Thank you all for supporting the initiative of Live Technical Discussion series. Our aim is to arrange the live technical discussion on the areas related to engineering where in industry is facing practical difficulties. We had very interesting live technical discussions so far on the important subjects like Gravity column, Stiffness modifiers as per IS 1893 & IS 16700, Irregularities as per IS 1893, Time period calculation as per IS 1893, Recent amendments to IS 1893 & IS 13920, Interface between geotechnical and structural engineer, Wind force estimation for low rise buildings & tall buildings as per IS 875, Pile foundation, Quality assurance in structural engineering firms, etc.
There are many interesting live discussions at planning stage for other engineering disciplines as well.
In the comment box, you may mention the areas for which the future live technical discussions may be arranged. Also, please let us know if you would like to appear in the live stream to address the audience.
Pl circulate this message with the engineers in your circle.
Background : We created a telegram group for structural engineers with a purpose of knowledge sharing and to serve as a medium for discussion related to technical matters, professional issues, guidance for young engineers, career advice, etc.
Dr. H. J. Shah had replied to number of queries in the group. In the next live session, we would like to summarise and present them along with the sketches. We wish to take up following points in the next live session :
The building columns are classified based on various criteria as (a) Braced and unbraced, (b) No-sway and sway, (c) Tied, spiral and Composite, (d) Short and long, (e) Axially loaded and eccentrically loaded, and (f) Ordinary and Ductile.
The buildings are classified based on the type of columns and walls occurring in them. Both are dependent on each other.
In addition to primary stresses, Gravity loads result in buckling, while horizontal loads try to overturn the building. In both the cases, moments are induced. Sufficient factor of safety should be there against overturning.
Buckling of a local column due to gravity loads is taken into account by using additional moments in columns which may be negligible (short column) or considerable (long column). To decide whether the column is long or short, we need effective length of the column that can be determined as per guidance of IS: 456.
Horizontal loads result in building sway. This sway may be negligible or considerable. The total horizontal shear acting on storey, Vi, will induce a moment equal to Vihi where hi is the height of the ith storey. This is called primary moment.
Relative sway of consecutive storeys is called drift. Due to drift, the vertical loads become eccentric and induce moments equal to, where is drift of the storey. This is called P effect. The total moment induced due to loads on all vertical elements of the storey = S P, is called secondary moment.
Ratio of secondary moment to primary moment represents an index of stability of the building called stability index, Q. If Q is not greater than 4%, the lateral sway may be neglected and the columns in the storey may be considered as no-sway. If Q > 0.04, the columns in the storey may be considered as sway. IS: 16700, refers Q as inter-storey drift stability coefficient, q. For stability of building, .
Once the loads on the columns are calculated, we can design the columns. Note that there are a number of load combinations through which the column should pass.
Interaction diagrams are prepared for column design. These may be global or local.
The interaction diagrams as prepared by SP: 16 are global and can be used for variety of dimensions and materials used in columns.
An interaction diagram as prepared for one column with given dimensions and materials is called a local interaction diagram. It will be used to design a particular column with a number of load combinations.
Columns for a given storey are designed at top and bottom with given load combinations. If I am considering 25 load combinations, one column should pass through 50 column design calculations. Then one can get area of reinforcement.
Deciding the sizes of columns, the grade of materials along the height of the building requires through knowledge. Similarly, arranging the reinforcement along height, number and diameter at a section, is also a skilful job.
After arranging all, you need to satisfy strong column – weak beam analogy as per IS: 13920.
We wish to take up the above-mentioned areas in the upcoming live session. For making the session more successful, you are all requested to send your queries in advance. This will facilitate us to arrange the queries in order and prepare sketches for clarification, if required.
You are also requested to send your queries for following topics.
