A note on the structural system and progress at Dr. Bhavesh Dave’s residence at Kensville

The Kensville site is located just before the great marshes of Nalsarovar bird sanctuary on a natural drainage path, and therefore has a high water table. This geological / geomorphologic feature has led to foundation soil being dominantly of silty sand type. Approximately, seventy five percent (75%) of the soil is grainy and rest is highly shrinking clay. In colloquial terms*, the soil is also known as black cotton soil. The soil is highly draining in nature besides its average bearing capacity. This soil condition along with existing loads required us to consider a circular masonry foundation, on which the ferrocement shell and landscape grass composite would rest.  It is intended that enough integrity is achieved by the foundations and the superstructure shell independently, which then would account for differential movement conditions because of the soil. See the sketch below for details.

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Construction of this masonry foundation is complete and the floor plinth is being readied now.  Like other parts of the country, availability of qualified workforce is a concern, and the site’s remoteness keeps the pace of our work slow. However, our contractors Nirav and Dakshesh found local workforces proficient in brick masonry and excavation. Soon after completion of excavations, constant interaction with the brick masons, before starting the work and during execution, ensured desired quality.


For pictures click 


At present, mobilization of materials for construction of ferrocement shell is underway; and we will keep uploading information here as work progresses. Please keep visiting.

*black cotton soil is a local technical simlie for highly shrinking clay

18th September 2011 Earthquake

Update: 29th April 2012
The progress at Sangkhola school is slow but strong. The slow progress is largely due to non-availability of qualified workforce which can work with Reinforced Cement Concrete (RCC ) as a construction material. The State Education Department has also expressed its desire to construct new buildings using RCC only, and is keen that the work is completed at its earliest. It is well understood and established that the damage during this earthquake has been primarily due to badly retained earth, retaining walls, and inadequate designing, especially of RCC joints. In many cases the soil wasn’t properly compacted; in some cases soil has been just dumped from other places in creating levelled land and is therefore very loose, and retaining walls were inadequate for the soil and therefore the building they were supporting. Due to the insufficient loose foundation soil, the structures underwent more shaking and resulted in greater damage despite Sikkim’s buildings having relatively good construction quality. Inadequate attention to design therefore seemed to be an important reason for the extensive damage caused by the earthquake.

Now, with a revised project plan we are expecting foundation work to complete by mid May; and structural skeleton with other finishing works envisaged to complete by the middle of June. See pictures of the foundation work here, where present emphasis is on preparing highly compacted foundation trenches to support RCC column pedestals.

We are looking at building the local contractor's competency in both technical and managerial aspects of construction. This made us put more experienced engineering team on the ground with Rakesh from SEEDS in the lead now along with the mason Ramesh from Patanka village in Gujarat, to facilitate the re-construction of the school.

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In addition, preparations are underway for reconstruction of the damaged buildings in three school campuses in the East district of Sikkim. We are additionally looking at overall Life Safety in these school campuses for future extreme events, and improvement of the local built environment of through awareness building and community participation exercises.

Sikkim updates-18'th September 2011 earthquake

Update: 4th Feb. 2011

Due to some administrative hiccups we had to change our chosen school. This time, after surveying some more government as well as private schools, we could find Sangkhola primary school, which is located some 20 kms before the state capital Gangtok on National Highway 31A .

The SEEDS team of Rakhee, Rahman, Harjeet, and Rinkoo is working tirelessly on the ground to design for reconstruction of the school building in Sangkhola. The aim is not only to put structures that are safer than before, but also has a built environment fabric more conducive to learning.

The team is in regular consultation process with the Local village population, Panchayat, and various government departments, especially HRDD (The State Education Department). These informal workshops have been very successful, please see pictures later, in evolving design alternatives for the new school building. Sooner, as the construction gears up we will be in a position to conduct community workshops as well as some hands on interaction sessions aimed at Engineers and Masons.

