12. COMPUTER AIDED BUILDING PLANNING AND DRAWING (BCV305)

Draw plan and sectional elevation of RCC dog legged staircase for an office building which measures 3m x 5.5m. The vertical distance between the floor is 3.3m (including landing). Thickness of the floor slab is 150mm. Provide steps with tread of 300mm and rise of 150mm. Thickness of waist slab and landing slab is 150mm. Width of stair is 1.5m. Reinforcement details: main steel: 10ϕ@125c/c spacing and distribution: 8ϕ@ 250 c/c spacing.

The exercise focuses on creating a drawing of a specific type of staircase called a 'dog legged staircase' that is commonly used in buildings. The dimensions provided indicate that the staircase is intended for an office building and has a total measurement of 3 meters in width and 5.5 meters in length. The vertical distance between two floors where this staircase is located is 3.3 meters, which includes the landing. The floor slab, which provides a flat surface for stepping, is specified to be 150mm thick. The staircase steps are to be designed with a tread depth of 300mm for walking and a rise of 150mm between each step, which creates a comfortable walking angle. Additionally, both the waist slab (which connects the steps) and the landing slab (the flat area at the top and bottom of the staircase) are also 150mm thick. The width of the entire staircase is set at 1.5 meters, providing ample space for two people to ascend or descend simultaneously. Finally, the reinforcement details specify how the main steel and other reinforcing bars should be arranged within the staircase structure, ensuring strength and safety during its use.

Think of a dog legged staircase like a stairway in a multi-level shop or office. It’s not just one straight line of stairs; it has turns (just like making a dog leg turn) that allow you to change direction while going up or down. Imagine you're climbing stairs in a mall—your comfortable pace is ensured because the steps are designed just right, making it easy to walk. Additionally, just as a solid foundation is necessary for building a house, the reinforced materials in the staircase ensure it can handle the daily foot traffic of people coming and going.

Draw plan and sectional elevation of an open newel staircase with a rectangular well for an office building with the following data: Inside dimensions of staircase = 4.5m x 5.4m. Height between the floors is 3.6m. Thickness of the floor slab and landing slab is 150mm. Width of landing=1.5m. Width of stair = 1.5m. Tread=300mm, riser=150mm. Waist slab thickness = 150mm. Reinforcement details: Main steel: 12ϕ@150 c/c spacing and Distribution: 8ϕ @ 250 c/c spacing.

In this exercise, the task is to create a drawing for an open newel staircase, which allows an open area or 'well' in the middle that can act as a light source. The interior dimensions of the staircase indicate that it has a width of 4.5 meters and a length of 5.4 meters, making it larger than the previous example. The height from one floor to the next is listed as 3.6 meters, providing a grand vertical space. Much like the previous exercise, both the floor and landing slabs are specified to be 150mm thick, ensuring structural integrity. The width of both the landing and the stairs is again set at 1.5 meters, enhancing accessibility. The design follows the same comfortable measurements for tread depth (300mm) and riser height (150mm). Similar to the previous staircase, a waist slab of 150mm thickness is noted, along with reinforcement details that involve main steel at a spacing of 12ϕ@150 c/c and distribution steel at spacing of 8ϕ@250 c/c, indicating how the staircase must be constructed to withstand usage.

Imagine entering a trendy restaurant and encountering a stairway that spirals up with an open space in the middle—this is an open newel staircase. The spaciousness not only looks appealing but also allows natural light to flow down. Just like how a barn needs strong wooden beams to remain standing and functional, a well-designed staircase requires careful attention to the materials and structure. The specification of reinforcement bars in this staircase ensures it stays stable and safe for everyone using it, just like how the beams in the barn keep it standing strong.

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