Week 3 Challenge

Ans1.1) 

The primary load cases to be considerd for the design are the

• Dead load
• Live load / Imposed load 
• Wind load 
• Earthquake load 

Ans1.2) 

One -way slab is the slab whose ratio of longer span to the shorter span is greater than two where ly/lx is greater than two , where lx stands for shorter dimension and ly for longer span dimensions.

Ans1.3)

 The unit weight of structural steel and soil as per the  IS 875 part 1 is

• The unit weight of structural steel is 7840 Kg / m^3
• The Unit weight of soil is 18 kN/m3 

Ans1.4) Sections that can be defined using Properties tab in STAAD Pro are 

• Circular section 
• Rectangular section 
• Trepezodial section 
• Tee section 
• Genaral section 
• Tapered I 
• Tapered tube 

Ans1.5) 

• Primary Beams are the beam located at the exterior of the Structural elements
• The beam can not have much load on the exterior Beams or primary Beams
• Secondary beam are laid on the primary beam 

Ans2.1)

 The factors that influence the design presure 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 design wind pressure at any height above mean ground level shall be obtained by the following relationship 
   between wind pressure and wind velocity

        Pz = 0.6 v^2

Ans2.2)

The load transfer process of a reinforced concrete building is as follows

1. Slab 
2. Secondary beam                                        
3. Primary beam
4. Columns
5. Foundation 

Ans3.1)

One - way slab 

• The ratio of the longer span to the shorter span is greater than 2 is know as one - way slab
• Where LY / LX is greater than 2

Two - way slab 

• The ratio of the longer span to the shorter span is less than or equal to 2 is know as two way slab 
• Where LY / LX is Less than 2

Ans3.2)

• Secondary beam are the internal beam that are restrained on the primary beam
• They are the simply supported beam 
• In secondary beam the moment is Zero at the end of the beam 

Ans3.3)

Indian Standards for each load case

• For Dead load  : IS code 875 Part 1
• Live load         : IS code 875 part 2
• Wind load        :  IS code 85 part 3
• Seismic load    : IS 13927  

Parameters of each load case

• The parameter of Dead load are 1) unit weight 2) Volume of the section that may be rectangular section , circular section etc
• The parameter of Live load are depend on the building type residential building, commercial building, industrial building , area type room , toilet room , corridoors , roof etc.

Each load case

• A load case is a combination of different types of loads with safety factors applied to them.
• A structure is checked for strength and serviceability against all the load cases it is likely to experience during its lifetime.

Ans3.4)

• Go to property section 
• Click on Define material
• Select the section , Rectangular section , circular section etc
• Select the material type concrete , steel , aluminum
• For the rectangular  section enter YD and ZD in the 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 the create 
• Select the type of support do we want to assign the section 
• Click on add close 

Ans3.5)

• First create a simple model by using the node in staad pro.
• Click on the create beam option and create a beam in the direction of x and Z axis 

 PRACTICAL

ANS1.1) 

Wind presure  Pz  =  0.6 v^2

     where Vz = Vb X k1 X k2 X K3 

        Vb = Wind speed at the certain location  = 47m/sec 

        K1 = Risk coffiecient   =1.07

        K2 =  Terrain height and structure factor = 1.12

        K3 =  Topography factor = 1.0

        Vz = Vb X k1 X k2 X K3 

             = 47 X 1.07 X 1.12 X 1.0

             =  56.88

Pz=0.6(vz)2 = 0.6*56.88^2

= 1941.2 N/m2

Ans1.2)

The Dead load of the section considering the section length 5 m and width 0.23 m and depth is 0.5m

        Dead load of the section =  Unit weight x volume of the section  

                                            = unit weight of concrete is 25 KN/m

                                            =  Volume of the section = 0.5 x 0.23 X1

                                            = 0.115 m^3

                          Dead load   =  25 X 0.115 

                                           =   2.875 KN/m

           Live load = considering the General Building 

Bathrooms & Toilets in all types of buildings

2

1.8

kitchens

Dwelling houses hostels hotels & hospitals.

2 3

1.8 4.5