1. BOX JACKING

2. EXPLANATION It is the process in which a pre-cast R.C.C box or a rigid box is pushed into the soil with the help of hydraulic jacks It is non-intrusive method beneath the existing surface. It is more often used when a subway or a aqueduct or a underground structure is to be constructed. It enables the traffic flow without disruption.

3. R.C.C BOX JACKING First the box section is designed and cast at the site or can be transported to the site according to the requirement. The foundation boxes are jacked into the ground designed to carry the dead and the live loads. Then the high capacity jacks are placed at the back and it pushes the box into the ground. A purpose designed tunneling shield is provided in the front end.

4. Then the box is jacked carefully through the earth. Excavation and jacking are done in small increments in advance. Measures should be taken to prevent the soil being dragged towards the box. R.C.C BOX JACKING Cont…

5. R.C.C BOX JACKING

6. ARCHED JACKING

7. THRUST BORING METHOD It is a process of simultaneously jacking the pipe through the earth while removing the earth inside the box by means of a rotating auger. Unstable conditions- the end of auger is kept retracted inside the encasement so as not to cause voids. Stable conditions- the auger can be successfully extended beyond the encasement. This can be successfully used in any kind of soil conditions.

8. PROBLEMS ENCOUNTERED IN JACKING Settlement of the above ground. Seepage of ground water. Caving in of soil etc.

9. FREEZING OF GROUND This method is used when we encounter the problem of ground water seepage and settlement of ground. In this method a brine solution is continuously passed through the pipes fixed in the soil. The temperature of the brine would be -30°c. So when this brine solution is circulated through these pipes it freezes the ground and the ground behaves like an ice block.

10. FREEZING OF GROUND Cont… The spacing of the freezing pipes will vary according to the type of soil, its permeability and other factors. Generally it is kept at a spacing of 1.2 m

11. PROBLEMS IN FREEZING The main problem in the freezing method is the UPHEAVING of the above ground. To avoid the upheavement problem we should be careful in the ground freezing process and the temperature of the brine solution.

12. CASE STUDY - SOUTHERN BOSTON PIERS TRANSIT WAY The carriageway has to go beneath – a Russian building,100 year old 2m thick soil was frozen. Under pinning was also done using mini piles.

13. PLAN OF THE RUSSIAN BUILDING

14. ADVANTAGES Timely completion of project. No disruption of traffic. No need to divert the traffic. DISADVANTAGES Cost of project increases. Skilled personnel required. Safety precautions to be done properly.

15. PIPE JACKING

16. ABOUT THE TECHNIQUE It is generally referred as “Micro tunneling” Pipes are pushed through the ground behind the shield using powerful jacks. Simultaneously excavation takes place within the shield. This process is continued until the pipeline is completed. The method provides a flexible, structural, watertight, finished pipeline as the tunnel is excavated.

17. ABOUT THE TECHNIQUE Cont… No theoretical limit to the length of individual pipelines. Pipes range from 150mm to 3000mm diameter can be installed in straight line or in curvature. Thrust wall is provided for the reaction of the jacks. In case of poor soil, the thrust wall may punch inside the soil. Then piles or ground anchoring methods can be used.

18. PROCEDURE The thrust pit and the reception pit are excavated at the required places. Then the thrust wall is set up in the thrust pit according to the requirement. In case of mechanized excavations, a very large pit is required. But in case of manual excavation, a small pit is enough. Thrust ring is provided to ensure the even distribution of stress along the circumference of the pipe.

19. The number of jacks vary upon the frictional resistance of the soil, strength of pipes etc., The size of the reception pit is to be big enough to receive the jacking shield. To maintain the accuracy of alignment a steer able shield is used during the pipe jacking. In case of small and short distance excavations, ordinary survey method is sufficient. But in case of long excavations, remote sensing and other techniques can be used. PROCEDURE Cont…

20. GENERAL ARRANGEMENTS

21. PIPE JACKING SETUP

22. THRUST SETUP

23. COMPUTER GUIDANCE SYSTEM The computer system enables us to control the work remotely.

24. ADVANTAGES It avoids the excavation of trenches. So it is also called as “Trench less Technique”. There won’t be any leak problems in the future. Timely finish of projects.

25. DISADVANTAGES Very costly method. Skilled personnel is required.

26. DIAPHRAGM WALLS

27. Diaphragm walls are underground structural elements commonly used for retention systems and permanent foundation walls. Diaphragm walls provide a water tight barrier and are constructed with a minimum back slope subsidence. They are formed from reinforced concrete and are constructed as normal cast-in-place walls with support, which become part of the main structure. They can also be used as deep groundwater barriers.

28. SLURRY TRENCH METHOD The slurry trench method involves the excavation of alternating panels along the proposed wall, using bentonite slurry to prevent the sides of the excavation from collapsing. The slurry trench technique was developed in Europe and has been used in the United States since the 1940's. The technique involves excavating a narrow trench that is kept full of an engineered fluid or slurry. The slurry exerts hydraulic pressure against the trench walls and acts as shoring to prevent collapse. Slurry trench excavations can be constructed in all types of soil, even below the ground water table.

