design and behavior of jib cranes

CIVL 510 Design of behavior of jib crane Zhen Sun, Abdul Wajid, Qijun Chang

Design of behavior of jib crane 4/28/2010 PAGE 1 OF 20

Design and behavior of jib crane

(Source: Google) For: Dr. Stiemer CIVL 510 University of British Columbia

By: ZHEN SUN (83204081)

ABDUL WAJID (83210088)

QIJUN CHANG (83263087)

Date: April 22, 2010

Abstract A jib crane is a type of crane where a horizontal member (jib or boom), supporting a moveable hoist, is fixed to a wall or to a floor‐mounted pillar. Jib cranes are used in industrial premises and on military vehicles. The jib may swing through an arc, to give additional lateral movement, or be fixed. Similar cranes, often known simply as hoists, were fitted on the top floor of warehouse buildings to enable goods to be lifted to all floors. Design of jib crane for Canadian applications is based on CMAA (Crane Manufacturers Association of America) specifications # 74 which is for Top Running and Under Running Single Girder Electric Overhead Traveling Cranes Utilizing under Running Trolley Hoist is reviewed. Steel structure components design of jib crane should follow Canadian steel structure design code which is Handbook of Steel Construction. Design of jib crane includes structural design, mechanical design and electrical equipment design part. In this case, it focused on structural design for jib crane, such as steel girder, steel mast, base plate, bolts design. Development of a formatted spreadsheet application based on spreadsheet template for tension member, compression member and bolts connection.



Table of Contents

Design and behavior of jib crane .............................................................. 1 Abstract ................................................................................................ 1 Table of Contents ................................................................................. 2 Table of Figures .................................................................................... 2 1.0 Introduction ................................................................................... 3 2.0 Background .................................................................................... 3 3.0 Applications of jib crane ................................................................. 5 4.0 Canadian design code .................................................................... 5 5.0 Design example .............................................................................. 8 6.0 Spreadshhet applications ............................................................. 13 7.0 Conclusion .................................................................................... 13 8.0 Bibliography ................................................................................. 14 Appendix A: Spreadsheet Application ................................................ 14

Spreadsheet application screenshot ............................................. 15

Table of Figures

Figure 1: Free standing jib crane ........................................................... 3 Figure 2:.Wall mounted jib crane ............................................................. 3 Figure 3: Wall bracket jib crane ................................................................ 5 Figure 4: Mast style jib crane ................................................................... 5 Figure 5: Round mast design for free standing jib crane. ........................ 9 Figure 6: I‐shape mast design for wall mounted jib crane .................. 10 Figure 7: I‐shape mast design for mast style jib crane ........................... 10 Figure 8: Tie rods picture ........................................................................ 13 Figure 9: Wall bracket connection picture ............................................. 13



DESIGN AND BEHAVIOUR OF JIB CRANES 1.0 Introduction A cantilevered beam with hoist and trolley. The lifting device may

pick up loads in all or part of a circle around the column to which it is attached and are made of rolled steel I‐beams.

A jib crane is a type of crane where a horizontal member (jib or boom), supporting a moveable hoist, is fixed to a wall or to a floor‐mounted pillar. Jib cranes are used in industrial premises and on military vehicles. The jib may swing through an arc, to give additional lateral movement, or be fixed. Similar cranes, often known simply as hoists, were fitted on the top floor of warehouse buildings to enable goods to be lifted to all floors.

2.0 Background 2.1 HISTORY OF JIB CRANE In 1934, Mr Gibb, of Aberdeen accompanied by Mr Mitchell, of Inverness, inspected the harbour, and Mr Telford being consulted, plans were drawn for its reconstruction. At this work travelling jib crane was used. First actual jib crane was used by The David Round Company in 1869. 2.2 TYPES OF JIB CRANES 2.2.1 Free standing jib crane.

