Review comments on canal bridge drawings

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Review observations and comments on canal bridge drawings

Content Brief:

  • Review comments on canal bridge drawings: This content pertains to the Review observations and comments on canal minor bridge GAD drawings. These observations are made by the IE following the concessionaire’s submission of GAD drawings.
  • The details and letters contain the following information:
  • Canal minor bridge General arrangement drawings submission.
  • Review observations on drawings.
  • The observations, including the clarification and justification needed on the following

a. General arrangement details of Existing and proposed span details.

b. Geotechnical technical investigation report

C. Hydrological data, hydraulic calculations.

d. Type of widening respect to CA and proposal.

e. Founding levels of piers

f. Canal lining and protection measures

g. About the bearings

h. Method statement for work when close to or near existing bridge.

  • Additionally, there are elements that are not consistent with the Concession Agreement (CA).
  • Finally, provide IE feedback in line with the review.

   Review comments on canal bridge drawings

Case-1: Letter on Review observations and comments on GAD Drawings of Canal Minor Bridge.

To

The concessionaire

Subject: Comments on Canal Minor Bridges Km.11+745-reg.

Dear sir,

With reference to the review of Final drawings and Designs for the Canal Minor Bridges, in the Project Highway our Sr. Bridge Design Engineer has reviewed the following drawings and designs and consecutively made his observations

 Design Note on Canal Minor Bridge at Ch. 11+745

  • In Schedule-A of CA the existing bridge is shows as 4*9 RCC slab whereas in Schedule-B the existing bridge is shown as 2*18 m. The GAD shows four spans but no details of existing bridge is shown like span arrangement, distance from proposed structure, FRI, vertical clearance from FSL, etc.
  • The proposed total length of the bridge as per CA is 36 m whereas Concessionaire has proposed a total length of 53.1 m (6*8.85 m). Concessionaire to clarify reasons for the increased length.
  • Hydraulic calculations have not been included in the design note. Concessionaire is required to design canal bridges as per hydraulic requirement of the irrigation authority as well as get the GAD approved by the highway authority
  • Geotechnical investigation report is not included. SBC and settlement calculations should be included.
  • Schedule-B of CA indicates concentric widening with total width of 21 m. Concessionaire has proposal eccentric widening by retaining the existing bridge and constructing a new parallel bridge with a carriageway of 9 m and a total width of 11.5m. Is this in accordance with the provision of CA?
  • Concessionaire may clarify why founding levels of piers P1 and P5 (117.8 m) are kept higher than piers P2-P4 (114.95m)
  • Details of existing canal lining and floor details with proposals if any should be shown on the drawings.
  • Bed level (BED LVL) may be shown correctly in the sectional elevation.
  • .The design note shows elastormeric bearings whereas drawings show tar paper.

So, you are being instructed to comply his recommendations and submit the final drawings and designs for our necessary certifications.

Thanking you.

Case-2: Letter on Review observations and comments on GAD Drawings for Canal Minor Bridge.

To

The concessionaire

Subject:-Review comments on canal bridge drawings (minor bridge) at ch:- 20+919-reg

Dear Sir,

The following observations are noted there in 20+919 irrigation canal Minor Bridge

  1. Irrigation department permission is required.
  2. Design Report is not received by us to get the review done.
  3. As per Concession Agreement Vol-1, page no. 204, proposed over width shall be 21.00 mts but in submitted Drawing it is not fulfilling the agreement condition. Kindly explain.
  4. Hydrological data has not been received by us.
  5. Bore hole data shall be mentioned in GAD.
  6. Existing is 5 Spans where as proposed is proposed is 7 Spans. Please Explain.

Thanking you

Case-3: Letter on Review comments on GAD Drawings of Canal Minor Bridge.

