Project 2

1.

Design Basis Report (DBR)

Project Title: Design of Warehouse Building
Location: Chennai, India
Software Used: STAAD Pro Connect Edition
Codes Followed:

• IS 800:2007 – General Construction in Steel – Code of Practice

• IS 875 (Part 1, 2 & 3): Wind, Dead & Live Loads

• IS 1893 (Part 1): 2016 – Earthquake Resistant Design

• IS 456:2000 – for concrete foundation if applicable

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1. Project Description

The project involves the design of a single-storey industrial warehouse with the following dimensions and constraints:

Parameter	Value
Width (Span)	30 m
Length	50 m
Eave Height	9 m
Bay Spacing	6 m
No. of Bays (Length)	50 / 6 = 8.33 (~9 bays)
Roof Slope	1 in 12
Location	Chennai, India
Soil Type	Medium
SBC	200 kN/m²

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2. Design Philosophy

The warehouse is designed as a steel portal frame with a pitched roof. The primary framing system will consist of rigid steel frames spanning across the 30 m width, spaced at 6 m intervals along the 50 m length.

• Portal Frame System with roof bracing and wall bracing.

• Pin-based column supports at base.

• Gable roof with 1:12 slope.

• Trapezoidal sheeting for roof and side cladding.

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3. Load Considerations

A. Dead Load (DL) [IS 875 Part 1]

• Self-weight of structural members: Automatically considered in STAAD.

• Roofing sheets: 0.15–0.25 kN/m²

• Purlins, bracings: 0.10–0.15 kN/m²

• Miscellaneous: 0.10 kN/m²
  Total DL on Roof: ~0.5 kN/m² (conservative)

B. Live Load (LL) [IS 875 Part 2]

• Roof Live Load: As per slope <10°, LL = 0.75 kN/m²

C. Wind Load (WL) [IS 875 Part 3]

• Basic Wind Speed (Chennai): 50 m/s

• Risk Coefficient, k1: 1.0

• Terrain Category: 2 (semi-open)

• Topography factor, k3: 1.0

• Structure Class: C (warehouse)

• Roof angle <10°, use appropriate Cp coefficients

Wind load to be applied in:

• Along-span direction (0°)

• Across-span direction (90°)

• Suction on roof slope (uplift)

D. Seismic Load (SL) [IS 1893 (Part 1): 2016]

• Zone: III (Chennai)

• Zone Factor (Z): 0.16

• Importance Factor (I): 1.0

• Response Reduction Factor (R): 3.0 (Steel Frame with bracing)

• Soil Type: Medium (Type II)

• Damping: 5%

4. Structural System

A. Primary Members

• Portal Frame Columns: ISMB 400/ISWB 500 (Tentative)

• Rafter Beams: ISMB 450/ISWB 550

• Purlins: ISMC 150 @ 1.5 m spacing

• Bracings: Rod bracings 16 mm Ø

B. Secondary Members

• Side/End wall girts: ISMC 100

• Roof sheeting: Trapezoidal GI sheet, 0.6 mm thick

• Side sheeting: Corrugated GI sheet

5. Foundation Design

• Type: Isolated RCC footing

• SBC: 200 kN/m²

• Size: Designed based on column load reactions (to be extracted from STAAD)

6. STAAD Pro Modeling Steps

1. Define geometry (portal frame, bays)

2. Assign properties to members (sections)

3. Define material – Steel (Fe 250 / Fe 345)

4. Define supports – pinned at base

5. Assign loads:

   • Dead load (self + roof sheeting)

   • Live load

   • Wind load (IS 875–3 wind generator)

   • Seismic load (IS 1893 parameters)

6. Load combinations as per IS 800:2007 – LSD method

7. Run Analysis

8. Design Check using IS 800:2007 (LSD)

9. Extract reactions for foundation design

7. Design Output & Drawings

• STAAD Output: Member forces, deflections, stress ratios

• Structural Drawings:

  • Column & Frame layout

  • Bracing details

  • Foundation plans

  • Connection details

8. Assumptions

• All members are adequately connected by bolted/welded joints

• Temperature effects are negligible

• Construction tolerances as per IS 7215

• Fabrication as per IS 800:2007

Creating the Structural Model in STAAD Pro Connect

STEP 1: Start a New Project

1. Open STAAD Pro Connect Edition

2. Create New Project → Give name: Warehouse_Chennai

3. Units: Metric (kN, m)

4. Save in preferred location

STEP 2: Define Geometry

Use Structure Wizard → Frame Model → Portal Frame

You can also manually define it:

• Create Nodes at bay intervals (X-direction) and height (Y).