(Source: http://www.jherbertcorp.com/crane‐jib.htm)

Free standing Jib Cranes is directly fixed on the floor without any support to keep it upright. To maintain its stability and not topple over it you fix it to a foundation of 3 to 5 feet deep and up to 4 to 10 feet square foundation base. The foundation depends on the load and reach. Advantage of this type of crane is it doesn’t need a support wall or structure and provides optimal range of span and control compare to wall mounted cranes and other types of Jib cranes. The picture here shows a 2 ton free standing jib crane used in a yard environment. 2.2.2 Wall mounted jib crane




Wall mounted jib crane. Like the name suggests this kind of jib crane is fitted onto the wall. It requires very little headroom, so it can be fitted very close to the underside of roofs etc. to provide maximum lift for your hoist. The coverage like other types of cranes is circular and generally around 20 feet. But it requires a strong wall or column structure to fit it and degree of rotation is lesser than that of Mast style and free standing jib cranes. This crane is very efficient way to move material when floor space is not available and digging a foundation for the crane is not feasible. 2.2.3 Wall bracket jib crane


This crane is similar to wall mounted jib cranes but with a bracket. It’s a most economical means of providing hoist coverage for individual use in bays, along walls or columns of plants. The installation requirements and load and rotation are like the wall mounted crane. Use a lot for swinging around obstacles and over obstructions. 2.2.4 Mast style jib crane


This is similar to free‐standing jib cranes but doesn’t need a special foundation making it more economical. But they do require mounting at the top and bottom. They also provide a full 360 degree rotation jibs depending on the manufacturer and maximum amount of lift with full use of available headroom and allows specific placement of boom to clear obstructions. 2.2 WORKING OF JIB CRANE The underlying layout of a jib cranes consists of a solid boom shackled to a fixed pivot point. In turn, this pivot is securely mounted onto a wall or on top of a freestanding column. This pivot moves freely, allowing 180 or 360‐degree rotation, and a wide arc of operation. The lifting is performed by an incorporated pulley or motorized chain hoist, which can slide along the book and offer a large footprint of operation. Free standing and mast type jib cranes offer 360‐degree rotation. Wall mounted types offer 200‐degree rotation.



3.0 APPLICATIONS OF JIB CRANE Jib cranes are arranged, for example, in shipbuilding yards for use

in transportation of heavy burdens. A jib crane is provided which can prevent an unexpected

movement of a burden and can sufficiently ensure the safety of a burden handling work.

The major strength is its stability and flexibility of the device. It is ideal for lifting a product to or from material handling system

to a work station or machine. Jib crane is commonly used for workstation and simple

loading/unloading operations where it is not necessary to spot a load precisely.

Jib cranes most often handle lighter loads at lower duty cycles than their bridge and gantry crane counterparts.

4.0 Canadian Design Code 4.1 Capacity for Jib Crane The maximum weight of the application should match and not exceed design weight. The capacity rating is based on a design load which includes the capacity rating of the crane plus 15% of the capacity for the weight of the hoist and trolley, 25% of the capacity as an allowance for impact. The deflection is based on a design load which includes capacity plus 15% of capacity for the hoist and trolley. 4.2 Loads on Jib crane: (CMAA Page ‐13) Trolley load: the weight of the trolley and equipment attached to the trolley. Dead load: the weight if all effective parts of the bridge structure, the machinery parts and the fixed equipment supported by the structure. Lifted load: The working load and the weight of the lifting devices Vertical inertia Forces: Dead Load Factor + Hoist Load Factor.

According to CMAA Page‐14, Dead load factor equals to 1.2 and Hoist load factor equals to 0.15. Inertia forces from drives: the inertia forces occur during acceleration or deceleration or crane motions and depend on the driving and braking torques. IFD equals to 2.5% of the vertical load. Loads calculation for jib crane: (Crane in regular use under principal loading) DL (DLFB) +TL (DLFT) + LL (1+ HLF) +IFD (Inertia Forces from Drives) Test Loads will be 125 percent of related load. 4.3 Girder design: Based on HSC page 5‐157, beam diagrams and formulae No.32, simple beam‐ two equal concentrated moving loads, see the equation below:

And then, it is easy to get the maximum bending moment on the beam section. Design check:



M 0.9 ZF12

For steel E=200000 MPa And for biaxial bending, the member shall meet the following requirement which is MM

MM

1.0

The girder’s spreadsheet can be used to check girder section. 4.4 Column design: based on HSC page 1‐35, clause 13.8.2 applies: Class 1 and Class 2 sections of I‐Shaped Members require to resist both bending moments and an axial compressive force should follow: Using in the wall mounted jib crane’s column design:

And clause 13.8.3 applies: All classes of sections except Class 1 and Class 2 sections of I‐Shaped Members, which require resisting both bending moments and an axial compressive force, should follow: Using in the free standing jib crane’s column design:

Value of U1:

Values of ω1:

The compression member spreadsheet can be used to check column design. 4.5 Bolts connection design Bolts connection is recommended to use for larger spans and capacities because of shipping considerations. Stiffeners are welded to the mast at the point where wall brackets are connected to stiffen the web of the I‐beam.