29. BASEMENT TOP-DOWN CONSTRUCTION USING DIAPHRAGM WALLS

30. PROCEDURE The panel dimensions 50 to 100 cm thick and up to 7m height, extending to the excavation bottom. The installation starts with the construction of shallow concrete or steel guide walls. The excavation is then made using special equipment, such as the thin-grab clamshell. Bentonite slurry is then pumped into the trench to provide temporary support and a prefabricated reinforcing cage is lowered in. The bentonite slurry is then replaced by concrete and the sequence proceeds onto the next panel.

31. GRAB USED FOR EXCAVATION

32. DIAPHRAGM WALLS Diaphragm walls of shallow depths are often left unsupported since they are classed as semi rigid structures. However for deeper excavations support is required to restrict lateral deflections. Diaphragm walls are ideal for soft clays and loose sands below the water table where there is a need to control lateral movements.

33. REINFORCEMENT

34. DIAPHRAGM WALL REINFORCEMENT & CONCRETING

35. FINISHED WALL AFTER EXCAVATION

36. APPLICATIONS As permanent and temporary foundation walls for deep basements. In earth retention schemes for highway and tunnel projects. As permanent walls for deep shafts for tunnel access. As permanent cut-off walls through the core of earth dams. In congested areas for retention systems and permanent foundation walls. Deep ground water barriers through and under dams.

37. BENEFITS OF DIAPHRAGM WALLS Can be installed through virtually all soil conditions, to any plan geometry and to considerable depths. Can be constructed ahead of time and independent of other site activities. Can be constructed in relatively low headroom and in areas of restricted access walls can be quickly formed several hundred feet deep and through rock, with good control over geometry and continuity.

38. DISADVANTAGES They are relatively costly. They are also unsuited to strong soils conditions where penetration is slow and difficult due to the use of the slurry trench method.

39. CAISSON FOUNDATION

40. INTRODUCTION The term caisson has been derived from the French word ‘CAISSEE’, meaning BOX. It can be round or rectangle in plan. It is commonly used where foundation under water is done. It can sunk from surface of either land or water to the desired depth.

41. TYPES OF CAISSON Open caisson Box caisson Pneumatic caisson

42. OPEN CAISSON Also called as well caisson. They are open at both the ends. These are boxes of timber, steel or R.C or masonry. Small caisson consists of one opening or well, while larger one contain a series of wells.

43. PROCEDURE The caisson is cast and flatted to the site and sunk. When it reaches the required depth concrete is deposited through water to some depth. After the concrete gets hardened, the water will be pumped out. The caisson is finally filled completely with concrete.

44. BOX CAISSON Also called as Floating caisson. They are open at top and closed at bottom. They can be made of steel, R.C or timber.

45. The caisson is built on land, then launched and brought to the site where they have to be sunk. They are filled with concrete or stone masonry and sunk until it rests on the river bed, which has been prepared to receive it, or on a pile cluster to form a lower part of a bridge pier. PROCEDURE

46. TOWING OF CAISSON

47. APPLICATIONS OF BOX CAISSON Bearing stratum is available at shallow depth Loads are not heavy For wharfs and break waters

48. PNEUMATIC CAISSON “Pneumatic" means "with air" “Caisson" means "a box“ The pneumatic caisson method works on the same principle as a cup pressed into some water upside down

49. 1.Preparation of the ground for installation We level surface of working site where the caisson is to be installed and improve the surface conditions so that appropriate supporting force can be supplied. 2.Construction of working chamber We construct a working chamber at a bottom of the caisson, in which earth is excavated and removed. The chamber is pressurized to the same pressure as the ground water pressure to make it watertight EXECUTION OF THE PNEUMATIC CAISSON

50. 3. Rigging Cylindrical steel shafts are used for workers to enter or exit the pressurized working chamber and to remove excavated earth. These shafts have locks (for both men and materials) to regulate the difference between the atmospheric pressure on the ground and the pressure in the chamber. Installation of such locks and shafts is called "rigging work". 4. Repeated excavation to sink & construct caisson We excavate and construct the caisson every 4m height, and repeatedly sink it by excavating the ground and constructing it to the desired depth. EXECUTION OF THE PNEUMATIC CAISSON

51. 5. Testing the bearing capacity of soil After the caisson has sunk to the specified depth, we test and confirm that if sufficient bearing capacity of soil has been obtained. 6. After concrete filling for working chamber After confirming the bearing capacity, we remove equipments in the working chamber and fill concrete, which means completion of works. EXECUTION OF THE PNEUMATIC CAISSON

52. 1.PREPARATION OF THE GROUND FOR INSTALLATION

53. 2.CONSTRUCTION OF WORKING CHAMBER

54. 3.RIGGING

55. 4a.REPEATED EXCAVATING TO SINK AND CONSTRUCT THE CAISSON

56. 4b.REPEATED EXCAVATING TO SINK AND CONSTRUCT THE CAISSON

57. 5.TESTING THE BEARING CAPACITY OF SOIL

58. 6.AFTER CONCRETE FILLING FOR WORKING CHAMBER

59. APPLICATIONS The Pneumatic Caisson Method is used for many different structures: Foundations of road and railway bridges Subway tunnels facilities Basements and foundations buildings Water supply and sewage facilities Other facilities (e.g. garbage pits)