• Span (Z-direction) = 30 m

• Bay Spacing (X-direction) = 6 m × 9 bays = 54 m total length

Define rafter slope using 1:12 → Roof Rise = 30 / 24 = 2.5 m

So ridge height = 9 + 2.5 = 11.5 m

STEP 3: Define Properties

From Properties → Section Database → IS Sections:

• Columns (Vertical): ISMB 400

• Rafters (Sloped beams): ISMB 450

• Purlins: ISMC 150 (spaced at ~1.5 m)

• Bracings (Diagonals): Circular rod 16 mm or IS angle

• Side girts: ISMC 100

Assign sections to corresponding members.

STEP 4: Define Material

Use default:

• Steel (Fe 250/345) → Check material constants

STEP 5: Define Supports

• All Columns at base → Use Pinned support (Fixed but no moment)
  Support Type → Pinned

STEP 6: Apply Loads

A. Self-Weight

• In Load Case 1 → Selfweight -Y → factor = -1

B. Dead Load (Roof Sheeting, Purlins, etc.)

• Uniform load on rafter beams: ~0.5 kN/m² × tributary width (1.5 m)
  → Apply member load on rafters

C. Live Load

• As per IS 875 (Part 2): 0.75 kN/m² on roof
  → Same method as DL

D. Wind Load

Use Wind Load Generator:

• Chennai → Basic Wind Speed = 50 m/s

• Terrain Category: 2

• Building Class: C

• Apply load on frames in X & Z directions

• Consider suction/uplift on roof

E. Seismic Load

• Use Seismic Definition → IS 1893

• Zone = III → Z = 0.16

• I = 1.0, R = 3.0

• Soil = Medium (Type II)

STEP 7: Load Combinations

Auto-generate combinations based on IS 800 LSD:

• DL + LL

• DL + WL (±X, ±Z)

• DL + EQ (±X, ±Z)

• DL + LL + WL

• Etc.

STEP 8: Perform Design

• Go to Design → Steel Design → IS 800:2007 (LSD)

• Select members → Assign → Define parameters (Fy, Section Check, etc.)

• Click Design → Run Analysis

STEP 9: Post-Processing

• Check member utilization ratios (Should be ≤1.0)

• Check deflections (Span/300 typically)

• Adjust sections if needed

STAAD SPACE

START JOB INFORMATION

ENGINEER DATE 10-APR-2025

END JOB INFORMATION

INPUT UNIT METER KN

UNIT METER KN

JOINT COORDINATES

0 0 0;

0 0 6;

0 0 12;

0 0 18;

0 0 24;

0 0 30;

0 0 36;

0 0 42;

0 0 48;

0 0 54;

REM Eave height 9m; Ridge = 11.5m (slope 1:12), Span = 30m

DEFINE XZ FRAME AT EACH BAY:

REPEAT 10 TIMES

10 0 0;

10 9 0;

10 11.5 15;

10 9 30;

10 0 30;

ENDFOR

ELEMENT INCIDENCES

* You will need to manually generate frame elements or use GUI to auto-frame

MEMBER PROPERTY INDIAN

1 TO 100 PRIS ISMB450 // Example for rafters and columns

101 TO 120 PRIS ISMC150 // Purlins

121 TO 140 PRIS ISMC100 // Side girts

CONSTANTS

MATERIAL STEEL

E 2.05E8

POISSON 0.3

DENSITY 76.8

ALPHA 1.2E-5

SUPPORTS

1 TO 100 PINNED

LOAD 1 LOADTYPE Dead TITLE DL

SELFWEIGHT Y -1

MEMBER LOAD

1 TO 100 UNI GY -0.5

LOAD 2 LOADTYPE Live TITLE LL

MEMBER LOAD

1 TO 100 UNI GY -0.75

LOAD 3 LOADTYPE Wind TITLE WL+X

* (Add member or joint loads based on wind pressure distribution manually or via GUI)

LOAD 4 LOADTYPE Seismic TITLE EQ+X

DEFINE 1893 LOAD

ZONE 0.16

RF 3

I 1

TYPE 2

X 0.05 Y 0.05 Z 0.05

LOAD COMB 101 DL + LL

1 1.0 2 1.0

LOAD COMB 102 DL + WL+X

1 1.0 3 1.0

LOAD COMB 103 DL + EQ+X

1 1.0 4 1.0

PERFORM ANALYSIS

FINISH

Basic Building Specs Recap

Parameter	Value
Width (Span)	30 m
Length	54 m (9 bays × 6 m)
Eave Height	9 m
Roof Slope	1:12
Ridge Height	11.5 m
Roof Type	Gable
Terrain Category	2
Class of Structure	C
Risk Coefficient (k1)	1.0
Wind Speed (Vb)	50 m/s
Seismic Zone	III
SBC	200 kN/m²
Soil Type	Medium (Type II)

1.Dead Load (DL) – IS 875 Part 1

Component	Unit Load (kN/m²)	Area (m²)	Total Load (kN)
Roofing sheet (GI)	0.20	1620	324
Purlins	0.10	1620	162
Insulation, bolts	0.05	1620	81
Bracing/cladding	0.10	1620	162
Total Dead Load	0.45 kN/m²	1620	729 kN

Apply DL as uniform load on rafters considering tributary area (~1.5 m between purlins).

Live Load (LL) – IS 875 Part 2

For Roof:

• For slope < 10°, LL = 0.75 kN/m² (as per IS 875 Part 2, Cl. 4.1)

So, total live load on roof =
LL = 0.75 × 1620 = 1215 kN

Apply LL as uniform load on rafters

3.Wind Load (WL) – IS 875 Part 3

Basic Parameters:

• Vb = 50 m/s (Chennai)

• k1 = 1.0 (General building)

• k2 = 0.98 (Terrain Cat. 2, Height 10-15 m)

• k3 = 1.0 (No topography)

• Design Wind Speed, Vz = Vb × k1 × k2 × k3 = 50 × 1 × 0.98 × 1 = 49 m/s

Design Wind Pressure:

$P_z = 0.6 \cdot V_z^2 = 0.6 \cdot 49^2 = \boxed{1440.6 \, \text{N/m}^2} = 1.44 \, \text{kN/m}^2$Pz​=0.6⋅Vz2​=0.6⋅492=1440.6N/m2​=1.44kN/m2

Wind Pressure Zones (Based on Gable Roof)

Use IS 875 Part 3 Fig. 5 & Table 5 for Cp values (Roof <10° slope):

Surface	Cp (Pressure Coefficient)	Net Pressure (kN/m²)
Windward Wall	+0.7	1.44 × 0.7 = 1.008
Leeward Wall	-0.25	1.44 × (-0.25) = -0.36
Side Walls	-0.7	-1.008
Roof (windward)	-0.7	-1.008
Roof (leeward)	-0.5	-0.72

Apply as member or surface loads on purlins/rafters/cladding.

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4.Earthquake Load (EQL) – IS 1893 (Part 1): 2016

Basic Parameters:

Parameter	Value
Seismic Zone	III
Zone Factor (Z)	0.16
Importance Factor (I)	1.0
Response Reduction (R)	3.0 (Steel Frame with bracing)
Soil Type	Medium

Seismic Weight (W):

Use Dead Load + % of Live Load (as per IS 1893 Cl. 7.3.1)

• Total DL = 729 kN

• LL = 1215 kN × 25% = 303.75 kN

• W = 729 + 303.75 = 1032.75 kN

Base Shear (Vb):

$$V_b = \frac{Z \cdot I \cdot S_a/g}{R} \cdot W$$Vb​=RZ⋅I⋅Sa​/g​⋅W

Assume:

• Fundamental Time Period T = 0.09h/√d = 0.09×11.5/√30 ≈ 0.19 sec

• From IS1893 Fig. 3 (Medium Soil), for T=0.19 ⇒ Sa/g ≈ 2.5

$$V_b = \frac{0.16 \cdot 1.0 \cdot 2.5}{3.0} \cdot 1032.75 = \boxed{137.7 \, \text{kN}}$$Vb​=3.00.16⋅1.0⋅2.5​⋅1032.75=137.7kN​

Distribution of Lateral Force:

Distribute using:

$$Q_i = V_b \cdot \frac{W_i h_i^2}{\sum W_i h_i^2}$$Qi​=Vb​⋅∑Wi​hi2​Wi​hi2​​

• For 2 storey frame: roof and eave levels can be used (h = 9 m and 11.5 m)

• Can be simplified if you apply as a single-level lateral load (Chennai has low seismic activity)

Summary Table

Load Type	Magnitude (per m²)	Notes
Dead Load	0.45 kN/m²	Sheeting + purlins etc.
Live Load	0.75 kN/m²	For <10° slope
Wind Load	Up to ±1.0 kN/m²	Use Cp values
EQ Load	Base Shear = 137.7 kN	IS 1893:2016

1. Steel Column Design (IS 800:2007 – LSD)

Inputs

• Column height: 9 m

• Axial Load (Pu): from STAAD or DL+LL

• Section (e.g., ISMB 400)

• Fy = 250 MPa

Steps

1. Effective Length (Leff):

   • For pinned ends: Leff = 9 m

2. Slenderness Ratio (λ):

   $$\lambda = \frac{L_{eff}}{r_{min}} \quad (r_{min} \text{ from section table})$$λ=rmin​Leff​​(rmin​ from section table)

3. Design Compressive Strength (fcd): Use IS 800 Table 9(c) for fcd based on λ

4. Capacity Check:

   $$P_d = A_g \cdot f_{cd} \quad \text{(Ag = cross-sectional area)}$$Pd​=Ag​⋅fcd​(Ag = cross-sectional area)

5. Check:

   $$P_d > P_u \Rightarrow \text{Safe}$$Pd​>Pu​⇒Safe

2. Rafter Design (IS 800:2007 – LSD)

Inputs

• Span = 15 m each side (gable)

• Slope = 1:12

• Load: DL + LL + WL from earlier

• Fy = 250 MPa

Steps

1. Bending Moment (M):

   $$M = \frac{w \cdot L^2}{8} \quad (\text{for UDL})$$
   

2. Section Modulus (Z):

   $$M_d = \beta_b Z_p f_y / \gamma_{m0} \quad \text{Check } M_d > M$$
   

3. Shear & Deflection Checks

3. Base Plate Design (IS 800 & IS 456)

Inputs

• Axial load Pu

• SBC = 200 kN/m²

• Column size

Steps

1. Bearing Area Required:

   $$A_{req} = \frac{P_u}{SBC}$$​

2. Base Plate Size:

   • Provide ≥ Areq with some edge clearance

   • Example: 400 mm × 400 mm

3. Bearing Check:

   $$\sigma_b = \frac{P_u}{A_{plate}} < SBC$$
   

4. Anchor Bolt Design (Optional uplift case)

4. Pedestal Design (IS 456:2000)

Inputs

• Load from column

• Size from base plate

• Concrete: M25

• Reinforcement: Fe500

Steps

1. Check compressive stress:

   $$\sigma = \frac{P_u}{A_ped} < 0.45f_{ck}$$​

2. Provide nominal reinforcement:

   • Min = 0.15% for mild steel

5. Z-Purlin Design (IS 800)

Inputs

• Spacing = 1.5 m

• Span = spacing between frames (6 m)

• Load = DL + LL + WL on purlin

Steps

1. BM on simply supported Z-section:

   $$M = \frac{wL^2}{8}$$​

2. Section modulus Zp:

   • Select Z-section from catalog (e.g., 200×60×20×2.0 mm)

3. Check capacity:

   $$M_d = \frac{Z_p f_y}{\gamma_{m0}}$$​

2.

