Proposal For Change Of DBM Crust Thickness

Table of Contents

Letter on proposal for change of DBM Crust thickness

Content Brief:

Letter on proposal for change or modification of DBM Crust thickness: This content pertains to the review observations on the proposal to change the specifications of the bituminous components of DBM and BC. And offer comments upon the concessionaire’s proposal by the independent engineer.
These observations of IE are followed by the concessionaire’s submission. And intimate the concessionaire through a letter of IE’s findings and observations.
The following content includes an approval or denial of permits with site, financial, environmental, and legal-specific reviews, terms, and conditions.
This content also includes the pavement composition for new construction/reconstruction/realignment as per CA.

CA provisions regard Pavement composition for new construction/reconstruction/realignment.

As per CA Schedule B, Development of the Project Highway, the pavement composition for new construction/reconstruction/realignment is as follows:.
The pavement composition shall be designed as per IRC: 37 and for a life of 15 years. The minimum composition of the new flexible pavement shall be as shown in Table B-3 below, which is based on the subgrade CBR value (4-day soaked value) at 97% modified Proctor density.
The indicated pavement composition is for the purpose of guidance alone. Any additional thickness in the design over that indicated in the bidding documents shall not constitute a change in scope of work nor qualify for a variation order.

Table B-3: Composition of new flexible pavement for main carriageway

Chainage		Design Traffic (MSA)	Proposed Pavement Thickness (mm)					Remarks
From	To	Design Traffic (MSA)	Wearing course BC (mm)	Binder course DBM (mm)	Granular base WMM (mm)	Granular Sub-base GSB (mm)	Total (mm)	Remarks
00.000	10.000	65	40	125	250	200	615	New Construction
10.000	20.000	55	40	120	250	200	610	Reconstruction
20.000	30.000	35	40	105	250	200	595	Realignment
40.000	60.000	25	40	100	250	200	590	Bypass

Table B-4: Composition of new flexible pavement for main carriageway

Chainage		Proposed Pavement Thickness (mm)		Remarks
From	To	Wearing course BC (mm)	Binder course DBM (mm)	Remarks
30.000	40.000	40	105	Overlay portion

Letter on proposal for change of DBM Crust thickness

The Concessionaire

Subject: Proposal for change or modification of DBM works of the project highway-reg

Dear Sir,

In connection with the proposal for changing the specifications of the following bituminous components as proposed in the agreement tables B-3 and B-4 as highlighted above. i.e. From km. 20+000 to km. 30+000 As per CA table B-4, new pavement. And,From km. 30+000 to 40+000 as per CA table B-4 Overlay thickness.

Proposal by the Concessionaire:-

Reducing DBM thickness from 105 mm to 100 mm.
Increasing BC thickness from 40 mm to 45 min

(Based on the improved subgrade CBR (10%) in comparison to the designed subgrade CBR (8%))

We have completed our review and have no objection to allowing you to follow the new proposed composition based on the following terms and conditions.

If it is found anywhere in the aforesaid patch, that the subgrade CBR is less than 10%, then you have to follow the original proposal of the agreement.
Regular, random sample collection and following soaked CBR tests are to be taken in the presence of IE’s representatives.
The laying must be in full width only.
The surface regularities must be improved.

Moreover, it is allowing you to follow the new proposed composition as cited upon the above conditions without any financial implications to the highway authority.

These are for your information and necessary actions.

A note to the visitor about the letter on proposal for change of DBM Crust thickness

Please note that the concession agreement for the DBFOT project under the PPP mode serves as an example of the aforementioned contractual conditions. For the period 2016–2018,

Afterwards, make sure to make the necessary modifications to the existing contractual conditions. Write a letter that aligns with the concession agreement applicable to the particular project.

It is that a few important and mandatory aspects are only discussed herewith. Kindly note that the above Letter on Proposal for Modification of DBM Crust Thickness 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 draughting, you need to ensure the specific material, other aspects, etc.

Also read the reconstruction methods of carriageway and the site instruction letter notice on various issues of ongoing DBM construction works:

You can find various sample draft formats for highway construction phase, operation, and maintenance correspondence.