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PRELIMINARY STRUCTURAL TOOL NSCP 2015

Steel Truss Design Calculations

Generates a statically-determinate steel roof truss, takes off dead / live / wind loads per the National Structural Code of the Philippines 2015, solves member forces by the method of joints, and auto-selects equal-angle sections against AISC 360 allowable-stress checks.
Disclaimer & Terms of Use
  1. This is a structural steel design analysis and calculations tool intended to support preliminary structural computations for steel roof trusses. Every output must be reviewed, verified, corrected as necessary, and signed and sealed by a duly licensed and registered Civil/Structural Engineer before it is used for construction, permitting, or any other purpose.
  2. This tool, and any report or output generated from it, shall not be used, copied, reproduced, or distributed for construction, permitting, or any professional purpose without the express review and written approval of a licensed Professional Civil Engineer.
  3. The creator/programmer of this tool assumes no obligation, responsibility, or liability of any kind for errors, omissions, damages, injuries, or losses β€” direct, indirect, incidental, or consequential β€” arising from the use, misuse, or reliance on this tool or its outputs. It is provided "as is," with no warranty of any kind, express or implied, including as to accuracy, completeness, fitness for a particular purpose, or compliance with any code or regulation.
  4. All computations here β€” geometry, loads, member forces, and steel section sizing β€” are intended to be independently double-checked by a duly licensed Civil and/or Structural Engineer before being relied upon for design, construction, or regulatory submission. The Engineer of Record bears full professional responsibility for the final, sealed design.
  5. This tool does not replace professional engineering judgment, a complete structural analysis, a geotechnical investigation, connection design, or verification against the National Structural Code of the Philippines (NSCP), the National Building Code of the Philippines, and other applicable laws and regulations currently in force.
  6. No warranty, guarantee, or representation is made as to this tool's suitability for any specific project, site condition, steel truss configuration, or structural system.
  7. Not calculated by this tool, under any input combination: seismic load combinations (a single 2D truss is not the correct structural model for horizontal seismic force, which needs a lateral-force-resisting system this tool does not represent); a code-compliant rain/ponding load per NSCP/ASCE 7 Ch.8 (this depends on the roof's actual drainage design β€” drain/scupper locations and size, secondary drainage flow rate, site rainfall intensity β€” none of which this tool collects; a slope-based advisory is shown for low-slope roofs, but it is a warning, not a load calculation); full Main-Wind-Force-Resisting-System windward/leeward/corner zone wind pressures or Component & Cladding pressures (a single governing roof Cp by slope is used instead of the complete code table); and gusset/connection plate net-section rupture, block shear, or compression buckling (only gross-section yielding on the Whitmore effective width, and the weld itself, are checked). Any of these that apply to a given project must be checked separately by the Engineer of Record.

Found a discrepancy, error, or have a suggestion for this calculation platform? Please email reyas@engineer.com.

STRUCTURAL DESIGN REPORT β€” STEEL ROOF TRUSS
Untitled Roof Truss Project
Truss markT1
Quantity1 pc
Locationβ€”
Owner / Clientβ€”
Dateβ€”
Governing codeNSCP 2015
Structural Engineer of Record
PRC Reg. No. β€”
PTR No. β€” Β· Valid until β€”
Signature over printed name
SEAL
This report and its member sizing are preliminary output from an automated calculator. It becomes a design document only once reviewed, signed, and sealed above by the structural engineer of record.
"Save as JSON" downloads this truss's inputs as a small data file you can re-load later or hand to someone else. "Load JSON" restores a previously saved truss. "Print / Save as PDF" opens your browser's print dialog for a clean design report.
Project
Truss mark
Qty
Date
Ref. code
Compression
Tension
Pin / roller support
Line thickness = actual chosen section size, not force
↑ arrows = net wind uplift case included in combos

Load Takeoff

Per-joint loads applied at each top-chord panel point, combined per NSCP 203 basic ASD combinations: D+L, D+0.6W, D+0.75L+0.75(0.6W), and 0.6D+0.6W (the last two govern net uplift/reversal checks).
Dead & live load derivation
Wind pressure derivation (qh, Cp, per-joint force)

Member Force & Design Schedule

Governing tension / compression per member across all load combinations, checked against the lightest passing equal-angle section.
MbrChordL (m)Gov. force (kN)Type SectionAg (cmΒ²)Capacity (kN)Util.Check

Chord Cross-Sections

Schematic only β€” not to exact scale, and not a fabrication detail. Shows what's actually driving the report: single or double angle (with the arrangement picked in "05 Β· Steel"), tube, or pipe, for whichever size(s) ended up in each chord.

