Forums Search/Statistics.
Track Forum02/09 21:47
Brainstorming for 2nd Phase Track Modernisation01/08 15:09
Rly Bridge Forum02/09 12:33
General Forum02/09 14:39
Works Forum02/09 14:41
Track Machine Forum11/08 17:22
ROB/RUB/LXING Forum24/08 18:37
Track Procurement Forum23/08 10:13
 How to use RSS
Warning: Cannot modify header information - headers already sent by (output started at /var/www/html/IRICEN1/themes/fisubsilversh/theme.php:138) in /var/www/html/IRICEN1/includes/sessions.php on line 249 Warning: Cannot modify header information - headers already sent by (output started at /var/www/html/IRICEN1/themes/fisubsilversh/theme.php:138) in /var/www/html/IRICEN1/includes/sessions.php on line 250
Indian Railways Institute of Civil Engineering: Forums

Warning: Cannot modify header information - headers already sent by (output started at /var/www/html/IRICEN1/themes/fisubsilversh/theme.php:138) in /var/www/html/IRICEN1/includes/page_header.php on line 477 Warning: Cannot modify header information - headers already sent by (output started at /var/www/html/IRICEN1/themes/fisubsilversh/theme.php:138) in /var/www/html/IRICEN1/includes/page_header.php on line 479 Warning: Cannot modify header information - headers already sent by (output started at /var/www/html/IRICEN1/themes/fisubsilversh/theme.php:138) in /var/www/html/IRICEN1/includes/page_header.php on line 480
 
Post new topicReply to topic
View previous topic View next topic
Author Message

V. B. Sood
Director (B & S)

View user's profile
Shared Documents

Joined:
No. of
Replies: 1644

PostPosted: Mon Jan 06, 2014 1:31 pm Back to top

Dear all,

Correction slips have been issued to IRS Steel Bridge Code as well as IRS B1 to incorporate the High Strength Friction Grip Bolts for use on bridges in Indian Railways. This is a new development and henceforth, RDSO and others shall design steel bridges with HSFG bolts in place of rivets. This is expected to improve the quality and speed of construction. The open web girders are expected to get lighter as a result of this change.

All are requested to acquaint with the new provisions and read the BS-111 revision-2 issued on this subject by RDSO. For any queries, contact me at directorsteel2@gmail.com.
            
            
            
- V. B. Sood Director (B & S) ... 06-01-14

V.R. Naidu
AGM/RVNL/MAS

View user's profile
Shared Documents

Joined:
No. of
Replies: 45

PostPosted: Thu Jan 23, 2014 11:06 pm Back to top

Sir,
Field staff are to be educated on use of 1.type of torque wrench,2.Calibration check .3.application of ist stage and second stage torque application 4.how to measure the applied torque 5.brand names suiting to rly spans.
this will help proper fixing of HSFG bolts.
            
            
            
- V.R. Naidu AGM/RVNL/MAS ... 23-01-14

E. Santharam
Executive Engineer,Con, VSKP

View user's profile
Shared Documents

Joined: Jan 16, 2006
No. of
Replies: 6

PostPosted: Thu Jan 30, 2014 9:05 pm Back to top

Sir,
details of RDSO's Aprroved vendors or any other agency for Supply of HSFG bolts may please be given
            
            
            
- E. Santharam  XEN/Con/VSKP ... 30-01-14

V. B. Sood
Director (B & S)

View user's profile
Shared Documents

Joined:
No. of
Replies: 1644

PostPosted: Fri Feb 07, 2014 9:59 pm Back to top

At the moment there are no approved vendors. The 82nd BSC has decided that there shall be approved RDSO vendors for HSFG bolts. Hope we will have the list in place is 6-8 months' time.

Regarding education, I have been taking classes in IRICEN to educate people. I believe the correction slips are quite clear and unambiguous, answering most of the questions that arise. So, if the constructing engineers just read the correction slips, they shall be able to do good job. Also, we have published BS -111 Revision 2 which can be referred for understanding the logic of the provisions. If any unit wants to know more about this, I am available to take lectures on skype of google hangouts to answer all the questions of the field engineers.
            
