High reach demolition excavator

Browsing through various social media channels, I came across a number of worrying examples of how NOT to use specialist High Reach Demolition equipment. One such example led to the tragic loss of life, a high reach operator who I "suspect" made a fatal mistake... undercutting a building, which subsequently collapsed on top of the cab of the machine. Very sad and very concerning....

The variety and sheer quantity of alarming images that I saw, prompted me to share some of our management procedures, we use to ensure the safe use of this potentially hazardous equipment. These procedures have been developed and refined over the last 20 years of our extensive experience working with this equipment. We currently a variety of rigs which provide a diverse range of working configurations. Having said that some of our experience has been as a result of near misses and incidents on our own projects. The procedures implemented have ensured that these mistakes have not been repeated.

I hope that this post may help people when considering the safe use of this specialist method of demolition....

Generally check that all necessary experience, competencies and certification are in place relevant to the project in hand. This should include:- management, designers, supervision, operators, supporting staff to include the plant and equipment itself.

The risk profile directly correlates to the size of the building and therefore the size of the machine used. As each increases so do the risks of the operation.

Main points to consider (not intended to be everything)...

1 - Check that all possible methods of demolition are assessed and evaluated prior to concluding that High Reach Demolition is the correct method to select. Possible factors to consider....

• Height - can High Reach equipment be used, if so what size plant is needed to reach and work safely, allowing for the necessary stand off? The HSE provide guidance in this area.
• Access - can the equipment be delivered to site, once on site is there enough room for it to work?
• Environment - proximity to other buildings, sensitive activities? Vibration, dust, noise etc.
• Structure - section size of structural members? risk of premature collapse
• Exclusion zone - safe area for plant to work and debris to fall?
• Programme - timing of demolition, duration to suit school holidays, public transport not running, does the programme work?

We have demolished structures where we have deconstructed floor by floor, then used high reach demolition techniques, followed by explosive demolition all on the same building! In demolition the options are endless.

2 - If selected, ensure that the equipment proposed is the correct size to carry out the work. The machine will need to work safely with adequate reach and height. The safe working reach is not the same dimension as the machines maximum reach, we generally reduce the machines maximum reach taken from the spec sheet between 20-35% to calculate the safe working height for demolition. Although each project and set of circumstances will require a more detailed review to ensure all of the factors are considered before finally selecting the correct plant. So a narrow chimney is different to a deep high rise structure.

3 - Ensure that the equipment can safely carry the right demolition tool at the end of the high reach boom, this must be suited to the machine first and foremost and then secondly to the structure being demolished. The attachment will need to have the correct jaw appropriate for crushing, cracking or shearing, the right power and opening size to ensure the material can be demolished safely and efficiently. So heavy tall structures such as power stations may be within the machines reach, but the tool that is used at the end of the high reach boom may not demolish the building. The temptation is to put heavier tools on the end of machines that are simply not designed to carry them. This should of course should be avoided. Working within the guidelines set by the manufacturer is essential in this respect.

4 - Check the ground conditions typically over site slabs, ground make up, water table level, look generally for voids, basements and the like. This information should be collated by suitably qualified engineers in the form of a ground investigation report. The report should be issued to the Demolition Design Engineer typically a professionally qualified Civil or Structural Engineer who is responsible for all aspects of the demolition design on the project. Appropriate levels of Professional Indemnity insurance must be in place.

5 - Some of these machines weight over 200 tonnes, they have significant dead loads and very lively live loads! So it is essential that the area that the machine travels on and more importantly the area that the machine works from is treated in the same way as a piling rig. It is imperative that the Demolition Design Engineer ensures that the plant is stable at all times. The ground investigation report will be used to assess the need for any temporary works and then the design of such temporary works. Typically steel road plates and crane mats are used for access, engineered fill conforming to a recognised specification is used for the working platform for example crushed 6F2. If ramps are intended there use should be limited they should also form part of the temporary works design. Demolition debris that is not pulverised or crushed to 6F2 should not be used.

6 - Check the structure on site using a competent engineer to establish in detail the following:-

• Type of structure - cast in-situ or steel frame, large panel etc.
• Condition of the structure - defects, corrosion, cracks and general stability.
• Trial pits for reinforcement details, connections, dimensions and sizes of structural components.
• Refer this information to any existing as built information to ensure no immediate issues arise.

For some structures it may be necessary for temporary works to be designed and installed to facilitate the same demolition. This is particularly relevant for pre-cast concrete large panel high rise structures, that become very unstable when using High Reach Demolition techniques.

This I believe is one of the main problems with a lot of demolition projects generally and High Reach Demolition projects are no exception....

