Week 3 Challenge

1

i,

The primary load cases to be considered for the design are :

Dead load

Live load/Imposed load

Wind load

Earthquake load

ii,

The one-way slab is a slab, which is supported by parallel walls or beams, and whose length to breadth ratio is equal to or greater than two and it bends in only one direction (spanning direction) while it is transferring the loads to the two supporting walls or beams, because of its geometry. Simply stating it spans and bends in only one direction.

The direction (shorter side of slab) in which load is transferred is known as span. A one-way slab is designed for the spanning direction alone as it bends in only one direction.
The main tension reinforcing bars therefore run parallel (spaced uniformly) to the shorter span and are usually placed at the bottom of slab.
In the transverse direction (a longer direction), a minimum amount of reinforcement is provided to take care of the temperature and shrinkage effects in that direction. This steel reinforcement is called the distribution steel or secondary reinforcement.

iii,

The unit weight of structural steel and soil is given in IS 875 part1

The unit weight of a structural steel is 7840 kg/m^3

The unit weight of soil is 18kN/m^3

iv,

Circular section

Rectangular section

Trapezoidal section

Tee section

General section

Tapered I

Tapered tube

v,

Those type of horizontal flexural (beam) structure member which directly connected to supporting compressive structure member that is column.

Primary beam is also known as main beam which Safely transfer the load to the column acting on it by the slab or by secondary beam if it is present

2

i,

The factors that influence the design pressure intensity of a high rise building are:

Step 1: Design wind speed
Vz= Vb K1 K2 K3 K4

Vb=Basic wind speed (m/sec)
K1=Risk coefficient (Table 1 of IS 875 (Part 3)-2015)
Table 1 (K2 factor)
Height K2
0 to 10m- 0.91
10 to 15m- 0.97
15 to 20m -1.01
20 to 30m -1.06
30 to 40 m -1.12
K3=Topography factor (Clause 6.3.3 of IS 875 (Part 3)-2015)
K4 =Importance factor for Cyclic Region

Step 2 : Design wind pressure pd
Design Wind Pressure, pd= Kd Ka Kc pz where
Kd= Wind directionality factor for buildings as per clause 7.2.1 of IS875 part3- 2015
Ka=area averaging factor
Tributary area of a panel TA= Column spacing x storey height

Combination factor = Kc as per clause 7.3.3.13 for frames over the building envelope when roof is subjected to pressure and internal pressure is suction or vice-versa
pd= Kd Ka Kc pz

The wind pressure pz at any height z is given by
Pz= 0.6 Vz^2 where
Pz= Design Wind speed in N/m2 at height z is given by Pz= 0.6 Vz^2
Vz= Design wind speed in m/s.

ii,

Slab

Secondary beam

Primary beam

Columns

Foundation

3

i,

ii,

Secondary Beam: The beams which are constructed to transfer the load of slab on main / primary beams are called secondary beams.Those type of horizontal flexural (beam) structure member which directly connected to primary beam and not connected directly to column.this beam is known as secondary beam which Safely transfer the load to the primary beam acting on it by the slab.

Secondary beam is directly connected to primary beam and form primary -secondary beam joint.

Secondary beam have shorter span than primary beam.

Secondary beam is indirectly connected to column.

Secondary beam transfer the load to the primary beam which is acting on by slab

Depth and width of secondary beam is less than primary beam

Secondary beam are provided for supporting and reducing the deflection of primary beam and slab

Secondary beam act as medium between primary beam and slab

Secondary beam is non regular component of building frame

iii a

The parameter od dead load are:

Unit weight

Volume of the section that may be rectangular section

Circular section etc

The parameter of live loads are dependent on the building type residential building , commercial building , commercial building , industrial building , Area type room , toilet room , corridor etc

c

A load case is a set of constraints and loads used to define a particular loading condition. You can use one .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 or more load cases for the study. The optimization result is separately calculated for each load case. However, the final design is generated considering all the load cases associated with the model

4

Go to property section

Click on define material

Select the section , Rectangular section , circular section etc

For the rectangular section enter YD and ZD in the column below

Select the material type concrete, steel, aluminium

Click add and close

Select the material type and assign to the selected view

Click on the support

Click on the create

Select the type of support do we want to assign the section

Click on add close

5

INTRODUCTION:

Secondary Beam: The beams which are constructed to transfer the load of slab on main / primary beams are called secondary beams.Those type of horizontal flexural (beam) structure member which directly connected to primary beam and not connected directly to column.this beam is known as secondary beam which Safely transfer the load to the primary beam acting on it by the slab.

Secondary beam is directly connected to primary beam and form primary -secondary beam joint.

Secondary beam have shorter span than primary beam.

Secondary beam is indirectly connected to column.

Secondary beam transfer the load to the primary beam which is acting on by slab

Depth and width of secondary beam is less than primary beam

Secondary beam are provided for supporting and reducing the deflection of primary beam and slab

Secondary beam act as medium between primary beam and slab

Secondary beam is non regular component of building frame

PROCEDURE:

Open STAAD.pro Connect Edition

Go to create

Go to Grids - Beam grids

1

Wind pressure Pz= 0.6 Vz^2

where Vz = Vb x k1 x k2 x k3

Vb = Wind speed at the certain location = 50

k1= Risk coefficient = 1

k2= Terrain height and structure factor = 1.12

k3= Topography factor = 0.5

Vz= Vb x k1 x k2 x k3

= 50x1.0x1.12x0.5

=28 m/sec

2

The dead load of a section considering the section length 5m and width 0.23 m and depth 0.5m

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

Unit weight of concrete = 25kN/m

Volume of the section = 0.5x0.23x1= 0.115m^3

Dead load = 25 x 0.115

= 2.875kN/m

Live load= considering the general building guidelines

Following are the live loads for different buildings:

Sl. No.	Description	UDL Load (kN/m2)	Concentrated Load (kN)
1.	Bathrooms and toilets in all types of buildings	2	1.8
3	Office rooms in
	(i)Hostel, hotels, hospitals and business building with separate store	2.5	2.7
	(ii)In assembly buildings	3	4.5
4.	Kitchens in
	(i) Dwelling houses	2	1.8
	(ii) Hostels, hotels and hospitals	3	4.5
5.	Banking halls, class rooms, X-ray rooms, operation rooms	3	4.5
6.	Dining rooms in
	(i)Educational buildings, institutional and mercantile buildings	3	2.7
	(ii)Hostels and hotels	4	2.7
7.	Corridors, passages, stair cases in
	(i) Dwelling houses, hotels, and hostels	3	4.5
	(ii)Educational, institutional and assembly buildings	4	4.5
	(iii) Mercantile buildings	5	4.5
8.	Reading rooms in libraries
	(i)With separate storage	3	4.5
	(ii)Without separate storage	4	4.5
9.	Assembly areas in assembly buildings
	(i)With fixed seats	5
	(ii)Without fixed seats	5	3.6
10.	Store rooms in educational buildings	5	4.5
11.	Store room in libraries	6 for a height of 2.24 2kN/m2 for every 1m additional height	4.5
12.	Boiler rooms and plant rooms in
	(i)Hostels, hotels and hospitals, mercantile and industrial buildings	5	4.5
	(ii)Assembly and storage buildings	7.5	4.5