To

The Concessionaire

Subject: Review comments on canal bridge drawings at Km.56+919-reg

Dear Sir,

With reference to the review of Final drawings and Designs for the Canal Miror Bridge km.20+919, in the Project Highway our Sr. Bridge Design Engineer has reviewed the drawings and designs and consecutively made his observations

(A) Canal Minor Bridge at Km.20-919,

  1. The proposed total length of the bridge as per Schedule B of CA is 46.15m whereas Concessionaire has proposed a total length of 63.15 (1*9.7+5*8.75+1*9.7) noted that Concessionaire has proposed this span arrangement for Concessionaire’ s ease of construction and own convenance and not warranted by any specific technical requirement. The width of structure does not conform to Schedule D of CA
  2. As per Schedule B of CA the new bridge is to be provided on right side of alignment but it has shown on the left side. Why?
  3. As per Schedule B of CA the new widening width should be 11.5 m but it has proposed 9.75 n. Also total width to be provided is 21 im but it has proposed 20.74 m (9.75 +3.76+723). Please clarify
  4. The flooring and side slope arrangement is to be provided to avoid any scouring of the foundations and as per requirement of the irrigation authority.
  5. The methods statement should provide for precautions while working close to sting structure.
  6. Drawing of solid slab not submitted.
  7. The note about lap length is not only worded differently on the various sheets but the requirement of maximum lap percentage is also different-it is advisable to use the same language.
  8. Dry G-01 Sht 2/2

i. Note 7: The specification of 40 mm layer is not clear

ii. Note 8: Does the Concessionaire propose to conduct further geo technical investigations? Please specify how the SBC to be verified

iii. Note 9 The proposed piers are to be constructed in line with existing piers and adjustment to abutment location should be avoided.

iv. Note 11: The extent of backfilling to be marked in GAD and abutment drawing

v. Note 18: See note 9 i below.

vi. Note 19: Delete the word “DEVELOPMENT LENGTH as this pertains to design office requirements.

vii. Note 32: Provision of buried type expansion joint should be reviewed as it is not recommended for 20 mm gap shown in the drawing

viii. Note on type of bearings should be included

9. Drg E-01 Sh 1/2

i. Note 6: Review and modify the note about lap length in conjunction with Note 18 of GAD Sht.1.

10. Org. E-02 Sht 2/4

i. Note 5: Delete the word “DEVELOPMENT LENGTH

So, you are being instructed to comply with his recommendations and submit the final drawings and designs for our necessary certifications.

Thanking you

Letter on  review and approval of  Canal Bridge drawings subject to general condition

To

The Concessionaire

Subject: comments on compliance report to IE review observations.

Ref: As above

Dear Sir,

Under the above cited subject and your above reference letter, the Drawings submitted, are being reviewed by us and we have got no objection in accepting the same following the compliances of under mentioned observation.

“If there is any variation between the GFC issued and the site data, then the same must be notified to us immediately, for further review” and provide the safety precaution signs for the existing bridge on RHS.

Thanking you

Review of Deck Slab Drawings of Canal Minor Bridge

To

The Concessionaire

Subject: Review of Deck Slab Drawings of Canal Minor Bridge at Ch. 10-919-Regarding

Ref No: Your Letter submission

Dear Sir,

With reference to your submissions, the drawings were reviewed as per clause 12.3 of CA and we don’t have any further comments. Please find the signed copy of drawings.

This is for your information.

Thanking you,

Letter on Request for submission of SBC of soils at abutments of canal

To

The Concessionaire

Subject: SBC of Soil for Abutments (A1&A2) Canal Bridges of following chainages 1.  Ch 20+919, 2. Ch 41+805 and 3.Ch.41+745-reg

Dear Sir,

With reference to the above mentioned subject, please submit the SBC of Soil results (original copy) for Abutments (A1&A2) for our review and Analysis.

Thanking you

Letter on Ambiguity in Existing structures widths of Canal Minor Bridges widening and strengthening

To

The Concessionaire

Subject: Existing structures widths of Canal Minor Bridges at Ch 10+919, Ch 14+745 and Ch 14+805-Reg

Ref No: Your Letter submission

Dear Sir,

With reference to your submissions, reviews have been done as per Clause 12.3 of CA and please find our comments.

SI. No Location of Canal Bridge Deck width as per C.A Deck width as per Site Condition Required Deck Width Required widening (Extended) Width Remarks
1 Km 10+919 8.500 m 7.100m 10.25 m 3.150m 10.25=9.75+0.50
2 Km 14+74 8.500m 8.500m 10.25 m 1.750m 10.25=9.75+0.50
3 Km 14+805 8.500m 7.750m 10.25 m 2.500m 10.25=9.75+0.50

From the above data it is Clear that, vide Clause 7.3 (iv) (b) of Four Lanning Manual is not applicable to this case as mentioned in your letter. The Clause 10 (ii) or (viii) of Schedule B of C.A will applicable to this case according to the Condition Survey for the above Canal Bridges.

