StructAI generates a preliminary structural sizing report structured across six sections. The first is a member sizing section that derives indicative dimensions for your primary structural elements — beams, columns, slabs, foundations, or roof structures — using span-to-depth ratios and simplified design approaches drawn from the applicable design code. The second is a load analysis section that builds up the characteristic loads from first principles, applies the relevant load combinations from your selected code, and derives the design load on each member. The third is a foundation design section recommending a foundation type based on your ground conditions, sizing the footings for the column loads, and flagging geotechnical investigation requirements. The fourth is a material specifications section defining concrete classes, reinforcement grades, cover requirements, and durability specifications for your country's climate and exposure conditions. The fifth is a design checks section performing preliminary verification against bending, shear, deflection, vibration, and fire resistance criteria. The sixth is an engineering notes section covering key assumptions, critical design issues, alternative structural schemes, specialist studies required, and an indicative structural frame cost per square metre for your country. The difference from a structural engineer's output is significant and should not be understated. A structural engineer performs rigorous calculations using actual soil investigation data, detailed architectural drawings, site-specific wind and seismic data, and the full complexity of connection design and construction detailing. Their output carries professional indemnity insurance and statutory sign-off. StructAI performs simplified preliminary calculations using assumed inputs, published span-to-depth rules, and conservative defaults. The output is appropriate for early-stage feasibility, cost planning, and design brief preparation — not for construction.

StructAI handles eight structural element types. Beams — including simply supported, continuous, and cantilever configurations in RC, steel, timber, or composite. Columns — sizing for axial load with indicative slenderness checks. Flat slabs — two-way spanning RC slabs without beams, including post-tensioned options where specified. One-way slabs — RC or composite deck spanning between beams or walls. Foundations and pad footings — sizing for individual column loads with bearing capacity checks. Retaining walls — preliminary sizing for gravity and cantilever retaining structures. Staircases — RC and steel stair flights with indicative thickness and reinforcement. Roof structures — pitched and flat roof framing in steel, timber, or RC. For complex projects involving multiple elements simultaneously, selecting Full Structural Scheme generates a coordinated preliminary design covering all primary elements in a single calculation.

StructAI works with six major international structural design standards. Eurocode covers EC2 for reinforced concrete, EC3 for structural steel, and EC5 for timber, and is the applicable standard across the European Union and is widely adopted in East Africa, parts of the Middle East, and many countries with British engineering heritage. British Standard covers BS 8110 for reinforced concrete and BS 5950 for structural steel, applicable to older UK projects and many Commonwealth countries still working to legacy codes. ACI 318 and AISC cover US reinforced concrete and structural steel respectively, applicable across North America and widely used in the Middle East for US-practice projects. AS 3600 and AS 4100 cover Australian reinforced concrete and structural steel, applicable in Australia, New Zealand, and the Pacific. IS 456 and IS 800 cover Indian reinforced concrete and structural steel, applicable across India and the Indian subcontinent. Local building code applies country-specific standards where none of the above are directly applicable, with the AI drawing on its knowledge of local regulatory requirements. For countries in East Africa including Kenya, Tanzania, and Uganda, the Eurocode is now the adopted standard following the transition from British Standards, and this is the appropriate selection for new projects in those markets.

Span-to-depth ratio is the ratio of the clear span of a structural member to its effective depth. It is the primary sizing tool used in preliminary structural design because it allows a member size to be determined quickly and reliably without performing full bending and shear calculations. Every major structural design code publishes basic span-to-depth ratios for different member types, support conditions, and loading situations — for example, Eurocode 2 Table 7.4N gives a basic span-to-effective depth ratio of 20 for a simply supported RC beam under normal loading, meaning a beam spanning 8 metres should have an effective depth of approximately 400mm. StructAI applies these code-referenced ratios to your span and loading inputs to derive the preliminary member depth, then selects an appropriate width based on standard proportioning rules, and produces a final indicative section size. This approach is exactly how experienced structural engineers perform preliminary sizing before undertaking detailed calculations — it is a legitimate and well-established method for early-stage design, not a shortcut.

The accuracy depends heavily on how closely your inputs match the actual project conditions. For standard, regular structures — a straightforward rectangular floor plate with uniform loading, regular column grid, normal ground conditions, and no unusual features — the indicative sizes will typically be within ten to twenty percent of the sizes a structural engineer would arrive at in detailed design. For more complex scenarios — irregular floor plates, heavy point loads, transfer structures, post-tensioned slabs, seismic design, or poor ground conditions — the preliminary sizes may be less accurate and should be treated as a starting point for engineering judgement rather than a reliable prediction. The most important single input for accuracy is the span. A correct span produces a reasonable preliminary size. An incorrect span — for example, entering a room dimension rather than a structural grid dimension, or confusing clear span with centre-to-centre column spacing — will produce a systematically wrong result. Similarly, the imposed load has a large influence on beam depth: an office floor at 3 kN/m² and a library floor at 7.5 kN/m² will require materially different beam sizes for the same span.

Selecting Metric SI means all your inputs should be in metres for spans and heights, and kN/m² for loads. All output member sizes will be expressed in millimetres for dimensions and kN for forces, consistent with Eurocode, British Standard, Australian Standard, and Indian Standard practice. Selecting Imperial means all inputs should be in feet for spans and heights, and psf (pounds per square foot) for loads. All output member sizes will be expressed in inches for dimensions and kips or psf for forces, consistent with ACI 318 and AISC practice. The AI calibrates its calculations, span-to-depth ratios, code references, and material specifications to the unit system you select. Mixing units — entering a span in feet while the toggle is set to metric, or entering loads in kN/m² while the toggle is set to imperial — will produce incorrect results. Always verify your unit system selection before entering values, particularly if you are working from drawings in a different unit convention than your usual practice.

