1. Hi Guest Pls Attention! Kazirhut Accepts Only Benglali (বাংলা) & English Language On this board. If u write something with other language, you will be direct banned!

    আপনার জন্য kazirhut.com এর বিশেষ উপহার :

    যেকোন সফটওয়্যারের ফুল ভার্সনের জন্য Software Request Center এ রিকোয়েস্ট করুন।

    Discover Your Ebook From Our Online Library E-Books | বাংলা ইবুক (Bengali Ebook)

Educational Basic Civil Engineering

Discussion in 'Education' started by Tazul Islam, Jun 15, 2016. Replies: 62 | Views: 3493

  1. Tazul Islam
    Offline

    Tazul Islam Kazirhut Lover Member

    Joined:
    Apr 20, 2016
    Messages:
    23,674
    Likes Received:
    534
    Gender:
    Male
    Location:
    Dhaka
    Reputation:
    131
    Country:
    Bangladesh Bangladesh
    Structural Design Criteria for Coastal Structures



    Coastal structures are the structures that are constructed near to the coastal areas for different purposes. Different types of coastal structures are constructed under different circumstances but the criteria to be used for the selection and design of specific type of coastal structure must be authentic and comply with the standards.


    There are a various set of criteria that need to be considered in the selection and design of coastal structures.


    • Structural stability criteria
    • Functional performance criteria

    These two areas are of primary concern for selection and evaluation of coastal structures. Structural stability criteria are usually associated with extreme environmental conditions, which may cause severe damage to, or failure of a coastal structure. These stability criteria are, therefore, related to episodic events in the environmental (severe storms, hurricanes, earthquakes) and are often evaluated on the basis of risk of encounter probabilities. A simple method for evaluating the likelihood of encountering an extreme environmental event is to calculate the encounter probability (Ep) as:


    Ep =1-(1-1/TR)

    where TR = the return period


    L = the design life of the structure (see Borgman, 1963)


    [​IMG]


    Typical Example of Coastal Structure

     
  2. Tazul Islam
    Offline

    Tazul Islam Kazirhut Lover Member

    Joined:
    Apr 20, 2016
    Messages:
    23,674
    Likes Received:
    534
    Gender:
    Male
    Location:
    Dhaka
    Reputation:
    131
    Country:
    Bangladesh Bangladesh
    The greatest limitation to structural stability criteria selection is the need for a long-term data base on critical environmental variables sufficient enough to determine reasonable return periods for extreme events.


    For example coastal wave data for U.S. coasts is geographically sparse and in most locations where it exists the period of collection is in the order of 10 years. Since most coastal structures have a design life well in excess of 10 years, stability criteria selection often relies on extrapolation of time limited data or statistical modeling of environmental processes.


    Functional performance criteria are generally related to the desired effects of a coastal structure. These criteria are usually provided as specifications for design such as the maximum acceptable wave height inside a harbor breakwater system or minimum number of years for the protective lifetime of a beach nourishment fill project. Functional performance criteria are most often subject to compromise because of initial costs.


    The U.S. Army Shore Protection Manual (1984) provides a complete discussion of coastal structures, their use, design and limitation. A P-C based support system entitled Automated Coastal Engineering System (ACES) is also available through the USAE Waterways Experiment Station, Coastal and Hydraulics Laboratory, Vicksburg, MS 39180-6199.


    TYPES OF COASTAL STRUCTURES

    Following are the few types of Coastal structures


    • Sea walls and groynes
    • Culverts and storm water pipes
    • Cables
    • Boat ramps and launch access
    • Fencelines and posts
    • Wharves and jetties
    • Buildings and Maimai
    • Bridges, causeways and fords
    • Dump sites and derelict structures
    • Marine farms
     
  3. Tazul Islam
    Offline

    Tazul Islam Kazirhut Lover Member

    Joined:
    Apr 20, 2016
    Messages:
    23,674
    Likes Received:
    534
    Gender:
    Male
    Location:
    Dhaka
    Reputation:
    131
    Country:
    Bangladesh Bangladesh
    ENVIRONMENTAL IMPACTS OF COASTAL STRUCTURES

    The placement of engineered structures on or near the coastline must be contemplated with extreme care. In general, alteration of the natural coastline comes with an associated environmental penalty. Hard (structures made of stone, steel, concrete, etc.) or soft (beach nourishment, sediment filled bags, etc.) engineering structures can alter many physical properties of the beach to often induce undesired effects. These alterations of natural processes can take the form of increased reflectivity to incident waves,


    These coastal engineering structures increase in scope and complexity, moving down the page. Anticipated regions of shoreline sediment accretion and erosion are also indicated for each type of structure. A significant body of recent research has indicated that these regions of structural impact along the shoreline extend between five and ten times the length of the structure. Hence, for a structure protruding from the undisturbed shoreline a distance of 100 m, the anticipated region of impact should be expected to extend from 500 to 1000 m either side of the structure.


