950 1.370 0.70 - - 1) On any page of book, the first reading is always a B.S and last reading is always a F.S. If you are not getting F.S as last reading on each page, then it means you have done mistake while booking readings. 2) From the B.S next F.S is subtracted. If the answer is positive (+), it will be Rise and if the answer is negative (-) it be Fall and put that reading in respective box. 3) In the above table, I have assumed that Reduce Level (R.L) of point A is 100.0 and you can see R.L of point B is 100.67, which shows that point B is .67 units higher than point A. In case of numerous readings, the check should be applied at the end of each page while booking reading, ∑ (B.S) - ∑ (F.S) = ∑ Rise - ∑ Fall = R.L of last point - R.L of first point; 5.620 - 4.950 = 1.37 - 0.70 = 100.67 - 100.00 = 0.67 = 0.67 2. Using height of collimation method (H.O.C)For this method use the following formulas, R.L + B.S = H.O.C and H.O.C - F.S = R.L B.S I.S F.S H.O.C R.L Remarks 2.50 - - 102.50 100.00 - 1.75 1 1.95 102.30 100.55 - - 2.55 - - 99.75 - - 2.70 - - 99.60 - 2.95 - 3.10 - 99.20 - - - 2.75 - 99.40 - 7.20 - 7.80 - - - All other considerations are same as Rise/ Fall method. Below check have applied, ∑ (B.S) - ∑ (F.S) = R.L of last point - R.L of first point = 7.2 - 7.8 = 99.4 - 100 = -0.6 = -0.6

Types of sewers1. Sanitary sewerIt carries sanitary sewage i.e. wastewater from municipality including domestic and industrial wastewater. 2. Storm sewerIt carries storm sewage including surface runoff and street wash. 3. Combined sewerIt carries domestic, industrial and storm sewage. 4. House sewerIt is the sewer conveying sewage from plumbing system of a building to common/municipal sewer. 5. Lateral sewerThis sewer carries discharge from house sewers. 6. Submain sewerThis sewer receives discharge from two or more laterals. 7. Main or trunk sewerIt receives discharge from two or more submains. 8. Outfall sewerIt receives discharge from all collecting system and conveys it to point of final disposal. Types of sewer systems1. Separate systemIf stormwater is carried separately from domestic and industrial wastewater, the system is called separate system. Separate systems are favored when: There is an immediate need for collection of sanitary sewage but not for stormwater. When sanitary sewage needs treatment, but the stormwater does not. 2. Combined systemIt is the system in which the sewer carries both sanitary and stormwater. Combined system is favored when: Combined sewage can be disposed off without treatment. Both sanitary and stormwater need treatment. Streets are narrow and two separate sewers cannot be laid. 3. Partially combined systemIf some portion of storm or surface runoff is allowed to be carried along with sanitary sewage, the system is known as partially combined system. In urban areas of developing countries, mostly partially combined system is employed.

History of electronic distance measurementIn surveying distance measurements were always a challenge for surveyors specially when long distances were to be measured with high accuracy. In 1950 scientist tried to calculate the distance by using light beam to travel over unknown distance with measured time. Ordinary lights travel at a velocity of 186,000 miles per second, therefore the time taken will be very small to cover a short distance. This idea was soon dropped but the scientists succeeded in finding a low velocity light beam in form of Infra-Red Rays generated by solid state Gallium Arsenide Diode (GAD). This was put into laboratory experimentation in 1960 and finally instrument called Electronic Distance Measurement came into existence. Initially the instruments were very expensive but as the demand increased the price was within the reach of most professionals. Revolution in surveying due to EDMModern EDM equipment contains hard-wired algorithms for reducing the slope distance to its horizontal and vertical equivalent. For most engineering surveys, Total stations combined with electronic data loggers are now virtually standard equipment on site. Basic theodolites can be transformed into total stations by add-on, top-mounted EDM modules. The development of EDM has produced fundamental changes in surveying procedures e.g. Traversing on a grandiose scale, with much greater control of swing errors, is now a standard procedure. The inclusion of many more measured distances into triangulation, rendering classical triangulation obsolete. This results in much greater control of scale error. Setting out and photogrammetric control, over large areas, by polar coordinates from a single base line. Deformation monitoring to sub-millimeter accuracies using high-precision EDM The latest developments in EDM equipment provide plug-in recording modules, capable of recording many thousand blocks of data for direct transfer to the computer. There is practically no surveying operation which does not utilize the speed, economy, accuracy and reliability of modern EDM equipment. For example, the EDM instrument Model # LEICA RM100 BUILDER POWER have the following particulars, Absolute circle reading Laser plummet Endless drives 30x magnification Dual-Axis compensation High resolution LCD display Electronic laser distance measurement Graphic sketches EDM measurement with red laser on target Upload and transfer data Data editing and exchange Connectivity to 3rd party devices Hence, the advent of EDM equipment has completely revolutionized all surveying procedures, resulting in a change of emphasis and techniques. Taping distance, with all its associated problems, has been rendered obsolete for all base-line measurement. Distance can now be measured easily, quickly and with great accuracy, regardless of terrain conditions.