Shear Wall- Design and detailing of isolated shear wall
Hidden beam,
Floating columns,
Live load reduction
The session will be live streamed at the following youtube channel. You may subscribe and share details of the youtube channel with interested engineers to receive the wider participation from group of engineers :
The course GEO-STR-001 : Interactive process of geotechnical investigation is started on 16-JAN-21 and will be completed at end of January month. There is participation from different parts of India, like from Gujarat, Maharashtra, Goa, Delhi, Kerala, Hyderabad, etc. as well as from Malaysia. In the sessions, practical problems related to geotechnical investigation are being discussed along with the case studies which make the session highly interactive.
The next batch for this course will begin in February, 2021.
Bhavin Shah has become a part of Expertrons as a mentor to guide the aspirants in the domain of engineering. Also, he will share his experience gained through the corporate journey like people management, resolution of workplace related conflicts, quality assurance, etc.
Join us for live technical discussion related to “Pile foundation” on 10-JAN-21 at 11:00AM IST. We are going to discuss the important areas related to geotechnical and structural aspects of the pile foundation.
Please share your points of discussion in the below comment box which will be taken up during the live session. Vivek Kumar MITRA will join as a guest expert during the session.
Link for joining the session is mentioned in the first comment below.
Please tag or share this message with the interested engineers in your circle.
Facilitator : Bhavin Shah (Founder & CEO, SQVe Consultants)
An initiative of SQVe Consultants (Enhancing the engineering profession)
We will discuss following areas during the session. Please suggest the other points which may be taken up during the live session.
1. When pile foundations are required? 2. What are the different types of piles and their applications? 3. How to decide diameter and length of pile? 4. What are the major factors affecting pile capacities? 5. Can we go ahead with only friction piles? 6. What is negative skin friction for piles? 7. What are the different tests required to ascertain pile capacity? 8. Is it mandatory to perform pile test? 9. What is PDA and how it is useful for pile testing? 10. Major steps for performing structural design of piles 11. What are secant piles?
Session 12 – Discussion on Pile Foundation – Live technical discussion
Please participate in the unique 2 days’ workshop on 26-DEC-20 & 27-DEC-20 (10:30am to 1:30pm) named as “Decoding of IS 800:2007 for design of steel structures”. It is organized by MX Business Media. In the workshop, we will address some of the challenges being faced by practicing engineers while design of the steel structures as per IS 800:2007.
Link of registration for the workshop: Please participate in the unique 2 days’ workshop on 26-DEC-20 & 27-DEC-20 (10:30am to 1:30pm) named as “Decoding of IS 800:2007 for design of steel structures”. It is organized by MX Business Media. In the workshop, we will address some of the challenges being faced by practicing engineers while design of the steel structures as per IS 800:2007.
Expert sessions by : Bhavin Shah (Founder & CEO, SQVe Consultants)
Glad to announce our first LinkedIn Live session on 24-DEC-20 at 11:00AM IST related to importance of the interface between Geotechnical engineer & Structural engineer.
For safety & stability of the structure as well as for the cost optimization, interface between geotechnical engineer and structural engineer is extremely important in the project. We will discuss few such important interface areas and also, we will take up the discussion points suggested by the participants through live chat.
Vivek Kumar MITRA (Founder & CEO, VKM Geotechnics) will join us in the live session.
Recently, BIS published the amendments related to IS 1893 (Part 1) : 2016 & IS 13920 in November, 2020. The article shows some of the major changes made in the code as per my understanding. Only brief details are mentioned below, for details please refer the amendments.
Amendment no. 2 of IS 1893 (Part 1) : 2016
1. Clause related to vertical earthquake shaking is modified. The requirements are added for embankments, dams, bridges, etc. Also, the criteria for consideration of vertical earthquake shaking are modified.
2. The methodology for calculation of torsional irregularity is updated. The maximum displacement should be checked against the average displacement as against the minimum displacement in the previous version of the code. For more details, please refer the amendment.
3. For a building with re-entrant corners, three dimensional dynamic analysis to be performed with the flexible floor diaphragm. If there is a rigid diaphragm in the building then two separate analysis to be performed, firstly with flexible diaphragm and secondly with the rigid diaphragm. The worst effects to be considered from both the analysis.