            
            
- V. B. Sood Director (B & S) ... 07-02-14

MOHAMMAD BAKHSH
Rtd. Dy Chief Engineer

View user's profile
Shared Documents

Joined:
No. of
Replies: 1031

PostPosted: Tue Feb 18, 2014 1:45 pm Back to top

High strength friction grip (HSFG) bolts have replaced the rivets because of their distinct advantages However, the material cost is greater than that of
ordinary rivets and special workmanship is required in installing and tightening these bolts.Lesser number of bolts are required as compared to rivets which brings overall economy.
            
            
            
- MOHAMMAD BAKHSH  Rtd. Dy Chief Engineer ... 18-02-14

V. B. Sood
Director (B & S)

View user's profile
Shared Documents

Joined:
No. of
Replies: 1644

PostPosted: Tue Feb 18, 2014 9:19 pm Back to top

Slight clarification:

1. The cost of HSFG bolts is less than rivets but since we are advocating use of direct tension Indicator washers, which are not yet produced in india, the cost per bolt is likely to be higher than rivets.

2. No skill is required for installing HSFG bolts. These bolts can be installed by few ordinary workers who have been trained and given a 'competency certificate' by the AEN in charge of work. These people shall know how to operate a torque wrench and shall know the tightening procedure and sequence given in the codes. The skill required is much lower than that required for rivets.

3. The saving with HSFG bolts is in the steel members which are subject to fluctuating tensile loads. the fatigue category for HSFG bolts is 112 on gross area as compared to rivets which are having category 80 on net area.

4. The real saving with these bolts will be in bracing etc which are prone to cracking. The HSFG bolts will ensure lesser failures in field.

5. With HSFG bolts, the members are required to be metallised per force. that is another advantage to the structure.

The only thing required is education in field engineers to ensure proper tightening of bolts, which is not a difficult task at all.
            
            
            
- V. B. Sood Director (B & S) ... 18-02-14

MOHAMMAD BAKHSH
Rtd. Dy Chief Engineer

View user's profile
Shared Documents

Joined:
No. of
Replies: 1031

PostPosted: Wed Feb 19, 2014 4:19 pm Back to top

The HSFG Bolts will not act correctly unless a method is developed which will guarantee a minimum shank tension.The minimum tension induced in the bolt should be 70% of minimum tensile strength of the bolt.
The torque control method of tightening consists essentially of determining the torque required to achieve the specific shank tension.
            
            
            
- MOHAMMAD BAKHSH  Rtd. Dy Chief Engineer ... 19-02-14

Jagtar Singh
Dy.CE/Bridges/N.Rly.

View user's profile
Shared Documents

Joined:
No. of
Replies: 46

PostPosted: Sat Feb 22, 2014 12:13 pm Back to top

With HSFG bolts, the members are required to be metallised per force. that is another advantage to the structure.

The only thing required is education in field engineers to ensure proper tightening of bolts, which is not a difficult task a
t all.

In view of the above, it is great RDSO achievement and solved the long pending demand specially Ganga Rail cum road bridge at Patna being delayed.Due to
acute shortage of Riveting labour
same can be tried to safe guard after some period schedule can be fixed to check loose HSFG bolts as we check loose Rivets.
This aspect needs to be looked into
jagtar singh
            
            
            
- Jagtar Singh Dy.CE/Bridges/N.Rly. ... 22-02-14

V. B. Sood
Director (B & S)

View user's profile
Shared Documents

Joined:
No. of
Replies: 1644

PostPosted: Sun Feb 23, 2014 5:40 pm Back to top

A couple of things here:

1. The HSFG bolts do not get loose under vibrations. These are tightened beyond yield point of the material, so these are fit and forget type bolts. These cannot be tested like the rivets by hitting on head. Rather, it has been prescribed that the loose bolts be identified through the rust streaks etc in the joints.

2. The torque method has NOT been prescribed for tightening of the bolts. This method is not reliable. Rather "turn of nut" method with some modifications has been prescribed as a less preferred method. The preferred method of tightening HSFG bolts is using Direct Tension Indicator (DTI) washers, which are quire fool proof to show that the bolts have been tightened properly.
            