CA Clause for structures as per Schedule-B for ready reference

Structures Following guidelines shall be followed in design and construction of bridges and other structures:

Clause 10 (ii) of Schedule B of C.A:

 (ii) The existing structures shall be widened i.e. extended to match the new road cross sections.

Clause 10 (viii) of Schedule B of C.A:

The existing bridges which are proposed to be retained, rehabilitation of foundation, substructure and superstructure of any kind including but not limited to repairing of honeycomb, spalled concrete, corroded and exposed reinforcement, filling of cracks by epoxy injection, removal of vegetation, replacement of bearings, expansion joints, profile correction course pier protection, dismantling of existing parapets/railings and replacement of the same with crash barriers shall be done by the Concessionaire under the Contract.

Cross sectional elements for structures shall follow the drawings of structures in the drawing volume. Ali the bridges, cross-drainage structures and other structures shall be designed in accordance with the design standards set out in Schedule D. All the bridges cross drainage structures and any other structure for the widened highway shall be designed for six-lane capacity unless noted otherwise. The existing retainable structures shall be widened (extended) to match with the new road cross sections as required.

The approaches to the bridges, flyovers underpasses and any other structure shall be kept equal to that of the bridge cross section for that portion and the approach shall be merged with the normal-road cross section with suitable transition length.

Width of Structures

Width of the culverts and bridges shall be adopted as below

  1. iv) Existing bridges: Components like bearings, expansion joints, railings, crash barriers, wearing surface, etc., which are not in sound condition, shall be replaced. Minor non-structural works shall be suitably repaired as per Para 7.22(Structures Repair and strengthening).

This is for your information and compliance.

Thanking you,

Subsequent correspondence on Ambiguity in Existing structures widths of Canal Minor Bridges widening and strengthening and conclusion with conditions of Change of scope provisions of CA

To

The Concessionaire

Subject: Existing structures widths of Canal Minor Bridges at Ch 10+919, Ch 14+745 and Ch 14+805-reg

Dear Sir,

With reference to your submissions, reviews have been done as per Clause 12.3 of CA and please find our Sr Bridge Design Engineer comments.

  1. Concessionaire may note that the IE is only reviewing the drawings as per clause 12.3 of the CA. The IE has no authority to give approval to drawings as per CA. The Concessionaire is to take notice of this once and for all and not refer to approvals in future. Concessionaire may also read Clause 12.3 (e) of the CA regarding the obligations and liabilities of the Concessionaire.
  2. The width of existing bridges is to be adopted as per clause 7.3 (iv) of the four lane manual.
  3. As per clause 10 (viii) of Sch. B of the CA the existing retainable structures shall be widened to match with new cross sections.
  4. Fig 7.4 (b) of the four laning manual pertains to bridges with well/ pile foundation and hence is not applicable in the instant case.
  5. The Concessionaire should read Article 8 – Disclaimer of the CA; specifically about the accuracy/ completeness of the information provided by the Government.
  6. The comments of IE furnished vide letter no. As above remain unchanged.
  7. Clause 16.2.1 (i.e. procedure for Change of Scope: in the event of the highway authority determining that a change of scope is necessary, it shall issue to the Concessionaire a notice specifying in reasonable detail the works and services contemplated thereunder (the “Change of Scope Notice)) of the CA does not fall in the purview of the IE.

This is for your information and compliance.

Note to a visitor about the Review comments on canal bridge drawings

It is that a few important and mandatory aspects are only discussed herewith. Kindly note that the above Review observations and comments on canal bridge drawings are considered examples. You may adopt the gist of the subject and change it to suit the current need. And before using this content in your letter  drafting, you need to ensure the specific CA Contractual conditions and other aspects, etc.

It is suggested to read article about Review on major bridge GAD drawings on Highway project

Also, read about the highway Review observations on MNB drawings and site Instruction letter on structure construction works. 

Additionally, you can find various sample draft formats for highway operation and maintenance correspondence.

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