Bearing in bolted connections: B 3 tdnF , Bolts in shear: Vr=0.6ΦbnmAb Fu, Bolts in Tension: Tr=0.75ΦbnAbFu, Bolts in combined shear and tension: (Vf/ Vr)

2+ (Tf/Tr )2 �1,

Bolts in slip‐critical connections: V 0.53c k mnA F ,

Connections in combined shear and tension: V

V1.9 T

A F1.0.

Therefore, bolt connection spreadsheet can be used to check bolt grade for the connection. 4.6 Tension members design: (shear lag design)

The tension member spreadsheet can be used to check.

4.7 Anchor rods for the base plate 1. The factored tensile resistance of an anchor rod shall be taken as T Φ A F Where: Φ 0.67 A = the tensile area of the rods =

π d 0.938P for metric rods

= π d .

for imperial rods

Where: P= the pitch of thread, mm n=number of threads per inch 2. Anchor rods in bearing The factored bearing resistance of an anchor rod shall be taken as B 1.4Φ Af , 3. Anchor rods in shear The factored shear resistance of an anchor rod shall be taken as V 0.60Φ A F When the rods threads are intercepted by the shear plane, the factored shear resistance shall be taken as 0.70V . 4. Anchor rods check in shear and tension:

VV

TT

1. Anchor rods are not required at base plate for concentrically loaded columns carrying gravity loads only since neither end moments nor horizontal forces are present. Anchor rod holes in base plates which will receive anchor rods that are grouted may be flame cut. Anchor rod hole sizes will vary with individual fabricators depending on shop and field practices. 4.8 Base plate design:

4.8.1 The loaded base plates the required bearing area is less than or about equal to the area bounded by the column dimensions b and d. Plate thickness:



tp = 0.43bβB

ΦF β

Where: Br= o.85Φcf f = specified 28‐day strength of concrete (MPa)

β= 0.75λ λ

λ= 2d/b b= column width (mm) d= column depth (mm) To minimize deflection of the base plate, the thickness should be generally not less than about 1/5 or the overhang, m or n. 4.8.2 The loaded base plates the required bearing area exceed the

area bounded by the column dimensions b and d.

Plate thickness:

t CBC F

Or t CBC F

whichever is greater.

Where: Br= o.85Φcf , C = total factored column load (KN) A=B*C=area of plate (mm2) f = specified 28‐day strength of concrete (MPa) = 0.90 for steel

To minimize deflection of the base plate, the thickness should be generally not less than about 1/5 or the overhang, m or n. 4.9 Tie rods design A tie rod threaded at ends, a fabricated beam bracket, and two wall brackets; one for the tie rod and one for the boom. Tie rods are used to support wall bracket jib crane. Tie rods belong to tension member, which is similar to steel component, bar part. Tie rods design should follow tension member design requirements.

5.0 Design example The jib crane design example is light service using in the industry area. So some values of jib crane come from Manufactory Company. Jib crane design target assumption and some values of Jib crane from Manufactory Company: (free standing jib crane) 1. Capacity of jib crane: 5 tonnes= 5000kg 2. Span length: 6.096 m 3. Overall height: 4.572 m 4. Height under boom: 3.658m 5. Mast: D= 406.4 mm 6. Trolley model: 311D‐1423, weight: 374.21kg (For 5 tonnes Jib crane) 7. Wheelbase: 232mm=0.232m 5.1 Loads calculation: try standard I‐beam shape: W920*238 (W36*160)

Lifted load= ,

49.05 KN

Due to the HLF= 0.5* 49.05= 24.53KN, Impacting on LL =0.25*49.05=12.26 KN. Therefore, total LL = 49.05+24.53+12.26= 85.84 KN

Trolley load= . .

