Preliminary reference workbook — supports preliminary sizing only; must be reviewed, signed, and sealed by a licensed Professional Civil/Structural Engineer before use in construction or permitting. Full terms: see "Disclaimer & Terms of Use" below.
Structural Calculation Set · NSCP-Based
Structural Design Analysis & Calculations
Dead, live, wind, and seismic load computations for a 2–3 storey residential building, with a gravity capacity check — organized as a working calculation sheet set.
This is a structural design analysis and calculations tool intended to support preliminary structural computations. 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.
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.
The creator/programmer of this tool assumes no obligation, responsibility, or liability of any kind for errors, omissions, damages, injuries, or losses — direct, indirect, incidental, or consequential — 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.
All computations here 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.
This tool does not replace professional engineering judgment, a complete structural analysis, a geotechnical investigation, 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.
No warranty, guarantee, or representation is made as to this tool's suitability for any specific project, site condition, or structural system.
Found a discrepancy, error, or have a suggestion for this calculation platform? Please email reyas@engineer.com.
Calculation Sequence — House Mode
Each step below feeds the next — geometry drives loads, loads drive the column/footing check, and that check drives member design. Working through them in this order means every number downstream is already using the correct upstream value, instead of a placeholder you'll have to circle back and fix.
Design Criteria (S-0.1) — No. of storeys, floor-to-floor height, footprint area, roof area, opening deductions. Every load calculation below reads from this, so set it first.
Dead Loads (S-1.1) — Slab thickness (computes self-weight at 23.6 kN/m³), floor finish, ceiling/MEP, partition allowance, roofing. Auto-computed per level from Step 1's areas.
Live Loads (S-1.2) — Occupancy per level (residential, balcony, stairs, garage, etc.) and roof live load. These are code-prescribed allowances that already include furniture, occupants, and typical contents — not something you add up separately.
Wind Loads (S-2.1) — Wind speed/zone, exposure category, mean roof height. Computes velocity pressure and wall/roof pressures independently of Steps 2–3.
Seismic Loads (S-2.2) — Zone, soil profile, lateral system. Uses the dead and live load totals from Steps 2–3 to compute the design base shear.
Summary & Check (S-3.1) — Set the column's bay dimensions and grid position (corner/edge/interior) — this determines tributary area, which multiplies against Steps 2–3's per-level loads to get the column's cumulative service and factored load. Also checks footing bearing against your proposed footing size.
Member Design (S-3.2) — Beam, Slab, Column, and Footing sub-tabs, each pulling its demand from the steps above (beam/slab from Dead+Live per level and tributary width; column from Summary's Pu; footing from Summary's bearing size and column load). Bar sizes and counts auto-calculate from the demand by default — you can still override any of them manually.
Bar Bending Schedule (S-4.3) — Auto-compiles cutting lengths, quantities, and total steel weight directly from whatever's entered in Step 7 — nothing to re-enter here.
General Notes & Specifications (S-3.3 / S-3.4) — Reference sheets; add project-specific notes if needed. No calculation happens here.
Design Report (S-4.1) — Auto-compiles a signed summary of every section above. Fill in the Engineer of Record block and review status here.
Submission Checklist (S-4.2) — Reference list of typical permit submission requirements — not project-specific, just a checklist.
Fence and Mixed-Use modes follow the same underlying logic (geometry → loads → member design → report), each fully independent from House and from each other — switch modes using the tabs at the top, and each keeps its own save file.
Each Beam/Slab/Column/Footing tab has its own "Save this [member] (.json)" button, separate from the whole-project save — use that to build up a set of named checks (e.g. corner, edge, interior) without one overwriting another.
Deducted from Level 2/Level 3 floor area for dead and live load totals. If the opening also cuts through the roof (e.g. an open stairwell to a roof hatch), reduce "Roof area" above by the same amount manually — the deduction here doesn't touch it automatically.
