1. General
1.0.1 Purpose
The provisions further define the purpose of development of this standard, namely, "to strengthen the quality management for highway engineering, unify the quality inspection and evaluation standards for highway engineering and ensure the engineering quality", so that the quality inspection and evaluation of the construction items form an organic whole. Moreover, its contained technical content is still the quality inspection and evaluation standards for highway engineering.
1.0.2 Scope of application
Since the Ministry of Transport of the People's Republic of China has been specifically developed quality inspection and evaluation standards for large and medium repair projects, so this Standards no longer requires large and medium repair projects taking this as reference. According to the newly revised "Technical Standard of Highway Engineering", scope of application of this Standard has been extended to 4th-grade highway. This Standard does not explicitly specify the applicability of urban highway and other special highway.
Scope of application of Environmental engineering and electromechanical engineering comply with their own specific regulations.
This Standard is not only applicable to the project supervision of the quality supervision departments, project supervision and construction unit specified in the original standard (JTJ 071-98), but also applicable to that of the construction unit.
This Standard specifies, from the quality management system aspect, such quality management process as engineering quality inspection, identification, spot test authentication, self-examination and self-control conducted by quality supervision department, quality inspection mechanism, construction unit, project supervision unit and construction unit.
Article 1.0.7 of the original standard (JTJ 071-98) specifies some requirements for the "quality management for highway engineering", but in consideration of this content have been specified explicitly in the construction administrative laws for highway engineering issued in the last few years, this revision will no longer cover them.
1.0.3 Relationship with the relevant codes
This Standard notes the coordination with the relevant codes, but there may be some inconsistency. When this occurs, it shall be carried out subject to this standard generally. New codes shall consider fully the relevant regulations of this Standard in the revision procedure, such as the inconsistent still exist, which may be used by referring to the newly promulgated standard.
This Standard cannot replace all the technical standards, so the highway construction, quality management, inspection and evaluation shall not only comply with this Standard, but shall also comply with the relevant codes issued by the ministry and nation.
1.0.4 Special projects
It proposes possible solutions to the technology disputes and problems in the implementation process of this Standard.
This Standard is mandatory technical regulation or document, so it must be carefully implemented. However, the standard and code are technical experience summary with universality; for the large bridges and long tunnel projects, or taking into account the geography, soil, hydrology and other special circumstances and technical development, or due to the adoption of new materials, new process and new structure, this Standard lacks appropriate technical requirements, it may refer to the relevant standards, and put forward feasible the solution in the premise of guaranteeing the quality of the project, and then, report to the competent department for approval according to the relevant provisions.
2. Terms
The major specific terminologies appear on this Standard refers to national standard GB 50300 "Uniform Standards for Acceptance of Construction Quality of Construction Projects". Other highway engineering terminologies may refer to the relevant national standards, professional standards and particularly the construction technical specification.
3. Engineering Quality Evaluation
Adjust and enrich Article 1.0.2, 1.0.3, 1.0.4 and 1.0.5 of the original standard (JTJ 071-98), and list them independently as one chapter to further specify the content, method and procedure of quality evaluation.
3.1 General rules
3.1.1~3.1.3 are general rules, and the quality evaluation for highway engineering includes three parts: items segregation, quality scoring and quality grade evaluation.
Engineering quality evaluation grade is classified into qualified and unqualified ones, but cancel the fine grade, so as to be concord with the newly-promulgated "Completion and Handover Acceptance Methods for Highway Engineering".
3.1.4 This revision further defines the role and accomplished work of construction unit, project supervision and construction unit for highway engineering in the quality inspection and evaluation process for highway engineering, so as to strive to concord with the newly-promulgated "Completion and Handover Acceptance Methods for Highway Engineering" and explicitly specify that this Standard is the reference for quality supervision department and quality inspection mechanism in the process of quality inspection for highway engineering.
3.2 Engineering quality scoring
This Section lists quality scoring method of sub-divisional work, scoring method of partitioned project and unit project, while the scoring method of the engineering quality for contracted section and construction project is calculated in accordance with the new "Completion and Handover Acceptance Methods for Highway Engineering".
3.2.1 Quality scoring of sub-divisional work
Quality inspection and evaluation of sub-divisional work is the basis of quality evaluation for construction project. The quality inspection and evaluation of sub-divisional work must be carried out in the premise of meeting the basic requirements, without serious appearance defect and quality assurance information is true and complete basically.
This revision increases the minimum requirements for qualification rate and specified extreme value of dominant observed items in the sub-divisional work, mainly aiming at ensuring the engineering structure safety and functions of use. When the qualification rate of the dominant item does not comply with 90% of the specified value, or the single-point detection value exceeds the extreme value, it must be reworked.
The specified extreme value of the observed items refers to the extreme that no single testing value could break; when it does not meet the requirements, the observed items are unqualified. Therefore, the original "extreme value" specified in the pavement structure layer thickness is replaced by "single-point acceptance value", which is only used to calculate the qualification rate.
It increases that the qualification rate of dominant items for electromechanical engineering must be as high as 100%.
In consideration of that the quality requirements of bridge hardware processed and manufactured by the plant is higher than that for the civil engineering, so the text specifies that the qualification rate of dominant items of bridge hardware processed and manufactured by the plant is no less than 95%; the qualified scores is also increased to 90 scores accordingly when evaluating the quality grade for sub-divisional work.