    The field of coastal engineering is far from a mature science. This is a time of rapid and significant advances in our understanding of the physical processes, which control the response of the near shore region to wind, waves and water level changes. Furthermore, advances in the design, implementation and in predicting the response of coastal structures and fortifications are made almost daily. Hence, it is nearly impossible to provide a comprehensive review of the most current material.
     
  4. Tazul Islam
    Offline

    Tazul Islam Kazirhut Lover Member

    Joined:
    Apr 20, 2016
    Messages:
    23,674
    Likes Received:
    534
    Gender:
    Male
    Location:
    Dhaka
    Reputation:
    131
    Country:
    Bangladesh Bangladesh
    Floors - Notes, Lectures



    1. Mud Floor:

    Suitability:

    These floors are not prepared in commercial or professional buildings but only in residential buildings in rural areas.


    2. Brick floor:

    The floor whose topping is of brick. These are easy to construct and repair. but the surface resulting from these is not smooth and is rough, hence, easily absorbs and retains moisture which may cause dampness in the building.


    Method of construction:

    For constructing a brick floor, the top surface of earth or muram filling is properly consolidated. Over this compacted earth, a layer of clean sand about 10 cm thick is evenly spread. Then a layer of lime concrete (1:4:8) or lean cement concrete (1:4:16) is laid, compacted and cured. Over this base concrete well soaked bricks are laid in cement mortar (1:4) in any suitable bond. In case pointing is to be done, the minimum thickness of joints should not exceed 2 mm and and the mortar in joints is struck off with a trowel. When the pointing is to be done, the minimum thicknessof joints is kept 6mm and the pointin may be done.


    Suitability:

    The floors are suitable for stores, godowns etc.


    3. Tile floor:

    The floor whose topping is of tiles is called tile floor. The tiles used may be of any desired quality, colr, shape or thickness.
     
  5. Tazul Islam
    Offline

    Tazul Islam Kazirhut Lover Member

    Joined:
    Apr 20, 2016
    Messages:
    23,674
    Likes Received:
    534
    Gender:
    Male
    Location:
    Dhaka
    Reputation:
    131
    Country:
    Bangladesh Bangladesh
    Method of construction:

    For constructing a tile floor, the base course is prepared in the same manner as in case of brick flooring.Over the base course thus prepared, a thin layer of lime or cement mortar is spread with the help of screed battens. Then the screeds are properly levelled and fixed at the correct height. When the surface mortar has hardened sufficiently, the specified tiles are laid on a 6 mm thick bed of wet cement mortar.(1:5). The surplus mortar which comes out of the joints is cleaneed off. After 3 days, the joints are well rubbed a carborundum stone so as to smoothen the surface, specially the edges.


    Suitability:

    These floor are used for paving courtyard of buildings. Glazed tiles floors are used in modern buildings where a high class building is desired.


    4. Flagstone floor:

    The floors whose topping consists of stone slabs is called flagstone floor. The stone slabs used here may not be of the same size but should not be more than 75 cm length and not less than 35 cm in width and 3.8 cm in thickness.


    Method of construction:

    For constructing a flagstone floor, the same method is applied as in case of tile floor. The slabs are soaked well in water atleast one hour before laying. They should be evenly and firmly bedded in mortar. The thickness of joints should not exceed 4mm and they should be struck off with a trowel while laying.


    Suitability:

    These type of floorings are suitable in godowns, motor sheds, stores, pavements etc.


    5. Cement concrete floor:

    The floors whose topping consists of cement concrete is called cement concrete floor or conglomerate floor. These floors consists of 2.5 cm to 5cm thick concrete layer laid over 10 cm thick base concrete and 10 cm thick clean sand over ground whose compaction and consolidation is done. These floors are commonly used these days.


    Following are the advantages of concrete floors:


    1. They are hard & Durrable
    2. Provide a smooth & non absorbent surface
    3. They are more fire resistant
    4. They provide more sanitary surface as they can be cleaned & washed easily.
    5. They are economical as they require negligible maintenance cost
    6. They can be finished with a pleasing appearance.

    Types of cement concrete floors:


    1. Non-Monolithic or bonded floor finish floor
    2. Monolithic floor finish floor
     
    Last edited: Jun 26, 2016
  6. Tazul Islam
    Offline

    Tazul Islam Kazirhut Lover Member

    Joined:
    Apr 20, 2016
    Messages:
    23,674
    Likes Received:
    534
    Gender:
    Male
    Location:
    Dhaka
    Reputation:
    131
    Country:
    Bangladesh Bangladesh
    Structural joints in building construction

    Properties of a good sealant

    1. Protection

    2. Durability

    3. Less expansion

    4. Good adhesion

    5. Chemical inertness

    6. Sound insulation - Air tight

    7. Must be of softer grade and not stiff

    8. Good wetting behaviour

    9. Must be able to absorb thermal stresses
     
  7. Tazul Islam
    Offline

    Tazul Islam Kazirhut Lover Member

    Joined:
    Apr 20, 2016
    Messages:
    23,674
    Likes Received:
    534
    Gender:
    Male
    Location:
    Dhaka
    Reputation:
    131
    Country:
    Bangladesh Bangladesh
    Characteristics and Properties of good Joint filler materials
    The followings are the different requirements of good joint fillers.