3.67 KN

TL due to DLF, which equals to 3.67*1.2= 4.4KN For the W920*238, the mass is 238kg/m, which equals to 2.34 KN/m. Therefore, the section mass is 2.53 KN/m, which include rail and conductors. Dead load can be computed as 2.53KN/m* 6.096m= 15.42 KN Dead load due to DLF, which equals to 15.42*1.2= 18.5 KN For the IFD, IFD= 2.5%* Vertical load, Vertical load= TL+LL+DL= 4.4+85.84+18.5=108.74 KN. Accordingly, IFD= 2.5%*108.74= 2.72KN Therefore, total load= 108.74+ 2.72= 111.46 KN And test load is 125%*111.46= 139.3 KN 5.2 Determine side trust for jib crane:



Use 20% of the sum of the lifted load and trolley (see Table 2.1 of CMAA‐page 4), equally distributed to each side. Side thrust=20% of combined weight of lifted load and trolley=0.2*(4.4+85.84) =18.05 KN=4.51 KN/wheel. Ratio of side thrust to maximum wheel load= 4.51/110=0.041 Specified moment MH due to side thrust: MH=0.041*322.65=13.2 KN*m Factored moment due to side thrust: MHF=1.5*13.2=19.9 KN*m 5.3 Girder design For the free standing jib crane, make assumption for the beam design, span length is 20 inch (6.096m). Using the girder design formulation, according to CISC‐ page 4, make assumption that maximum wheel load of per wheel is P= 110 KN which include impact.

The point of maximum bending moment is at0.5 6096 2990mm, Based on crane wheel base a = 232mm < (2‐√2)*6096=3570mm,

So the M P 1 = .

6.096 322.64 KN

R V P 2 110 2 216KN, MLL 322.65 KN m. And M due to impacting= 322.65*0.25= 80.66 KN*m

MDL 2.53 6.096 . 11.75 KN*m

Therefore, factored moment M 1.25 11.75 1.5 322.6480.66 619.64 KN*m Design check W920*238, after using the spreadsheet to check, it is OK.

5.4 Column design Cf=139.3 KN Mfx= 139.3*2.99= 417 KN*m 1. For the free standing jib crane, try the column HS406*13, mass is

123kg/m, D=406.4mm, t=12.7mm, r=139mm. Dead load: .

1.206 KN/m. Column height= 3.658m


Try a HS406*13 column

1) Cross‐sectional strength From Table of Factored Axial Compressive Resistance, Page 4‐58, Cr=Cro= 621 KN. From Table 4‐6, page 4‐18, ω 1.0 KL 1.0 26.3,

From table 4‐7, page 4‐19, C A 2810 MPa (by interpolation), which is Euler buckling load. Ce= 2810*15700mm2= 44117 KN, CC

. 0.003, from Table 4‐8, page 4‐20,

U CC

.1.003, therefore, U1x= 1.003

Accordingly, . . 0.028 0.675 0.703 1.0,



It is OK. 2) Overall member strength KL 1.0 26.3, from Table 4‐4, page 4‐13, C A⁄ 298, for Fy=345 MPa , Cr=Crx= 298*15700=4679 KN (for uniaxial strong‐axis bending), U1x= 1.003

Therefore,. . 0.03 0.675 0.705 1.0,

It is OK. 3) Lateral‐ torsional buckling strength Cr=Cry=4679 KN, Mr=621 KN*m, U1x= 1.0

Accordingly,. . 0.03 0.671 0.701 1.0,

It is OK. 2. For the wall mounted jib crane, try the I‐shape column W310*118,

column height is 2900mm, r=136mm, A=15000mm2.


1) Cross‐sectional strength From Table of Factored Axial Compressive Resistance, Page 4‐37, Cr=Cro= 606 KN. From Table 4‐6, page 4‐18, ω 1.0 KL 1.0 21.3,

From table 4‐7, page 4‐19, C A 4350 MPa (by interpolation), which is Euler buckling load. Ce= 4350*15000mm2= 65250 KN,

CC

. 0.002, from Table 4‐8, page 4‐20,

U CC

.1.002, therefore, U1x= 1.002

Accordingly,. . . 0.03 0.6 0.63 1.0,

It is OK. 2) Overall member strength KL 1.0 21.3, from Table 4‐4, page 4‐13, C A⁄ 303, for Fy= 345MPa , Cr=Crx= 303*15000=4545 KN (for uniaxial strong‐axis bending), U1x= 1.002

Therefore,. . . 0.031 0.6 0.631 1.0,

It is OK. 3) Lateral‐ torsional buckling strength Cr=Cry=CrL=3850 KN, (by interpolation, table on HSC page 4‐37) L=2900 mm L 4920mm, Mrx=606 KN*m, U1x= 1.0

Accordingly, . . . 0.036 0.585 0.621 1.0,

It is OK. 3. For the mast style jib crane, try the I‐shape column W310*118,

column height is 4267mm, r=136mm, A=15000mm2.


