Week 3 Challenge
Aim:-
1) 1. State the primary load cases to be considered for design.
The primary load cases to be considered for design are ,
Answar:-
- Dead Load
- Live Load/Imposed Load
- Wind Load
- Earthquake Load
2. What is One – Way slab?
Answar:-
- The ratio of the longer span to the shorter span is greater than 2 is known as one way slab.
- Where Lx/Ly is greater than 2
3. What is the value of unit weight of structural steel and soil?
Answar:-
The value of unit weight of structural steel and soil is given in IS 875 Part 1
- The unit weight of structural steel is 7840 Kg/M^3
- The unit weight of soil is 18KN/M^3
4. Name few sections that can be defined using Properties tab in STAAD Pro.
Answar:-
- Circular section
- Rectangular section
- Trapezoidal section
- Tee section
- General section
- Tapered Tube
5. Define Primary Beams.
Answar:-
- Primary Beams are the beams Located at the exterior of the structural Elements
- The beam cannot have much load on the exterior beam or the primary beam
- Secondary beam laid on the primary beam.
2) 1. State the factors and parameters that influence the design pressure intensity of a high-rise building.
Answar:-
The factors and parameters that influence the design pressure intensity of a high-rise building are,
- K1 = Probability Factor (risk coefficient)
- K2 = Terrain , height and structure size
- K3 = Topography factor
Design wind pressure,
- The wind pressure at any height above mean ground level shall be obtained by the following relation ship between wind pressure and wind velocity.
- Pz = 0.6 Vz^2
2. Mention the load transfer process of a Reinforced Concrete Building.
Answar:-
The load transfer process of a Reinforced Concrete Building is
- Slab
- Secondary Beam
- Primary Beam
- Columns
- Foundation
3) 1. Differentiate One-Way and Two way slabs. Elaborate each slab type.
Answar:-
One way slab,
- The Ratio of the Longer span to the shorter span is greater than 2
- Where Lx/Ly is greater than 2
- the bending moment occurs only in one direction i.e. the shorter direction in One Way Slab
Two way slab,
- The ratio of the longer span to the shorter span is less than or equal to 2
- Where Lx/Ly is less than or equal to 2
- bending moment occurs in both directions i.e. shorter and longer
2. Explain the concept of secondary beams with proper sketch.
Answar:-
Secondary Beam: A horizontal beam connecting primary beams (simply supported or shear connected.)
- Function: It will transfer the load to the primary beam and not directly connected to the columns.
- Tie Beam: A horizontal beam connecting two rafters in a roof or roof truss
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
Answar:-
A) State the Indian Standards for each load case
- For Dead load : IS 875 Part 1
- Live load : IS 875 Part 2
- Wind Load : IS 875 Part 3
- Seismic Load : IS 13927 ,
B) Detail the parameters of each load case
- Dead Load Depends on Unit weight,
- Volume of the section Rectangular/circular section.
- Live load Depends on Building type, Residential/ Comercial/Industrial
- Area type Room/ Corrider/Toilet/Roof etc ,
C) Brief each load case
- A load case is a set of constraints and loads used to define a particular loading condition.
- You can use one or more load cases for the study. The optimization result is separately calculated for each load case
- A load case is a combination of different types of loads. During the analysis, loads or forces are applied to the structure, and the resulting deflections are measured.
- These loads and forces can be combined to create one or several load cases.
4. Detail the steps involved in assigning Properties and Support to a model using STAAD Pro sequentially.
Answar:-
- Go to property section
- Click on Define material
- Select the section, Rectangular/Circular etc,
- Select the material type concrete, steel , aluminium
- For the rectangular section enter YD & ZD in column below
- click add and close
- Select the material type and assign to the selected view for the support
- click on the support
- click on create
- select type of support do we want to assign the section
- click on add close
5. Brief the steps to be followed to create and assign secondary beams in STAAD Pro
Answar:-
- First create a simple model by using node in staad Pro
- Click on Create beam option and create a beam in the direction of x is 6m and z is 8m axis
- click on the primary beam in the section
- right click and add new node in the beam section a node will be added
- again click on the create beam
- Cleck Assing concrete
- Let me create a fixed joint
Practical
Result:-
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 , according to Is 875 Part 3,
pz = 0.6Vz^2
Where vz = Vb*K1*K2*k3
Vb = Wind speed at certain location = 50
K1 = Risk coefficient = 1.0
K2 = terrain height and structure factor = 1.12
K3 = Topography factor = 0.5
Vz = Vb * K1*K2*K3
= 50 *1.0*1.12*0.5
= 28
pz = 0.6*28^2 = 470.4 = 0.47N/m^2
2. Calculate the Dead load and Live load for the above building with reference to IS standards ( assume suitable sections )
The dead load of the section considering the section length 5m and width 0.23m
- Dead load of the section = unit weight * volume of the section
- Unit weight = 25KN/m
- Volume of the section = 0.5*0.23*1 = 0.115m^3
- Dead load = 25 *0.115 = 2.875 KN/m
Live Load = Considering the general building ,
Bath rooms and toilets in all types of the building, kitchens in,
- Dweeling houses 2 , 1.8
- Hostel, hotel, hospital 3 , 4.5