Monorail Crane Girder Calculation

CALCULATION FOR UNDERHUNG MONORAIL STRUCTURE

A) OBJECTIVE The objective of the of  the calculation report is to provide design calculations for various Underhung Monorail Cranes for the cooling plant 1)

TYPE 1 A/B, 8TON ABOVE EACH CHILLER IN GROUND FLOOR

B) DESIGN CODES AND REFERNCES 1)

AISC 360‐10

:

SPECIFICATION FOR STRUCURAL STEEL BUILDINGS

2)

ASCE 07‐10

:

MINIMUM DESIGN LOADS FOR BUILDINGS AND OTHER STRUCURES

3)

MBMA 2006 :

METAL BUILDING SYSTEMS MANUAL

4)

AISC DG7

INDUSTRIAL BUILDINGS ROOFS TO ANCHOR RODS, 2ND EDITION

5)

MODERN STEEL CONSTRUCTION / DECCEMBER 1999

:

C) MATERIAL SPECIFICATIONS 1)

2)

3)

I SECTION

BOLTS

WELD

:

:

:

S275 GRADE Fy

=

275 MPa

Fu

=

410 MPa

8.8 GRADE Fy

=

580 MPa

Fu

=

800 MPa

=

480 MPa

E70XX FU

D LOAD CALCULATION 1)

Dead load Weight of steel of  steel sections are assigned by default in staad

2.1)

Live load for Crane type 1 A/B Lift Capacity

=

8 Ton

=

80 kN

=

580 kg

=

5.8 kN

Total live load

=

85.8 kN

Vertical Impact factor

=

Live load with Impact factor

=

Weight of trolley of  trolley + hoist

25 % of live of  live loads 107.3 kN

CALCULATION FOR UNDERHUNG MONORAIL STRUCTURE

Lateral loads

=

Lateral loads

=

Longitudinal loads

=

Longitudinal loads

=

20 % of live loads 17.16 kN 10 % of live loads 8.58 kN

E LOAD COMBINATIONS 1)

ASD load Combination i)

2)

(service load combination)

D+L

ULS load combination i)

1.4D

ii)

1.2D+1.6L

(strength load combination)

F DEFLECTION LIMITS Vertical deflection limit

=

L / 450

( LC: D+L)

G DESIGN CALCULATION Design Philosophy

The monorail frame is supported by above RCC slab. Monorails are hung from RCC slab using vertical members and bracing members are provided for lateral bracing at every 2200mm c/c spacing. Members are designed for flexure, shear and deflection in staad as Space Frame. Also an additional check for Monorail Bottom flange loading capacity is done as the crane is under hung. The supports are assumed to be fixed as base plate are embeddded in the RCC slab, on to which the monorail support members are welded using fillet weld.

Only a single support span is considered for the design. The crane live load is applied at centre with vertical impact factor, lateral and longitudinal loads.

Design parameters DFF

=

450

(check for monrail vertical deflection)

METHOD

=

LRFD

(design method)

CALCULATION FOR UNDERHUNG MONORAIL STRUCTURE

Monorail Bottom Flange Check

The bottom part of the crane beam must be checked for :‐ 1)

Tension in the web

2)

Bending of the bottom flange

Total load on wheels

P

=

107.3 kN

Load on each wheel

P/4

=

26.81 kN

width of flange

b

=

206 mm

thickness of web

tw

=

15 mm

thickness of flange

tf

=

25 mm

root size

k

=

18 mm

wheel center from steel beam edge

m

=

25 mm

Use, I BEAM HEM200 as crane monorail

Alloawable stress in beam

=

0.6 x Fy

= 1)

165 MPa

Tension in the web Load acting on each side of web due to a pair of wheels

= =

Area under tensile stress

= =

Tensile stress in web

ft

P/2 53.63 kN tw x 3.5k 945 sq.mm

=

56.75 MPa

<

165 MPa

Hence Safe 2)

Bending of the bottom flange Load on each wheel on flange Eccentricity from centre of beam Flange bending moment

e M

=

P/4

=

26.81 kN

=

(B‐tw‐2k)/2‐m

=

52.5 mm

= =

Section Modulus Bending stress

S fb

Pe/4 1408 kNmm 2

=

2e x tf  /6

=

10938 mm

=

128.7 MPa

<

165 MPa

3

Hence Safe

CALCULATION FOR UNDERHUNG MONORAIL STRUCTURE

H PRELIMINARY DESIGN OUTPUT Underhung monorail crane is safe in strength and serviceability considerations as per AISC360‐10 and ASCE 07‐10.

Utility ratios < 0.9 for all the members Monorail section

:

HEM200, S275 grade

Vertical and Bracing Members

:

UC152x152x23, S275 grade