Step 1: Given Data

Parameter	Value
Span of gantry girder (L)	7 m
Span of crane girder	9 m
Crane capacity (Q)	250 kN
Self-weight of trolley & motor	40 kN
Self-weight of crane girder	100 kN
Min hook approach (c)	1.0 m
Wheel spacing (a)	3.0 m
Rail weight	0.2 kN/m

Step 2: Load Calculations

A. Crane Load on Wheels

1. Total moving load = Crane Capacity + Trolley

$$= 250 + 40 = 290 \, \text{kN}$$=250+40=290kN

2. This acts as a point load on the crane girder, which is transferred to the two crane wheels

• Assuming worst-case (hook closest to one wheel):

  • Max wheel load = $\frac{290 \cdot (L - c)}{L}$L290⋅(L−c)​

$$= \frac{290 \cdot (9 - 1)}{9} = 257.78 \, \text{kN}$$=9290⋅(9−1)​=257.78kN

• Load on nearer wheel = 257.8 kN

• Load on farther wheel = $290 - 257.8 = 32.2 \, \text{kN}$290−257.8=32.2kN

3. Crane girder self-weight = 100 kN

• Divide equally on two wheels → 50 kN per wheel

• Add to both:

  • Max wheel = 257.8 + 50 = 307.8 kN

  • Min wheel = 32.2 + 50 = 82.2 kN

Max vertical wheel load = 307.8 kN

B. Load Transfer to Gantry Girder

• Assume gantry girder supports one crane wheel

• Max reaction on gantry = 307.8 kN

• Impact factor (as per IS codes) = 25%

$$\text{Factored wheel load} = 307.8 \cdot 1.25 = \boxed{384.75 \, \text{kN}}$$​

Step 3: Moment and Shear on Gantry Girder

A. Maximum Moment (Single Point Load at midspan)

$$M_{max} = \frac{W \cdot L}{4} = \frac{384.75 \cdot 7}{4} = \boxed{673.31 \, \text{kNm}}$$Mmax​=4W⋅L​=4384.75⋅7​=673.31kNm​

B. Maximum Shear

$$V_{max} = \frac{W}{2} = \boxed{192.38 \, \text{kN}}$$

Step 4: Section Selection

• Use built-up I-section with channel cap or ISMB rolled section + plate

• Use trial section: say ISMB 600 + 400×20 flange plate

Calculate:

• Plastic section modulus $Z_p$Zp​

• Use IS 800:2007:

$$M_d = \frac{Z_p \cdot f_y}{\gamma_{m0}} \Rightarrow Z_p = \frac{M_d \cdot \gamma_{m0}}{f_y}$$​​

For Fy = 250 MPa, $\gamma_{m0} = 1.1$γm0​=1.1

$$Z_p = \frac{673.31 \times 10^6 \cdot 1.1}{250 \times 10^6} = \boxed{2.963 \times 10^6 \, mm^3}$$Zp​=250×106673.31×106⋅1.1​=2.963×106mm3​

Check your trial section $Z_p \geq 2.96 \times 10^6 \, mm^3$

Step 5: Rail Load

• Self-weight of rail = 0.2 kN/m

• Uniformly distributed over 7 m:

  $$w = 0.2 \, \text{kN/m} \Rightarrow M = \frac{w L^2}{8} = \frac{0.2 \cdot 7^2}{8} = 1.225 \, \text{kNm}$$
  

Summary

Item	Value
Max Factored Wheel Load	384.75 kN
Max Moment (factored)	673.31 kNm
Max Shear	192.38 kN
Required Zp	2.96 × 10⁶ mm³

Design Parameter	Value
Span of Gantry Girder (L)	7 m
Crane Capacity (Q)	250 kN
Self-weight of Trolley + Hook	40 kN
Self-weight of Crane Girder	100 kN
Minimum Hook Approach (c)	1.0 m
Wheel Spacing (a)	3.0 m
Max Crane Load on Wheel (with Hook closest)	257.8 kN
Self-weight per Wheel	50 kN
Max Wheel Load	307.8 kN
Impact Factor	25%
Factored Max Wheel Load	384.75 kN
Max Moment (Mmax)	673.31 kNm
Max Shear (Vmax)	192.38 kN
Required Plastic Section Modulus (Zp)	2.96 × 10⁶ mm³