Sheet S-0.1
Design Criteria
Governing code, project geometry (set above), and reference values used throughout this workbook.
Governing code
Structural codeNSCP, latest edition
Occupancy categoryResidential (standard)
Importance factor, seismic (I)1.0
Importance factor, wind (Iw)1.0
Standard-occupancy residential construction — not an essential or hazardous facility. Increase importance factors if the structure includes an essential function (e.g. an emergency shelter room).
Typical unit weights (reference)
Material
Unit weight
Reinforced concrete
23.6 kN/m³
Reinforcing steel (density, for bar weight)
7850 kg/m³
CHB wall, 100 mm
1.53 kPa
CHB wall, 150 mm
2.30 kPa
Cement plaster, both faces
+0.48 kPa
Floor finish (tile/cement)
1.10 kPa
Partition wall allowance
0.75 kPa
Suspended ceiling
0.24 kPa
GI roofing on purlins
0.40 kPa
Typical values commonly referenced from NSCP Table 204-1 material unit weights, plus the standard steel density used in the Bar Bending Schedule's weight calculation. Not exhaustive — live loads (occupancy-based, not material density) are on the Live Loads tab, and soil unit weight is set directly on the Footing tab since it's site-specific. Confirm against the current code edition and actual specified materials before finalizing.
Sheet S-1.1
Dead Load Computation
Superimposed dead load per elevated level. Slab self-weight computed from thickness × concrete unit weight.
Sheet S-1.2
Live Load Computation
Minimum uniform live loads by occupancy, typical of NSCP Table 205-1.
Static lateral force procedure — base shear per NSCP 208.
Sheet S-3.1
Load Summary & Capacity Check
Governing load combinations and a gravity load check on a typical column/footing.
Governing load combinations (NSCP 203, USD)
Combo 11.4D
Combo 21.2D + 1.6L
Combo 31.2D + 1.0W + 1.0L
Combo 41.2D + 1.0E + 1.0L
Combo 50.9D ± 1.0W (or 1.0E)
Listed for reference — the column/footing check below uses Combo 2 (1.2D+1.6L) only, since it's a gravity-only check (tributary area method). Combos 1, 3, 4, and 5 apply to the lateral system (frames or shear walls) and aren't fed into this simplified per-member check — see the Load Combinations section of the Design Report for the full scope note.
Presumptive bearing values are typical figures used for preliminary sizing only — they are not a substitute for an actual geotechnical/soil investigation, which governs the final design value. The NSCP Table 304-1 group reflects the code's own presumptive bearing table (for cases where no site investigation has been performed, per NSCP Section 304.2 — an increase of up to 20% per additional 300mm of footing width/depth beyond the minimum 300×300mm applies per the code, not modeled here). These figures were sourced from an available reference copy of the table, not independently verified against your specific NSCP edition — confirm the exact classification names and values against your own current copy before relying on them.
Sheet S-3.2
Member Design Checks
This is where individual members get sized and checked — enter trial dimensions and reinforcement, and each check compares factored demand (U) against design capacity (φRn) to return Pass or Fail. Simplified singly-reinforced / axial-only checks — no deflection, development length, or ductile-detailing verification.
Two-way slabs use a different minimum-thickness rule (perimeter ÷ 180) than the one-way rule above — shown in the results once a two-way panel is detected.
Demand Pu and footing size B are read from the Summary & Check sheet (tributary column load and proposed footing) — adjust the inputs there to change the loads used here.
Sheet S-3.5
Stair Design
Designs the stair's own waist slab (an inclined one-way slab) — separate from the "Stair reaction" helper on the Beam tab, which only computes the point load a stair applies to a supporting beam. This checks the stair itself.
Sheet S-3.3
General Notes & Specifications
Standard structural general notes, an auto-compiled materials specification summary, and space for project-specific notes.
