Site Visit Report

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DEPARTMENT OF CIVIL ENGINEERING

Report On:Site Visit

Repair And Rehabilitation of Structures

Prepared by : Submitted to: Kaushal Patel. Mrs.Niketa panchalD12CL067 Associate ProffesorSemester 7 Civil department CSPIT

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GENERAL DETAILS:

Date of visit :18th September to 20th September, 2014

Name of site :

1) B J Wadia Children Hospital, Parel, Mumbai

(Project Site of Structwel Designers and Consultants Pvt. Ltd)

2) Structwel Designers and Consultants Pvt. Ltd., Turbhe,

NaviMumbai(Main Office and Laboratory)

3) Ultratech Specialty Chemicals Ltd,Taloja

[Aditya Birla Science and Technology Company (ABSTC)]

4) Global Vipassana Pagoda, Gevrai, Maharashtra.

Students: 4th Year B. Tech., Department of Civil Engineering

Objectives of Visit :

To explore real concrete investigation methods. To interact with the practicing engineer and to get the knowledge of

repair and retrofitting techniques/ practice To visit Pagoda dome - this was retrofitted under Heritage restoration

Guiding Faculties :

1) Mrs. Niketa Panchal

2) Dr. AV Thomas

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DAY 1(SEPTEMBER 18):

VISIT TO BJ WADIA CHILDREN HOSPITAL

On the first day, we visited the Bai Jerbai Wadia Children Hospital which was built in 1928 and it is a heritage structure under 2-B category and is currently undergoing extensive repair and retrofitting.

This project is being executed under the consultancy of Structwel Designers and Consultants Pvt. Ltd. The hospital consists of five blocks – A, B, C, D& E.The blocks B, C & D were undergoing repair work at the time of our visit. The main aim of carrying out the repair work is to increase the strength of the building while maintaining the same architectural style and layout.

The building itself is an interesting structure. It is a load bearing structure (G+2). The buildings looks like it has been made out of Stone Masonry but actually it is constructed in brick masonry with Ashlar Stone Masonry Cladding. This was done to give a very appealing architectural view to the building.

The building is made from 400 mm thick brick masonry with 4 inch thick Stone Cladding. First of all we did External Condition Assessment of the building followed by Internal Condition Assessment during which we also discussed various tests that were carried out during the investigation phase and we were also made familiar with the repair works that were being carried out in the structure.

During the External Condition Assessment, we noticed various distresses in the structure such as severe cracks due to corrosion of reinforcement, deterioration of RCC Weathershed (Spalling), CI pipe deterioration, Lintel Cracking (Caused due to corrosion of Steel Reinforcement), Separation Cracks, Vegetation Growth, Unfinished through holes for pipes (Potential entry way for water), Discoloration of stone masonry (Caused due to Weathering).

During the Internal Condition assessment, we noticed Spalling of concrete, delamination, corrosion of steel, Dampness in the structure, Structural Cracksand settlement of flooring.

We discussed the various tests such as Rebound Hammer Test, Ultrasonic Pulse Velocity, Carbonation Test, Covermeter / Rebar Locator, Core Sampling and Endoscopy that were carried out.

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The whole structure of the hospital is quite interesting.There were no RCC columns used. Stub columns and floating columns were used where needed. It consists of a cantilever Open to sky which is supported by steel girders which are encased in brick masonry.Also the slabs used in rooms are “Pressed Coba type Slabs” (8m to 10m length) which consists only of Steel Girders and MB400 I-Sections and are designed as per British standards. The passage slab is Simply Supported One Way slab.The I-Sections used and the design is based on British Standards.The structure also features Roof Truss.

After performing these tests, a detailed report was generated from the analysis of the test data. The extent of damage in the structure was graphically represented using color coding, with each color representing a specific extent of damage.Based on the extent of damage, the immediate actions to be taken and the type of repair works to be carried out were suggested.

Based on the suggestions, repair works were being carried out in the structure by B.N. Mistry Contractors. The repair work consisted of improving the strength of the structure by providing additional girders to support the structure. The girders provided for strengthening meticulously follow the original design philosophy of the structure. Along with providing additional girders, the rust on existing girders and I-sections was removed by extensive grinding on the top, bottom as well as the sides of the steel members. After removal of rust, rusticide is applied to prevent any further corrosion followed by 2 coats of paint. The thickness of the existing flooring in the building is very high which added a lot of extra weight on the structure. Hence, in order to decrease the weight on the floor, Foam concrete will be adopted in the flooring. Crack Sealing, Water Proofing, and Epoxy grouting injection was also being carried out. We learnt that epoxy grouting should be carried out from bottom to top in the same member in order to increase the efficiency of grouting. Micro-Concreting was also adopted in the structure for high strength and durability. During the repair work the main aim of using micro concreting was to give high strength in short period of time.

Later on we had an extensive Q&A session followed by lunch which was graciously arranged for us by the Contractors. We then headed to our hotel and retired for the day.

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DAY 2 (SEPTEMBER 19):

VISIT TO STRUCTWEL DESIGNERS AND CONSULTANTS

PVT. LTD.

Structwel Designers and Consultants is one of the premier consulting

companies in India in the field of Repair and Rehabilitation of structures.

We were given presentations regarding different type of instruments used

during assessment of structure. Along with the presentation we were also given

demo of various instruments used. Patil Sir gave the presentation of the various

instruments and Vinayak sir discussed the various instruments.

We discussed in depth, the Non-Destructive Tests such as

Rebound Hammer Test, Ultra-Sonic Pulse Velocity test, Core Cutting test,

Covermeter test, Carbonation test and Half-Cell Potential Test. We learned

about the application, interpretation and significance of each test.

