Post lintel structure

Hereby, I have uploaded a basic structural system of post- lintel structure. Hope that it may help anyone to get an idea of this structural system.

1. Presentation on Post-lintel structure Presented by Tonmoy Barua 132082001 Nizam Uddin 141081005 Presented to, Ar. Mehreen Hossain Dept. of Architecture

2. Content Definition Loads on structure Load transferring system Foundation Wall Footing Column Footing Combined Footing Structural Types Framed structure Load bearing structure Column – Beam structural system Column – Beam connection Conventional approach Punch in post- lintel structure Structure in staircase Thumb rules Advantages and Disadvantages Case study Examples References

3. Definition A structure is a system of inter connected elements to carry loads safely to under ground earth.  Structures have defined boundaries within which each element is physically or functionally connected to the other elements. In structure elements themselves and their interrelationships are taken to be either fixed (permanent) or changing only occasionally or slowly.

4. Loads on structure DEAD LOAD LIVE LOAD Live loads may be fully or partially in place or present at all. They may change in location. Dead load is a constant load in a structure that is due to the weight of the members, the supported structure, and permanent attachments or accessories. Most lateral loads are live loads. Typical lateral loads would be a wind load against a facade, an earthquake, the earth pressure against a basement wall. Mainly there are 2 types of loads : LATERAL LOAD WIND LOAD EARTHQUAKE LOAD

5. Load transferring system Load Dead load and Live load Lintel Columns Footings Ground

6. Foundation The foundation is the part of a structure that is usually placed below the surface of the ground & that transmits the load to the underlying soil or rock. TYPES OF FOUNDATION FOOTING Wall Footing R.C.C. Wall Masonry Wall Column Footing Rectangular Square Combined Footing Pile Mat, Raft or Deep Foundation

7. Structural Types Basically in building structures there are 2 types of structures: (1) load bearing structure. (2) framed structure A  load-bearing  wall or bearing wall is a wall that bears a load resting upon it by conducting its weight to a foundation structure. Framed structures  are the structures having the combination of beam, column and slab to resist the lateral and gravity loads.

8. COLUMN-BEAM STRUCTURAL SYSTEM COLUMN Columns are vertical support members subjected to compressive loads. They are also referred to as pillars, posts, stanchions and struts. They transmit loads from the upper floors to the lower levels and then to the soil through the foundations. Classification on the basis of shape Rectangular column Square column Circular column L -section T -section TYPES OF COLUMN Classification on the basis of Reinforcement Tied column Spiral column Composite column Pipe column/ Concrete fill column

9. COLUMN-BEAM STRUCTURAL SYSTEM BEAM A beam is a horizontal pole. It is usually shaped as a rectangle so there is more balance between the poles. A beam is held up by one or two columns. If there are two columns, they are placed on either side of the beam. If there is one column, it is placed in the middle of the beam so each side is balanced. TYPES OF BEAM According to Reinforcement Single reinforcement beam Double reinforcement beam SINGLE REINFORCEMENT BEAM SECTION (USED IN TENSILE ZONE) DOUBLE REINFORCEMENT BEAM SECTION ( USED IN TENSILE AND COMPRESSED ZONE) According to Support Simply Supported Beam One end Continuous Supported Beam Both end Continuous Supported Beam Cantilever Beam Simply Supported Beam 20 One end Continuous Supported Beam Both end Continuous Supported Beam

10. COLUMN-BEAM STRUCTURAL SYSTEM Cantilever Beam A  cantilever  is a beam anchored at only one end. The beam carries the load to the support where it is forced against by a moment and shear stress. Cantilevers can also be constructed with trusses or slabs. Cantilever Beam

11. COLUMN-BEAM (SLAB) STRUCTURAL SYSTEM One-way slab A one-way slab is essentially a rectangular beam of comparative large ratio of width depth. And steel use to short direction of slab. There are two type of slab use in Column- Beam structural system Two way slab Most rectangular reinforced concrete slab are supported on all four side by beam , girders or walls.