7 - Ensure that a suitably qualified, experienced structural or civil engineer has been central to the development of the demolition method statement, safe systems of work and overall sequence of the demolition to safely reduce the structure to the ground, safely without any premature collapse. That the working method and sequence is simply and clearly set out by whatever means to suit each company, so drawings, photos and text are common with the use of videos and 4D models now being used also. It is essential that the plan is effectively communicated to the site delivery team, that they understand the documents, and have been included in there development. All general site management procedures apply with regard to proposed changes, new information and contingency planning. Any new information gathered as the site works progress must be fed back to the Demolition Design Engineer to ensure that no unnecessary risks are taken. Any proposed changes to the working method and sequence must not proceed without being discussed, proposed and considered by the Demolition Design Engineer.

This post is not intended to be the absolute guide that covers every aspect of the process for High Reach Demolition or demolition generally. I may have missed some points that other people feel are equally if not more important than those I have listed. Please feel free to add thoughts, comments and personal experiences to this post to help educate us all so that we may prevent in the future more lives being lost.

If you would like further information the National Federation of Demolition Contractors have written guidance notes on the safe use of High Reach Demolition Rigs, as does the HSE.

author:Mark FCIOB, MIDE, AIExpE Managing Director - The Coleman Group - Specialist Demolition, Design, Engineering, Specialist Cutting, & Remediation

19m excavator long reach attachment for pc400-7

In Jan. 2016, a valuable buyer from U.A.E. inquire about offer of 60ft Long Reach Attachment for their PC400-7 excavator, they need long reach attachment to carry out some long distance dredging and dredge work underwater.

After several rounds of discussion, we calculated and confirmed that  a set of 19m long reach boom stick suitable for their project and excavator, Considering of saving time in process of exchanging standard booms and long reach booms, we offered all necessary part: arm & bucket cylinder, a 1M3 bucket, linkage, hoses,and pins, customer just need to remove standard boom and install long booms and connecting hoses and cylinder.

the long reach boom can dig Max. forward reach 18.6m , Max. digging depth 13m underground.

How To Test A Hydraulic Cylinder

Posted on 26 May 2015 by Brendan Casey

Excavator boom cylinder

In a previous post, I described the danger associated with the intensification of pressure in a double-acting hydraulic cylinder. In this post, I will explain how to use the intensification effect to test the integrity of the piston seal in a double-acting hydraulic cylinder. But before attempting this test procedure, it is absolutely essential that the danger associated with pressure intensification in a hydraulic cylinder is fully understood. Therefore, read this article FIRST!

The conventional way of testing the integrity of the piston seal in a double-acting cylinder is to pressurize the cylinder at the end of stroke and measure any leakage past the seal. This is commonly referred to as the “end-of-stroke bypass test”.

The major limitation of the end-of-stroke bypass test, is that it generally doesn’t reveal ballooning of the cylinder tube caused by hoop stress. The ideal way to test for ballooning of the cylinder tube is to conduct a piston-seal bypass test, mid-stroke. The major difficulty with doing this is that the force developed by the cylinder has to be mechanically resisted, which in the case of large diameter, high-pressure cylinders is impractical.

However a mid-stroke bypass test can be conducted hydrostatically using the intensification effect. The necessary circuit is shown in Figure 1 below.

Figure 1. Hydraulic cylinder test circuit.

Test procedure

The procedure for conducting the test is as follows:

1. Secure the cylinder with its service ports up.
2. Fill both sides of the cylinder with clean hydraulic fluid through its service ports.
3. Connect ball valves (1) and (2), gauges (3) and (4), relief valve (5) and directional control valve (6) as shown in Figure 1.
4. With ball valves (1) and (2) open, stroke the cylinder using the directional control valve (6) multiple times to remove all remaining air from both sides of the cylinder – take care not to ‘diesel’ the cylinder.
5. Position the piston rod mid-stroke and close ball valve (2).
6. With the adjustment on the relief valve (5) backed out, direct flow to the rod side of the cylinder.
7. Increase the setting of relief valve (5) until the cylinder’s rated pressure is seen on gauge (3).
8. Close ball valve (1) and center directional control valve (6). Note: it is assumed that the hydraulic power unit used to conduct the test has its own over-pressure protection – not shown in Figure 1.
9. Record the respective pressure readings on gauges (3) and (4) and monitor any change over time.

If the ratio of effective area between the piston and rod side of the cylinder is 2:1, then if the rod side of the cylinder has been pressurized to 3,000 PSI, gauge (2) on the piston side should read 1,500 PSI. If the differential pressure across the piston is not maintained, this indicates a problem with the piston seal or tube.

Under no circumstances should flow be directed to the piston side of the cylinder with ball valve (1) closed. Failure of the cylinder and/or personal injury could result. When conducting this or any other hydrostatic (pressure) test, always wear appropriate personal-protection equipment.