            
            
- V. B. Sood Director (B & S) ... 23-02-14

G. Radhakrishnan

View user's profile
Shared Documents

Joined: May 11, 2010
No. of
Replies: 469

PostPosted: Mon Feb 24, 2014 8:20 am Back to top

1. Previously, microwave towers were under the maintenance of bridge organisation. In self supported towers, the maintenance activities are
(i) checking the verticality of towers by using theodolite
(ii) tightening all the bolts by using torque wrench.
The bolts provided were of HSFG and people used to check the tightness of bolts and found loose if any, re-tighten the bolts every year. (Mechanism adopted was, setting the required torque in the torque wrench, keeping in position on the nut and rotating the same) Without adequate awareness such activity had been done in our maintenance, authorised manner. Fortunately, MW towers are not in the maintenance of Engineering department and MW towers became obsolete.

The concept of HSFG bolts does not permit the re-tightening; we have to go for replacement with new HSFG bolts

2. I have seen at many places, if rivets found loose, those had been replaced with HSFG bolts. That’s also wrong; turned bolts can be used for replacement of loose rivets isolated manner. But, in a complete joint, HSFG bolts can be used.
            
            
            
- G. Radhakrishnan  ... 24-02-14

MOHAMMAD BAKHSH
Rtd. Dy Chief Engineer

View user's profile
Shared Documents

Joined:
No. of
Replies: 1031

PostPosted: Mon Feb 24, 2014 5:45 pm Back to top

I agree with methodology of tightening the bolts.This is a safe bet as modified tool appears to be spanner cum wrench.The second is that tightening will be up to yield point.The area should be checked for local stresses as the nut will eat in to the parent material in the long run and schedule for replacement can be fixed based on load cycle.
            
            
            
- MOHAMMAD BAKHSH  Rtd. Dy Chief Engineer ... 24-02-14

MOHAMMAD AZIZUR RAHMAN
AEN/INSP DIGHA PATNA

View user's profile
Shared Documents

Joined: May 10, 2011
No. of
Replies: 29

PostPosted: Tue Feb 25, 2014 6:58 pm Back to top

Respected sirs,

Can we think of using mechanised wrenches (used with help of air compressor) to tighten the nuts. I hope by this, tightening will become faster.
            
            
            
- MOHAMMAD AZIZUR RAHMAN AEN/INSP DIGHA PATNA ... 25-02-14

V. B. Sood
Director (B & S)

View user's profile
Shared Documents

Joined:
No. of
Replies: 1644

PostPosted: Wed Feb 26, 2014 5:42 pm Back to top

The issues are all very important:

1. The HSFG bolts shall not be retightened under any circumstances. If the HSFG bolts are found loose, these ought to be replaced by new bolts of same make. In fact, reasons for the looseness might also need investigation.

2. The concept of HSFG bolts was not well understood that is why the instructions were to check the bolts with pre-calibrated torque wrenches. I don't think the HSFG bolts were getting loose in microwave towers also. In fact, it is over 10 years since these were transferred back from BRIs and there might be none looking at the bolts. Instances of problems in these towers have not been reported.

3. The washers are a must to be used with the HSFG bolts to avoid damage to the parent steel material. Proper washers shall be used both under the head and under the nut, one of which can be DTI washer.

4. Torque wrenches normally are either hand operated, hydraulic or pneumatic. These can also be electrical operated. Hand operated wrenches might not be preferred except in very small works. All other types are good and give excellent quality.
            
            
            
- V. B. Sood Director (B & S) ... 26-02-14

MOHAMMAD AZIZUR RAHMAN
AEN/INSP DIGHA PATNA

View user's profile
Shared Documents

Joined: May 10, 2011
No. of
Replies: 29

PostPosted: Thu Feb 27, 2014 8:23 am Back to top

Thank you sir.
            
            
            
- MOHAMMAD AZIZUR RAHMAN AEN/INSP DIGHA PATNA ... 27-02-14
Display posts from previous:      
Post new topicReply to topic
View previous topic View next topic
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum