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DESIGN BASIS For Construction of Structures on South Boulevard

The following design basis is assumed for the preliminary analysis and design of the structures on South Boulevard.

1. Material Strength

- Minimum concrete cylindrical compressive strength = fck =30MPa; Ecm=30GPa, γc = 1.5; εcu=0.0035; assumed aggregate = limestone. - Reinforcement Type = B500C (For both Longitudinal and Transverse directions)

γs = 1.15,

2. Building Type

The building is a reinforced concrete structure, constructed top-down. The structure has reinforced concrete frame system with added shear walls or cores, also termed as "Frame Equivalent Dual system".

3. Gravity Loads

Based on the architectural usage, the minimum distributed design loading to be applied on the structures is in accordance with Eurocode-1 "Actions on structures". However, for specific mechanical or equipment loads, the loading data should be explicitly provided.

Type Load (kN/m2) Finishes 2.0 Partitions 1.5 Live (Shops) 5.0 Live (offices) 3.0 Live (Stairs) 6.0 Live (Car Parking) 3.0 Live (Heavy Trucks) 5.0 Equipment Live Load 10.0 Soil Using γs = 20 kN/m2 Snow 2.5

4. Effective section properties

The cracked section properties assumed for the section design and deflection control checks is as follows:

Element Effective EI Beams 0.5

Columns 0.7 in compression (inner columns) 0.5 in tension (Edge columns)

Walls 0.5*EI & 0.5*GA Joints Rigid offsets with factor 0.5

 

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 5. Wind Resistant Design

The wind loading on the structures is considered based on the design guidelines of Eurocode-1 "Action on structures; Part1-4: General actions - Wind actions". Basic wind speed is assumed equal to 33 m/sec. However, actual value of wind speed will be required depending on the local wind zonation maps of Macedonia.

6. Seismic Design

The seismic design parameters are assumed as follows in accordance with Eurocode-8 Part 1 based on the information provided in the "Elaborate: Geotechnical investigation on location foreseen for construction of structures on south boulevard". Foundation Soil: Silty Sand and Sandy Clay [geotechnical Report] Ground type: C [Eurocode 8 Table 3.1 and NSPT from Geotech. Report] * The Ground Category in accordance with Macedonian Regulation is II. Horizontal PGA on Rock (PoE = 10% in 50 years) for Design basis Earthquake = 0.3g. [Ref: Annex1]

Importance Class = II: γI = 1.0 Building Ductility Class = DCM (ductility class medium) Consequence class = CC3; Reliability Class = RC3 Behaviour Factor = 3.14 Mass Source: All Dead load + Probable Live load + Snow load has to be included in the effective mass for seismic forces calculation. The factor for combination is selected from EC-0 and is as follows; Dead = 1.0; Live = 0.6 (0.5 recommended in Macedonian Regulation); Snow = 0.2 Maximum lateral deflection for building during seismic event = Total height/600 (in accordance with Macedonian Code)

7. Soil Parameters for Foundation Design

The bearing capacity of the soil is assumed as 400 kN/m2 as per geotechnical investigation report. The value of subgrade Modulus Kv, in order to define soil-structure interaction, is approximated using equation 3.1 below, (Bowles, 1996). Kv = 40[c Nc + γ z Nq + 0.5 γ B Nγ ] --------------------------------- (3.1) where, c = Cohesive strength Nc Nγ Nq = Coefficients from Terzaghi B = width of foundation z = Depth of foundation bottom level γ = Specific weight of the soil However, the value of subgrade modulus "Kv" should be explicitly provided in the geotechnical calculation report.

 

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8. Pile Capacity

The minimum allowable pile capacity along with its subsequent diameter should be specified. In addition, horizontal sub-grade modulus "Kh" for lateral stability of piles and vertical subgrade modulus "Kv" for raft foundation design should be explicitly provided.

 

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 ANNEXURE -1