The subgrade pavement compaction degree, deflection, pavement structure layer thickness, cement concrete compression resistant and bending resistance and semi-rigid material strength evaluated by statistical method in the original standard are all used as dominant items.
Compactness evaluation points are: ① to control the lower confidence limit of average compaction degree to ensure the overall level; ② to specify that the single-point extreme value shall not exceed a given value to prevent local hidden trouble; ③ to specify the point-deduction limits to distinguish the quality.
The pavement thickness is an important index of quality and cost, which can not only provide the contractors with jerry-built possible opportunities, but shall also consider the thickness deviation at normal construction condition; the lower confidence limit of average value is used as a negative index and single-point acceptance value is used as a point-deduction index.
The scores of sub-divisional work are calculated by observed items with weighted average method, and the sub-divisional work scoring is the scores of the sub-divisional work subtracting the appearance defect point-deduction and inadequate information point-deduction. Change the specified scores of the original observed items into the weight number, so as to be concord with the new "Completion and Handover Acceptance Methods for Highway Engineering" on the one hand, and on the other hand, solve the scoring problems when the increasing observed items or observed items is incomplete.
(1) The basic requirements are provided with quality veto power; when they are not competent by inspection, it shall not carry out engineering quality inspection and evaluation. It is proposed that the basic requirements shall establish contact with the scoring, but it is difficult to find out a quantitative ways to contact. Whether the construction unit could construct by the basic requirements mainly depends on the strict control of the supervisor. If the construction unit does not strictly follow the basic requirements, it will not only inevitably be reflected in the quality index of the engineering, but also shall be incarnated in scoring and point-deduction.
(2) The calculation formulas of qualification rate and scoring for the observed items are separate: first, specify the calculation formula of the qualification rate; second, avoid using the qualification rate as the point value directly, so the concept and meaning are much clearer.
The observed items are generally scoring by the qualification rate, but the compaction degree, deflection, pavement thickness, cement concrete compression resistance, bending resistance and semi-rigid material strength of subgrade pavement are evaluated by mathematical statistics method. The relevant methods are included in the appendix.
(3) It was proposed that the appearance point-deduction is greatly affected by the human factor, so point-deduction shall be further refined. This revision further makes some adjustment in chapters according to the point-deduction refinement requirements; there are some solutions to the human factor: first, the personnel for inspection and evaluation shall avoid bring in emotional color, but to be objective and fair; second, when there are disputes for distinguishing some appearance defects, it may make first pilot, in order to understand the relative unity.
In addition, when making the evaluation, the appearance point-deduction inspection shall conduct a comprehensive inspection for full line and all the successive terms, not just randomly inspect them thereof.
3.2.2 Quality scoring for partitioned project and unit project
When adopting weighted average calculation, the main engineering and general engineering are respectively given with 2 and 1 weight, in order to pay more attention to and ensure the quality of main engineering.
3.2.3 The quality scoring for contracted section and construction project engineering
The new "Completion and Handover Acceptance Methods for Highway Engineering" makes important modification for the standard, and the handover acceptance is made according to construction contracted section, and it also adds the quality evaluation for the contracted section, which is specified to be calculated thereby in this revision. "Completion and Handover Acceptance Methods for Highway Engineering" specifies:
Quality scoring for construction contracted section engineering adopts weighted average containing the quality scoring of various unit projects. Namely:
Quality scoring value for construction and workshop section engineering =∑(quality scoring value of unit project × investment cost of that unit project) / gross investment of contracted section
Quality scoring value for engineering project =∑(quality scoring value of contracted section engineering × investment cost of that contracted section) / ∑ investment cost of the construction contracted section
3.3 Engineering quality grade evaluation
It is necessary to expound the quality grade evaluation for the sub-division, sub-section, contracted section and construction item in different items.
3.3.1 With the rapid development of highway engineering construction in recent years, there is a general increase in quality awareness, so the corresponding construction equipment and construction technology have markedly improved, and higher requirements have been put forwards for the highway engineering quality; after extensively soliciting expert opinions, the acceptable quality level (AQL) of sub-divisional work may be mounted up to 75 points, and the AQL of the electromechanical engineering and sub-divisional work for bridge hardware processed and manufactured by the plant will be mounted up to 90 points.
The original standard "unqualified sub-divisional work inspected and evaluated by the quality supervision department" shall re-evaluate the quality grade of strengthening, reinforcement or rework no matter who evaluate the unqualified sub-divisional work. As the fine grade is cancelled when making handover acceptance, the original "can only be re-evaluated as qualified" is replaced by "the quality grade may be re-evaluated, but the partitioned project scoring value shall be calculated by 90% of the re-evaluating scores", that is, when calculating the subsidiary partitioned project scoring value, only 90% of the re-evaluating scores of the sub-divisional work is used in the calculation.
4. Subgrade Earthwork
4.1 General rules
4.1.1 As for the theoretic value or permissible variation of the observed items technical index for earthwork subgrade and stonework subgrade, this Standard and other relevant codes mostly set the express highway, arterial road and other highways (refers to second grade and below highway) into two steps, whereas the newly-promulgated "Technical Standard of Highway Engineering" (JTG B01-2004) improves the compaction degree index of the subgrade, and classify the subgrade compaction degree into three steps according to express highway, arterial highway, secondary road, 3rd and 4th-grade highway, so this revision will also set the subgrade according to the three steps, while other indexes are still set by two steps.
