Azhar Shahzad

Advantages of steel construction1. ReliabilitySteel structures are very reliable. The reasons for this reliability include consistency and uniformity in properties, better quality control because of factory manufacture, large elasticity, and ductility. If different specimens of some types of steel are tested in the laboratory for yield stress, ultimate strengths and elongations, the variation is much lesser than other materials like concrete and wood. Further, because of truly homogeneous and elastic material, steel satisfies most of the assumptions involved in the derivation of the analysis and design formulas and the results obtained and reliable. This may not be the case in concrete structures because of heterogeneous material, cracking and non-linearity of stress-strain relationship. 2. Industrial behaviorRolled steel sections are manufactured in factories. Also, the members may be cut and prepared for assembly in factories wile only joining of these components is carried out at the site by installing rivets or bolts and by welding different components. Sometimes parts of the structure are also assembled in the factories, that is, there is a great adaptation to prefabrication. Manual errors reduce greatly in such cases, the speed of construction increases, and the total cost reduces. 3. Lesser construction time / greater erection speedBecause of the industrial nature of steel construction. Progress of the work is fast making the structures economical. The reason is that these structures can be put to use earlier. The reduction in labor cost and overhead changes and the benefits obtained from the early use of the building contribute to the economy. 4. High strength and light weight natureThe high strength of steel per unit weight means that the dead loads will be smaller. It is to be noted that dead loads are a bigger part of the total loads on structure. When dead load reduces, the underneath members become still smaller due to less weight acting on them. This fact is of great importance for long-span bridges, tall building, and for structures having poor foundation conditions. 5. Uniformity, durability and performanceSteel is a very homogeneous and uniform material. Hence, it satisfies the basic assumptions of most of the analysis and design formulas. If properly maintained by painting, etc. the properties of steel do not change appreciably with time, whereas the properties of concrete in a reinforced concrete structure are considerably modified with time. Hence, steel structures are more durable. 6. ElasticitySteel behaves closer to design assumption than most of the other material because it follows Hooke’s law up to fairly high stresses. The stress produced remains proportional to the strain applied oft the stress-strain diagram remains a straight line. The steel sections do not crack or tear before ultimate load and hence the moments of inertia of a steel structure can be definitely calculated. The moments of inertia obtained for a reinforced concrete structure are rather indefinite. 7. Ductility and warning before failureThe Property of a material by which it can withstand extensive deformation without failure under high tensile stresses is said to be it ductility. Mild steel is a very ductile material. The percentage elongation of a standard tension test specimen after fracture can be as high as 25 to 30%. This gives visible deflections of evidence of impending failure in case of overloads. The extra loads may be removed from the structure to prevent collapse. Even if collapse does occur, time is available for occupants to vacate the building. In structural members under normal loads, high stress concentrations develop at various points. The ductile nature of the usual structural steel enables them to yield locally at those points, thus redistributing the stresses and preventing premature failures. 8. Additions to existing structuresAdditions to existing steel structures are very easy to be made. Connections between new and existing structures can be employed very effectively. New bays or even entire new wings can be added to existing steel frame building, and steel brides may often be widened. 9. Possible ReuseSteel sections cab be reused after a structure is disassembled. 10. Scrap valueSteel has a scrap value even though it is not reusable in its existing form. 11. Water-tight and air-tight constructionsSteel structures provide completely impervious construction and structures like reservoirs, oil pipes, gas pipes, etc. are preferably made from structural steel. 12. Long span constructionHigh-rise buildings, long span bridges and tall transmission towers are made up of structural steel. Industrial buildings up to a span of 90.m can be designed by plate girders or trusses. Bridge spans up to 260.m are made with plate girders. For through truss bridges, Bridge spans of 300.m have been used. 13. Temporary constructionFor temporary structures, steel construction is always preferred. Army constructions during war are mostly made out of structural steel. The structures may be disassembled by opening few bolts, component parts are carried to new places are the structure is easily reassembled. Disadvantages of steel construction1. High maintenance costs and more corrosionMost steels are susceptible to corrosion when freely exposed to air and water and must therefore be periodically painted. This requires extra cost and special care. The use of weathering steels, in stable design applications, tends to eliminate this cost. If not properly maintained, steel members can lose 1 to 1.5 mm of their thickness each year. Accordingly, such constructions can lose weight up to 35% during their specified life and can fail under the external loads. 2. Fireproofing costsAlthough steel members are incombustible, their strength is tremendously reduced at temperatures prevailing in fires. At about 400ºC, creep becomes much more pronounced. Creep is defined as plastic deformation under a constant load for a long period of time. This produces excessively large deflections/deformations of main members forcing the other members to higher stresses or even to collapse. Steel is an excellent conductor of heat and may transmit enough heat from a burning compartment of a building to start fire in other parts of the building to start fire in other parts of the building. Extra cost is required to properly fireproof the building. 3. Susceptibility to bucklingThe steel sections usually consist of a combination of thin plates. Further, the overall steel member dimensions are also smaller than reinforced concrete members. If these slender members are subjected to compression, there are greater chances of buckling. Buckling is a type of collapse of the members due to sudden large bending caused by a critical compressive load. Steel when used for columns is sometimes not very economical because considerable material has to be used merely to stiffen the columns against buckling. 4. Higher initial cost / less availabilityIn few countries, steel is not available in abundance and its initial cost is very high compared with the other structural materials. This is the most significant factor that has resulted in the decline of steel structures in these countries. 5. AestheticsFor certain types of buildings, the steel form is architecturally preferred. However, for majority of residential and office buildings, steel structures without the use of false ceiling and cladding are considered to have poor aesthetic appearance. A considerable cost is to be spent on such structures to improve their appearance. Cladding is a covering of metal, plastic or timber put on the surface of a structural member to completely encase it. The cladding not only protects the member but also improves its appearance.