    • The ability to create an effective water seal.
    • It should absorb the impact and shock of heavy loads and steel wheeled traffic, preventing erosion of control joint edges.
    • The ability to expand and contract, as the joint widens or narrows in response to environmental or other conditions, while maintaining an effective seal against the sides of the joint.
    • It should be durable and economical
    • The ability to flex in every direction, as the joint flexes due to structural conditions, loading, or environmental conditions, while maintaining an effective seal against the sides of the joint;
    • It must give aesthetically acceptable appearance; the capability of being installed in a joint by fairly unskilled labor;
    • It must posses' long life, Wear resistant, durable and resilient; it does not harden or become brittle with age.
    • The ability to adhere to numerous surface materials, such as concrete, steel, or aluminum without extensive or expensive surface preparations.
    • The ability to fit into joints of a large variety of widths.
    • It must posses' Small density, high recovery rate, with independent air bubble structure.
    • Low surface water absorption rate with good seepage resistance.
    • Good resistance to corrosion of acid, alkali, salt and oil among other organic solvents and good resistance to aging.
    • No flowing under high temperature and no cracking under low temperature.
    • Flexibility provides for joint movement and protects slabs edges from chipping Cures on damp or wet surfaces
    • Penetrates and fills without running
    • Flexible enough to absorb hard heavy wheeled traffic.
    • The ability to reduce stress cracking and telegraphing.
    • The ability to bonds tightly to the sides of the concrete joint prevents contaminant penetration and delivers high wear resistance and durability.
    • It should be environment friendly.
    • It must have uniform consistency with no measurable shrinkage.
    • It must posses' adequate tensile strength. As tensile strength relates to the capacity of this material to hold together when stretched. Percentage tensile elongation is the length the material can be stretched before failure.
    • It must deliver adequate support to joint shoulders receiving the force of hard wheel traffic carrying heavy loads.
    • Delivers tight bond to faces of joint
     
  8. Tazul Islam
    Offline

    Tazul Islam Kazirhut Lover Member

    Joined:
    Apr 20, 2016
    Messages:
    23,674
    Likes Received:
    534
    Gender:
    Male
    Location:
    Dhaka
    Reputation:
    131
    Country:
    Bangladesh Bangladesh
    Stone Masonry and brick stone masonry

    Definition:

    The art of building a structure in stone with any suitable masonry is called stone masonry.


    Types of Stone Masonry:

    Stone masonry may be broadly classified into the following two types:


    1. Rubble Masonry
    2. Ashlar Masonry
      1. Rubble Masonry:

    The stone masonry in which either undressed or roughly dressed stone are laid in a suitable mortar is called rubble masonry. In this masonry the joints are not of uniform thickness. Rubble masonry is further sub-divided into the following three types:


    1. Random rubble masonry
    2. Squared rubble masonry
    3. Dry rubble masonry

    1. Random rubble masonry: The rubble masonry in which either undressed or hammer dressed stones are used is called random rubble masonry. Further random rubble masonry is also divided into the following three types:
      1. Un coursed random rubble masonry: The random rubble masonry in which stones are laid without forming courses is known as un coursed random rubble masonry. This is the roughest and cheapest type of masonry and is of varying appearance. The stones used in this masonry are of different sizes and shapes. before lying, all projecting corners of stones are slightly knocked off. Vertical joints are not plumbed, joints are filled and flushed. Large stones are used at corners and at jambs to increase their strength. Once "through stone" is used for every square meter of the face area for joining faces and backing.
        Suitability: Used for construction of walls of low height in case of ordinary buildings.
      2. Coursed random rubble masonry: The random rubble masonry in which stones are laid in layers of equal height is called random rubble masonry. In this masonry, the stones are laid in somewhat level courses. Headers of one coursed height are placed at certain intervals. The stones are hammer dressed.
        Suitability: Used for construction of residential buildings, go downs, boundary walls etc.
     