4. For out of plane offset in vertical elements, the forces and moments due to earthquake effects in the elements connecting the two vertical elements with out of plane offset elements, the vertical element supporting the offset, and connections shall be enhanced by a factor of at least 2.5.
5. The provisions for stiffness irregularity are further clarified and few changes are made as well. In the note, it is mentioned that this provision is not applicable to such storeys, which have: (a) lower height, where services and utilities are housed, or (b) outrigger frame members placed in them.
6. For weak storey irregularity – buildings with strength irregularity shall not be permitted. In case, the weak storey is because of URM infills, provisions of 7.10 shall be followed.
7. Floating columns – Such columns are likely to cause concentrated damage in the structure, and are undesirable. A building with floating columns shall not be permitted, if the floating columns are part of or supporting the primary lateral load resisting system.’
8. Irregularity related to “Irregular Modes of Oscillation in Two Principal Plan Directions” is further clarified. It is also mentioned that this provision is not applicable to buildings with large podiums in the lower storeys.
9. For importance factor, “school” is replaced with the “educational building”.
10. OBF is not allowed in seismic zone III, IV & V.
11. Provisions for flat slab – structural wall system are further clarified.
12. Formula for Aw is modified and now it is same as when the code was published in 2016. It is mentioned that The value of Ta obtained shall neither be taken to be more than that given in 7.6.2 (a) nor less than that given in 7.6.2 (c).
13. In case of URM, RC members shall be designed for the governing combinations of stress resultants arising from structural analysis of:
a) Bare frame building, and
b) Frame building with URM infills.
14. For other details, please refer the amendment.
Amendment no. 2 ofIS 13920 : 2016
1. Steel reinforcement shall comply with all of the following:
a) Elongation shall be at least 14.5 percent,
b) Ratio of ultimate stress to 0.2 percent proof stress shall not exceed 1.25,
c) Ratio of ultimate stress to 0.2 percent proof stress shall be at least 1.15, and
d) Steel shall be only of strength grades with minimum 0.2 percent proof stress of 415 MPa, 500 MPa or 550 MPa, in addition to other requirements of IS 1786.’
2. In cl no. 9.1.1, modifications are made for calculation of nominal shear strength of concrete in a beam-column joint.
3. In cl no. 9.1.2, provisions related to design shear stress demand are further clarified.
4. For other details, please refer the amendment.
We are planning live technical discussion for the amendments on 20-DEC-20 at 11:00AM IST. Please share your comments / discussion points in the below comment box. We will discuss the same during live session of 20-DEC-20.
Link of the live session is attached below. Please like and share this video with the interested engineers in your circle.
Session 11 : Recent amendments for IS 1893 (Part 1):2016 and IS 13920:2016 – Live discussion
An online course related to earthquake resistant design will start from 17-MAR-22. Please watch the introductory video below:
EQ-STR-002 : Learn concepts of earthquake resistant design
Click below for more details and registration for EQ-STR-002
Thank you all for participation in the live session for “Importance of Quality Assurance in structural engineering firm” and for raising important discussion points. Bhavin Shah (Founder & CEO, SQVe Consultants) had conducted the session.
The link of video is shared below, in case you have missed out the live session.
Your further views/comments are welcome on the subject.
Join us for Live Discussion on 13-DEC-20 at 11:00am IST for “Importance of Quality Assurance in Structural Engineering firms”.
Quality assurance is one of the extremely important area for the design engineering consultancy firms. The Quality Assurance covers the broader aspects like compliances to the prevailing regulatory standards, meeting functional & aesthetics requirements, ensuring strength and stability of structures, effective interface to avoid rework at site, generating error free design documents, inclusion of sustainability, safety, constructability aspects, etc.Please tag the engineers in your circle who may be interested in the topic. Also, pl share your discussion points in the below comment box. We will take up the same during the live session.
Session 10 : Importance of Quality Assurance in Structural Engineering Firms
