Live loads for houses in the Philippines (NSCP 2015)

The National Structural Code of the Philippines (NSCP) 2015, Volume I (Buildings, Towers and Other Vertical Structures), 7th Edition, is published by the Association of Structural Engineers of the Philippines (ASEP) and is the structural referral code of the National Building Code (PD 1096). Chapter 2 sets the minimum design loads: Section 203 the load combinations, 204 dead loads, 205 live loads, 207 wind and 208 earthquake.

Section 205 and Table 205-1 give the minimum uniform live load for each occupancy or use, in kPa (1 kPa = 1 kN/m²). The table also gives concentrated loads, which are not listed on this page; check them in the code. Table 205-3 gives the minimum roof live loads. The values are minimums: where the actual live load will be greater, design for the actual load.

The NSCP is sold by ASEP and has no free official copy. Older load tables that are reprinted in other documents may come from NSCP 2010, so check the edition before you use one.

For comparison, light storage is 6.0 kPa and heavy storage 12.0 kPa. Live loads over 4.8 kPa may not be reduced under 205.5, except that columns may be reduced 20% for storage loads.

Table 205-3 Method 1 gives the roof live load by roof slope and by the tributary area of the member: the larger the area, the lower the load. Method 2 instead uses one uniform value and reduces it under 205.5; use one method or the other. On flat roofs the live load acts in addition to ponding loads (206.7; see also 210.3).

A roof used as a deck or terrace is not a roof for live load purposes: take the live load of the area served (Table 205-1, roof decks). For houses, typhoon wind (Section 207) usually governs the roof framing and its connections, not the roof live load.

In the NSCP, partitions are a dead load. Where partition locations may change, as on office floors, Section 204.3 requires a uniform partition load of 1.0 kPa (0.5 kPa on access floor systems) in addition to the other loads. This is a design allowance; it is not the 0.24 kPa that Table 204-2 gives as the own weight of movable partitions.

In a house the walls are usually fixed CHB walls shown on the plans. Use their actual weight from Table 204-2 instead, as a line load on the beam or slab that carries them.

A two-storey reinforced concrete house. A second-floor beam spans 5.0 m between columns. One-way slabs span 3.0 m onto it from each side, so its tributary width is 3.0 / 2 + 3.0 / 2 = 3.0 m and its tributary area is 5.0 × 3.0 = 15 m². A 150 mm CHB wall, 2.7 m high and plastered both faces, stands on the beam. The roof framing spans to the exterior walls, so the wall carries no roof load.

Assumed values (check them for the actual build-up): 125 mm slab at 23.6 kN/m³ (Table 204-1, reinforced concrete) = 2.95 kPa; ceramic tile on 25 mm mortar bed 1.10 kPa (Table 204-2); suspended ceiling 0.20 kPa; 150 mm CHB, no grout, 16.5 kN/m³ units, 1.15 kPa of wall face plus 0.24 kPa for each plastered face (Table 204-2), 1.63 kPa in all; beam 250 × 400 mm. The wall is fixed and shown on the plans, so its actual weight is used, not the 204.3 allowance. Live load 1.9 kPa (Table 205-1, residential basic floor areas).

Factored loads, NSCP 2015 Section 203.3.1. Eq. 203-1, 1.4(D + F): 1.4 × 19.51 = 27.3 kN/m. Eq. 203-2, 1.2(D + F + T) + 1.6(L + H) + 0.5(Lr or R), which here is 1.2D + 1.6L: 1.2 × 19.51 + 1.6 × 5.70 = 23.4 + 9.1 = 32.5 kN/m. Eq. 203-2 governs. F, T and H are zero, and Lr and R are zero because the roof does not bear on this beam.

For the simply supported 5.0 m span: factored moment Mu = 32.53 × 5.0² / 8 = 101.7 kN·m, and each end passes 32.53 × 5.0 / 2 = 81.3 kN to its column. Live load reduction under 205.5 is R = r(A − 15) with r = 0.08 for floors; with A = 15 m² it is zero.

Service load: D + L = 19.51 + 5.70 = 25.2 kN/m. Use it for deflection checks and, with the allowable soil bearing pressure, to size footings.

To carry the load down, add the column's other beams, the roof, and the ground floor at each level. Where a CHB wall bears the slab instead of a beam, the floor and wall loads go onto that wall in the same way, without the beam self-weight.

• Using the residential 1.9 kPa for stairways and exit corridors. Exit facilities take 4.8 kPa in all occupancies.
• Using 1.9 kPa for an exterior balcony. Exterior balconies take 2.9 kPa.
• Treating a roof deck or terrace as a roof at 1.0 kPa or less. Use the live load of the area served and add the paving, soil and planters as dead load.
• Leaving out CHB wall weight, or forgetting the plaster. Plaster adds 0.24 kPa per face, and grouted cells add much more (fully grouted 150 mm CHB is 2.63 kPa or more before plaster).
• Using Table 204-2's 0.24 kPa movable partition weight where 204.3 requires the 1.0 kPa partition allowance, or adding the allowance on top of fixed CHB walls already counted at their actual weight.
• Taking values from a table based on NSCP 2010. Check that the table you use is from NSCP 2015.
• Mixing strength design and allowable stress design: factored loads (Eq. 203-1 to 203-7) go with design strengths; unfactored D + L goes with allowable stresses, deflection and soil bearing.