Recent questions tagged precast-&-prestressed-concrete

Description : For what type of structures do you recommend post-tensioning?

Last Answer : 1) High rise buildings. In long span slab where beam is not provided & the slab of assembly hall, cinema theaters etc. like structure where the distance between columns are more, then post ... Post Tensioning is used extensively for slabs on grade where soils are likely to move (expansive soils)

Description : Explain freyssinet system of prestressing with respect to process and application with sketches.

Last Answer : Process: - 1. The freyssinet system was the first to be introduced among the post - tensioned system high tensile steel wires 5mm to 8mm diameter about 12 in number are arranged to form a group into a cable ... gas (LNG) storage tank 4. Off share platforms. 5. Wind turbine towers etc.

Description : Depict the effect of pre-fabricated building on the surrounding environment with respect to noise pollution, staking at elements and transportation. 

Last Answer : Noise pollution is the serious or more noise that may damage the activity or human life. The contribution of most outside noise is mainly due to building activities. Noise pollution affects both health and ... iv) Sleep interference v) Habit of talking loudly vi) Hearing loss vii) Concentration

Description : Illustrate cable profiles for eccentric straight and parabolic cables with sketches. 

Last Answer : i) Eccentric straight cable profile: The stress due to prestressing alone are generally combined stresses due to the action of direct load bending from an eccentrically applied load. In this case, the load is ... section as shown in the figure below. ii) Parabolic cable profile

Description : Explain the loss of prestress due to friction and slip of anchorage and state two remedial measures to avoid them.

Last Answer : Loss due to Friction: This loss occurs only in post-tensioned members. There always exists a certain amount of friction in the jacking and anchoring system and on the walls of the duct. So, ... over-extending the tendon in the prestressing operation by the amount of the draw - in before anchoring

Description : State the advantages and disadvantages of prestressed concrete.

Last Answer : Advantages: 1. The c/s ismore efficiently used in fully prestressed members. 2. Dead loads are reduced considerably. 3. Improved shear resistance, due to the effect of compressive prestress, ... cube strength of 35 N/mm2 for Posttensioned system and 45 N/ mm2 for pretensioned system.

Description : Justify the necessity of use of high-grade materials in prestressed concrete.

Last Answer : 1) If mild steel is used, the working stress in it (i.e. 140 N/mm2) is more or less completely lost due to elastic deformation, creep and shrinkage of concrete. 2) The ... structural elements. With reduced dead weight of the material, larger spans become technically and economical practicable. 

Description : Explain any one method of Prefab system.

Last Answer : Prefab system: It refers to any part of a building that has been fabricated at a place other than its final location. For this reason, it can be referred to by other names such as off-site fabrication, ... If you need further assessing, feel free to contact us; your needs are all that matter to us.

Description : Explain the procedure of the storage, transportation and erection of prefabricated building elements. 

Last Answer : Storage of pre-fabricated building elements: 1) Procurement storage of Unloading raw materials 2) Testing of raw materials 3) Design of concrete mix 4) Fabrication of reinforcement cages 5) ... differs with risk condition, hence skilled foremen, and workers to be employed on the job.

Description : Explain determination of Water absorption of paver block and state acceptable limits as per IS. 

Last Answer : Step 1. Saturation  The test specimen shall be completely immersed in water at room temperature for 24 * 2 h. The specimen then shall be removed from the water and allowed to drain for 1 min by ... more than 6 % by mass and in individual samples, the water absorption should be restricted to 7 %

Description : Describe with sketch any two joints in doors and window frame.

Last Answer : 1. Connections must be adequate structurally. 2. Means of connections between adjacent must allow safe and speedy erection regardless of minor inherent inaccuracies in precast elements and in-situ concrete. 3. ... height) of the frames shall confirm to the requirements of IS : 4021-1976

Description : Describe any two design considerations for Precast Canal lining.

Last Answer : 1. Precast concrete slabs, laid properly on carefully prepared sub-grades and with the joints, effectively sealed, constitute a serviceable type of lining. The precast slabs are about 5 to ... . However, seepage losses are obviously more. Transportation of precast slabs may contribute to breakage. 

Description : State any four advantages and four disadvantages of precast concrete.

Last Answer : Advantages: 1. Very rapid speed of erection 2. Good quality control 3. Entire building can be precast-walls, floors, beams, etc. 4. Rapid construction on site 5. High quality because of ... is required in the application of the panel on site. 11. Cranes are required to lift panels.

Description : State cable profile in simply supported rectangular beam section.

Last Answer : Cabe profile: In a prestressed concrete member, external type of loads is balanced by transverse component of suitable cable profile, on effect of loading the net deformation increases the stress, strain and length of the tendon, extension of tendon, increase in strain, increase in stress.

Description : List the various types of losses of prestress in pretensioned pre-stressed member.

Last Answer : i. Elastic shortening ii. Shrinkage of concrete iii. Creep of concrete iv. Relaxation of steel

Description : What is the basic principle of Prestressed concrete?

Last Answer : Principle: The compressive stresses induced by high strength steel tendons in a concrete member before the application of load, will balance the tensile stresses imposed in the member during its service.

Description : Define Prestressed concrete and state types of prestressing steel.

Last Answer : Prestressed concrete: Prestressed concrete is basically a concrete in which internal stresses of a suitable magnitude and distribution are deliberately introduced so that the stresses resulting from external loads are ... 1962, and. 4) Uncoated stress relieved strand conforming to IS: 6006-1970. 

Description : Define Modules and modular co-ordination

Last Answer : Modules: Modules are a standard unit of size used to coordinate the dimensions of buildings and components. They are of two types: 1. Multi modules 2. Basic modules  Modular Co-ordination: The modular ... for basic module is M 1M = 100mm 100 mm = 1M = It is international standard value.

Description : State any four precast non-structural components that can be used for speedy construction.

Last Answer : 1. Architectural Precast 2. Insulated Architectural Cladding 3. Insulated Wall Panels 4. Column Covers 5. Precast Concrete Light Wall 6. Precast Concrete Spandrels 7. Precast Concrete Solid Walls 8. Stormwater Deflector 9. Façade 10. Concrete panels for partition walls 11. Concrete planks

Description : State any two names of materials used in precast concrete

Last Answer : 1. Cement 2. Sand 3. Steel 4. Water 5. Polystyrene 6. Fly ash. 7. Ground granulated blast furnace slag