Load bearing Structural Design Report Template

1

1. REFERRED CODES, DOCUMENTS AND STANDARDS OF
PRACTICE
The following are the referred codes and documents utilized for the analysis procedures:
• UBC 97/ACI-99 is used for seismic loading, service combinations for allowable stress
design evaluation of existing stone masonry building by linear static analysis
• FEMA 356 is used for stone masonry properties

2. SOFTWARE UTILIZED FOR ANALYSIS
The software utilized for evaluation of existing structure as well as for the evaluation of
designed retrofitted structure is CSI ETABS 16.2.1, which is internationally certified software
for performance based analysis and design.

3. DATA ASSUMED ON BASIS OF GIVEN CONDITIONS
The following data was assumed on basis of given/indicated conditions:
• Assuming fair condition for masonry; F’m = 600 psi ( FEMA 356, Table 7-1)
• Masonry Elastic Modulus; Em = 550 x F’m ( FEMA 356, Table 7-1)
• Masonry shear strength; 20 psi ( FEMA 356, Table 7-1)
• Assuming masonry as low strength (600psi compressive strength) concrete for property
modifiers to incorporate cracked moment of inertia (0.35 for moment of inertia of walls)
• Soil type : SD
• Masonry Shear Modulus as per UBC 97; G = 0.4 x E
• Assuming concrete used in beams, slabs; f’c = 3000 psi.
4. CALCULATED PARAMETERS
Following are the calculated parameters for the evaluation of the existing buildings:
• Importance factor for seismic loading as per UBC-97; I = 1
(building is not confirmed to have emergency surgical equipment neither has 5000
occupants)
• Seismic Zone 3 and soil type SD; hence : Ca = 0.36 , Cv = 0.54
• For time period value of Ct as per UBC 97; Ct = 0.02
• Value of strength reduction factor for masonry shear wall as per UBC-97; R = 4.5
• Modulus of elasticity for masonry; Em = 550 * 600 = 330,000 psi
• Shear modulus = 0.4*330,000 = 132,000 psi
• Ɛy = F’m / Em = ,000 = 0.0018 in/in
• Poissons ratio; µ = {E / (2*G)} -1 = 0.25




STRUCTURAL ENGINEER | ENGINEERING LEARNING PLATFORM

, 2

5. STRUCTURAL MODELLING
5.1. MODELLING PARAMETERS
The modelling parameters adopted for the models are mentioned respectively;

5.2. LINEAR STATIC ANALYSIS MODEL
The parameters utilized in linear static analysis model are as follows:

• Material properties for concrete beams and slabs; fc’ = 3 ksi
• Material properties for rebar; fy = 60 ksi
• Material properties for masonry walls; f’m = 600 psi
• Frame properties for concrete band beams : 8” x 12” reinforced with 2+2-#3 bars
• Frame properties for masonry wall reinforced corners defined as columns : 8” x 18”
reinforced with 2-#3
• Wall section for masonry wall : 8” thick wall
• Slab properties for concrete slab : 6” thick slab
• Gravity loading was taken as; Dead = Slab self + wall self
SDL = 36 psf for finishes
Snow = 20 psf
Roof LL = 20 psf
• Seismic loading parameters were taken as; Zone = 3
Soil = SD
Importance factor = 1
Ct = 0.02
R = 4.5 (Masonry shear walls)
• Rigid type diaphragms
• P-Delta effects based on iterative loads; 1.2 x DL , 1.6 x LL
• Analysis combinations using allowable stress design (ASD)
D+L
D + L ± E/1.4
D + L + S/2
D+L+S
D + L + S ± E/1.4




STRUCTURAL ENGINEER | ENGINEERING LEARNING PLATFORM