  9. Tazul Islam
    Offline

    Tazul Islam Kazirhut Lover Member

    Joined:
    Apr 20, 2016
    Messages:
    23,674
    Likes Received:
    534
    Gender:
    Male
    Location:
    Dhaka
    Reputation:
    131
    Country:
    Bangladesh Bangladesh
    1. Squared rubble masonry: The rubble masonry in which the face stones are squared on all joints and beds by hammer dressing or chisel dressing before their actual laying, is called squared rubble masonry.
      There are two types of squared rubble masonry.
      1. Coursed Square rubble masonry: The square rubble masonry in which chisel dressed stones laid in courses is called coarse square rubble masonry. This is a superior variety of rubble masonry. It consists of stones, which are squared on all joints and laid in courses. The stones are to be laid in courses of equal layers. and the joints should also be uniform.
        Suitability: Used for construction of public buildings, hospitals, schools, markets, modern residential buildings etc and in hilly areas where good quality of stone is easily available.
      2. Un coursed square rubble masonry: The squared rubble in masonry which hammer dressed stones are laid without making courses is called un coursed square rubble masonry. It consists of stones which are squared on all joints and beds by hammer dressing. All the stones to be laid are of different sizes.
        Suitability: Used for construction of ordinary buildings in hilly areas where a good variety of stones are cheaply available.

    2. Dry rubble masonry: The rubble masonry in which stones are laid without using any mortar is called dry rubble masonry or sometimes shortly as "dry stones". It is an ordinary masonry and is recommended for constructing walls of height not more than 6m. In case the height is more, three adjacent courses are laid in squared rubble masonry mortar at 3m intervals.

    2. Ashlar masonry:

    The stone masonry in which finely dressed stones are laid in cement or lime mortar is known as ashlars masonry. In this masonry are the courses are of uniform height, all the joints are regular, thin and have uniform thickness. This type of masonry is much costly as it requires dressing of stones.


    Suitability: This masonry is used for heavy structures, architectural buildings, high piers and abutments of bridges.


    Ashlars masonry is further sub divided into the following types:


      1. Ashlars fine or coarse ashlar masonry
      2. Random coarse ashlars masonry
      3. Rough tooled ashlar masonry
      4. Rock or quarry faced ashlars masonry
      5. Chamfered ashlars masonry
      6. Block in coarse masonry
      7. Ashlar facing
        1. Ashlar fine or coarsed ashlar masonry: In this type of stone masonry stone blocks of same height in each course are used. Every stone is fine tooled on all sides. Thickness of mortar is uniform through out. It is an expensive type of stone masonry as it requires heavy labor and wastage of material while dressing. Satisfactory bond can be obtained in this type of stone masonry.
        2. Random coursed ashlar masonry: This type of ashlar masonry consists of fine or coursed ashlar but the courses are of varying thick nesses, depending upon the character of the building.
        3. Rough tooled ashlar masonry: This type of ashlar masonry the sides of the stones are rough tooled and dressed with chisels. Thickness of joints is uniform, which does not exceed 6mm.
        4. Rock or quarry faced ashlar masonry: This type of ashlar masonry is similar to rough tooled type except that there is chisel-drafted margin left rough on the face which is known as quarry faced.
        5. Chamfered ashlar masonry: It is similar to quarry faced except that the edges are beveled or chamfered to 450 for depth of 2.5 cm or more.
        6. Block-in course masonry: It is the name given to a class of ashlar masonry which occupies an intermediate place between rubble and ashlars. The stones are all squared and properly dressed. It resembles to coursed rubble masonry or rough tooled ashlar masonry.
        7. Ashlar facing: Ashlar facing is the best type of ashlars masonry. Since this is type of masonry is very expensive, it is not commonly used throughout the whole thickness of the wall, except in works of great importance and strength. For economy the facing are built in ashlars and the rest in rubble.
     
  10. Tazul Islam
    Offline

    Tazul Islam Kazirhut Lover Member

    Joined:
    Apr 20, 2016
    Messages:
    23,674
    Likes Received:
    534
    Gender:
    Male
    Location:
    Dhaka
    Reputation:
    131
    Country:
    Bangladesh Bangladesh
    Dampness, DPC and Damp Proof Methods in buildings by Damp course
    Dampness in buildings and DPC
    Definition:

    The access and penetration of moisture content into building through its walls, floor, roof etc. is called dampness.

    Effects of dampness in buildings:
    1. Causes rotting of wood.
    2. Causes corrosion of metallic fixtures.
    3. Deteriorate electric installations.
    4. Deteriorate carpet & furniture’s.
    5. Causes spots on the floors and walls.
    6. Causes petting off and removal of plaster.
    7. Causes bleaching and blistering of paints.
    8. Causes effloresce.
    9. Dangerous for the health of occupants.
    10. Reduce the life of structures
    Causes of dampness in buildings
    1. Rain penetration
    2. Level of site
    3. Drain ability of soil
    4. climate condition
    5. Defective orientation of building
    6. Moisture entrapped during construction
    7. Defective construction e.g. joints
     

Pls Share This Page:

Users Viewing Thread (Users: 0, Guests: 0)