Some photographs of damaged state of Sangkhola school is shown in the Picasa Album here below

120204SangkholaDamage

Some design alternatives are shown in the Picasa Album here below

120204SangkholaNewDesignAlternatives

Some of our recent assignments

While this has been Quakeschool’s first year in a seemingly tough home environment, India, there were some useful lessons, rather these were reminders. The work has been reflective, mostly reinforcing the fact that efforts put in reiterative engineering, wherever it is carried out, help bring down project costs significantly. These efforts also lead to simplicity in design and its execution. At the same time, we also tried to understand the term sustainability in our projects.

We recently concluded some task-based assignments for a few of our new clients. Three interesting ones among these were-

1. Design for foundations of a solar plant in Samakhyali, Gujarat <link>

2. Design analysis of a bamboo structure in Nagpur, Maharashtra <link>

3 . Value engineering analysis of a ground-plus-ten-storied structure in Ahmedabad city, Gujarat <link>

The Samakhyali project is an upcoming electricity generation plant being run on solar energy. One of the important components is the plant’s structural foundation on which its panels and assembly will rest. The project was an opportunity for us to work with mechanical and instrumentation engineers from the US and India, where as a team we worked together to optimize the size of these foundation units, six thousand in numbers, hence also reducing costs. More on this project can be found at this link.

A completely different structural design work was an exercise with Wondergrass that introduced us to one of the fifteen species of the bamboo family used in housebuilding, called Dendrocalamus Strictus (or simply D. Strictus). We tested structural adequateness of this bamboo in a typical housing unit designed by Wondergrass. We also again learnt that although significant avenues in rural areas as well as government policies exist in India to promote bamboo as a housing material, it is still not being exploited to its fullest. A key reason for this being most people, including researchers and building practitioners, perceive bamboo as a non-durable and obsolete material; and more so for house building on a large scale, hence overlook the versatility it offers as an alternative material. For details of this project please visit this link.

Through the ground-plus-ten-storied structure project, we conducted a computer based 3-D analysis of a typical high rise building in Ahmedabad city. This high rise structure is made of cement and embedded steel for extra tensile strength, which are most expensive of these materials. This type of construction can be seen in almost all developing countries because of the flexibility its primary ingredients—cement and steel—offer. Engineering in a way is for ensuring safety and reducing costs, and here our aim has been to analyze this structure from a ‘value engineering perspective’, so we could reduce its cost by checking consumption of its basic ingredients. Project’s details can be found here on this link.

In executing these small projects, we realized that whatever be the scale of building structures we design, or the material we use, if intelligently engineered will not only bring down the costs but can help in addressing the issues of sustainability as well, which has societal and economic at their own levels.

Sikkim Visit- Post 18th Sept. 2011 earthquake

My second trip to Sikkim this time was well restricted within the state capital, Gangtok. The priority task was to start rehabilitation activities in a damaged school identified during the last trip. It has been a part of our long term agenda of school safety, where through reconstruction of schools we are looking at Sikkim for:

• Strengthening of existing school building stock
• Introduce and integrating the concepts of safety and accessibility in school buildings
• Conducting dissemination programmes on safe construction to various user groups including the local government

To begin with, we started our work in Lumsey Junior School, which is within Gangtok city limits and has two classrooms damaged. The idea is not only to repair the damage and strengthen the school building, but also utilize this opportunity for hands-on training of masons on retrofitting activities. Me and Rehman (from SEEDS) started with interviews and discussions, and taking necessary information from the site including pictures and measurements.

Rapid visual surveys during my first visit and also by the SEEDS team members on their respective visits had helped us finalize Lumsey then. Lumsey seemed to be the best accessible school as we would want various groups such as engineers from various agencies and government departments, schools, and other groups to visit the school and interact. Currently, we are undergoing the process of finalising on a small team and also look forward to conduct our activities in the Junior High until the end of March 2012. Rakhi has joined us on SEEDS payrolls, and two masons from D.A. soon to join us.

Pictures of Lumsey school can be accessed here .

