Difference between Frame structure building construction & Brick structure
Laymen, might not have an idea about house construction methods that are adopted in Pakistan according to geographical terrain of respective area, however different methods of construction are adopted in different parts of country. Each terrain has its own features and technical specifications and Pakistan has all the kinds of terrain i-e flat, plain, hilly, un-even etc. Out of all construction methods that are used in Pakistan, most commonly and widely used methods are Frame structure and Brick structures.
Frame structure building construction
As its name suggests, frame structure building consists of a complete structure of columns and beams that carry the load of building. Whereas bricks or blocks used in this kind of structures are only for making the non-load bearing walls and filling the gaps. Frame structure is the most widely used and recommended method for building or house construction in all kinds of terrains. In frame structures all columns and beams are connected to each other along with the raft foundation that makes it a strong one unit. All load of building is transferred from slabs to columns/beams and then to concrete raft foundations. This method also allows to go for multi-storey buildings meant to be used for residential buildings in form of flats or commercial buildings in form of offices, malls etc.
In Pakistan, frame structure method is widely used for house construction in Sindh, Balochistan, Khyber Pakhtunkhawah, Upper Punjab, Islamabad and Northern areas. Following picture below shows typical frame structure method being applied for house construction in a hilly terrain of Islamabad. A very important and first critical step before starting frame construction of house in such terrains is the soil test. Soil test is carried out to check the quality of earth-fill and soil that has to actually bear the load of whole building. Types of foundation required is decided on the basis of results of soil tests. Soil with good bearing capacity can have a simple strip foundation, whereas soil with loose contents might require raft foundation or even piles along the raft foundation. Second step of frame structure after foundations is the plinth beam and as its name suggests, it finishes at the plinth level of house also known as finish floor level. After plinth beam, columns are raised up to the level of slab or in some cases a tie beam at lintel level (window shades level) is also required to tie all the columns together. Finally the slab is casted and columns are connected to slab. In case of multi-storey buildings, dowel bars (overlap steel bars) are raised for continuity of columns of upper floors before casting the slab.
Frame structure buildings require more reinforcement and concrete as compared to other non frame structure buildings, it also requires more scaffolding and shuttering works, hence this method of construction is costly as compared to others.
Brick structure building construction
This method is only used in a terrain that is plain, even or non-hilly and has a soil with best load bearing capacity. In Pakistan this method is only used for construction of residential double storey houses in lower and central Punjab and some parts of Sindh. Picture below shows a typical brick structure under construction house in Lahore. In brick structure houses, all the foundations are also made in bricks however it is made sure during excavation that soil has the best load bearing capacity. DPC or Damp proof courses are used for protection from dampness instead of a plinth beam. Walls are raised up to the slab level and slab is casted load of which is carried all by the walls alone. Recommended height with brick structures is only a double storey house however people also used this method for constructing more than two storeys or floors.
Cost for brick structure is slightly lesser as compared to frame structure method as it requires comparatively lesser reinforcement and concrete.