Understanding responsibilities
The US-headquartered American Concrete Institute (ACI)* outlines the duties of each stakeholder in the design, fabrication and installation of precast concrete projects.
01 November 2020
As precast concrete projects increase in popularity in the Gulf, it is important to understand how a team needs to work together for a successful project. These projects can be a balancing act, requiring collaboration among all the participants.
Hence, it is crucial to establish the scope of the precast concrete work and define the responsibilities of each party at an early stage.
Outlined below are the responsibilities of each of the stakeholders in a project:
Owner
The owner’s project requirements should be to define the overall goals with regard to building type, intended use, project delivery method, budget, and schedule. He then enters into a contract with a licensed design professional. These contract documents can then be used to obtain bids by a construction manager or general contractor.
The owner should allow sufficient time in the various phases of the construction process to achieve the necessary review, coordination, and implementation of the project requirements. Late changes will likely add cost and schedule delays.
Architect
The architect develops the project’s design concept, establishes overall structure geometry, selects the precast materials for appearance and function, provides details and tolerances for proper material interfacing and weatherproofing, specifies performance and quality characteristics, and specifies inspection and testing requirements in the contract documents.
The architect and structural engineer of record then have a responsibility to coordinate the design aspects of the architectural precast concrete units. State and local building codes must be met by the architect.
Structural engineer of record
The structural engineer of record has the responsibility of including in the contract documents any delegated design responsibilities and to show all relevant design information, which is in keeping with state or local city building codes, which typically references the ACI 318 standard for concrete design. When interfacing with the specialty structural engineers, the structural engineer of record should be the one who delineates responsibility for the various structural requirements. He has responsibility for specifying the design criteria for the precast concrete elements and for describing the intended load paths. He should define the type of loading to be applied to the units and to the structure, as well as provide information and applicable codes, including wind, seismic, and blast design when applicable.
General contractor
The general contractor/construction manager is hired by the owner to manage and administer the construction. He has the responsibility to implement the design of the contract documents, which includes furnishing materials, equipment, and labour; maintaining specific quality and schedule requirements; and coordinating all trades. The general contractor is responsible for construction means, methods, techniques, sequences, site access, and construction procedures.
Precaster
Normally, the precaster is a subcontractor to the general contractor. The responsibilities of the precaster should be clearly defined in the contract between the precaster and the general contractor. Most precasters accept responsibility for preparation of component design and precast shopdrawings. He generally accepts responsibility for design and detailing of connections to the structure and the forces acting on the connections, determined from global loads defined by the structural engineer of record.
Specialty structural engineer
The specialty structural engineer is a consultant to the precaster and responsible for the design of the precast components, connections, and structural systems. The specialty structural engineer is responsible for reviewing the contract documents to understand the responsibilities assigned and the design criteria set forth by the structural engineer of record.
Erector responsibilities
The responsibility for field erection of the precast concrete units may be part of the precaster’s contract, to be performed by the precaster’s own crews or subcontracted to specialised precast erection firms, or it may be assigned separately by the general contractor/construction manager.
When the precaster is responsible, a meeting should be held between the specialty structural engineer and the erector before erection commences. This meeting should discuss the sequence and details of erecting the precast structure and to plan for the safe erection of the structure at various stages until fully completed. The erector should be responsible for handling and bracing all components that comprise the precast structure, whereas the general contractor/construction manager and structural engineer of record are responsible for the temporary stability of structures of other materials that support precast concrete components.
The ACI’s “Guide for Design and Construction Responsibilities for Architectural Precast Concrete (533.1R-20)” provides guidance on the defining scopes of work and responsibilities, including a chapter reference guide that directs users to relevant sections based on responsibilities and bid process.
* The ACI, which has a regional office in Dubai, UAE, is a leading authority for the development, dissemination, and adoption of its consensus-based standards, technical resources, educational and training programmes, certification programmes, and proven expertise in concrete design, construction, and materials.