12. Column – Beam connection Beams are all set on bearing pads on the column corbels Steel angles are welded to metal panels cast into the beams and columns and the joint is grouted solid Joint demands moments , shears, axial loads acting on joint Joint geometry Interior Corner Exterior

13. Structure in staircase IN THE POST LINTEL STRUCTURE THERE USED THREE TYPES OF STAIR SECTION. 1. BEAM HANGING FROM LANDING LEVEL. 2. BEAM INVERTED ON LANDING LEVEL. 3. BEAM HANGING FROM SAME AS SLAB LEVEL. BEAM HANGING FROM LANDING LEVEL. BEAM INVERTED ON LANDING LEVEL . BEAM HANGING FROM SAME AS SLAB LEVEL.

14. Conventional approach Assume load transfer in One-Way or Two-Way manner Assume beams to support the slabs in similar ways as walls Design slabs as edge supported on beams Transfer load to beams and design beams for slab load Load transferring system Transfer of Area Load To Points Transfer of Area Load To Lines and Points Transfer of Area Load To Lines Single Path Slab On Walls Single Path Slab on Columns Dual Path Slab On Beams, Beams on Columns Wall Wall must be placed over a beam. As wall does not carry any load opening can be created anywhere of the wall,100% opening in wall surface is possible.

15. Punch Punched on the slab can be obtained without any disturbance . L/2 L/4 L/4 Not possible possible possible

16. Thumb rules Three thumb rules of column to be followed are as follows: Size of the Columns Distance between Columns Alignment of columns Thumb rule no.1- Size of the columns : The size of the columns depends on the total load on the columns . Minimum size of the column should not be less than 9”x9”. 9”x9 ” columns are to be used for a single storey structure with M15 grade of concrete. In case, 9”x9” column size is to be used for 1 and half storey structure, then it is advised to use M20 grade concrete . A safe and structurally sound column size for a 1 and half storey structure should not be less than 12”x9” using M15 grade concrete. This should be in your most preferred and practical options list. Thumb rule no.2: Distance between the columns Try to maintain equal distance between the centers of two columns. Always plan a column layout on a grid. The distance between two columns of size 9”x9” should not be more than 4m centre to centre of column. If larger barrier free distances are required then going for larger column size is to be used

17. The size of the columns increase because of two factors: Increase in the distance between two columns (This increases the dimensions of the columns as well the depth of the beam.) Height of the building (Increase in the number of floors is directly proportional to the dimensions of the columns.   Thumb rule no.3 : Alignment of Columns A rectangular grid is to be made for placing the columns. This helps in avoiding mistakes and placing in columns can be done in the right way. The columns can preferably be arranged in two different fashions: In a straight line with the help of a grid In a circular fashion for circular buildings. Thumb rules

18. Here we usually design beam spans up to 20-22 ft (approx.) and cantilever slabs spans up to 6-8 ft (approx.) without any special considerations.  Span for Reinforced concrete beams and Cantilever slabs BEAM THICKNESS Clear span of column & the beam thickness is convert to inches for column span length. For an example column span clear 20’-0” so for this region beam thickness 20” for this span Thumb rules Two thumb rules of beam to be followed are as follows: Span of RCC beam Size of the Beam

19. Advantages and Disadvantages ADVANTAGES AESTHETICS Sometimes the heavy or rigid masses are treated politely by using the framework of the post-lintel which gives an extra ordinary looks. SPAN & SPACE Larger span (column to column distance) of building is possible. ECONOMIC The maintenance cost of this system remains lower than the other structural system for its long lasting characteristics. CLIMATE Considering the climate this system is more suitable for our country. The control of openings admits the little amount of heat in the building. For the free flowing plan light and ventilation can easily insert the building.

