Calculation Crane

Bridge Structure Inspections

kamarkhani — Mon, 22 May 2023 15:28:31 +0000

Item	Description	Points of Interest for Inspection
1	Trolley rail bolted splices.	Loose and missing splice bolts, check for improper hardware. Joint bar bolts have straight shanks to the head and are made per ASTM A449. Nuts are per A563 grade B. A325 bolts and nuts may also be used. Check/tighten splice bolts every 3 months. Fasteners should include a helical spring lock washer per AREA specification.
2	Trolley rail clamps or clips.	Check for fractured clamps, cracked welds, loose and broken bolts.
3	Trolley rail: erosion under rail base	Under the base of the rail, check for erosion of the girder flange or the wear plate (if present).
4	Trolley rail support.	Check for top flange cracking at the edge of the rail base. Check for tack welds at the edge of the rail base.
5	Trolley rail elevations.	From one end of the trolley rail, sight down the rail head. Sight over the entire length of the rail for dips in elevation. Check for local deformation of the girder flange that supports the rail. “Dishing” or dips in the girder flange may indicate broken intermediate diaphragms or broken welds. Check this condition at both trolley rails. See Figure 7‐1.
6	Girder camber.	Position the trolley at the extreme end of the bridge. From the end of the bridge opposite the trolley, position your line of sight to be in‐line with one of the trolley rails, and nearly at the same elevation as the rail head. The elevation of the rail near the middle of the bridge span should be visibly higher than near the ends (positive camber). If conditions do not permit this observation, or if positive camber is not observed, detailed measurements are required. Repeat the procedure for the other trolley rail.
7	Torsion‐box rail support.	For box girders that support the trolley rail directly over the inside web plate, check for cracking of the girder flange‐to‐web weld.
8	Trolley end stops.	Welds, base metal, and attachment to girder. Confirm that trolley bumpers make simultaneous contact with the end stops at both ends of trolley travel.
9	Bridge drive mounting bases	Check the condition of girder web where bridge machinery is attached. Look for out of plane deformation of the girder web or cracking of the material adjacent to where bars are welded. S
10	Line shaft bearing supports.	Check the condition of girder web where bearing supports are attached. Look for out of plane deformation of the girder web or cracking of the material adjacent to where bars are welded.
11	Platform connections to girder.	Check the condition of girder web where platform support gusset plates are attached. Look for out of plane deformation of the girder web or cracking of the material adjacent to gusset attachments.
12	Festoon/span conductor supports.	Check the condition of girder web where conductor supports are attached. Look for out of plane deformation of the girder web or cracking of the material adjacent to where gussets or bars are welded.
13	Pendant festoon supports.	Check support members, welded and bolted connections.
14	Riveted girders.	Inspect riveted construction
15	Girder welds.	Longitudinal flange‐to‐web welds. Inspect the location of shop splices for web and flange plates
16	Girder lower flange and web.	Inside edges of the bottom flanges, including the adjacent web area for damage due to wire rope abrasion, impact from load blocks, or lifting beams. For cranes with lifting beams, also check the condition of the bottom surface of the bottom flange for impact from two‐blocking accidents. If rope guards are present, inspect the rope guard attachments to the girder.
17	Walk‐in girders.	Welds and base metal for intermediate and full depth diaphragms, girder webs, girder flanges.
18	Bolted girder splices.	Check bolts in top and bottom flange splices and web splices .
19	Girder connection notch.	See Figure 7.6. Check welds and base metal at corners and where welds meet at corners. Check welds where girder webs are welded to horizontal shelf plate.
20	Equalizer saddles.	See Figure 7‐7. Check welds and base metal where the vertical saddle plates are welded to the horizontal saddle plate. Also check welded connections to girder.
21	Platform truss.	Welds and base metal for all truss members and gusset plates. See Figure 7‐4.

Figure 7‐1
Schematic illustration of how the trolley rail deflects. The upward force produced by
leverage from the trolley wheel is resisted by the rail clips or clamps.

Figure 7‐2
Bridge machinery supports.
Check girder web and welds for vertical bars to web.

Figure 7‐3
Crane with an outrigger truss. The diagonal members are part of the truss that supports the
platform, bridge machinery, and festoon track.

Figure 7‐4
The girder web is cracked at
the toe of the fillet weld for
platform connection bar.