Definition of BIM: Building information modelling (BIM) is a digital representation of physical and functional characteristics of a facility. A BIM is a shared knowledge resource for information about a facility forming a reliable basis for decisions during its life-cycle; defined as existing from earliest conception to demolition. BIM benefits: Faster drafting without loss of cost and quality High level of customization and flexibility Optimization of schedule and cost Seamless coordination and collaboration Conflict detection and risk mitigation Easy maintenance of building life cycle Here is the nice info-graphic which compares BIM based process to the 2D drawings based process: Learn more about BIM solutions for structural engineers

1. BIM will be the backbone of future Construction Building Information Modeling is taking over the industry globally at the speed of light. In the UK, for example, the industry adoption rate has boomed from 13% in 2010 to 39% in only two years and many countries are introducing initiatives such as national BIM recommendations to push the adoption forward. It is reasonable to expect this trend to continue as the construction industry recovers from recession and as BIM continues its path towards becoming an industry requirement. Whether you are studying structural engineering, construction engineering or architecture, expect BIM to be a major factor and competitive advantage upon graduation. 2. The "I" in the BIM will become even more Significant While impressive illustrations and 3D models are a highly visible part of BIM, robust opportunities for collaboration, coordination, fabrication, as well as, integration to production automation systems and machinery is what really puts the “I” in BIM. Information management and Integration between models allows each professional to focus on what they do best while simultaneously improving clash checking and accuracy. BIM makes relevant information available to everyone when they need it. Models become more than a sum of their parts, making BIM a highly attractive tool for both companies and professionals in related industries. 3. The Industry will look for BIM experts instead of CAD Assistants With the industry changing at a rapid pace, companies start looking for skilful BIM users to keep up with this speed of change. To mention a few sought-after skills, employers start looking for experts who can create and develop different models and perform analyses and simulations based on these models. Companies who are at early adoption stages of BIM are looking for BIM specialists who are capable of implementing BIM, managing and modeling all project information and also educating others within the organization. Academia and schools need to meet this demand by delivering a new generation of professionals who are fluent in BIM. 4. With BIM You will... Practically everyone involved in the design and construction process will gain benefits from BIM. Engineers, architects and contractors can virtually walk through construction models, explore structural components and details, and identify any potential design, construction or operational issues. BIM allows builders to bring even to the most complicated structures into reality by enabling the high detail modeling of multiple materials while simultaneously saving time, resources and space. Users will be able to focus on the essential instead of the menial. Learn more about BIM solutions for structural engineers

Study some basic mathematical topics like Geometry, Vectors, and Matrices etc. It will greatly increase your understanding towards engineering mechanics. Must read relevant theory first before attempting problems. Start from easy problems then go on as your concepts developed.