General notes
All construction shall conform to the National Structural Code of the Philippines (NSCP), latest edition, and the National Building Code of the Philippines (PD 1096) and its Implementing Rules and Regulations.
Design loads, load combinations, and wind/seismic parameters are as indicated on Sheets S-0.1 through S-3.1 of this set.
Concrete: normal-weight, unit weight 23.6 kN/m³ unless noted; f'c per member as scheduled in the Materials Specification Summary below.
Reinforcing steel: fy per member as scheduled below, conforming to PNS 49 (Philippine National Standard for Steel Bars).
Minimum concrete cover, unless noted otherwise: 75 mm for footings cast against earth; 40 mm for beams, columns, and footings not cast against earth; 20 mm for slabs.
Lap splices for reinforcing bars shall be Class B tension splices unless noted otherwise; splice locations shall avoid regions of maximum stress where practicable.
All dimensions are in millimeters and elevations in meters unless noted otherwise.
The Contractor shall verify all dimensions, levels, and site conditions before commencing work and shall notify the Engineer of any discrepancy.
Shop drawings for reinforcement (and structural steel, if any) shall be submitted for the Engineer's review prior to fabrication.
This workbook is a preliminary design-computation reference. It shall not be used for construction until reviewed, signed, and sealed by the Engineer of Record.
Materials specification summary (auto-compiled)
Project-specific notes
Project-specific notes are included when you Save the project file, so they carry over the next time you Load it.
Sheet S-3.4
Structural Specifications
Material, workmanship, and quality-control provisions — the technical specification companion to the General Notes and computations above.
1. Concrete
Ready-mixed concrete shall conform to ASTM C94 (or equivalent PNS standard). Cement shall be Portland cement, ASTM C150 Type I, unless a different type is noted for sulfate exposure or other site conditions.
Aggregates shall conform to ASTM C33. Water shall be clean and potable, free of oil, acid, or organic matter.
Concrete strength class (f'c) for each member is as scheduled on the Materials Specification Summary (General Notes sheet) and the Member Design sheet. Maximum water-cement ratio and slump shall follow the approved mix design for the specified class — typical slump range 75–100 mm for conventionally placed structural concrete, adjusted for pumping or congested reinforcement as needed.
Formwork shall remain in place until concrete reaches sufficient strength to support its own weight and construction loads — typical minimum stripping times: vertical forms (columns, walls) 24 hours; beam and slab soffits, shored until concrete reaches 70% of specified f'c or per the Engineer's written approval.
Concrete shall be moist-cured for a minimum of 7 days (or per ACI 308 for the specific cement type and ambient conditions) following placement.
Testing: sample and test concrete per ASTM C172 (sampling), C31 (cylinder preparation), and C39 (compressive strength). Typical minimum frequency: one set of test cylinders per 40 m³ of concrete placed, or per day's pour, whichever gives more sets, with at least one set per structural element type per pour.
2. Reinforcing steel
Deformed reinforcing bars shall conform to PNS 49, of the grade scheduled on the Materials Specification Summary and Member Design sheet for each member.
Bar bending and fabrication shall conform to the approved shop drawings; field bending of bars partially embedded in concrete is not permitted without the Engineer's approval.
Minimum concrete cover and lap splice requirements are as stated in the General Notes sheet. Mechanical couplers, if used in place of lap splices, shall develop at least 125% of the bar's specified yield strength.
Mill test certificates shall be furnished for each heat/batch of reinforcing steel delivered to the site, confirming grade and chemical/mechanical properties.
3. Earthwork & foundation
Excavate to the bearing stratum assumed in the design or identified in the geotechnical report, at minimum to the governing embedment depth computed on the Footing sheet. Notify the Engineer if the bearing stratum encountered differs from what was assumed.
The foundation subgrade shall be free of loose soil, debris, and standing water immediately prior to placing lean concrete or footing concrete.
