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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Geoprofessions | 4/6 | https://en.wikipedia.org/wiki/Geoprofessions | reference | science, encyclopedia | 2026-05-05T03:47:44.331397+00:00 | kb-cron |
== Construction-materials engineering and testing (CoMET) == Construction-materials engineering and testing (CoMET) comprises an array of licensed-engineer-directed professional services applied principally for purposes of construction quality assurance and quality control. CoMET services commonly are provided as a separate discipline by firms that also practice geotechnical engineering, possibly among other geoprofessional disciplines. The geoprofessional-service industry has evolved in this manner because geotechnical engineering employs the observational method. Karl von Terzaghi and Ralph B. Peck – the creators of modern geotechnical engineering – used the observational method and multiple working hypotheses to expedite and economize the subsurface-exploration process, by using sampling and testing to form a judgment about subsurface conditions, and then observing excavated conditions and materials to confirm or modify those judgments and related recommendations, and then finalize them. To economize still further, geoprofessionals educated and trained paraprofessionals to represent them on site (hence the term "field representative"), especially to apply their judgment (much as a geotechnical engineer would) in comparing observed conditions with those the geotechnical engineer believed would exist. Over time, geotechnical engineers expanded their CoMET services by providing the additional education and training their field representatives needed to evaluate constructors' attainment of conditions commonly specified by geoprofessionals; e.g., subsurface preparation for foundations of buildings, roadways, and other structures; materials used for subgrade, subbase, and base purposes; site grading; construction of earthen structures (earth dams, levees, reservoirs, landfills, et al.) and earth-retaining structures (e.g., retaining walls); and so on. Because many of the materials involved, such as concrete, are used in other elements of construction projects and structures, geoprofessional firms expanded their field representatives' skill sets still more, to encompass observation and testing of numerous additional materials (e.g., reinforced concrete, structural steel, masonry, wood, and fireproofing), processes (e.g., cutting and filling and rebar placement), and outcomes (e.g., the effectiveness of welds). Laboratory services are a common element of many CoMET operations. Also operating under the direction of a licensed engineer, they are applied in geotechnical engineering to evaluate subsurface-material samples. In overall CoMET operations, laboratories operate with the equipment and personnel required to evaluate a variety of construction materials. CoMET services applied to evaluate the actual composition of a site's subsurface are part of a complete geotechnical engineering service. For purposes of short-term economy, however, some owners select a firm not associated with the geotechnical engineer of record to provide these and all other CoMET services. This approach precludes the geotechnical engineer of record from providing a complete service. It also aggravates risk, because the individuals engaged to evaluate actual subsurface conditions are not "briefed" by the geotechnical engineer of record before they go to the project site and seldom communicate with the geotechnical engineer of record when they discern differences, in large part because the firm associated with the geotechnical engineer of record is regarded as a competitor of the firm employing the field representatives. In some cases, the field representatives in question lack the specific project background information and/or the education and training required to discern those differences. CoMET services applied to evaluate constructor's attainment of specified conditions take the form of quality-assurance (QA) or quality-control (QC) services. QA services are performed directly or indirectly for the owner. The owner specifies the nature and extent of QA services that the owner believes is appropriate. Some owners specify none at all or only those that may be required by law. Those required by law are imposed via a jurisdiction's building code. Almost all U.S. jurisdictions base their building codes on "model codes" developed by associations of building officials. The International Code Council (ICC) is the most prominent of these groups and its International Building Code (IBC) is the most commonly used model. As a result, many jurisdictions now require IBC "Special Inspection," a term defined by the IBC as "the required examination of the materials, installation, fabrication, erection, or placement of components and connections requiring special expertise to ensure compliance with approved construction documents and referenced standards." Special Inspection requirements vary from jurisdiction to jurisdiction based on the provisions adopted by the local building official. While some of the services involved may be similar to or the same as conventional CoMET services, Special Inspection is handled differently. Most commonly, the owner or the owner's agent is required to retain a building-official-approved Special Inspection-services provider. Special Inspection is often required to obtain a certificate of occupancy. QC services are those applied by or on behalf of a constructor to ensure the constructor has attained conditions the constructor has contractually agreed to attain. Most CoMET consultants are engaged far more to provide QA services than QC services. Many CoMET procedures are specified in standards developed by standards-developing organizations (SDOs) such as the American Society of Civil Engineers (ASCE), ASTM International, and American Concrete Institute (ACI), using standards-development protocols approved by the American National Standards Institute (ANSI) and/or the International Organization for Standardization (ISO). All such standards identify what is minimally required to conform. Likewise, several organizations have developed programs to accredit CoMET field and laboratory services to perform certain types of testing and inspection. Some of these programs are more comprehensive than others; e.g., requiring regular calibration of equipment, participation in proficiency testing programs, and implementation and documentation of a (quality) management system to demonstrate technical competence. As with all such programs, of course, accreditation identifies what is least acceptable. Many CoMET laboratories go far beyond minimum requirements in an effort to attain higher levels of quality. A variety of organizations – including local building departments – have developed personnel-certification protocols and requirements. In many jurisdictions, only appropriately certified individuals are permitted to perform certain evaluations. Individuals typically are required to meet certain prerequisites for certification and must pass examinations, in some cases involving performance observation in the field. The prerequisite for higher degrees of certification often include a requirement that the individual has met requirements for a lower degree of certification (e.g., Soils Technician I is in some cases a prerequisite for Soils Technician II). Field representatives are sometimes referred to as "soil testers," "technicians," "technicians/technologists," or "engineering technicians." The Geoprofessional Business Association developed the term "field representative" to encompass all the many types of paraprofessionals involved (e.g., those involved with specific types of materials, such as reinforced concrete, soil, or steel; those who observe or inspect processes or conditions, such as welding inspectors, caisson inspectors, and foundation inspectors), and especially to underscore their significant, mutual responsibility, that purpose titles such as "technician" fail to signify. In fact, the engineers who direct CoMET operations are personally and professionally responsible and liable for their field representatives' acts and statements while representing the engineer on site. Especially because CoMET consultants have more hands-on experience with construction activities than many other design-team members, many owners involve them (among other geoprofessionals) from the outset of a project, during the design phase, to help the owner and/or design team members develop technical specifications and establish testing and inspection requirements, instrumentation requirements and procedures, and observation programs. Geotechnical engineers employ CoMET services during the earliest stages of a project, to oversee subsurface sampling procedures, such as drilling.