Connection Design β€” Welded, All Joints

Every joint, with every member framing into it, the fillet weld it needs there, and a Whitmore-section check of the gusset plate itself at that same weld. Weld leg size is fixed at the AISC J2.4 code minimum for that member's own thickness; length is solved for that size and the member's governing force (AISC J2.4, Ξ©=2.00). The Whitmore column checks the plate's gross-section YIELDING only (effective width = member width + 2Β·LΒ·tan30Β°, per AISC) β€” it does NOT check net-section rupture, block shear, or compression buckling of the plate; a † marks a connection governed by compression, where plate buckling (not checked here, and typically the lower, governing capacity) still needs a separate check. Not included: the actual weld layout/return detail, joint eccentricity for 3+ members meeting at odd angles, and fatigue/dynamic loading checks β€” a licensed engineer must complete and verify the connection design.
JointMemberForce (kN)Thickness (mm)Weld size (mm)Cap. (kN/mm)Total length req'd (mm)Whitmore width (mm)Gusset check

Bottom Chord ↔ Vertical Connection Detail

Schematic only, not to scale or a fabrication detail β€” one card per distinct combination of vertical size (and diagonal size(s), if any diagonal also frames into that same joint), showing them framing into the bottom chord through a shared gusset plate. Weld hatch marks are illustrative of where each fillet runs, not the actual layout; see the Connection Design table above for the governing size and required length per member (the worst of the members shown, if more than one shares the same combination).

Top Chord ↔ Vertical Connection Detail

Same idea, upside down: the top chord runs through, with the vertical (and any diagonal(s) at that joint) framing UP into it from below through a shared gusset plate. Schematic only, not to scale or a fabrication detail β€” see the Connection Design table above for the governing size and required length per member.

Bar Schedule (Bill of Materials)

Section sizes rolled up from the member schedule above, with an estimated steel weight (density 7,850 kg/mΒ³) for fabrication quantity take-off.
SectionMembersQtyTotal length (m)Unit wt. (kg/m)Total wt. (kg)

Cutting Layout (Stock Optimization)

Nests members of the same section onto standard-length stock bars to minimize offcut waste β€” for the full project quantity (all pieces of this truss mark), not just one. Every bar is cut into whole, single-piece members only; nothing is ever spliced together to reach a length. Each cut also consumes the saw kerf allowance set in "05 Β· Steel" so the layout doesn't come up physically short. Members longer than one stock bar are flagged separately β€” they need a special-order length or an unavoidable field/shop splice. Reported lengths are theoretical work-point-to-work-point lengths from the truss geometry β€” the actual cut length at each end (setback for the gusset plate, weld gap, bolt clearance) is a shop/detailer decision this tool doesn't attempt, since it depends on the actual connection detail, not just the member force.
⚠ Before cutting β€” shop checklist
  • Confirm the design is sealed. This layout is only as good as the member schedule behind it β€” don't release stock for cutting until the final sizes are reviewed, signed, and sealed by the engineer of record.
  • Match the kerf to your actual saw. The 4 mm default assumes a typical cold saw/bandsaw cut β€” verify against your shop's blade before trusting the "fits" calls, especially on tightly-packed bars.
  • Check delivered stock length, not just nominal. Mill/supplier bars can run short of the nominal length by tens of millimeters β€” measure actual stock before cutting the last, tightest-fitting piece on a bar.
  • These are work-point lengths, not final cut lengths. Get the actual end setback (gusset overlap, weld gap, bolt clearance) from the connection/shop detail before cutting to final size β€” don't cut straight to the number shown here.
  • Label every piece as it's cut. Mark the member ID (M1, M2, ...) immediately β€” pieces of the same section but different lengths are easy to mix up once cut and stacked.
  • Never field-splice an "oversized" piece without engineer approval. Members flagged as exceeding stock length need either special-order stock or an engineered splice detail β€” not an improvised joint.
  • Re-verify grade and section marking at the yard. Confirm the steel actually pulled matches the grade and size assumed in this schedule β€” substitutions happen, and this tool can't detect them.
  • Standard shop safety practice applies throughout β€” PPE, machine guarding, and material handling per your own safety program.

Reactions & Serviceability

Purlin Check

Auto-selected lipped C-purlin spanning between trusses (span = truss spacing c/c), checked against the same roof loads used for the truss itself. Preliminary gross-section check β€” see the hint on the Specifications tab for what's excluded.

Design Summary