Pre-fabricated steel components created from accurate structural steel fabrication drawings are key to ensuring efficient and high-quality erection of structures at the construction site. It is this precise, off-site fabrication of thousands of pieces of steel components which creates a competitive advantage of steel construction over concrete buildings.
The use of construction-site fabrication of steel members has long been deemed as producing inferior quality workmanship, as the many operations from surface cleaning, machining, fitting, and finishing lack the controlled environment of fabricators that use shop drawings to create steel assemblies with tight tolerance and quality assurance standards.
The American Institute of Steel Construction (AISC) states that structural steel is the standard against which all other construction methods are measured, and cites these pertinent statistics:
- 3D CAD technology allows the input of erection efficiencies during the design phase saving time and dollars in the construction process.
- typical 5% to 7% overall project cost savings has served as an industry leader and preferred method of construction for over 30 years.
- increased architectural creativity and aesthetics as structural members can be rolled and bent for non-linear structures; and supports large, column-free spans which invite natural lighting and beauty.
- a high strength material excelling concrete in both compression and tension – and has a higher strength to weight ratio over other construction materials.
For these reasons and many others, owners and stakeholders agree that structural steel offers competitive project advantages from design and construction to safety and maintenance. Central to the entire building process is the structural steel fabricator. These shops play an imperative role in the steel supply chain, using advanced CNC machinery and material handling equipment to consistently produce a high-quality product in a controlled environment from accurate steel shop drawings
A&E firms will generally outsource the production of these drawings to services which employ skilled structural steel designers and detailers to ensure the structural engineer’s intentions are reduced to manageable pieces for fabrication and transportation, incorporating detailed symbology with accurate tolerances, and consistently marked pieces for seamless and sequential erection procedures.
In examining the role structural steel fabrication drawings play in successful steel construction projects, a look at the type of information supplied by or needed by four key actors – the structural engineer, CAD detailer, fabricator, and erector – will highlight the significant construction improvements provided by these drawings.
Detailed 3D Models Assists in Engineering Approved Fabrication Drawings
Structural engineers have the dual task of supporting the architectural design on a system-level, focusing on the structural integrity and safety during erection, while keeping in constant view the component-level requirements; long spans of heavy girders and beams capable of modification in the shop, that can be transported to the construction site, and will allow maneuvering into place during erection.
The present trend is a shared 3D model-centric approach to the design process, which places a detailed 3D model at its center, complete with object specific information to be used downstream in all phases of the design-bid process. Within the 3D model, an early ‘design for erection’ consideration is incorporated to manage erection risks.
Design for erection will guard against possible collapse during temporary overloading in the construction phase and includes adding increased structural strength, providing alternative load patterns, and incorporating opportunities for temporary bracing and shoring. The 3D model provides the immeasurable benefit of viewing each element in the context of surrounding members to dramatically reduces erection risks and aide in building a safe and sequential erection procedure.
Structural models shared as a Tekla Structure will provide valuable input into fabrication drawing approval process because it will utilize the precise 3D model geometry and underlying engineering data to generate the additional views and information needed for structural steel fabrication drawings, such as connection size, type, and spacings, type and quantity of welds and bolts, and the dimensions and grade of connection plates.
Critical Role of the Structural Detailer
Bridging the gap from design to erection lies the crucial role of the structural design detailer in creating the structural steel fabrication drawings needed for building erection. To achieve the level of detail steel shop drawings require, a detailer must be educated in structural design and drafting, and have keen industry knowledge of machining processes and construction practices.
Establishing an outsourced partnership with a quality CAD service will give A&E firms a cost-effective solution for fast drawing turn-around and assurance these drawings are constructed under the approval of certified engineers and experienced detailers. From 3D model to detailed shop drawings our technicians are trained to:
- Use of 3D model to extract 2D views and sections which will enforce dimensional integrity and ensures the continuity of engineering changes.
- Increase productivity by utilizing an extensive library of standard connections and commonly used arrangements of stiffeners, plates, welds, and bolts.
- Accurate connection design and detail, including beam-to-column, beam-to-beam, and complex multi-member connections.
- Use of industry standard symbology for welding, dimensioning, and notation.
- Employ structural steel piece and assembly marking guidelines required by erection team at construction.
Steel connections and assemblies modeled by structural detailers as opposed to being independently constructed as 2D orthographic views are needed to support BIM technology projects which provide a clear and timely view of the entire construction sequence, optimizes quantity take-offs and supports facility asset management. This exchange of information which detailers input into the structural steel model allow fabricators to quickly generated BOM’s and order steel much earlier than previous workflows.
Quality Control in Fabrication and Erection Starts with Accurate Drawings
Working from the engineer approved shop drawings, the fabricator must manage construction risk by providing quality structural assemblies from raw steel stock – paying keen attention to poorly administered and untested welds, incomplete fabrications or fabrication errors, and pieces that are not clearly or correctly marked.
An accurate set of structural steel fabrication drawings that comply with the structural design engineering drawings will ensure fabricators use the proper grade and strength of steel, and will aide the erection process by detailing the requirements for lifting and locating each piece, emphasize structurally critical dimensions, and specify the locations of bracing and temporary supports.
Historically, steel erection fatalities have ranked fourth highest in the top 14 economic sectors in the US. Improper use of fall protection is the leading cause of these accidents, yet the collapse of steel structures, whether permanent or temporary, have input into these statistics. Intervention strategies are constantly being implemented to provide insight into the structure’s stability under unforeseen loading during erection.
Steel erection accidents highlight the importance of structural steel fabrication drawings which accurately convey the engineer’s intentions of load bearing and load shedding. Often, several different factors prove to be the culprit in a collapse, but reducing or removing engineering and fabrication errors will certainly help in preventing tragedies. At this final stage of erection, if the 3D model is used in the design phase, which enables engineering analysis and simulations of structural loading and stresses, a major portion of these fatal accidents are avoided.
Accurate structural steel fabrication drawings contribute to making steel construction an industry leader in building innovative and safe modern structures. Trust our firm which has completed all manner of steel construction drawings for many different types of projects, both large and small – from connection details to fabrication shop drawings and erection drawings.