60. FOUNDATIONS OF ROAD AND RAILWAY BRIDGES

61. BRIDGES CONSTRUCTED AT THE WATER DEPTH OF 50 TO 60 M.

62. SUBWAY TUNNELS FACILITIES

63. BASEMENT AND FOUNDATION BUILDINGS (Eg. UNDERGROUND PARKING ZONES)

64. WATER SUPPLY AND SEWAGE FACILITIES (Eg. TREATMENT PUMP BUILDING)

65. OTHER FACILITIES (E.G. GARBAGE PITS)

66. OTHER TYPES There are few more methods in caisson foundation. Jacking caisson method Space System Caisson

67. JACKING CAISSON METHOD Jacking caisson method is to sink large scale caisson thruster into ground by using jacks with rods connected to earth anchor.

68. Intake shaft of 14 meter ø. is thrusted in the ground at 50.7 meter below by using 12 jacks of 240 ton thrust force. The caisson itself is constructed on the ground by each rot of 5 meter. Dimension of 26x19 meter is sunk by 8 jacks in the ground depth 18.5 meter, while inside of caisson is excavated by clam shell JACKING CAISSON METHOD

69. SPACE SYSTEM CAISSON The gravel is filled between wall surface and ground, and the skin friction resistance is reduced. The SS caisson method gently and accurately install the caisson in non- loading. The problem of the conventional open caisson method is solved.

70. FEATURES OF THE SS CAISSON METHOD It is gently installed only at the dead weight at the good accuracy. Subsidence and collapse of the ground in the circumference are not caused. It is applicable for various geology.

71. COFFERDAMS

72. COFFERDAM

73. A cofferdam is a temporary structure designed to keep water and/or soil out of the excavation in which a bridge pier or other structure is built. When construction must take place below the water level, a cofferdam is built to give workers a dry work environment. Sheet piling is driven around the work site, seal concrete is placed into the bottom to prevent water from seeping in from underneath the sheet piling, and the water is pumped out The word "cofferdam" comes from "coffer" meaning box, in other words a dam in the shape of a box. DEFINITION

74. Braced Earth-Type Timber Crib Double-Walled Sheet Pile Cellular TYPES

75. Formed from a single wall of sheet piling Driven into the ground to form a box around the excavation site The "box" is then braced on the inside Interior is dewatered Primarily used for bridge piers in shallow water (30 - 35 ft depth) 1.BRACED COFFERDAMS

76. It is the simplest type of cofferdam. It consists of an earth bank with a clay core or vertical sheet piling enclosing the excavation. It is used for low-level waters with low velocity and easily scoured by water rising over the top. 2. EARTH-TYPE

77. Constructed on land and floated into place. Lower portion of each cell is matched with contour of river bed. It uses rock ballast and soil to decrease seepage and sink into place, also known as “Gravity Dam”. It usually consists of 12’x12’ cells and is used in rapid currents or on rocky river beds. It must be properly designed to resist lateral forces such as tipping / overturning and sliding 3. TIMBER CRIB

78. They are double wall cofferdams comprising two parallel rows of sheet piles driven into the ground and connected together by a system of tie rods at one or more levels. The space between the walls is generally filled with granular material such as sand, gravel or broken rock. 4. DOUBLE-WALLED SHEET PILE

79. Cellular cofferdams are used only in those circumstances where the excavation size precludes the use of cross- excavation bracing. In this case, the cofferdam must be stable by virtue of its own resistance to lateral forces. 5. CELLULAR

80. Scouring or undermining by rapidly flowing water Stability against overturning or tilting Upward forces on outside edge due to tilting Stability against vertical shear Effects of forces resulting from: Ice, Wave, Water, Active Earth and Passive Earth Pressures DESIGN CONSIDERATIONS

81. Allow excavation and construction of structures in otherwise poor environment. Provides safe environment to work Contractors typically have design responsibility Steel sheet piles are easily installed and removed Materials can typically be reused on other projects ADVANTAGES

82. Items needed for installation: Pile driving hammer Vibratory or Impact Crane of sufficient size Steel sheet piles are typically used H-piles and/or wide-flange beams for wales and stringers Barges may be required INSTALLATION

83. Sheet piling Bracing frame Concrete seal Bearing piles COMPONENTS

84. The typical cofferdam, such as a bridge pier, consists of sheet piles set around a bracing frame and driven into the soil sufficiently far to develop vertical and lateral support and to cut off the flow of soil and, in some cases the flow of water. DESCRIPTION

85. The structure inside may be founded directly on rock or firm soil or may require pile foundations. In the latter case, these generally extend well below the cofferdam. In order to dewater the cofferdam, the bottom must be stable and able to resist hydrostatic uplift. Placement of an underwater concrete seal course is the fastest and most common method. DESCRIPTION

86. An underwater concrete seal course may be placed prior to dewatering in order to seal off the water, resist its pressure, and also to act as a slab to brace against the inward movement of the sheet piles in order to mobilize their resistance to uplift under the hydrostatic pressure. CONSTRUCTION

87. For a typical cofferdam, such as for a bridge pier, the construction procedure follow the listed pattern. 1. Pre-dredge to remove soil or soft sediments and level the area of the cofferdam. CONSTRUCTION SEQUENCE