Snow load is the structural load imposed by accumulated snow on a roof or elevated surface. It is a variable action that must be included in structural load combinations wherever the building is located in a region that experiences snowfall. Snow load is relevant in the United Kingdom and Ireland, most of continental Europe, Canada, the northern United States, mountainous regions of North Africa and the Middle East including the Atlas Mountains in Morocco and parts of Turkey, high-altitude locations in East Africa including the Kenyan Highlands and Mount Kenya region, and most of Australia's alpine areas. Snow load is generally not applicable to most of sub-Saharan Africa, the Gulf states, lowland equatorial regions, or coastal tropical locations. When snow load is applicable, the characteristic ground snow load for your site can be found in the national annex to Eurocode 1 Part 1-3 for European projects, ASCE 7 for US projects, or the equivalent national standard for your country. The ground snow load must be converted to a roof snow load using a shape coefficient that accounts for roof pitch and thermal properties. For preliminary design, a roof snow load of 0.6 to 1.0 kN/m² is typical for most UK and European lowland locations. StructAI includes the snow load you enter as a variable action in all relevant load combinations when the snow load option is activated.

StructAI offers five ground condition categories. Rock or dense gravel represents ground with a presumed allowable bearing capacity of 600 kN/m² or greater — typical of sites on solid rock, dense granular deposits, or well-cemented soils. Firm clay or medium dense sand represents bearing capacities in the range of 100 to 300 kN/m² — the most common category for urban development sites across Africa and the Middle East. Soft clay or loose sand represents bearing capacities below 75 kN/m² — typical of alluvial deposits, coastal sites, reclaimed land, and areas with high groundwater tables, requiring larger foundations or piling. Made ground or fill represents sites where the upper soil layers consist of imported or disturbed material of variable composition and bearing capacity — common on brownfield sites, former quarries, and rapidly developed urban areas. Unknown should be selected where no geotechnical information is available and conservative foundation assumptions should be applied. If you genuinely do not know the ground conditions, select Unknown. StructAI will apply conservative bearing capacity assumptions and explicitly recommend a geotechnical investigation as a priority action before detailed foundation design. Selecting the wrong ground condition category — particularly overestimating the bearing capacity by selecting Firm Clay when the site is actually on Soft Clay — can produce foundation sizes that are dangerously undersized. If in doubt, select the more conservative option.

Wind and seismic zone is a simplified classification of the lateral load demand on your structure from wind pressure and ground motion. Low indicates a site with minimal wind exposure and negligible seismic risk — typical of sheltered inland locations in low-seismicity countries such as Kenya, Nigeria, and much of West Africa. Moderate indicates a site with typical wind exposure or low-to-moderate seismic risk — appropriate for most urban sites across East Africa, the Gulf states, and non-seismic European locations. High Wind indicates a site with significant wind exposure — coastal locations, exposed hilltops, sites in tropical cyclone zones, or tall buildings above 50 metres. High Seismic indicates a site in a recognised seismic zone — relevant to Ethiopia and the East African Rift Valley, Turkey, Morocco, parts of the Middle East, California, Japan, New Zealand, and seismically active regions of India. High Wind and Seismic applies to locations that combine both hazards — coastal seismic zones, cyclone-prone areas in the Pacific, and some island locations. For a preliminary structural assessment the zone classification primarily influences the lateral force system recommendation and the minimum design requirements for connections and detailing. A full dynamic analysis using site-specific seismic hazard data is required for detailed design in seismic zones.

StructAI generates six separate sections of technical engineering content simultaneously — member sizing, load analysis, foundation design, material specifications, design checks, and engineering notes. Each section is generated by an AI model reasoning through your specific structural scenario using the applicable design code, producing tables, calculations, and recommendations tailored to your inputs. The AI is not looking up a pre-written answer — it is reasoning through the structural engineering for your specific project, which requires processing time. The parallel generation approach means all six sections run at the same time rather than sequentially, cutting the total time from over a minute to approximately 15 to 25 seconds depending on server load and the complexity of your inputs. If the calculation button appears unresponsive after clicking, it has registered your click and is processing — the loading animation will appear within two to three seconds confirming the calculation is running.

StructAI can be used for preliminary sizing on buildings up to any height, including high-rise structures of 20 or more storeys. However, the reliability of the output decreases significantly for tall buildings for several important reasons. Lateral load governs the structural design of high-rise buildings — wind and seismic forces rather than gravity loads become the primary design driver above approximately 15 storeys, and the simplified approach used by StructAI does not capture the full complexity of lateral system design, inter-storey drift, dynamic response, or P-delta effects. Column sizes in tall buildings are governed by cumulative axial loads from multiple floors and the need to control shortening — a nuance that preliminary span-to-depth approaches do not address. The structural system for high-rise buildings — moment frame, shear wall, core wall, outrigger, tube — must be selected as a design decision before sizing can begin, and this selection has a larger influence on member sizes than any other single factor. For buildings above 10 storeys, StructAI is best used to size individual elements and check order-of-magnitude dimensions rather than to produce a complete preliminary structural scheme.

The disclaimer states that StructAI's outputs are indicative sizes for early-stage planning and feasibility only, and must not be used for construction or detailed design without verification by a registered structural engineer. This disclaimer is not a formality — it reflects a genuine and important limitation. Structural failure causes loss of life. The member sizes StructAI produces are based on simplified calculations using assumed inputs, without physical inspection of the site, review of actual soil investigation data, analysis of the full structural system, or verification of load paths and connection details. Every country in which StructAI operates requires structural drawings to be prepared and certified by a registered structural engineer before a building permit can be issued and before a contractor can build. StructAI does not replace that requirement and is not intended to. It is a planning and feasibility tool that reduces the time and cost of the early stages of structural design — not a substitute for professional engineering.