What is the purpose of keeping tremie pipe’s tip immersed in freshly-placed concrete for about 1m in underwater concreting?

  What is the purpose of keeping tremie pipe’s tip immersed in freshly-placed concrete for about 1m in underwater concreting? The size of tremie pipe is about 300mm with sections having flange couplings fitted with gasket to prevent water leakage. The tremie pipe should be closed initially to prevent water from entering the pipe. It should be designed with sufficient thickness and weight so that it would not be buoyant when empty inside water. The placement of tremie concrete is commenced by putting the closed pipe underwater to the location for concreting, followed by partial filling of tremie pipe with concrete. In order to have tremie concrete flowed out of the pipe, it is necessary to fill the pipe with concrete of sufficient height to overcome the water pressure and frictional head. After that the tremie pipe is raised about 150mm to allow concrete to flow out. To enhance sufficient bonding, each succeeding layer of concrete should be placed before the preceding layer has reached
Post a Comment

WHAT IS HOUSE WIRING SYSTEM ?? ISI RULES FOR WIRING

SYSTEMS OF WIRING

• Tree System
• Distribution System

Tree System:

• This system is not used in installation purpose. It is generally used for temporary connections nowadays. In this system branch circuits are tapped from the mains at required places.

• Advantages: Less cost.

• Disadvantages: Appearance is poor.
• Fault location is difficult.
• Large voltage drops.

Distribution System:

• This system is used widely now a days and is used for indoor wiring in buildings. In this system, mains are taken to one or more distribution centres and connected to the distribution boards. From these
distribution boards connections are taken to branch circuits. In this system no joints are required and is
systematic.

• Advantages: Appearance is Good.
• Fault location is easy.
• Each circuit is separately protected by a Fuse or MCB.
• Replacement of Fuse or MCB is easy.
• The system is simple and capable of further extensions.

• Disadvantages: It is costlier than the Tree System.







ISI RULES FOR WIRING

• In AC Supply, the 3 phases should be indicated Red, Yellow, Blue and Neutral should be indicated by Black.
• In DC Supply, +ve should be indicated by Red and -ve should be indicated by Black.
• Earthing should always be indicated by Green.
• In the domestic wiring, 3 pin plug should always be used.
• All metallic appliances should be earthed.
• All switches should be connected through live wire.
• All switches should be fixed at the left side of the entrance door.

IMPORTANT WORDS IN HOUSE WIRING 

• Switch: A manually operated device for closing and opening the circuit. Switches can be 1 way, 2 way, grid switch, push button switch.

• Main Switches:

• ICDP - Iron-Clad Double Pole Main switch is used for single phase supply control. 16/32/63Amps. 250Volt.
• ICTP - Iron-Clad Triple Pole Main Switch for 3 phase supply control.

Fuse: It is the weakest point on the circuit. It is a device used for protecting the installation and cables, & switchgears etc. on
the circuit. 
Types of Fuses:1) Rewireable Fuse (2) HRC Fuse (High Rupturing Capacity Fuse)
MCB: Miniature Circuit Breaker - Used nowadays as a Fuse for protection of the installation. It is very light and requires very less space. Available in Range of 0.5Amps to 63Amps.
MCCB: Moulded Case Circuit Breaker - Used as a protection in the higher range. Available in Range of 50Amps to 1000Amps.
ELCB - Earth Leakage Circuit Breaker - Used as a Protection against earth leakage. Available in Range of 25Amps to 125Amps.

Comments

Post a Comment

Popular posts from this blog

HOW DO YOU INSTALL ELECTRICAL CONDUIT ON CONCRETE SLAB???WHAT IS THE SPECIFICATION FOR SLAB CONDUITING???

Image
SLAB CONDUITING 1)   Preparation of slab conduiting drawing by electrical contractor. 2)   Verification by electrical dept. and approval by Engg dept authorized signatory. 3)   Slab conduiting on site as per approved plan. Accessories for Slab Conduiting 1)    PVC Pipes. 2)   Junction Boxes (1 Way to 4 Ways) 3)   Fan Junction Box 4)   Couplers 5)   Reducers 6)   Bends 7)   PVC Cement Solvent 8)   Paint STANDARD SPECIFICATION FOR SLAB CONDUITING 1)  Conduiting should be done only after slab re-bars are laid and after fixing of PVC cover. 2)  Gap between adjacent conduits should be min. 25mm. 3)  Conduits should not pass through RCC Column. 4)  Conduit drops should be on wall face only. 5)  Conduits should not be in cover zone of re-bars. 6)  Light / Fan points should be painted for easy identification on slab surface soffit (slab shuttering). 7)  Conduits & Junction openings to be sealed to avoid choking and should be touching shuttering. 8)  Light / Fan / TV / Tel. / Bracket light
Read more

What is the purpose of keeping tremie pipe’s tip immersed in freshly-placed concrete for about 1m in underwater concreting?

  What is the purpose of keeping tremie pipe’s tip immersed in freshly-placed concrete for about 1m in underwater concreting? The size of tremie pipe is about 300mm with sections having flange couplings fitted with gasket to prevent water leakage. The tremie pipe should be closed initially to prevent water from entering the pipe. It should be designed with sufficient thickness and weight so that it would not be buoyant when empty inside water. The placement of tremie concrete is commenced by putting the closed pipe underwater to the location for concreting, followed by partial filling of tremie pipe with concrete. In order to have tremie concrete flowed out of the pipe, it is necessary to fill the pipe with concrete of sufficient height to overcome the water pressure and frictional head. After that the tremie pipe is raised about 150mm to allow concrete to flow out. To enhance sufficient bonding, each succeeding layer of concrete should be placed before the preceding layer has reached
Read more

What Is GGBS ?? What is the advantage of using GGBS as replacement of cement in concrete??What Is The Differences Between GGBS and PFA

What is GGBS?? GGBS (ground granulated blast furnace slag). What is the advantage of using GGBS as replacement of cement in  concrete? From structural point of view, GGBS replacement enhances lower heat of  hydration, higher durability and higher resistance to sulphate and chloride  attack when compared with normal ordinary concrete. On the other hand, it  also contributes to environmental protection because it minimizes the use  of cement during the production of concrete. However, it is identified that there are still some hindrances that prevent the  prevalence of its usage in local market. Technically speaking, GGBS  concrete suffers from lower rate of strength development which is highly  sensitive to curing conditions. In this connection, certain site measures  have to be introduced to the construction industry to ensure better quality  of curing process in order to secure high quality of GGBS concrete. On the  other hand, designers have to be cautious of the potential bleeding 
Read more