88. 2. Drive temporary support piles 3. Temporarily erect bracing frame on the support piles. CONSTRUCTION SEQUENCE

89. 4. Set steel sheet piles, starting at all four corners and meeting at the center of each side 5. Drive sheet piles to grade. 6. Block between bracing frame and sheets, and provide ties for sheet piles at the top as necessary. CONSTRUCTION SEQUENCE

90. 7. Excavate inside the grade or slightly below grade, while leaving the cofferdam full of water. CONSTRUCTION SEQUENCE

91. 8. Drive bearing piles. 9. Place rock fill as a leveling and support course. CONSTRUCTION SEQUENCE

92. 10. Place tremie concrete seal. CONSTRUCTION SEQUENCE

93. Tremie concrete seal. CONSTRUCTION SEQUENCE

94. Tremie concrete seal.

95. 11. Check blocking between bracing and sheets. 12. Dewater. 13. Construct new structure. CONSTRUCTION SEQUENCE

96. COFFERDAMS

97. 13. Construct new structure. 14. Flood cofferdam. CONSTRUCTION SEQUENCE

98. 15. Remove sheet piles. 16. Remove bracing. 17. Backfill. CONSTRUCTION SEQUENCE

99. Installation of Wale and Strut System for Framework WALE AND STRUT SYSTEM

100. Installation of Wale and Strut System for Template WALE AND STRUT SYSTEM

101. In cofferdam construction, safety is a paramount concern, since workers will be exposed to the hazard of flooding and collapse. Safety requirements are: Good design Proper construction Verification that structure is constructed as per plan Monitoring the behavior of cofferdam and its surrounding Provision of adequate access Light and ventilation Attention to safe practices on the part of all workers and supervisors SAFETY REQUIREMENTS

102. TRADITIONAL SHEET PILE SHAPES

103. TYPES OF INTERLOCKS

104. Introduction: Excavations and other engineering constructions in the ground are central to many civil and mining projects. Ground reinforcement includes among other methods, the techniques of ground anchoring, cable bolting and rock bolting. Ground anchors tend to be longer with higher capacity, and are usually associated with civil infrastructure projects. Rock bolts tend to be shortest with lowest capacities. Cable bolts are used in stability problems that lie between the two, and are commonly used in mining engineering. CABLE ANCHORING

105. Anchors in rocks: In the majority of moderately weak to strong rocks, rotary or rotary percussive open hole drilling with air flush, followed by normal tremie grouting techniques, will achieve the required grout/rock bond capacity. Where fissures or voids are detected by loss of flush, by water ingress, by water testing, or inability to maintain a head of grout within the bore, then pre- grouting operations or alternatively pressure grouting operations may be required. Normally cement grouts are injected but if fissures are known to be wide, sanded mixes may be used. In coarse grained weak rocks similar techniques or alternatively rotary water flush drilling can be used and in most conditions a reasonable anchorage capacity can be obtained.

106. Anchors in clay In order to enhance the capacity of the anchorage within the normal range of fixed lengths, either under reaming or soil fracturing systems have been employed More recently, the single bore multiple anchor system has been allowed efficient use of non-enhanced bore holes and attained loads of 3500kn. The fracturing of soil prior to tendon installation, generally involves a larger diameter steel manchette, which after treatment remains in-situ. Treatment may be carried out over a 2 or 3 day period prior to tendon installation, by repeatedly injecting grout through manchette valves at 1/2 m centers in the fixed length. The anchor tendon is then, after pre grouting treatment, installed and grouted within the large tube.

107. The tube must efficiently transfer the entire load from anchor tendon and internal grout to the external grout and then into the ground. It must not exhibit creep losses and it must not in anyway degrade (by corrosion) in any way such that there is a reduction in bond capacity or performance within the grout body which may reduce the capacity of the anchor within its intended lifetime

108. Anchors in granular materials: Anchors are in the majority of instances installed in granular deposits by drive drilling with a knock-off bit or by use of duplex drilling techniques. Drive drilling involves the percussion driving of a strong casing with a conical lead bit resulting lateral soil replacement and no flush recovery. The lead bit is knocked off the casing allowing tendon installation and pressure grouting during withdrawal. There are limitations in the depth penetrable. Duplex drilling involves the advancement of both drill rods and drill casing, utilizing casing sizes of the 80 to 150mm ranges. Either air or water flush or augers can be used, although bit wear and casing wear may well be considerably higher without lubrications and cooling by water.

109. GROUTING

110. Grouting is a process of ground improvement attained by injecting fluid like material into subsurface soil or rock. Grouting is the injection specially formulated cement of stable suspensions or liquid into pores, fissures or voids, or the jetting of cement mixtures at high flow rate and pressure into the soil to create soil- cement to increase the strength.

