M.E. Structural Engineer
Query Received from - Sripriya Vijayaraghavan
Why load bearing structure is preferred in construction of houses to framed structure?
Solution by Gharpedia
Load bearing structures are preferred more over framed structures due to the following few common reasons.
01. They are generally preferred for G or G+1 storied small residential houses.
02. Load bearing structure is less costly as compared to a framed structure. However, this is true only if the bricks used in load bearing structure are cheap as compared to concrete used in beam and column for frame structure, and depth of foundation is not more than 1.00 m to 1.2 m.
03. Load bearing structure can be constructed without expensive plant and machines as compared to a framed structure.
04. Load bearing structures are preferred for low rise buildings and where good soil for a foundation is available at 3’0” to 4’0” depth, which is generally available everywhere.
05. It requires less skilled persons as compared to a framed structure leading to less labour cost.
06. The thick wall of load bearing structure gives more weather protection particularly from heat and rain, and noise protection as compared to a framed structure.
07. Design of load bearing structure is simple, for which skills are available even in villages because of traditional knowledge which has been transferred from one generation to other generation.
But, in fact, it is not always so
01. If good soil is not available up to 4’0” to 6’0”, the cost of foundation in brick walls will be much higher than the cost of RCC footing, even bricks are cheaper. Hence in such case load bearing structures are not preferred.
02. An earthquake prone zone 4 and 5construction of load bearing structure is also complicated, which requires skilled persons and ultimately it may cost more or at least same.
03. Further when there is black cotton soil in top crust of soil and say up to even 4’0” to 6’0”, load bearing structure will not even cost more but will create problem due to uneven settlement of foundation due to swelling and shrinkage of black cotton soil, especially for load bearing structure, and hence they are not preferred, not advisable over black cotton or other expansive soils.
04. When the structures are large and where you need flexibility in design i.e. you don’t want a wall over wall and when you have large span structures, R.C.C. framed structure is always preferred, as load bearing have a lot of limitations.
05. Load bearing structure is economical only if the bricks are available easily and at a competitive price. In area, where clay for bricks is not available easily, the cost of the load bearing structure may be more or might not be very competitive as compared to framed structure. The clay is generally not easily available in coastal areas, rocky areas, and even in dessert prone areas. Hence at such place’s bricks are costly.
06. Sometimes the difference in cost would not be substantial due to all above reasons and the nominal (5 to 10%) higher cost of RCC framed structure would be preferred due to its other advantages like flexibility in design and so on.