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Showing posts with label Building Materials. Show all posts
Showing posts with label Building Materials. Show all posts

What Is A Chartered Quantity Surveyor?

What Is A Chartered Quantity Surveyor?


Members and Fellows of the RICS entitled to use the designation (and a number of variations such as "Chartered Building Surveyor" or "Chartered Quantity Surveyor" or "Chartered Civil Engineering Surveyor" depending on their field .

How to determine the size of elastomeric bearings?

How to determine the size of elastomeric bearings?

 For elastomeric bearing, the vertical load is resisted by its compression while shear resistance of the bearing controls the horizontal movements.

The design of elastomeric bearings are based on striking a balance between the provision of sufficient stiffness to resist high compressive force and the flexibility to allow for translation and rotation movement. The cross sectional area is normally determined by the allowable pressure on the bearing support. Sometimes, the plan area of bearings is controlled by the maximum allowable compressive stress arising from the consideration of delamination of elastomer from steel plates. In addition, the size of elastomeric bearings is also influenced by considering the separation between the structure and the edge of bearing which may occur in rotation because tensile stresses deriving from separation may cause delamination. The thickness of bearings is designed based on the limitation of its horizontal stiffness and is controlled by movement requirements. The shear strain should be less than a certain limit to avoid the occurrence of rolling over and fatigue damage. The vertical stiffness of bearings is obtained by inserting sufficient number of steel plates. 

What are the advantages of assigning the central pier and the abutment as fixed piers?

 What are the advantages of assigning the central pier and the abutment as fixed piers? 

For abutment pier to be assigned as fixed pier while the bridge is quite long, the longitudinal loads due to earthquake are quite large. As the earthquake loads are resisted by fixed piers, the size of fixed piers will be large and massive. In this connection, for better aesthetic appearance, the selection of abutment as fixed piers could accommodate the large size and massiveness of piers. Normally abutments are relatively short in height and for the same horizontal force, the bending moment induced is smaller.

For the central pier to be selected as the fixed pier, the bridge deck is allowed to move starting from the central pier to the end of the bridge. However, if the fixed pier is located at the abutment, the amount of movement to be incorporated in each bearing due to temperature variation, shrinkage, etc. is more than that when the fixed pier is located at central pier. Therefore, the size of movement joints can be reduced significantly. 

Civil engineering Short Question

What is the purpose of the gap in the road on this bridge?
Purpose of the gap in the road is to allow the road to expand and contract with temperature changes without causing damage or deformation to the road.
What is a projection line?
Projection line is the way, in which the earth is shown on a flat piece of Paper.
What are moment of inertia and its importance in civil engineering?
The moment of inertia measures the opposition any kind of body will have against a certain momentum (along that same axis) trying to rotate that body.
What is the absolute pressure scale?
Absolute pressure is calculated from a vacuum (0 PSI) and atmospheric pressure is14.7PSIa or 14.7 PSI above a vacuum 1PSI on a tire pressure gauge is called 1PSIg = 15.7PSIa 10PSIg=24.7PSIa 100PSIg=114.7PSIa etc.

What is diversion tunnel in a dam?
When a dam is to be built, a diversion tunnel is usually bored through solid rock next to the dam site to byPAss the dam construction site. The dam is built while the river flows through the diversion tunnel.
How do you maintain water pressure?
If you have water pressure and wish to maintain it, do not cause flow in the line, which will reduce pressure due to friction. To keep pressure up, reduce friction by increasing the line size or eliminating some other restriction.
 Why does the pressure increase under soil?
Soil pressure increases with depth due to the overburden or self-weight of the soil and due to loads imposed upon the soil.
For example, the pressure variation below the depth of soil is linear and the relation is given by pressure = unit wt * depth. As depth increases, there will be a linear increase in the soil pressure.

Why should curing not be done by pounding and polythene sheets?

Why should curing not be done by pounding and polythene sheets?

The primary purpose of curing is to reduce the heat loss of concrete that is freshly placed to the atmosphere and in order to reduce the temperature gradient across the cross-section of the concrete. Pounding is not preferred for curing as this method of thermal curing is greatly affected by cold winds. In addition to that in pounding large amounts of water is used and has to be disposed off from the construction sites. Polythene sheets are used on the basis that it creates an airtight environment around the concrete surface henceforth reducing the chances of evaporation over fresh concrete surfaces. But the usage of polythene can be a drawback as it can be easily blown away by winds and also the water lost by self-desiccation cannot be replenished.

Why should pumping be not used in case of concreting works?

Why should pumping be not used in case of concreting works?

During the pumping operation the pump exerted pressure must overcome any friction between the pumping pipes and the concrete, also the weight of the concrete and the pressure head when the concrete is placed above the pumps. Since only water is pump able, all the pressure generated is by the water that is present in the concrete. The major problem due to pumping are segregation effects and bleeding. In order to rectify and reduce these effects, generally the proportion of the cement is increased in order to increase the cohesion , which leads to the reduction of segregation and bleeding. Also if a proper selection of the aggregate grading can vastly improve the concrete pump ability.
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