111. Producing mass concrete structures and piles Fixing ground anchors for sheet pile walls, concrete pile walls, retaining walls tunnels etc Repairing a ground underneath a formation or cracks and structural Defects on building masonry or pavement. Fixing the tendons in prestressed post tensioned concrete Filling the void between the lining and rock face in tunnel works APPLICATIONS

112. (a) Suspension grouts: These are multi-phase systems capable of forming sub systems after being subjected to natural sieving processes, with chemical properties which must be carefully scrutinized so as to ensure that they do not militate against controlled properties of setting and strength. Water in association with cement, lime, soil, etc., constitute suspensions. Emulsion (asphalt or bitumen) with water is a two-phase system which is also included under suspension. (b) Solution grouts: These are intimate one-phase system retaining an originally designed chemical balance until completion of the relevant reactions. Solutions in which the solute is present in the colloidal state are known as colloidal solutions. Chemical grouts fall into this category. GROUTING MATERIAL TYPES

113. Cement and water Cement, rock flour and water Cement, clay and water Cement clay, sand and water Asphalt Clay and water Chemicals MATERIALS USED FOR GROUTING

114. Common admixtures used with cement grouts: 1. Calcium chloride ] 2. Sodium hydroxide ]-----------------for accelerating setting time 3. Sodium silicate ] 4. Gypsum ] 5. Lime sugar ]----------------------for retarding setting time. 6. Sodium tannate ] 7. Fine bentonite ] 8. Clay ] 9. Ground shale ]--------for reducing cost of grout and reduces 10. Rock flour ] strength of grout ADMIXTURES

115. Grout is injected into the soil at low pressure and fills the voids without significantly changing the soil’s structure and volume. Variety of binders are used with this technique, the choice of which is dictated mainly by the permeability of the soil. When the coefficient of permeability is greater than 10 -2 cm/sec, water-cement mixes are used and for permeability as low as 10 -5 cm/sec, the more expensive resin based grouts are used. Soils with K values lower than 10 -6 cm/sec are normally not groutable by permeation. PERMEATION

116. The basic concept is of injecting an highly viscous grout with high internal friction, injected into a compactable soil, the grout acts as a radial-hydraulic jack and physically displaces the soil particles thus achieving controlled densification. Advantages 1.Minimum disturbance to the structure and surrounding ground, 2.Minimum risk during construction. 3.Ground water not affected. 4.Supports all portions of structures. COMPACTION PERMEATION

117. Disadvantages Grouting adjacent to unsupported slopes may be ineffective. Not suitable in decomposable materials. Danger of filling underground pipes with grout. Effectiveness questionable in saturated clays COMPACTION PERMEATION

118. Thick slurries can not penetrate fine cracks and higher injection pressures would cause fracturing of ground foundations. Because of the higher water requirements of micro fine cement, the slurry remains fluid enough to flow into and penetrate fine sands and small cracks in rock. These cements can treat finer grained sands not possible to treat with Portland cement alone. They are also used to stabilize waste plumes. MICROFINE CEMENT

119. A key advantage of chemical grouting is the ability to introduce grout into soil pores without any essential change in the original soil volume and structure, thus changing the support capability of granular soils without disturbing them. Another advantage is the ability to be less disruptive and enable tunneling to proceed without over-excavation. A possible drawback of chemical grouting is that only certain soil types are amenable. Another barrier to the use of chemical grouting techniques in the recent is increasing concern regarding potential pollution by chemical grouting in urban areas. Two trends have addressed this issue: 1. Improvement of grouts through the development of new formulae that enhance the penetrability of particulate suspensions and meet the strictest specifications for environmental safety 2. Development of alternative techniques which by-pass the penetrability restraints, such as jet grouting which allows the treatment of most types of soil, independent of its grain size and permeability, using simple cement grouts CHEMICAL GROUTING

120. COMPACTION PERMEATION

121. 1.Compensation (hydrofracture) grouting uses high-mobility grout to split the ground and thereby create lifting or densification under structures or other facilities. 2.The ground is deliberately split by injecting stable fluid cement- based grouts at high pressures in order to increase total stress by the wedging action of successive thin grout lenses, to fill unconnected voids, and possibly to consolidate the soil locally under injection. 3.This process is often undertaken as a reaction to movements while tunnel excavation is in progress. 4.It is important to keep in mind that the effects of compensation (hydrofracture) grouting are difficult to control and the potential danger of damaging adjacent structures by the use of high pressure may prove prohibitive COMPENSATION GROUTING

122. 1.It is a technology in which high- pressure jets of cement grout are discharged sideways into the borehole wall to simultaneously excavate and then mix with the soil. 2.The outstanding feature of jet grouting is the ability to treat a whole range of soils, from silty sands to cohesive deposits, by means of simple cement grouts. 3.Jet grouting can be performed in soils with a wide range of granulometries and permeabilites. JET GROUTING

123. 1.the ability to use very small drilling tools (90mm diameter) to create large elements (1.2m to 2.4m diameter) using pressure and flow; 2.the ability to drill underneath obstacles and solidify zones which are hard to access; 3.the use of technically sophisticated techniques such as high- powered pumps and monitoring devices with continuous measurement of all operational parameters. ADVANTAGES

