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What is the difference between pretension and post tension in concrete?
Soumyadeep Halder
difference between pretension and post tension in concrete Prestressing may be achieved either by pretensioning or by post-tensioning. To pretension concrete the steel is first tensioned in a frame or between anchorages external to the member. The concrete is then cast around it. After the concreteRead more
difference between pretension and post tension in concrete
Prestressing may be achieved either by pretensioning or by post-tensioning.
To pretension concrete the steel is first tensioned in a frame or between anchorages external to the member. The concrete is then cast around it. After the concrete has developed sufficient strength the tension is slowly released from the frame or anchorage to transfer the stress to the concrete to which the tendons have by that time become bonded. The force is transmitted to the concrete over a certain distance from each end of a member known as the transfer length
Post-tensioned concrete is made by casting concrete that contains ducts through which tendons can be threaded. An alternative is to cast the concrete around tendons that are greased or encased in a plastic sleeve. When the concrete has sufficient strength the tendons are tensioned by means of portable jacks. The load is transmitted to the concrete through permanent anchorages embedded in the concrete at the ends of the tendons. Ducts are usually grouted later or filled with grease to protect the tendons against corrosion. In some applications the post-tensioning tendons are run alongside the concrete member.
One advantage of post-tensioning is that it permits using tendons that are curved or draped. This can be achieved in pretension but not so easily.
pre tension is developed due to bonding between concrete as well as tendon where as post tension is developed due to bearing.
if structural member is heavy then we preffered post tendion whearas when structural element is lighter we choose pre tension.
See lessWhat are the alternate building blocks which can used in place of ordinary building stones and bricks?
Soumyadeep Halder
the alternate building blocks which can used in place of ordinary building stones and bricks are given below terracotta hollow block Natural Bangalore Stone Interlocking Mud Blocks Soil Stabilized Blocks Big Size Light Weight Aerocon Blocks concrete block fly ash brick calcium silicate brick theseRead more
the alternate building blocks which can used in place of ordinary building stones and bricks are given below
these are few alternative you can use instead of conventional brick.
See lessWhat is the Time period of a building and its relation with frequency?
Kuldeep Singh
Simply put, the time period of a building is it's natural period of oscillation when subjected to ground shaking in the event of an earthquake. The building is modelled to be under harmonic oscillation and the time period is calculated in a similar way as in harmonic oscillation T = 2π√(k/m) where kRead more
Simply put, the time period of a building is it’s natural period of oscillation when subjected to ground shaking in the event of an earthquake.
The building is modelled to be under harmonic oscillation and the time period is calculated in a similar way as in harmonic oscillation
T = 2π√(k/m)
where k is the total stiffness and m is the total mass.
k is calculated as the sum of the lateral stiffness of all stiffness providing and moment resisting vertical members (colomns, moment resisting frames, sheer walls, etc.) m is calculated as the sum of masses of all members on the storey.
[ Note : The above method is only applicable for single storey buildings and for multiple storey buildings, these are vector quantities depending on the mode of vibration. A detailed vector analysis (modal analysis) is done to calculated time periods for each vibration mode, which requires detailed explanation.]
Thankfully, IS 1893 part I lists empirical formulae for approximate estimation of time period of multi storey buildings given in section 7.6 on page 24.
The frequency is nothing but the number of vibrations in a second and is the inverse of the time period
f = 1/T
See lessWhat is the role of Direct Cost and Indirect Cost in a Budget?
Preet Chovatiya
Direct cost and Indirect cost plays the main role in any project budget. Direct cost is the cost that is related to the direct purchasing of any items or material on-site like cement, wood, steel, etc. Indirect cost is the overhead cost, which includes the cost like stationery cost, electricity billRead more
Direct cost and Indirect cost plays the main role in any project budget.
Direct cost is the cost that is related to the direct purchasing of any items or material on-site like cement, wood, steel, etc.
Indirect cost is the overhead cost, which includes the cost like stationery cost, electricity bill, library cost, cost of heat or air conditioning, security expenses, admin expenses, etc.
Direct and Indirect costs should be calculated perfectly; otherwise, It will be a loss in profit and as well as the budget affected by that.
See lessWhat is the Life Span of a Building?
Preet Chovatiya
The life span of a building generally depends on geographical location, and it is different in country wise. Here I explain the life span of the building and their components in India are as below: The average life span of a concrete building is 75 to 100 years. the lifespan of building the componenRead more
The life span of a building generally depends on geographical location, and it is different in country wise. Here I explain the life span of the building and their components in India are as below:
The average life span of a concrete building is 75 to 100 years. the lifespan of building the componentwise table is attached below:
The lifespan of Concrete Building Component wise
What are rental charges and prices for the various conventional construction equipment used for construction in India and around the world?
poojan
Rental charges are not fixed; there are many factors which affect the rental cost: Location of work, and availability of supplier in that location: Location of site, the terrain of the site, If there are no local suppliers than the cost may be higher. Type of terms and condition for the rental agreeRead more
Rental charges are not fixed; there are many factors which affect the rental cost:
There may be many other reasons, which can affect the rental cost of the machine, but an estimate can be done by working out its owning and operating cost.
See lessWhy are steel plates inserted inside the bearings in Elastomeric Bearings?
Madeh Izat Hamakareem
because it is responsible for a vertical stiffening effect and the simultaneous reduction in the rubber swelling. Please visit the following link to read more about the bridge bearing: https://test.theconstructor.org/structures/bridge-bearings-types-details/18062/
because it is responsible for a vertical stiffening effect and the simultaneous reduction in the rubber swelling.
Please visit the following link to read more about the bridge bearing:
https://test.theconstructor.org/structures/bridge-bearings-types-details/18062/
See lessExplain the effect of the construction of Weir or Barrage on the regime of the river?
Soumyadeep Halder
The effect of the construction of Weir or Barrage on the regime of the river are given below, that a weir is constructed across the river at a certain location (A). The immediate effect is an increase in water levels upstream (B). This increase is not uniform but varies from place to place. As a conRead more
The effect of the construction of Weir or Barrage on the regime of the river are given below,
that a weir is constructed across the river at a certain location
(A). The immediate effect is an increase in water levels upstream
(B). This increase is not uniform but varies from place to place.
As a consequence, flow velocities differ from place to place too. The variations in flow velocity and, hence, the variations in the capacity to transport sediment give rise to a pattern of initial erosion and sedimentation along the river . Sedimentation over a relatively long distance occurs upstream of the intervention, whereas punctuated local erosion occurs downstream. This erosion advances downstream as a rarefaction wave.
Eventually, in the long run, the river reaches a new morphological equilibrium without further trends of erosion or sedimentation . Upstream bed and water levels have become higher than at the start of the intervention. Downstream, the river resumes its original shape by sedimentation after an intermediate period of erosion.
The longitudinal profiles in the diagrams provide a simplified picture. They do not include the response of channel width, bed sediment composition or vegetation. Nonetheless, they offer the key to understanding the relation between local pressures or measures and their effects far upstream and downstream
See less