By building up environment Civil Engineers play with nature... Civil engineering is a professional engineering discipline that deals with the design, construction, and maintenance of the physical and naturally built environment, including works like roads, bridges, canals, dams, and buildings. Why Become a Civil Engineer? 1. Civil engineers create the world around us Civil engineers are the unsung heroes of the engineering world. Yet this jack-of-all-trades discipline is an incremental part of creating everything from tall skyscrapers and complex stadiums to bridges, railways and tunnels. As a civil engineer, your work influences where people work, relax, learn and live. You will be a part of helping society to become more advanced by adapting the infrastructure to meet challenges brought on by new technologies, population growth and climate change. Civil engineers know that even the simplest structure can include hundreds of “unknowns” which they have to be able to identify and solve in order to ensure the structure is operational, stays safe and stands the trial of use, environment and age. In addition to all this, civil engineers also play a key role during emergencies like droughts or natural disasters by helping those affected to recreate their living environment and the infrastructure that provides for their basic needs. 2. Civil engineers never have a dull moment Civil engineers can work in a versatile range of positions and projects. Civil engineering specializations such as structural, environmental, geo-technical and transportation engineering all entitle challenging, constantly changing work environments and require creativity, adaptability, good problem-solving skills and ability to think on one’s feet. As a civil engineer, despite your area of specialization, you need to be sensitive to local and environmental challenges as well as to the requirements of different construction project participants. You need to have attention to detail while simultaneously understanding “the bigger picture”. In addition to the wide spectrum of challenges, the versatility of projects civil engineers can participate in ensures that you are unlikely to have a dull moment at work. You can work below the surface delivering tunnels, underground railways and energy and water supplies as well as above the surface creating roads, bridges, stadiums, hospitals, skyscrapers and many more. As a civil engineer, you are likely to be constantly on the move, sharing your time between the site, the office and perhaps even different geographical locations. 3. Civil engineers have a monument to show that they were there While civil engineering can be somewhat stressful, the profession includes a huge sense of accomplishment to make it all worthwhile. Throughout history, civil engineers have participated in some of the most ambitious and incremental projects known to mankind. World-known ventures such as the Hoover Dam, the Great Wall of China and the Hardanger Bridge are tokens of the hard work and expertise of civil engineers. While you might have to start your civil engineering career with slightly smaller projects, the fact remains that by the end of the day you will have a monument to prove that "you've been there". You know all the challenges and effort that went into transforming the blueprints into a fully functional structure. What do you think about Civil Engineering?

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 degree from the earth's surface. The one which is greater than 30 degree 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 Tunneling There 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 most costly 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 Tunneling Tunnels 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 rail road 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.

Latitude and Departure In order to do start with Theodolite Traversing you should 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 aljebraic 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-ordinates When 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-ordinates Independent 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 Rule This 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 Table For the following traverse ABCD, I have applied the correction in Latitude and Departure using Bowdich rule. Line L(m) Beari.(° ′ ″) 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

Fore Bearing It 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 Bearing It 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 Attraction If 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 the 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 Problem In 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.

1 - Tripod It 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 screws These are provided for leveling the instruments. 3 - Plate level Provided for checking the level of the instrument. 4 - Horizontal clamp Provided to clamp the movement in horizontal plane. 5 - Vertical clamp For clamping movement in vertical plane. 6 - Slow motion screws These screws are used to move Theodolite either vertically or horizontally in small fractions. 7 - Telescope In 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. Collimeter is provided to bring the object in the field of view. 8 - Vertical axis It is the axis around which the telescope rotates in horizontal plane. 9 - Horizontal axis It is the axis around which telescope rotates in vertical plane. 10 - Optical plummet It is provided for centering the instrument over a ground station. 11 - Angle reading arrangement In screen display you can note angle measurements taken with Theodolite.

Leveling It is the branch of Surveying in which relative elevations of points are determined. There are following Types of Leveling 1 - Ordinary Leveling It is general purpose Leveling and unless otherwise stated all types of Leveling will come into this category. 2 - Reciprocal Leveling This 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 appearant difference of level. This method eliminates the error due to curvature and refraction. 3 - Precise Leveling This 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 Leveling This type of leveling is used in higher surfaces of earth like mountains. Application of Leveling Longitudinal 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 - Pacing Permissible error ≤ 1 feet in 20 feet. 2 - Chain Permissible error ≤ 1 in 1000. 3 - Metallic Tape Permissible error ≤ 1 in 1000. 4 - Steel Tape This tape is made of steel alloy of very small co-efficient of thermal expansion. Permissible error ≤ 1 in 1000. 5 - Invar Tape This 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 - Techometry Permissible error ≤ 1 in 50,000. 7 - Electronic Distance Meter Permissible error ≤ 1 in 100,000.

Introduction Sometime 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. Procedure open 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. Example Length of chain No of Paces Pace Length 30m 44 0.68 30m 43 0.69 Application Now, 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 Conversions 1 feet = 12 inch. 1 m = 3.28 feet. 1 inch = 2.5 cm. 3 inch = 0.25 feet.

Vertical angle It 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 angle During 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 booking Angle 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.

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 Traversing In 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.

By deflection angle method Bearing 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. Example let 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 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.