124. JET GROUTING

125. A grouting plant includes a mixer, an agitator, a pump, and piping connected to grout holes. Two systems: single line type and circulating type. In the circulation type, the unused grout is returned to the agitator and in the single-line type the grout refused is wasted. The basic items required for a grouting plant and their functions are: (a) Measuring tank-to control the volume of grout injected. (b) Mixer-to mix the grout ingredients (c) Agitator-to keep the solid particles in suspension until pumped (d) Pump-to draw the grout from the agitator to deliver to the pumping line. (e) Control fittings-to control the injection rate and pressure so that the hole can be regularly blend with water and thin grout. GROUTING PLANT AND EQUIPMENT

126. SCHEMATIC REPRESENTATION

127. PRECAUTIONS The following are the precautions while mixing a grout: Water is placed first in the mixer. Mixer is run at the maximum speed before adding the cement. Grout is mixed in batches. Ingredients have to be measured in volume Enough water should be maintained to cover the rotor while it is functioning. Mixer should not be allowed to run for more than a few minutes between batches. Mixers should be cleaned thoroughly after the day’s work.

128. Holes for the injection of grout may be drilled with jack hammers, wagon drills or diamond drills, depending on the terrain, class of foundation material, and size and depth of holes. Diamond drills usually give holes of uniform shape, while wagon drills are satisfactory for holes up to about 10 meters depth. DRILLING INJECTION HOLES

129. Preparations for washing or grouting seams, consists of installing a section of pipe of about 35 to 50mm dia and 0.50 to 1.0 m long in the grout hole with the top and projecting out a short distance for connection to an air line or a pump. For grouting the seams with neat cement for consolidation purposes it is desirable to deposit the cement in clean seams by removing any clay or any other unwanted materials. For this cleaning effective method is to force a mixture of air and water through the seams. For deciding the pressure for grouting operation, most common practice is to use a pressure 0.2kg/cm2 for each meter of depth of hole. WASHING AND GROUTING THE SEAMS

130. Construction Techniques, Equipment and Practice UNIT – II CONSTRUCTION PRACTICES

131. SYNOPSI S Specification Sequence of activities Site clearance, Marking Damp Proof Course, Weathering Course Masonry Flooring Roofing Construction Joints Foundation Precast Pavements Slip Forms Scaffoldings Fabrication & Erection of Steel Trusses Air Conditioning Acoustics Fire Protection Centering & Shuttering

132. Specification Specifications are statements which describe the nature and class of work, materials to be used, labour to be employed, method of work, precautions to be taken, quality of workmanship etc., Contract specification  General specification  Detailed specification Guide specification Manufacturer’s specification

133. Sequence of Activities to be done in Construction Excavation Concrete in Foundation Soiling Damp Proof Course(DPC) Masonry Work Lintel Reinforced Cement Concrete Flooring Roofing Plastering Pointing Doors Windows Wood Work Iron Work White Washing Colour Washing Painting

134. Masonr y  It is used to indicate the art of building the structures either in stones or bricks.  Masonry classification  Stone masonry  Brick masonry  Hollow block concrete masonry  Reinforced masonry  Composite masonry

135. Stone Masonry Based on the arrangement of the stones in the construction and degree of refinement in the surface finish.  Rubble Masonry  Coursed rubble  Uncoursed Rubble  Dry Rubble  Polygonal Rubble  Flint Rubble  Ashlar masonry  Ashlar fine  Ashlar Rough – tooled  Ashlar Rock or quarry face  Ashlar Chamfered  Ashlar Block – in - course

137. Brick Masonry Brick masonry is unified mass obtained by systematic arrangement of laying bricks and bonding them together with mortar.  Stretcher bond  Header bond  English bond  Flemish bond  Garden wall bond  Raking bond  Dutch bond  Brick on edge bond  English cross bond  Facing bond

139. Composite Masonry  Sometimes the facing and backing of a wall are constructed with different classes of masonry or of different materials.  Following are the usual combination  Facing of ashlar masonry and backing of rubble masonry brickwork  Facing of stone slabs and backing of concrete or brickwork  Facing of brickwork and backing of rubble masonry  Facing of brickwork and backing of cement concrete  Facing of brickwork and backing of hollow cement concrete blocks

141. Reinforced Masonry It’s a wall material. Beam, slabs have been built but with exception of deep wall beams. It does not require shuttering and expensive element of concrete. It lies in walls subject to bending perpendicular to the wall beams. It combines flexibility of form with good finish and frequently a large cost saving compared with reinforced concrete. Reinforced masonry is thus a cheap, durable, fire – proof, easy to construct and in most cases it results in the increase of floor space due to adoption of brickwork of lesser thickness. Reinforced Masonry Walls Masonry Reinforced Columns Reinforced Masonry Lintels Reinforced Masonry Slab

143. Flooring Floors are the horizontal elements of a building structures which divide the building into different levels for the purpose of creating more accommodation within a restricted space one above the other and provide support for the occupants, furniture and equipment of a building. Mud & Murram Flag – Stone or Stone Brick Timber Cement concrete & Concrete Mosaic Terrazzo Granolithic Tiled Rubber Linoleum Cork or Cork tiles Magnesite Glass Marble Plastic or PVC Asphalt

145. Roofing Roof is the uppermost part of a building which is supported on structural members and covered with a roofing material. The main function of a roof is to enclose the space or building and to protect the same from the damaging effects of weather elements such as rain, wind, heat, snow, etc., A good roof also increases the life of the building. Pitched or Sloping Roofs Flat or Terrace Roofs Shell or Curved Roofs Domes