20. ENVIRONMENT This structural system having less self-loads which reduces the risk of danger of earthquake. It can resist the buckling or bending effect of the building from the strong wind flow. It has the capability of fire resistance for the construction material (R.C.C.). CONSTRUCTION TECHNICS In this structural system construction process takes a long time for the casting of beam and slab In post-lintel system ducting process is not so easier compared to Post-slab. OPENNINGS In post-lintel system 50% area of the external facade is remaining for the openings of the building. For this there is a control over use of openings. SUSTAINABILITY This system has less possibility of failure than the other structural system. Advantages and Disadvantages ADVANTAGES

21. Advantages and Disadvantages FLOOR SLAB Floor slab is a slab supported on ground generally distribute load to the ground uniformly. It also increases the bearing capacity of soil as the load distributes combined. SOLID-VOID RATIO By using the framework of post-lintel system we can make a sense full solid-void ratio which illuminate the monotonous effect. CANTILEVER OR OVERHANG The portion of any structure that is over hanged without any support termed as cantilever. Sometimes cantilever construction is economical and looks aesthetically attractive which may become a useful part of that structure. ADVANTAGES

22. Advantages and Disadvantages Extreme variation of solid is not possible. Opening should be place considering the post. Stair must start with respect to a beam. Building height increases for the beam to get clear Space. Also duct for air conditioning are used under beam, so floor height increases which is not acceptable for height. This system more costly (30%more)than wall slab system but economic range can be kept in a lower gird when the span is limited 15’ to 25’. Uninterrupted vast space can not be created without using vault dome or waffle. Sometimes this problem creates visual disturbance, which is avoided, in flat slab. The construction cost of this system is slightly high for the time consuming costing of beam and slab and the use of R.C.C. DISADVANTAGES

23. Case Study 1 ( Nagar Bhaban ) NAGAR BHABAN ARCHITECT : LAILUN NAHAR & ABU H IMAM UDDIN LOCATON :DHAKA LEVEL : 15 BUILDING CONTAINING : Mayor's Office Offices a bank meeting rooms a museum dining facilities a prayer hall public terraces.

24. RCC Wall Slab & Waffle Slab

25. A DVANTAGES: MOST COMPACT AND STRUCTURAL SYSTEM. RECTANGLE GRID IS EASY FOR PARKING. EARTHQUAKE RESISTANT STRUCTURAL SYSTEM IS VISUALLY CLEAR. ENOUGH NATURAL LIGHT WELL USED SHADING DEVICE .

26. D ISADVANTAGES: HUGE LOBBY SPACE UNUSUABLE OPEN TERRACE UNNESSESARY EXTRA HEIGHT SPACE

27. Project Name : Mamun Residence Architect: Rafiq Azam House no: 67/A Road :01 South khulshi Chittagong Case Study 2 Mamun Residence

28. Case Study 2 ( Mamun Residence) Ground Floor Plan

29. Case Study 2 ( Mamun Residence) 1st Floor Plan 2nd Floor Plan

30. Materials: Wooden frames Concrete staircase Bare concrete frame cast on site Brick outer cladding Bare cement internal walls Marble and ceramic flooring Case Study 2 ( Mamun Residence)

31. Case Study 3 ( SA House) Project name : SA House Architect : Rahiq Azam Total useable surface area : 20667 m2 Plot size : 11970 m2 Location : Road100, Gulshan 1, Dhaka

32. Case Study 3 ( SA House) Oriented toward the south, where the home is most open to its surroundings. The courtyard has a glass roof which lets light, wind and rain through, creating an ever-changing environmental reservoir. The floor plan of the three levels reveals a noticeable absence of passageways, as direct communication between different rooms is preferred, without any clear divisions between the spaces.

33. Folding doors and windows to permit flexible management of the space as a whole. This is clearly an introspective building, in which every view and every glimpse of one room from another is designed to encourage observation of space and contemplation of the natural element. Case Study 3 ( SA House)

34. In the project opens large circular holes in the cement slabs: on the roof, to create the “rain room. The dark wood frames and the natural green contrast with the neutral cement surfaces designed to be contaminated and “interpreted” over time by the growing vegetation. Case Study 3 ( SA House)

35. Reinforced Concrete Building Construction

36. ANY QUESTIONS ????