Schmidt rebound hammer test :-

Rebound hammer test is done to find out the compressive strength of

concrete by using rebound hammer as per IS: 13311 (Part 2) – 1992. The

rebound of an elastic mass depends on the hardness of the surface against which

its mass strikes. When the plunger of the rebound hammer is pressed against the

surface of the concrete, the pring-controlled mass rebounds and the extent of

such a rebound depends upon the surface hardness of the concrete. The surface

hardness and therefore the rebound is taken to be related to the compressive

strength of the concrete. The rebound value is read from a graduated scale and

is designated as the rebound number or rebound index. The compressive

strength can be read directly from the graph provided on the body of the

hammer.

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Demonstration of rebound hammer at structwell laboratory

Some important notes:

Minimum number of rebounds for each face = 16

Minimum edge distance = 25mm

Used only for OPC cement & up to M50 grade concrete.

Correlation between rebound number and compressive

strength is given by below graph:

Graph to be used for correlation between rebound number and

hardness

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Ultrasonic pulse velocity test:-

This test is done to assess the quality of concrete by

ultrasonic pulse velocity method as per IS: 13311 (Part 1) – 1992. -

The method consists of measuring the time of travel of an ultrasonic pulse

passing through the concrete being tested. Comparatively higher velocity

is obtained when concrete quality is good in terms of density, uniformity,

homogeneity etc.

Demonstration of USVP

criteria for range of USVP

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Covermeter :-

This test is done to know the cover provided in the member

or the structure. This instrument is also used to identify the diameter of

bar provided in the member if the design drawings are not available.

During the presentation, full demonstation of how to operate a

covermeter was given by vinayak sir.

Thermography:-

Thermography is used to determine the possible presence of

moisture but the differential thermal temperature when using a thermo

graphic instrument is used.

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Image produced due to thermography

This was followed by a presentation on Advanced Investigation Tools in

which we learned about various new instruments such as Endoscope, Ground

Penetrating Radar (GPR), and Infrared Survey using Thermography Survey.

GPR image & CORE sampling together to understand the structure of the

core

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Ground penetrating radar (GPR)

Different diameter of cores by different core cutters

This was followed by snacks and then we visited their Laboratory and got

familiarized with the protocol followed by the company for testing of samples.

Afterwards we took leave from there and headed to Ultratech Specialty

Chemicals Ltd situated inside Aditya Birla Science and Technology Company

Limited, MIDC, Taloja.

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VISIT TO ULTRATECH SPECIALTY CHEMICALS

LIMITED

Ultratech Specialty Chemicals Limited is situated inside the

Aditya Birla Science and Technology Company (ABSTC) located at MIDC,

Taloja. ABSTC is the primary R&D facility for the Aditya Birla Group

Companies.

Ultratech Specialty Chemicals limited is the R&D Company of Ultratech

Cement Limited.

In the First Session we were given three different presentations.

The First presentation was delivered by Dr. Mohan Medhe. We were

familiarized with the Manufacturing process of Portland cement. We also

learned the chemistry of cement manufacturing. During this presentation a case

was discussed that how the Ultratech Cement Limited lost a tender due to the

problem in their own raw material and how the solved the problem after the

detailed study carried out by the available high tech instruments in their

research laboratory.

The Second Presentation familiarized us with the Standards and

Specifications in Cement Manufacturing. We learned how the specifications and

standards are met by the manufacturers and how it relates to the Producer, Seller

and Consumer.

The third presentation was delivered by Dr. Suresh K., which dealt with

Problem Solving in Concrete. We were also familiarized with the research work

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conducted by the company regarding the application of Nano technology in the

cement industry.

This was followed by a Second Session in which we visited their

laboratory and got acquainted with the state of the art instruments used by the

company for their research work.

Afterwards, we had high tea and snacks after which we headed to our

hotel and retired for the day.

DAY 3 (SEPTEMBER 20)

VISIT TO GLOBAL VIPASSANA PAGODA

On the third and final day of our visit, we checked out from our hotel in the morning and headed to Global Vipassana Pagoda before leaving for home.

The center of the Global Vipassana Pagoda contains the world's largest stone dome built without any supporting pillars. The height of the dome is approximately 29 metres. External diameter of the largest section of the dome is 97.46m and the shorter section is 94.82m. Internal diameter of the dome is 85.15m. The inside of the pagoda is hollow and serves as a very large meditation hall with an area covering more than 6000 m2 (65,000 ft2). The foundation of the dome consists of basalt, while the dome itself is made from sandstone imported from Rajasthan. The individual blocks of sandstone weigh 600–700 kg each and are kept in place due to the unique design of the bricks. Each of the bricks interlock with the ones adjacent to it and lime mortar is used to fill in any remaining gaps. The top keystone itself weighs 10 tons.The whole dome is supported by a ring beam which holds the structure in place.

The spire of the dome is covered in real gold, while the rest of the pagoda is covered in gold paint. The spire is topped with a special ornamental umbrella piece donated by the Burmese. The main doors to the pagoda are wooden and

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hand-carved in Myanmar. After wards, we spent some leisure time on the beach and then headed towards our hometown.

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CONCLUSION:

This site visit was an enriching experience and we gained a lot of knowledge onthe engineering practices and current trends in the field of Repair and Rehabilitation of Structures. We got a huge amount of exposure to the current industrial practices being followed in this sector. The involvement and enthusiasm of Mrs. Niketa Panchal and Dr. AV Thomas was immense and really commendable. I heartily thank Niketa Panchal mam for arranging such an extraordinary visit.

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