Lumsey Junior High School (Link to Picasa album)

Other than this, I also tried making a note on post earthquake activities undertaken by other agencies. It appeared from the news reports and discussions with peers that a clearer picture on larger funding from the Prime Minister’s and Chief Minister’s and other grants is still awaited by the administration and the civil society. It is interesting to see the debate at all levels on the mode of earthquake response the State should adopt in the future. Talks about meetings and conferences aiming for improvement in bye laws and infrastructure provisioning can be heard.

With a population of 6,00,000, Sikkim is a closely knit society. One and all are aware of the post earthquake consequences in the state, and have empathy for each other. House owners in towns such as Chungthang had to bear heavy losses. The rehabilitation style of an ex-gratia compensation by the government –as in this case, Rs.50,000 does not seem logical enough for a place like Sikkim.

It is unfortunate that one of the most prosperous States of India has no ready technical help available to its people in terms of safer building awareness and construction technology, and/or and/or counseling that would help them cope with this huge disruption in their lives and livelihoods- it being the need of the hour.

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Written: Chandra Bhakuni

Checks and Reviews: Pratul Ahuja, Shruti Nair, Smriti Saraswat

Engineering Lessons for Sikkim, India Earthquake (Magnitude-6.9)

I recently visited Sikkim, India after the 18th Sept. earthquake. The trip had a few-fold objectives, them being:

1. To understand the damage to buildings and infrastructure in the region

2. Visit the ‘School buildings’ and other institutional setups to understand the impact of this event

3. Observe the Disaster Response mechanism in place

Based on my field experiences and discussions with various people on this trip, I would like to make a few recommendations; as following:

1. Large engineering companies, universities in Gangtok, and individuals have studied Sikkim to a great extent, and their expertise should be utilized for safety and improvement of infrastructure.

2. The earthquake appears an opportunity for overall developmental improvements (access and amenities) in settlements that are urbanizing, such as worst hit Chungthang.

3. Traditional Wattle and Daub (Collq. Ekra) construction has performed well against the earthquake, and has low damage. This construction should be encouraged, and innovation in this area could yield comfortable and safer houses.

4. The damages in Chungthang have caused mental health issues to houseowners (especially who had made large investments) and counseling is an immediate need.

5. Damages in various school buildings have instilled fear/caution in children. Instead of listening to that fear, perhaps it is more prudent that opportunities are created for learning about earthquakes.

6. Sikkim is an opportunity, and can be shown as an example of collective governance, not only from the safety point of view but also development needs of the North East of Indian subcontinent.

For the detailed report refer www.quakeschool.org/files/110922SikkimEarthquake.html

By [With Acknowledgements]

Mr. Chandra Bhakuni, Structural Engineer, Quakeschool Consulting

[With sincere thanks to Manu and his SEEDS Delhi team, Mrs. Rinkoo Wadhera from local DOU unit, Mr. Prashant Pradhan and his team at Architects of Sikkim , Tshering (School Teacher), Sohel da (Faculty, Sikkim University), Col. Wadhera, Col. Vishal, and Quakeschool team and many others I could meet during this trip.]



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Magnitude 6.9 Sikkim Earthquake

Source: Maps Of India

Visit link (click) for updates.

Source: Assorted

Some earthquake feelers by Structural Engineers

Photos. Typical Reinforced Masonry buildings in India

The earth’s surface is under continuous movement, in other words is always vibrating. However, these vibrations are so low in magnitude that they are not felt by us humans at all; unless they are large in size, which happen during events such as earthquakes.

One of the methods which earthquake experts apply to understand earthquakes and these vibrations is by classifying these in the form of waves. These waves which are generated inside the earth’s crust during an earthquake have their movement in all directions. Known as seismic waves, these waves can be categorized in to two types- 1. Body, and 2. Surface. While the Body wave would move through the body of the earth; the surface wave would take a little longer route because it has to make its way to the nearest earth’s surface first, and thereafter travels as a surface wave. See some simple educational websites Website 1, Website 2 which provide simplified understanding of these earthquake waves.

The science of structural engineering is concerned how these waves travel and when they hit, have an impact on the building.