147. Pitched Roof or Sloping Roof  Single Roof Lean – to Roof Couple Roof Couple close Roof Collar beam Roof Collar & Scissors Roof Double or Purlin Roof  Triple – membered or Framed or Trussed Roof King post roof truss Queen post roof truss Combinations of both truss Mansard roof truss Truncated roof truss Belfast roof or bow string or latticed roof truss

149. Foundation  The structure which is in direct contact with the ground. It transfers the load of the structure to the soil below so as to avoid over – loading of the soil beneath.  It prevents the differential settlement by evenly loading the substrata.  It provides a level surface for building operations.  It also increases stability of structure by taking the structure deep into the ground.  Foundations are generally built of bricks, stones, concrete, steel, etc.,  The selection of material and type of foundation depends upon the type structure and the nature of underlying soil.  Foundations should be designed to be capable of being constructed economically and without risk of protracted delays.

150. Types of Foundation Open or Shallow foundation Wall footing Isolated footing Combined footing Inverted arch footing Continuous footing Cantilever footing Grillage footing Raft foundation

154. Pile Foundation Function Bearing piles Friction piles Screw piles Compaction piles Uplift piles Batter piles Sheet piles Well Foundation or Caisson Material & Composition Cement concrete piles Pre cast concrete piles Cast in situ concrete piles Timber piles Steel piles Sand piles Composite piles

157. Construction Joints Construction joints are provided construction stopped at end of day Proper bond between old work & new one(necessary to ensure) Joints may be horizontal or vertical In construction of large concrete members airfield pavements, road pavements, factory floors, residential floors, columns in framed structure cannot place concrete in one operation Joints are left between subsequent concreting operation Types of joints are Construction joint Expansion joints Contraction joints

158. Construction joint Temporary joint Position should be planned and concrete should be placed in one operation. Walls & columns – horizontal, vertical Beams & slabs – minimum shear Appearance disturbed Expansion joint Volume changed Floor, roof – joint not necessary for small building Large building – joint necessary(2-5cm) Maximum temperature : day : expansion Minimum temperature : night : contraction

159. Contraction joint  Plastic, drying shrinkage, concrete shrinks  Avoid cracks – joints provided 5 -10 m  Dummy or control joints  Unreinforced floors and pavements

161. Precast concrete piles  Piles are manufactured in factory & driven into ground. Tampered or parallel  Square, octagonal shaped cast in horizontal forms, round shaped cast in vertical forms  Size 30 – 50cm, length – 18m or more  Reinforcement is used for stress.  Main or vertical reinforcement 20 – 40mm, lateral 5 – 10mm, spacing - 10cm( top, bottom), intermediate - 30cm  Toe : steel shoe

162. Casting Form work prepared and coated with soap solution or oil to prevent adhesion Cage of reinforcement is prepared, placed in formwork with cover 50mm Concrete 1:2:2 or 1:2:4, CA – 10 to 25 mm size Pour concrete in formwork and consolidated with vibrators Formwork removed in 3days, remains 7days and then shifted to curing tank for 3 to 4 weeks

163. Advantage Position of reinforcement not disturbed from original position Piles can driven under water. Sulphate resistance Proper control & design is possible while manufacture Defect of cast is repaired before driven into the ground More piles are manufactured at convenient place & economical Pile is smooth while driving it takes load, no wastage of time High resistance to biological & chemical actions on ground

164. Disadvantage  Heavy weight : transport, driven is difficult  Costly extra reinforcement is provided to resist stresses develop during handling & driving  Wastage of material, if long pile is manufactured  Sufficient care should to taken while transport or driving  Piles not available – delay of work occur  Size, length of pile depend on available transport facility

166. Slip forms Essential parts of slip forms are as follows Sheathing Wales or ribs Yokes Working platform or deck Suspended scaffolding Lifting devices

167. Operation Over concrete base, slip form set is assembled and filled with concrete After setting of concrete, sufficient rigidity in bottom then upward movement started from bottom to top. Depending upon temperature, properties of concrete lifting rate is 50 to 80mm Experienced person is employed for movement of slip form while moving Uses Vertical structures : economical Used for piers, chimneys, towers, missile launching bases, water reservoirs, silos, resolving restaurants, etc.,

168. Removal Some factors: amount & nature of dead load Character & quality of concrete Shape, span & situation of structure Temperature of the atmosphere 2-3 days remove formwork – beam sides 10-21 days – between beam, floors Use rapid hardening cement within 3-4 days formwork can removed High – alumina cement, takes few hours to remove formwork

170. Scaffolding Temporary structure gives support to workman, structural material, other appliances, etc., Used in building construction, demolition, maintenance & repair works Erected either one(ordinary works) or both sides of walls(superior works) and heights can adjusted Components Planks – supporting men, materials, appliances Guard boards – working on ledgers level to guard materials Toe boards – parallel to ledgers for protection