REMEMBER: pressure intensification in a double-acting hydraulic cylinder is a potentially dangerous phenomenon. And failing to consider its implications can be a costly mistake. To discover six other costly mistakes you want to be sure to avoid with your hydraulic equipment, get “Six Costly Mistakes Most Hydraulics Users Make… And How You Can Avoid Them!” available for FREE download here.

Choose Excavator Booms and Sticks Wisely

Configuring an excavator for a specific application takes a little planning. Many factors come into play, such as the working range of the boom and stick, material density, desired production, use of attachments and quick couplers and lift capacity requirements to name a few.

“When you step out to the front end of the excavator, they get pretty hard to configure,” says Kent Pellegrini, global excavator specialist for Caterpillar. “It gets pretty intensive.”

Manufacturers offer several stick and boom options for mid-size excavators. For instance, Caterpillar typically offers four styles of booms depending upon model: heavy-duty (HD), extreme service (ES), mass excavation (M) and super long reach (LRE). Heavy-duty boom and stick configurations are typically for dirt digging applications. Extreme service stick and boom combinations are intended for demanding applications such as heavy lifting, demolition and use with heavy hydro-mechanical attachments.

“[The extreme service combination] adds some weight to the front end vs. using the heavy-duty boom, so your cycle times will be reduced,” says Pellegrini. “But it is for specific applications where durability is needed. When you run hammers or shears and multiprocessors continually, you want the machine to last longer, so you move to a boom and stick configuration that can handle that abuse.”

Caterpillar offers two sticks for the heavy-duty boom — not counting the super long reach — and two for the extreme-service boom. A working range chart is a good place to start when looking at these options.

“You have every stick option and every boom option, including the super long reach boom arm configurations,” notes Pellegrini. “You can see the maximum digging depth and the maximum flat-bottom depth for every machine.”

Let the Work Be Your Guide

“Contractors should understand the application they are using the machine for prior to selecting working equipment combinations,” says Brian Yureskes, product manager for excavators, Komatsu America. “General items to consider would include working range, transport dimensions, productivity and desired bucket selection, and if there is potential use for one or more attachments.”

The work you primarily bid will determine the appropriate configuration. “An underground contractor and basement digger will usually buy a long arm for reach and best productivity,” explains Mike Boyle, John Deere product consultant, excavators. “A cross-country pipe liner or a land clearing contractor will buy medium arms for stability and best productivity. A mass excavator contractor will buy a short arm for arm force and best productivity.”

A contractor that is trenching and putting in sewer/water pipe usually wants reach, so a long arm might be ordered with a coupler and two buckets. “If a contractor is adding an attachment such as a thumb, that person orders the medium arm for the stability aspect,” says Boyle. “If a contractor is excavating hard material, he buys a short arm for extra breakout.”

The Long and Short of It

In applications that utilize long boom/arm combinations, the main benefit is an expanded working range that can add versatility for certain applications.


“If there is a drawback to longer work equipment, it is that your digging forces can be reduced and, in order to maintain stability, the bucket size may need to be reduced,” says Yureskes.

Longer boom and stick options will usually reduce arm crowd forces. “Over the side lifting forces will typically be reduced due to the long work equipment having a larger impact on machine stability, whereas over the front lifting is more dependent on hydraulic forces,” says Yureskes. “Shorter boom/arm options have an opposite effect with a limited working range.”

Arm length also has a direct relation to the size of the bucket that can be used. “The shorter the arm, the more arm force and the larger the bucket,” says Boyle. Let’s take a look at arm force of a mid-size 76,557-lb. excavator for which Deere offers three arm lengths:

A short arm is 8 ft. 9 in. in length and has 45,914 lbs. of arm force. A medium arm is 10 ft. 6 in. in length and has 39,930 lbs. of arm force. A long arm is 13 ft. 1 in. in length and has 34,314 lbs. of arm force.

“There is 11,600 lbs. of breakout force difference between the short and the long arm,” says Boyle. “But many contractors are not worried about arm force. They need more reach for finishing the bottom of the trench, pulling the trench box and installing longer sections of pipe.”

Now let’s look at the difference in recommended bucket sizes for material that weighs 2,400 lbs./cu. yd.:

With a short arm, Deere recommends a 2.8-cu.-yd. bucket. With a medium arm, it recommends a 2.6-cu.-yd. bucket. With a long arm, it recommends a 2.4-cu.-yd. bucket.

“In all aspects, it looks like the shorter arm will provide more productivity,” says Boyle. “But in reality, it depends on the application and types of material the contractor is digging. The shorter arm will fill the bucket quicker with hard material; but with softer material, the excavator with the shorter arm will have more moves and more joints in the pipe.”

