Q Bank for Civil Engineer LDCE Exam- Write Short Notes on (26)

Q No. 10: Write short notes on any five of the following: 

(b) Guideline for disposal of human waste 

(c) Selection of ceramic/vitrified tiles for building work 

(d) Disinfection of water 

(e) Distressed Bridge 

(f) River training & Protection works 

(b) Guideline for disposal of human waste: - Discharged from water closets urinal, sinks, cattle shad gullies etc. is known as soil waste. W.C. with sufficient water arrangement required to provide for disposal of human waste. Further connection WC has been done following manner. 

i) Where water availability is sufficient and sewer line laid –by providing flushing cistern Further the sewage from sewer line connected into the treatment plant. 

ii) Where sewer line is not exist and no of users are more a septic tank should be provide for disposal of human waste. 

 iii) Where there is no adequate water supply exists- WC with bio laterrn/sockpit shall be provided.

(c) Selection of ceramic/vitrified tiles for building work: - Floor and wall tiles of appropriate design, color and texture enhance the touch and feel of a building. However, the aesthetic improvement potential may not be achieved if proper tiles are not selected. In public area there is a need to choose good tiles of reputed manufacturers confirming IS: 15622 having wear resistance and anti skid properties, modern design, color combination and scheme of laying. Types of Pressed Ceramic/Vitrified Tiles:- i) Ceramic Wall Tile: These tiles have high water absorption, due to high water absorptions these tile stain after contact with liquids.

ii) Ceramic Floor Tile: These tiles have medium water absorption, less in strength and low hardness. These are generally suitable for the area not likely to be wetted frequently and where foot traffic is low. 

iii) Ceramic Porcelain Tile: These tiles have low water absorption; these are hard, resistant to strain etc. These are suitable for heavy foot traffic. 

iv) Ceramic Vitrified Tiles: These tiles have very low water absorption. These are very strong and durable. These tiles are suitable for very heavy foot traffic areas. While selecting colour, design, etc. latest catalogue of manufacturer may be referred and put to record. Only qualified/trained mason should be allowed to do the work of fixing of tiles. It should be notice that all concealed pipe for plumbing/wiring should fixed in advance before laying the tiles.

(d) Disinfection of water:- Disinfection of water is required to remove disease producing organisms before it enters distribution system. The material used for disinfection of water is called disinfectants. A good disinfectant should economical and easily available in bulk quantity. It should destroy all harmful bacteria and other organisms. There should be no sludge formation in water. Working of plant, mixing of disinfectant should be simple after disinfectant, the water should not be come toxic and carry no objectionable odour and task. The dose should be such that there is always some residual concentration for protection of water from contamination during storage and conveyance of water through distribution system.

Method of disinfection are as under:-

1. Boiling of water 

2. Adding Potassium Permanganate (KMNO4) 

3. Excess lime Treatment 

4. Ozone gas Treatment 

5. Iodine and Bromine Treatment 

6. Ultra Violet rays 

7. Adding chlorine i.e. Chlorination Minimum residual chlorine should be available at farthest end shall be 0.5 mg per litre. During the monsoon month or if specific complaint are there super chlorination more than 2 DPM of chlorine may be resorted to effectively get rid of bacteria. 

(e) Distressed Bridge:- A distress bridge is one which show any physical sign of deterioration of its physical condition, indicating the needs for rehabilitation through special repairs, strengthening or rebuilding (including replacement of girders) 

1. The DEN/Sr. DEN, while including a bridge in the distressed bridge list should also indicate the priority classification depending on nature and severity of distress as detailed below:- 

(a) Category I should include those bridges where the distress is such that the rehabilitation work is required to be taken up immediately. 

(b) Category should include all those bridges which do not fall in category I. They may be taken up for rehabilitation on a program bases.

Inspection of distress bridge should be carried out as under:

2. Imposition of speed restriction: All distress bridge may not require speed restriction. It is not possible to lay down definite guideline for imposing speed restriction on Distress Bridge. Each case have to judge and decided on its merits by the inspecting officer, keeping in view the nature and severity of distress. However, for general guidelines speed restriction up to maximum of 15 Kmph is suggested for distressed bridge in group I and 25 to 50 Kmph for distressed bridge in group II. 

(f) River Training and protection work:- The object of river training/protection work is to prevent the river from damaging railway Formation Bridge and other structure. The following type of river training works is generally adopted in the Indian Railway:- 

a. Guide Bunds: Guide bunds are meant to confine and guide the river flow through the structure without causing damage to it and its approaches. 

b. Spur/groyne : It is structure constructed transverse to the river flow and is projected from the bank of the river. 

c. Marginal Bunds: these are provided to contain the spread of the river when the river in flood spills over the banks upstream of the bridge site over wide area and likely to spill in the neighboring water course or cause other damages. 

d. Closure of Bunds: Some time it is necessary to entirely block one or more channels of the river in order to prevent, the discharge of such channel developing into a main river channel after the construction of bridge. 

Protection of Approaches Banks:- 1. Approaches banks of bridges may be subjected to severe attack under the following conditions.

(a) When HFL at bridge is very high and there is spill beyond the flow channel.

(b) When the stream meets a main river just downstream of bridge.

(c) In case of bridge with insufficient of water way.

In all the above cases the pitching of the approaches bank upto HFL with sufficient free board is an effective solution. Provision of toe wall and narrow apron, in some cases will also useful. 

2. If deep borrow pits are dug near the toe to the approaches of the bank, the water flow through pits and forms a gradually deepening water course which may eventually threaten the safety of approach of the bank. In this case put rubble T-spurs across the flow to reduce the velocity. 

3. All the location with standing water against the embankment, special watch should be kept when the water level recedes rapidly and when slip is likely to occur.