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THERMEX REBARS

"The Best of Times"
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SPS Starts Thermex 500 Production

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THERMEX 500

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Typical Thermex Installation

These are exciting times for the Indian Region. The present decade signifies the excellent opportunity that exists today for the civil industry, one whereby the country can realise a saving of about Rs 500 crores each year by use of reinforcement steel bars as used in developed countries (Grade 460 or Grade 500), getting out of the CTD stranglehold and ensuring safer RCC structures, especially in seismic zones. An Indian life is not less precious than that of persons living in developed countries.

 

It is for us to seize this opportunity.

 

Thermex Licensees have, over the past few years, informed various government bodies, leading structural engineers and concerned authorities about the global practices and the regular availability of Thermex 500 & 550 bars in India. The Bureau of Indian Standards (BIS) after a detail study of available data, has on its part, issued a relevant amendment in March 2002 (see box) that permits use of thermo-mechanically treated bars of Grade Fe 500 & Fe 550 having elongation more than 14.5% in seismic zones III, IV & V. This is a major step in the right direction as the entire west coast, large parts of the north close to the Himalayas and large other areas of the country fall in such seismic zones. In light of this major break-through the restriction to use only Grade Fe 415 has now been removed.

 

The tragedy of Gujarat can and must be minimised.

             AMENDMENT NO. 2 MARCH 2002

                                              TO

IS 13920:1993 DUCTILE DETAILING OF REINFORCED

CONCRETE STRUCTURES SUBJECTED TO SEISMIC

                    FORCES, CODE OF PRACTICE

 

(Page 1, clause 1.1.1) Substitute the following for the existing:

'1.1.1   Provisions of this code shall be adopted in all reinforced

 concrete structures which are located in seismic zone III, IV or V.'

 

(Page 3, clause 5.2, line 3) Delete the word 'preferably'

 

(Page 3, clause 5.3) Insert the following at the end of the clause:

               

'However, high strength deformed steel bars, produced by the thermo-mechanical treatment process, of grades Fe 500 and Fe 550, having elongation more than 14.5 percent and conforming to other requirements of IS 1786:1985 may also be used for the reinforcement.'

 

Mr. M. R. Patil, a leading structural engineer in Mumbai with assignments all over the country, was invited in early October 2002 to make a presentation on use of Thermex 500 Grade bars in Nepal, a highly seismic zone, at a seminar arranged by the Nepal Engineers Association, where the Chairman of the Nepal Planning Commission was the Chief Guest. Mr. Patil and I also met Prof. Dr. Prem Nath Maskey, Director of the Centre for Applied Research and Development and heading the Civil Engineering Dept., Institute of Engineering, Tribhuvan University at Kathmandu. Prof. Maskey, an eminent authority in his field in Nepal, had personally inspected the Thermex Cooling System recently commissioned at Panchakanya Steel and carried out tests of the Thermex rebars rolled by this first Licensee in Nepal. Prof. Maskey was visibly relieved and pleased when I gave him a copy of the above-referred Amendment No. 2 of March 2002 issued by B. I. S. because it had great relevance in Nepal. Prof. Maskeys presentation at the seminar made specific reference of our meeting and the importance of Thermex 500 in light of the amendment issued by B.I.S.

 

A summary of the savings by use of Thermex 500 bars, as per design examples of beams and columns presented by Mr. Patil at the Nepal seminar is given below.

 

Beams 300 x 700 mm:

Case No.

Concrete

Mu/bd2

Kg., Steel  - Fe415

Kg., Steel  -Thermex 500

Savings by use of Thermex 500

1

M-20

3.2

109.69

93.18

15.05%

2

M-25

3.2

103.73

86.50

16.61%

3

M-30

3.2

98.87

84.34

14.70%

4

M-20

4.2

162.74

141.20

13.23%

5

M-25

4.2

150.90

128.43

14.89%

6

M-30

4.2

137.14

115.24

15.96%

7

M-20

5.0

212.40

178.70

15.87%

8

M-25

5.0

207.25

165.80

20.00%

9

M-30

5.0

177.94

150.80

15.25%

Columns:

Axial Loaded Columns:

Assumed: 300 x 900; Concrete M-25; Load - 3500KN;

Unsupported Length 3.0M,

 

Steel Fe 415 = 68.68 Kg; Steel Thermex 500 = 58.0 Kg; 

Savings = 15.55%

Rectangular Column with Uniaxial Bending:

Factored Load - 1200KN; Factored Moment - 200KN-m;

Unsupported Length 3.0M, Column size 230 x 600; Concrete M-25;

 

Steel Fe 415 = 52.7 Kg; Steel Thermex 500 = 44.4 Kg;      

Savings = 15.75%

It is foreseen that the use of Thermex 500, conforming to Fe 500 but with far greater elongation values, will gradually replace the use of Fe 415. The stage is now set for the pattern in Germany (see Fig. 1) to be repeated in India. It is merely a question of time. Not only will CTD bars be phased out in the coming years, we shall also be witness to gradual and definite reduction in the use of Fe 415. We have missed out in the past 10 to15 years but shall definitely not fail a second time. We owe it to the nation.

 

Truly, these are the 'Best of Times'. Let us make the most of it.

THERMEX is a registered trademark of H&K Rolling Mill Engineers Pvt. Ltd. in India and is owned by HSE, Germany in other Countries