Figure 7‐5
This is a close‐up view of Figure 7‐4. The arrow points to the end of the crack. The crack is
propagating toward the bottom flange of the girder. Cracks in the bottom flange of a girder
can cause a catastrophic girder failure.

Figure 7‐6
Girder End Connection

Figure 7‐7
Equalized bogie trucks with rigid end tie

نوشته Bridge Structure Inspections اولین بار در Calculation Crane. پدیدار شد.

Eye Self Locking Hook

kamarkhani — Sat, 13 May 2023 07:44:16 +0000

An eye self-locking hook is a type of hook used for lifting and rigging heavy loads. It is designed with a self-locking mechanism that helps to prevent accidental disconnection of the load. The hook has a latch or locking mechanism that must be manually opened to insert or remove the load, and then closes automatically to secure the load in place.

The “eye” in the name refers to the shape of the opening on the hook, which is typically a circular or oblong shape. This opening is designed to accommodate a variety of rigging hardware, such as chains, wire ropes, or web slings.

Eye self-locking hooks are commonly made of high-strength materials such as alloy steel or stainless steel, and are designed to withstand heavy loads and stresses. They are available in a variety of sizes and load capacities to suit different lifting and rigging applications.

When using an eye self-locking hook, it is important to ensure that the hook is properly rated for the load, and that it is inspected regularly for signs of wear or damage. It is also important to follow proper lifting and rigging procedures to ensure safety and prevent accidents.

نوشته Eye Self Locking Hook اولین بار در Calculation Crane. پدیدار شد.

Double Girder Wire Rope Hoist

kamarkhani — Sat, 13 May 2023 07:39:42 +0000

A double girder wire rope hoist is a type of material handling equipment used in industries such as manufacturing, construction, and mining. It is designed to lift and move heavy loads vertically and horizontally.

The double girder wire rope hoist consists of two parallel girders mounted on top of the building structure or on a freestanding framework. A trolley with a hoisting mechanism travels along the girders, and the load is suspended from the hoist by a wire rope.The hoisting mechanism is typically an electric motor-driven drum, around which the wire rope is wound. The motor can lift and lower the load, and the trolley can move the load horizontally along the girders. The hoist can also be equipped with additional features such as a variable speed control, overload protection, and anti-sway technology.

Double girder wire rope hoists are used in applications where heavy loads need to be lifted and moved over a long distance. They are commonly used in industries such as steel, paper, and automotive manufacturing, where heavy equipment and materials need to be lifted and moved between different areas of the factory.

نوشته Double Girder Wire Rope Hoist اولین بار در Calculation Crane. پدیدار شد.

ACCIDENTAL CRANE ACTIONS

kamarkhani — Wed, 22 Feb 2023 13:28:25 +0000

ACCIDENTAL CRANE ACTIONS

3D and Calculation Crane – Three accidental actions are provided for in EN 1991-3, which are buffer forces related to crane movement, buffer forces related to crab movement and tilting of a crane equipped with a mast. The buffer forces relate to the situation where the crane or crab runs into the end stops at the extreme
of their travel on the gantry or crane bridge respectively. This is an accidental situation because most cranes are equipped with limit switches which automatically slow and stop the crane or crab before the end of their travel and an impact would thus only occur in the event of failure of the limit switches.

1. Buffer forces related to crane movement

The principle that is given in EN 1991-3 for the determination of the end stop buffer forces related to crane movement is that the forces should be calculated considering “the kinetic energy of all relevant parts of the crane moving at 0,7 – 1,0 times the nominal speed.” An application of this principle is given in an equation for the calculation of the buffer force on each end stop as:

Where:
-7 is the dynamic amplification factor for the end stop forces
v1 is the initial speed of the crane, taken as 70% of the long travel speed [m/s]
mc is the total mass of the crane and hoistload [kg]
SB is the spring constant of the buffer [N/m], determined from the energy-deformation and force-deformation buffer curves.

2. Buffer forces related to crab movement

EN 1991-3 specifies that if the hoistload is free to swing, the total buffer force resulting from collision of the crab with the end stops may be calculated as 10% of the combined weight of the crab and the hoistload. In the case where the hoistload is not free to swing, the crab buffer forces should be calculated in a similar manner to the crane buffer forces.
The distribution of the buffer forces between the wheels of the crane depends on the wheel configuration and whether the wheels are fixed or free to move laterally.

نوشته ACCIDENTAL CRANE ACTIONS اولین بار در Calculation Crane. پدیدار شد.