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In recent last one year history has seen two unfortunate earthquake events, with some significant aftershocks. New Zealand and Japan, faraway places were in news. Last year significant damage was noted in other places such as Chile as well. See what the Structural Engineers have to say about what they felt:

New Zealand (22^nd Feb 2011)

Roberto T. Leon, president of the Structural Engineering Institute, ASCE has an interesting blog on being present in Christchurch, New Zealand when the 2nd earthquake had unexpectedly stuck there. The whole blog is an interesting read, where in a portion he summarizes a comparison with the Chilean event.

It was eerily different for me because my most recent recollections are from the large Chilean earthquakes that I experienced last year. The Chilean ones “build up” slowly and last a very long time. This one seemed to be three or four very sudden, violent jerks, with a strong vertical feel, and lasting probably no more than 15 seconds or so.

Japan (11^th March 2011)

Balaji, a friend and a structural engineer, was in the fourth floor his ten storey office building in Tokyo when the earthquake stuck. Pretty much inland where the Tsunami could not reach, a few days later he told me over Skype [http://skype.com] how he first felt the body wave which came stinging in no time and took him off ground, and then he waited for the surface waves to arrive. While he prepared himself for a floor dance, for the surface wave would arrive in no time, next moment he saw his colleague flying away and his back curved hitting the wall. It was a nasty bump but thankfully both are safe. The buildings their colleagues designed ensured they are.

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Ten years back, I personally felt the Gujarat, India earthquake (26^th Jan 2001), because it lasted for approximately two minutes. Halfway, it woke me up from my sleep; and the ground plus two building I was in, a typical Reinforced Cement Concrete (RCC) confined structure [See pictures] took the shaking well. One can contend such buildings, which are a typical design for institutional buildings across India, therefore take building movements and uncertainties into consideration when designing/constructing one. Otherwise, many buildings which are built keeping only enclosure in mind were not that lucky. Many had collapsed. A structural engineer colleague of mine, when we were students, in all this chaos, was wise in saying,

… either you design the building so stiff that nothing happens to it, or make it so flexible that you can bend or twist it endlessly anywhere, or you make the joint so ductile that no matter what the earthquake force or duration is, let it be endless, the joint shall never ever snap out.

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Website 1: http://www.matter.org.uk/schools/content/seismology/pandswaves.html

Website 2: http://earthquake.usgs.gov/learn/topics/?topicID=63

ASCE President blog: http://www.asce.org/PPLContent.aspx?id=12884904978

Skype: http://skype.com

Pictures of Typical Reinforced Cement Concrete (RCC) confined structure

Recent notification by National Disaster Management Authority (NDMA) and the Reserve Bank of India (RBI) on disaster resilient construction

Thanks to Anup Karanth for providing an update on a significant move by the National Disaster Management Authority (NDMA) and the Reserve Bank of India (RBI) towards making buildings and infrastructure more disaster resilient. Please refer below an e-mail I received from Anup Karanth (Anup is a Civil Engineer and Planner working extensively in Disaster Management and Capacity Building sector) for more details on this development. It is indeed encouraging that the RBI has come out with a notification on this issue, which may go a long way in ensuring that the NDMA Guidelines are taken more seriously.

One can download the document here (In English, directly from Government of India NDMA Website - or from our website.

In verbatim below:

From: Anup Karanth [mailto:anup.karanth@gmail.com]
Sent: 01 June 2011 12:42
To: undisclosed-recipients:
Subject: National Disaster Management Guidelines on Ensuring Disaster Resilient construction of Buildings and Infrastructure (NDMA, GoI)

The National Disaster Management Authority (NDMA), Government of India has formulated guidelines on ensuring disaster resilient construction of buildings and infrastructure financed through banks and other lending institutions. The NDMA has observed that in the context of disaster resilience there are certain critical gaps and the guidelines aim at addressing these gaps in the current process of approving the loan applications. It has been observed that the structural design of the proposed buildings and structures are not completed before submitting the application for a bank loan and no processes are in place at the banks to ensure that disaster resilience has indeed been incorporated in the assets during the design process at least before the construction begins. A copy of National Disaster Management Guidelines on Ensuring Disaster Resilient construction of Buildings and Infrastructure, September 2010 is enclosed.