Backfill around foundations shall be placed in lifts and compacted to at least 90–95% of maximum dry density (standard or modified Proctor, per the geotechnical report), avoiding damage to waterproofing or foundation walls.
4. Quality control & inspection
Special inspection shall be performed where required by NSCP and the local Office of the Building Official, including but not limited to concrete placement, reinforcing steel placement prior to concrete pour, and soil bearing verification at footing excavations.
An accredited testing laboratory shall perform concrete cylinder testing, and shall furnish written reports to the Engineer and the Contractor.
Shop drawings, concrete mix designs, and material certificates shall be submitted to the Engineer for review before fabrication or placement begins.
Any deviation from the approved structural drawings and this specification requires the Engineer's written approval before work proceeds.
Project-specific specifications
Standard clauses above reflect common ASTM/ACI/PNS practice — confirm exact requirements, testing frequencies, and standards references against the current codes and the project's actual geotechnical report before issuing for construction. Project-specific specifications are included in Save/Load, same as the General Notes.
Sheet S-4.1
Structural Design Analysis and Computations
Draft prepared for review, correction, and sealing by the licensed Engineer of Record — compiled from every sheet above into the document form typically bound with the structural drawings for permit submission.
This tab compiles the entries and results from every other sheet into one document. Fill in the header fields, switch to this tab, then use Print / Save as PDF — the tab strip and input forms are hidden automatically in the printed output. The status line updates to match "Review status" above — but it can never be turned off entirely, and none of its states claim the document is sealed. Only the Engineer of Record's actual signature and PRC seal in the box below does that; the status line just tracks where the draft stands on the way there.
Sheet S-4.2
Building Permit Submission Checklist
Documents commonly required alongside the structural report for a building permit application in the Philippines (National Building Code, PD 1096 and its IRR). Requirements vary by city/municipality — confirm the exact list with your Office of the Building Official (OBO) before filing.
Application & site documents
Duly accomplished Building Permit Application form
Proof of property ownership (TCT) or authority to build (e.g. contract of lease, owner's consent)
Current Tax Declaration and latest real property tax receipt
Lot plan / vicinity map prepared by a Geodetic Engineer
Barangay clearance and/or HOA clearance, where applicable
Structural documents (this report supports these)
Structural design plans — foundation, framing, and detail sheets
Structural design analysis / computations, signed and sealed by a Civil Engineer
Soil investigation / geotechnical report, where required by the OBO or building size
Bill of materials and cost estimate, signed and sealed
Specifications
Other engineering plan sets
Architectural documents, signed and sealed by an Architect
Sanitary / plumbing plans, signed and sealed by a Sanitary Engineer or Master Plumber
Electrical plans, signed and sealed by a Professional Electrical Engineer
Mechanical plans, where applicable (elevators, HVAC)
Electronics/fire alarm plans, where applicable
Clearances
Fire Safety Evaluation Clearance, Bureau of Fire Protection
DENR/ECC certificate, for projects that require it
Contractor's PCAB license and business permit, at construction stage
This list covers the documents typically requested; some LGUs add locality-specific requirements (e.g. traffic management plan, DPWH road right-of-way clearance for frontage on a national road). Always verify the current checklist with the OBO where the project will be filed.
Sheet S-4.3
Bar Bending Schedule
Cutting lengths and quantities for every bar already entered on the Member Design sheet — auto-compiled, not re-entered. Straight bars use the member's own dimension as the base length; stirrups/ties add standard hook allowances to the closed-loop perimeter.
Sheet S-5.1
Fence Design
Independent from the main house — a fence is wind-governed, not gravity-governed: the post is a cantilever fixed at the ground, resisting lateral wind pressure on the fence face rather than floor loads.
Fence general notes
All fence structural work shall conform to the National Structural Code of the Philippines (NSCP), latest edition, and the National Building Code of the Philippines and its IRR.
Fence posts shall be embedded to at least the depth shown on the Embedment Depth sheet, backfilled with concrete or well-compacted select fill as specified — not loose backfill.
