25-08-2017, 09:32 PM
A Mini-Project On DESIGN OF FOOTINGS & COLUMNS
DESIGN OF FOOTINGS.docx (Size: 1.54 MB / Downloads: 238)
Footings:
‘Footings’ is the term used to describe the designed and built portion of the sub structure. This can be constructed of brick, concrete or other purposely designed materials. For larger structures footings may require a structural engineers plan including council inspections and approval during the course of the project. For projects of this scale a Development. Application should be lodged with your local building approval body
The footings are majorly classified into three types:
• Single Step footing
• Double Step Footing
• Combine Footing
Foundations:
Foundations’ refers to the natural ground and its structure such as sand, clay, rock or mixed materials.
The foundations are classified into five major types such as:
• Matt or Raft Foundation
• Combined Foundation
• Pile Cap foundation
• Isolated Foundations
• Continuous Foundation
Grade Marking:
Grade marking is the marking made on the PCC block, In order to build the columns in a correct manner and in required measurements. The Grade marking is most commonly useful method in all type of constructions such as modern and ancient one. This gives an idea for the required construction.
Mostly the Grade marking are made by using the limestone and marking tools.
COMBINED FOOTINGS:
A combined footing is usually used to support two columns of unequal loads. In such a case, the resultant of the applied loads would not coincide with the centroid of the footing, and the consequent the soil pressure would not be uniform. Another case where a combined footing is an efficient foundation solution is when there are two interior columns which are so close to each other that the two isolated footings stress zones in the soil areas would overlap. The area of the combined footing may be proportioned for a uniform settlement by making its centroid coincide with the resultant of the column loads supported by the footing. There are many instances when the load to be carried by a column and the soil bearing capacity are such that the standard spread footing design will require an extension of the column foundation beyond the property line. In such a case, two or more columns can be supported on a single rectangular foundation. If the net allowable soil pressure is known, the size of the foundation B x L can be determined.