171. Types Single or bricklayers scaffoldings – BW used in construction, made of bamboos, poles except platform, single standard 1.5 to 2m, spacing 1.2m, ledgers 1.2 – 1.5m, put legs 1.2 – 1.5m Double scaffolding – stronger, stone work, two rows Ladder scaffolding – easily assembled, platform supported on brackets, heights can adjusted, used in light works such as exterior walls, paintings, decorations Cantilever scaffolding – Where standard not possible to fix in ground, busy street, traffic areas, upper storey of tall buildings Suspended scaffolding – light steel frame construction, maintenance work such as paintings, pointing, distempering, etc., working platform is suspended from roofs by means of wire ropes or chains

172. Steel scaffolding – same as timber scaffolding except wooden members are replaced by steel tubes and rope Removal Walls, beams, column sides(low load) Slabs Heavy load, girders, beam bottom Walls, columns, beams sides : 1 – 2 days Slabs : 3 Beam soffit (under) : 7 Slab upto 4.5 :7, over 4.5 :14 Beams upto 6 : 14 Arches over 6 : 21

174. Fabrication & Erection of Trusses Roof trusses : principle rafters, ties, struts, purlin, cleats etc., gusset plates, rivets, bolts Use of steel trusses proves to economical for span >12m Steel roof trusses designed should be compression or tension (no bending stress) Arrangement & size depends upon roof slope, span, loading wind pressure distance Compression member strut : short to avoid buckling, principle rafter : transverse stresses not larger than 3m & maximum T section best for principle rafter, channel for struts

175. Small trusses fabricated in factory or workshop & transport to site while large trusses fabricated at the job site Truss should be arranged to form triangles – truss not deform Distance not exceed 3m, light roofs – more distance or spacing Joints or connection of member called nodes or panel points, gusset plates In rivets, pitch should not less than 3times diameter. L 7 20mm diameter rivets Gusset plate thickness 6mm(small) & 10mm(large) roof trusses Three types of trusses north light roof trusses – factories, workshop, Bow string type trusses – 20m span, arched truss Small span end of truss fixed, large span one fixed, one end mounted on steel rollers

176. Air conditioning of buildings Process of treating air to control temperature, humid purity distribution to meet the meet the requirement of conditioned Classification of air conditioning Comfort – inside the room(Residential, institution, hospitals) Industrial – material processing, manufacturing storage etc., Steps of air conditioning Summer - outside temp is above inside temp, cycle of operation involves air cooling, dehumidifying, air distribution & air cleaning Winter – below, air heating, humidification Composite - both

177. Principle of comfort air conditioning Temperature control – comfortable zone for people both in summer & winter Air velocity control – velocity increases, temperature decreases 6-9m/s Humidity control – with conditioned air is important, dry air, moisture is added to heated air(summer), moisture extracted from cool air, humidity 40 – 60% Systems Central system – one focal point, conditioned air is distributed to all room, less space for installation, maintenance easy, one unit(economical), instead of more unit for every room Unit system – window Unitary control – from central to every unit Combined control –central or self conditioned, central or semi conditioned

178. Frames In portal frames structural roof members are rigidly connected to column or post for continuous structural member to withstand bending North light RC portal frames Span 9m, rafter south facing slope 221/2, north 60 - 80 Rafter divided into sections for convenience in casting & transporting Rafter is bolted together, gutter, purlin to support wood wool slabs Slabs(insulators) – roof deck covered with north light glazing Flat RC portal frames monitors Two span portal type – monitor light provided, made of glazing, open for ventilation At junction of monitor light & flat roof – large heavy precast reinforced concrete beams are bolted to frame Serve for fixing roof covering & glazing

179. Domes Semi – spherical or semi elliptical in shape Used as roof structure – material stone, brick or concrete Supported on regular or circular polygon shaped walls Certain height, diameter ratios, small thickness Used in monumental work(circular, hexagonal shape) Domes can be either smooth shell domes or ribbed domes Types of domes Spherical domes Cylindrical domes Rectangular domes Triangular domes Square domes Intersecting double curved barrel domes

180. Braced domes Oldest structural form, arch, three dimensional structure Enclose maximum space with minimum surface & economical in terms of material Material – high strength alloy(magnesium alloy, aluminum alloys) Types Frame or skeleton type – single layer dome Truss type – double layer dome, extremely rigid provides greater resistance to buckling, suitable for layer spans Stressed skin type – covering part an integral part of structural system Framed surface type – bent sheets interconnected along edges to form main skeleton

181. Acoustics The branch of science which deals with the planning of building or hall with a view to provide best audible sound to the audience Features of good acoustics The sound heard must be sufficiently loud in every part of the hall and no echoes should be present The total quality of speech and music must be changed ie., relative intensities of several components of a complex sound must be maintained The successive syllables spoken must be clear and distinct The reverberation should be quite proper ie., neither too low nor too high There should not be any concentration of sound in any portion of hall The boundaries should be sufficiently sound proof

182. Acoustical defects Formation of echoes Reverberation Sound foci & dead spots Insufficient loudness Exterior noise nuisance or out door noise effects

183. Fire Protection in Buildings For important buildings in addition to the use of fire resisting materials and adoption of fire resistant construction, the following general measure of safety have been recommended Alarm system Manual alarm system Automatic alarm system Fire extinguishing arrangements Normally operated equipments Fire hydrants Automatic sprinkler system Escape routes

189. Thank you