Fence posts do not require a separate spread footing or blinding layer beneath them — the post resists lateral wind load through soil confinement along its embedded depth (passive pressure), not through vertical bearing on a widened base, so the embedment depth itself is the complete foundation design for the post. This is different physics from a column-on-footing system, and different from the Wall Footing between posts (below), which does carry a genuine vertical bearing load from the CHB wall's self-weight and does need blinding beneath it.
CHB (concrete hollow block) fence walls shall have all cells containing vertical reinforcement filled solid with grout for the full height of the wall.
Corner, end, and gate posts typically require greater embedment depth, larger sections, or additional bracing than a typical line (intermediate) post, due to unbalanced or concentrated loading — this is not evaluated here, which checks a typical line post only.
A weep hole or drainage provision at the base of solid CHB fence walls is recommended to relieve water pressure buildup behind the wall.
Expansion/control joints in long CHB fence runs shall be provided at intervals per standard masonry practice (typically every 6–9 m, or as detailed) to control shrinkage cracking.
Where an intermediate tie beam is used, it shall be reinforced symmetrically on both faces (not just the bottom) — wind can push from either direction, so tension can develop on either face depending on wind direction that day.
This sheet is a preliminary design-computation reference. It shall not be used for construction until reviewed, signed, and sealed by the Engineer of Record.
Fence specifications
Fence post holes shall be excavated to the dimensions and depth shown on the Embedment Depth sheet, with the bottom of the hole free of loose material immediately before setting the post. No blinding course or formed footing pad is required beneath the post itself — this applies only to the Wall Footing between posts, where blinding is specified separately on that sheet.
Where posts are set in concrete, the concrete shall be a minimum of the class specified for the post itself and shall be consolidated to eliminate voids around the embedded post.
CHB units shall conform to PNS standards for concrete hollow blocks; grout for filled cells shall achieve the compressive strength scheduled on the CHB Wall Panel sheet.
Vertical reinforcing dowels shall extend from the footing/post into the CHB wall cells for the full required splice length, and shall be secured in position before grouting.
Fence alignment, plumbness, and top-of-wall/post elevations shall be verified by survey before and after concrete/grout placement.
Where an intermediate tie beam is called for, it shall be cast monolithically with the CHB wall's grouted cells at that course, and its reinforcement shall be continuous through (or properly spliced at) each post it passes, not simply butted against the post face.
Fence-specific notes (project)
Included in Save/Load, same as the house's project notes.
This is a fully independent report from the house's Design Report — its own header, its own Engineer of Record block, its own status, its own print output. Fill in the fields, then Print / Save as PDF.
Sheet M-0.1
Occupancy & Geometry
A 4–5 storey mixed-use building is a different code category from the 2–3 storey residential case — different occupancy classification per floor, different live loads, and a real possibility of a different seismic Importance Factor and structural-system height limit. This sheet sets that up before anything downstream uses it.
Sheet M-1.1
Dead Loads
Same unit-dead-load methodology as the house — thickness × 23.6 kN/m³ for slabs, plus finish/ceiling/partition allowances — generalized here to however many levels this building actually has (Level 2 through Level {storeys}, plus roof).
Sheet M-1.2
Live Loads
Pulled directly from the occupancy assigned to each level on the Occupancy & Geometry tab — this is the core mixed-use difference from the house: every floor can carry a different live load instead of one uniform residential value.
Sheet M-2.1
Wind Loads
Same NSCP 207 / ASCE 7 methodology as the house's Wind Loads sheet, independent inputs — a taller building sees a real increase in Kz (velocity pressure coefficient) at greater height, which this formula already captures continuously rather than needing a separate "tall building" table.
Sheet M-2.2
Seismic Loads
Same static lateral force procedure as the house, with one real difference: the Importance Factor here comes from the occupancy classification set on the Occupancy & Geometry tab, not fixed at 1.0 — a mixed-use building with an assembly-type space can have a materially higher design base shear than the same building purely residential.
