Week 3 Challenge
Week 3 Challenge
1. 1. State the primary load cases to be considered for design.
2. What is One – Way slab?
3. What is the value of unit weight of structural steel and soil?
4. Name few sections that can be defined using Properties tab in STAAD Pro.
5. Define Primary Beams.
ANSWER:
1. State the primary load cases to be considered for design.
- Dead Load
- Live Load
- Wind Load
- Seismic Load
- Snow Load
2. What is One–Way slab?
One-way slab is supported by parallel walls or beams, whose length to breadth ratio is greater than or equal to two
- Ly / Lx >= 2
3. What is the value of unit weight of structural steel and soil?
- Unit weight of steel = 7850 kg/m^3
- Unit weight of soil = 1800 kg/m^3
4. Name few sections that can be defined using Properties tab in STAAD Pro.
- Circle
- Rectangle
- Tee
- Trapezoidal
- Tapered l
5. Define Primary Beams.
The primary beams are connecting columns for transferring loads of a structure directly to the columns.
2. 1. State the factors and parameters that influence the design pressure intensity of a high-rise building.
2. Mention the load transfer process of a Reinforced Concrete Building.
ANSWER:
1. State the factors and parameters that influence the design pressure intensity of a high-rise building.
Wind Pressure, Pz = 0.6 Vz^2
Vz = Vb X K1 X K2 X K3 m/s
Where,
- Pz = Design Wind Pressure
- Vz = Design Wind Speed
- Vb = Basic Wind Speed
- K1 = Probability factor
- K2 = Terrain factor
- K3 = Topography factor
2. Mention the load transfer process of a Reinforced Concrete Building.
- Slab -> Secondary beam -> Primary beam -> Column -> Foundation
3. 1. Differentiate One-Way and Two way slabs. Elaborate each slab type.
2. Explain the concept of secondary beams with proper sketch.
3. Mention the Primary load cases.
a. State the Indian Standards for each load case
b. Detail the parameters of each load case
c. Brief each load case
4. Detail the steps involved in assigning Properties and Support to a model using STAAD Pro sequentially.
5. Brief the steps to be followed to create and assign secondary beams in STAAD Pro
ANSWER:
1. Differentiate One-Way and Two way slabs. Elaborate each slab type.
| S.no. | One-Way slab | Two-Way slab |
| 1 | Ly/Lx >= 2 | Ly/Lx < 2 |
| 2 | It is supported by a beam on two opposite side only | It is supported by a beam on all four sides |
| 3 | Load carried in one direction perpendicular to the supporting beam | Load carried in both direction |
| 4 | Main reinforcement is provide in short span due to bending | Main reinforcement is provide in both short and long span due to bending |
2. Explain the concept of secondary beams with proper sketch.
The secondary beams are connected to the primary beams mainly simply supported beams.
3. Mention the Primary load cases.
a. State the Indian Standards for each load case
b. Detail the parameters of each load case
c. Brief each load case
a. State the Indian Standards for each load case
- Dead Load (IS 875:Part 1)
- Live Load (IS 875:Part 2)
- Wind Load (IS 875:Part 3)
- Seismic Load (IS 1893-2016 Part 1)
b. Detail the parameters of each load case
- Member loads
- Concentration loads
- Floor loads
- Plate loads
c. Brief each load case
Dead Load:
- Weight of structure
- It is constant
Live Load:
- Based on occupancy and usage of building
Wind Load:
- The force exerted by the horizontal component of wind is to be considered in the design of building
Seismic Load:
- This load act perpendicular to the height of the building in two directions like X direction and Y direction.
4. Detail the steps involved in assigning Properties and Support to a model using STAAD Pro sequentially.
Assigning the properties:
- Go to properties tab
- Click on define materials
- Choose the section and material
- Click add
- Now select the given property and click Assign to view
- It can be assigningn
Assigning the support:
- Go to support tab and click create
- Choose the support type and click add
- Now assign the support
5. Brief the steps to be followed to create and assign secondary beams in STAAD Pro
- First create the primary beams in the model
- Assign the property, material and support
- Select the secondary beam, right click on mouse and select insert node option
- Specify the mid point option, it creates a node on primary beam at center
- Now select add beam option to create the secondary beam
Practical
1. Calculate the wind pressure for the given building
a. Building Dimension : 20m x 30m x 20m height RCC
b. Building usage : Hospital block in city centre
c. Location : Darjeeling
2. Calculate the Dead load and Live load for the above building with reference to IS standards ( assume suitable sections )
PROCEDURE:
1. Calculate the wind pressure for the given building
a. Building Dimension : 20m x 30m x 20m height RCC
b. Building usage : Hospital block in city centre
c. Location : Darjeeling
ANS:
Wind Pressure, Pz = 0.6 * Vz^2
Design Wind speed, Vz = Vb x K1 x k2 x K3
In IS 875-Part 3,
Vb = 47 m/s (Location-Darjelling)
K1 = 1.07 (Table-1, Cl-5.3.1)
K2 = 0.76 (Category-4, Class-B) (Table-2, Cl-5.3.2)
K3 = 1 (Cl-5.3.3)
Hence, Vz = 47 x 1.07 x 0.76 * 1
= 38.22 m/s
Design Wind Pressure = 0.6 * (38.22)^2
= 876.47 N/m^2
2. Calculate the Dead load and Live load for the above building with reference to IS standards (assume suitable sections)
ANS:
Building Dimension: 20m x 30m x 20m
Dead Load:
Dead Load due to Slabs:
Slab thickness = 150mm = 0.15m
Dead load = 20*30*0.15*25 = 2250 kN
Dead Load due to Beams:
Beam c/s = 300 x 450mm
Length = 20m
Dead load = 0.3*0.45*20*25 = 67.5 kN
Superimposed loads due to Walls:
Wall thickness = 230mm
Height of brickwork = 3.75 - 0.45 = 3.3m
Dead load = 3.3*0.23*18 = 13.66 kN
Live Load:
Live load calculate for a given structure by using (IS 875:Part 2)