MAIN CIVIL WORK FOR THERMAL POWER PLANT. part iv

We have discussed about the loading pattern on structure of Thermal Power Plant. Now we will give a few conditions for calculating the load.

We like to mention that these blogs will cover all the aspect of thermal power plant and the information provided are typical . This information will be eye opener and interesting for new comers in the construction field . Therefore all the blogs may be judge accordingly.

The different load conditions are to be taken from (IS:875 part-5) and other relevant IS codes.

1. Wind and Seismic force shall not be considered to act simultaneously.

2. The design of PH structure during Seismic conditions FST ( Feed Storage Tank ) should be considered full up to operating conditions. For other load condition it should be taken as flooded condition.

3. During Seismic condition lifted load of crane should not be considered.

4. For two crane operation ( not in tandem ) one crane considered to be fully loaded and  other crane in no load condition standing side by side . For tandem operation both the cranes considered to be full load conditions standing side by side.

5. For pipe and cable rack structure frictional forces on longitudinal direction , Seismic and wind load are not considered.

6. Clearance of 600 mm to be kept clear from nearest crane structure to B row column. The same clearance for A row will be approximately 1000 mm.

7. Where ever bolting connection is there High tensile bolts of 8.8 grade (min) provided.

8. For nominal connections ( perlins , stairs , wall beams etc) 4.6 grade black MS bolts are used.

9. Permissible deflection of lattice structure and frame except drive floor is span/325 mm.

10. Beams directly supported equipment is span/500 mm.

11. For manual operated cranes and hoist etc the beams deflection is beam span /500 mm in general.

12. EOT crane less than 50T the deflection is span /750  mm. and Crane more than 50T the deflection is  span/1000.mm

13. Bunker capacity to be designed 16 hrs operation on BMCR duty.

14. For all capacity calculation and structural design the unit weight of coal shall be 800 Kg/cu.m and 1200 Kg/cum respectively.

                                                         1.6x Rated capacity on conveyor  x 1200

15 The load on moving corridor  = ----------------------------------------------------

                                                           conveyor speed  x 800

16. Static and dynamic Analysis to be done for all major rotating parts  foundations like  TG , MILLS . ID ,  FD  AND PA FANS , BFP ,CEP CWP ETC. A. fatigue factor 2.0 to be assumed  for above foundations

17. Design criteria of CW duct :Following cases are considered  

-  Maximum design water pressure.

- Surge water pressure to be considered as 5.0 kg/cm2

- External surcharge loading will be 2.0 T / sq.m.

- Minimum headroom (clearance ) will be kept for cable racks and pipe racks.

Switch yard Structure. 

- Switch yard structure should be designed considering worst condition of following loans.

1. Dead Loads .          2. live loads           3. Wind loads        4. Seismic loads    5. Temperature  load

6. Loads due to deviation of conductor.   7. Loads due unbalanced tension of conductor. 8. Torsional

loads  9. Erection loads   10. Short Circuit including Snap of conductor. 

The factor safety for the design of  members is generally taken as 2.0. for normal and broken wire conditions. The factor of safety for short circuit and broken wire condition will be 1.5. These two conditions the factor of safety for designing the foundations will be 2.2 and 1.65 respectively.

Structural work at Power House Building under progress

  

 Bunker House Supporting structure and coal Gallery supporting structure under progress.

(to be continued).