Sheet M-3.1
Summary & Check
Column load and footing bearing check for a column at any level — generalized so a column starting partway up the building (e.g. a Level 4 column) only carries the levels above it, while a ground-floor column carries the full cumulative stack from Level 2 through the roof.
Sheet M-3.2
Member Design
Identical NSCP/ACI 318 methodology as the house's Member Design sheet (Whitney stress-block flexure, standard shear provisions, tied-column axial capacity, footing bearing/shear/flexure) — loads here pull from this building's own per-level dead/live values instead of the house's. Advanced cases the house sheet covers (cantilever beams, stair-reaction point loads, two-way slabs, skin reinforcement) aren't separately re-implemented here; the same underlying principles apply if you need them.
Sheet M-3.3
Bar Bending Schedule
Cutting lengths and quantities for every bar already entered on the Member Design sheet — auto-compiled, not re-entered. Same method as the house's Bar Bending Schedule sheet, independent settings.
Sheet M-3.3
Notes & Specifications
General notes
All structural work shall conform to the National Structural Code of the Philippines (NSCP), latest edition, and the National Building Code of the Philippines.
This is a mixed-use building — occupancy classification, live loads, and the seismic Importance Factor vary by level as set on the Occupancy & Geometry sheet. Confirm the actual final occupancy of each level against what's assumed here before construction.
Concrete: f'c per Member Design sheet, minimum 27.6 MPa (4,000 psi) for primary gravity/lateral members at this height, unless a lower grade is specifically justified.
Reinforcing steel: fy per Member Design sheet.
All computations here are preliminary and simplified — this is a design-computation reference, not a substitute for a full 3D structural analysis (see disclaimer). A building of this height and mixed occupancy should be modeled in full analysis software (e.g. ETABS) by the Engineer of Record before construction.
Where an assembly-type or other Special Occupancy space is included, verify the Importance Factor and any applicable additional detailing/exiting requirements against the current code — this tool flags the condition but does not verify compliance.
This sheet shall not be used for construction until reviewed, signed, and sealed by the Engineer of Record.
Specifications
Concrete cover, bar development/splice lengths, and detailing shall conform to NSCP/ACI 318 provisions for the exposure condition and member type.
Formwork shall remain in place until concrete reaches the strength required to safely support the load at that stage of construction.
Lateral system: as selected on the Seismic Loads sheet — confirm the selected system's height limit against the current code for the site's seismic zone before finalizing.
Fully independent from the house's and fence's Design Reports — its own header, Engineer of Record block, status, and print output.
Fill in the fields, then Print / Save as PDF.
Sheet M-4.2
Submission Checklist
Typical building permit submission requirements — mixed-use, 4–5 storeys
Structural design analysis and computations, signed and sealed by the Engineer of Record.
Complete structural drawings (foundation, framing, details) signed and sealed.
Architectural drawings signed and sealed by the Architect of Record — occupancy classification per level should be clearly labeled and match what's assumed in the structural computations.
Fire safety evaluation/compliance, especially where any level includes assembly-type or high-occupant-load space.
Occupancy Permit application will need each level's final use to match what was approved at building permit stage — flag any mismatch between assumed and actual occupancy early.
Geotechnical/soil investigation report — more likely to be required/expected at this height and load level than for a 2–3 storey residential building.
Electrical, sanitary/plumbing, mechanical (if applicable) plans, each signed and sealed by their respective professionals.
Fire code and accessibility (PWD-compliant) compliance documentation, more heavily scrutinized for mixed-use/commercial-occupancy floors than pure residential.
This list covers documents typically requested; LGU requirements vary, and a mixed-use building at this height is more likely to trigger additional review (fire, structural peer review, environmental) than a small residential project. Always verify the current checklist with the OBO where the project will be filed.