1) Cross‐sectional strength



From Table of Factored Axial Compressive Resistance, Page 4‐37, Cr=Cro= 606 KN. From Table 4‐6, page 4‐18, ω 1.0 KL 1.0 31.4,

From table 4‐7, page 4‐19, C A 2000 MPa (by interpolation), which is Euler buckling load. Ce= 2000*15000mm2= 30000 KN, CC

. 0.005, from Table 4‐8, page 4‐20,

U CC

.1.005, therefore, U1x= 1.005

Accordingly, . . . 0.03 0.59 0.62 1.0,

It is OK. 2) Overall member strength KL 1.0 31.4, from Table 4‐4, page 4‐13,C A⁄ 291, for Fy= 345MPa , Cr=Crx= 291*15000=4365 KN (for uniaxial strong‐axis bending), U1x= 1.005

Therefore,. . . 0.032 0.59 0.622 1.0,

It is OK. 3) Lateral‐ torsional buckling strength Cr=Cry=CrL=3575 KN, (by interpolation, table on HSC page 4‐37) L=4267 mm L 4920mm, Mrx=606 KN*m, U1x= 1.0

Accordingly, . . . 0.036 0.585 0.621 1.0,

It is OK. 5.5 Base plate design 5.5.1 For the free standing jib crane, the column is HS406*13, dead load for the column is 1.206*3.658=4.41KN. Dead load due to DLF, which equals to 4.41*1.2= 5.3KN

tp = 0.43bβB

ΦF β

Where: Br= o.85Φcf = 0.85 0.6 = 0.0102

β= 0.75λ λ

0.75 0.65

λ= 2d/b=2, b=d=D=406.4mm F 350 MP Φ= 0.9 for steel f = specified 28‐day strength of concrete (MP ) = 20 MP A=B*C= Area of plate (mm2) Determine the required area A= Cf/Br, total factored column load Cf= 5.3+ 139.3=144.6 KN. Determine B and C so that the dimensions m and n are equal.

Consequently, A= 144.6KN/0.0102 =14177 mm2 π D 3.14. 129651mm2.

Therefore, tp =

0.43bβB

ΦF β0.43 406.4 0.65 .

. .26.9

mm. Try plate B=C=500 mm And m=n=500‐ 406.4+12.7=53.15 mm

Therefore, . 10.6 t 26.9 mm

So it is OK. Use PL 27*500*500 mm for the base plate. 5.5.2 For the mast style jib crane, the column is W310*118, dead load

for the column is1.15 * 4.267= 4.9 KN. Dead load due to DLF, which equals to 4.9*1.2=5.9 KN. C 5.9 139.3 145.2KN.



For W310*118, b=307mm, d=314mm.

Area of plate requiredA .. . ⁄ 14235mm ,which is less

than he area bounded by the column dimensions b and d. Accordingly,

tp = 0.43bβB

ΦF β 0.43 406.4 0.66 .

. .

27mm.

β= 0.75λ λ

0.75. .

0.66

λ= 2d/b=2*314/307=2.05, b=307mm, d=314mm. F 350 MP . Try plate B=C= 500mm, m= (500‐0.95*314)/2=101mm, n= (500‐0.8*307)/2= 127mm. Therefore, n/5=127/5=25.4mm< tp= 27mm. It is OK. In this case, use PL 27*500*500 mm for the base plate. 5.6 Bolts connection design and anchor rods For the bolts connection on wall mounted jib crane, (Source: Vf is supported by side thrust, which equals to 18.05 KN. Tf is the total tension from the loads, which is 139.3 KN. Therefore, shear‐tension ratio is X= 18.05/139.3= 0.13. Try A325 bolts, bolts diameter d= 3/4 inch= 19.05 mm.

From HSC 3‐13 (Table 3‐8), permitted Vf =14 KN and permitted Tf =140 per bolt. Therefore, number of bolts required = 18.05/14 2. After using bolts connection spreadsheet to check design, four 3/4 inch A325 bolts are required. And then it is OK. Anchor rods size is decided as 20mm for rod diameter and hole diameter is 26mm. Four 20mm anchor rods will be used to connect to a prescribed reinforced concrete foundation. The recommended foundations are based on a soil pressure of 2,500 lbs. per sq. ft. Anchor rods check: When ASTM A325M‐ M20 uses for anchor rods The factored tensile resistance of an anchor rod shall be taken as T Φ A F = 0.67*

π 20 0.938 36 *830=82.7 KN

Anchor rods in shear: The factored shear resistance of an anchor rod shall be taken as V 0.60Φ A F =0.6*0.67*

π 20 *398=50.2 KN

Anchor rods check in shear and tension: VV

TT

1. Vf=18.05/4=4.5 KN, Tf=139.3/4=34.8 KN.

Therefore, ..

.

.0.008 0.177 0.185 1

It is OK. Consequently, four A325M‐ M20 bolts can be used for anchor rods. 5.7 Tie rods design Use 2 inch diameter tie rod to connect a fabricated beam bracket, and two wall brackets. Show the pictures below:



(Source: http://www.wallacecranes.com/jibwall.htm)

Span length A= 6096mm Bracket centers B= 2133mm Support beam bracket to beam end = 1066mm Support to pivot D=152.4mm 5.8 Wall bracket connection Top and bottom wall brackets utilize a formed steel channel, with two bronze bushings, bronze thrust washers, and formed tie rod clevises. Show the pictures below:


6.0 Spreadsheet applications (check design components). Jib crane has mast, girder, and base plate three major parts, different types of jib crane may use different shape of steel parts. Free standing jib crane will use round shape mast, wall mounted jib crane will use I shape column. For this situation, we develop four different spreadsheets for each connection and stress check. CAN/CSA S16.1 Limit States Design of Steel Structures was used as the source for the

equations and input values. A printed copy of this spreadsheet is provided in Appendix A of this report. The input parameters are limited to a specific selection, such as the bolt grades and diameters. Data validation is used on numerical inputs to ensure that the user has entered valid data. The spreadsheets are built on a formatted sheet provided by Dr. Stiemer and are available for download at www.sigi.ca/engineering/steel_design.html. This spreadsheet allows the user to define variables and write the formulas in text format. The Format Sheet macro is used to parse the formulas and write the excel formula in an adjacent cell. For the descriptions in the Format Sheet we use Google sketch up to build a 3D model and snap the perspective. Some of the descriptions look similar with the Format Sheet then we do not create our own model. Four types of spreadsheet are used to check steel components design: 1. Girder design check 2. Mast design check 3. Bolt connection check 4. Tension member check 7.0 Conclusion Jib crane design processes should be identified by each steel component design. And then check the condition for each component, jib crane design will be done. Using the same principle, the different capacities of jib cranes can be designed. Following the design processes, the installation would be easy by Manufactory Company.



8.0 Bibliography

CISC. Handbook of Steel Construction. Toronto, Ontario: Quadratone Graphics Ltd, 2007. CMAA. Crane Manufacturers Association of America. Guide for the design of crane‐supporting steel structures. Niagara Falls, Ontario: HATCH Ltd. http://www.jherbertcorp.com/crane‐jib.htm http://www.dearborncrane.com/crane_buyers_guide/jib_cranes.htm http://www.faqs.org/patents/app/20100072157 http://hubpages.com/hub/Guide‐to‐Bridge‐Cranes‐and‐Jib‐CranesThe‐Backbone‐of‐Logistics http://lims.mech.northwestern.edu/projects/jibcrane/ http://dcm‐reality.blogspot.com/2007/11/cranes.html http://www.bestjibcranes.com/4‐popular‐types‐of‐jib‐cranes/ www.sigi.ca/engineering/steel_design.html

Appendix A: Spreadsheet Application



Spreadsheet application screenshot

Girder design check



Mast design check I‐shape mast design check:



Round mast design check:



Bolts connection design check:

design and behavior of jib cranes

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