There are other trade-offs to consider. “A drawback to shorter working equipment is that the working range is reduced, limiting the ability to achieve desired depths or dump heights,” says Yureskes. “The benefit to short boom/arm combinations is that the working forces are closer to the machine, so generally the operator experiences greater stability and also has an expanded range of attachments and bucket sizes that can be utilized if the application requires.”



Sizing the Bucket

Matching a bucket to the application is critical. It is important to realize that the biggest bucket does not necessarily translate into the highest production. Consider bucket fill factors and cycle times, since larger buckets can reduce your cycle speed.

Pellegrini explains that he often captures the application completely before making the bucket recommendation. “When you have a big bucket on the front end, you put a lot of load through the stick and boom. Any kind of twisting or corner loading when a large bucket is placed on a machine can have adverse affects on durability,” he explains. “That is why it is important to match the boom, stick and bucket correctly from the manufacturer’s approved bucket, boom and stick matching guides. And it comes to material density as the deciding factor.”

Material density can vary with weather conditions. “Moisture can play into this, as well, where payload will increase considerably,” says Pellegrini. In some conditions, you might not be able load a large bucket to full capacity as the machine is not matched to the bucket size and the density of material is heavy and hard to get through. In this case, you might be better off choosing a bucket that was sized correctly to achieve a 100% bucket fill factor so payload and cycle times are maximized to the machine model. In other cases, smaller buckets out-produce larger buckets as the machine can cycle faster.

There are also multiple factors involved to properly select a bucket for a given boom or arm. “While all machines will have recommendations for bucket sizing, adding a long boom or arm will generally limit the size of buckets, and a short boom/arm combination will allow for more versatility in bucket selection,” says Yureskes. “Additionally, the application needs to be considered in order to select a bucket that will perform properly, as material density, bucket width and bucket wear packages can affect weight.”

Several other factors can also influence bucket size. “If the customer has installed a coupler or thumb on the machine, the bucket might need to be downsized to keep maximum performance,” says Boyle. “If the customer is loading trucks from a bench with limited reach, a larger bucket may be a consideration. Talk with the dealer or a product specialist to determine the best configuration.”


The Shorter the Better

Short sticks are often the best choice to carry attachments and work tools. “If the stick is too long with a large attachment, you will become stability limited,” says Pellegrini. “We go with our shorter sticks and equip them with auxiliary hydraulics. If you are going to use a thumb, we pull you back to a short stick for stability.”

Keep in mind that buckets and couplers can add a lot of weight. For this reason, you can use a coupler on a 12-ft. stick. However, Caterpillar only offers full auxiliary hydraulics on the shorter stick to maximize stability.

As previously stated, long boom/arms move the work load further from the center of gravity and can limit the size of attachments used. “The opposite is true for short boom/arm combinations because the work load is closer to the center of gravity, reducing stress to the work equipment and allowing for a wider range of attachments to be used,” says Yureskes.

Attachments Provide Options

Attachment manufacturers offer an alternative solution when a standard excavator stick comes up short.

Paul Wever Construction Equipment (PWCE) designs custom solutions to meet specific needs. “Too many people write off what can or cannot happen just based on their opinion of the task that needs to be done,” says Paul Wever. “It is difficult to get people to understand that it is worth the phone call to find out if your machine can accomplish the task.”

PWCE’s most popular attachment is the 16- to 20-ft. Extendavator model. “It pins on like a bucket,” says Wever. “We build them for all different size machines. Our most popular is the 40,000- to 70,000-lb. class… You can actually leave the extension on the machine and transport it based on how we have configured it.”


The ears on the EX70 Extendavator class unit are spread 16.5 in. and it has a 90mm pin. This is designed to fit the machine with the largest pins and bucket spread in that class. Bushing sets and longer pins are used to adapt the unit to other makes and models.

L&G Products offers the Add-a-Stick, which ranges from 12 to 20 ft. “It is a fast way to get extra reach without buying a different machine,” says Larry Heinneman. “In extreme cases, we will make something longer. We do not use a counterweight unless the ground underneath the machine is unstable. We work within the hydraulic limitations of the lifting capacity of the machine.”

What differentiates many of the attachments is the quality of materials used and customization offered. “It is structurally T1 steel and it is very strong,” says Heinneman. “We try to work with the customer and change things so they are convenient to use. Our engineering force will make something fit.”

For applications where you need to economically reach a little longer than the factory stick, L&G Products offers the Add-a-Boot. “That actually fastens to the stick and makes the stick longer,” says Heinneman. “You just replace the pins and pull the bucket. On a 40,000-lb. machine, you can gain 6 or 8 ft. You get up to the top end and we go up to 12 ft.”

PWCE also offers a hydraulically telescoping dipper for mid-size excavators. “I have built them on up to a 70,000-lb. class machine,” Wever notes.

While many companies currently offer telescoping dipper sticks as an option on mini-excavators, very few are offering these attachments on mid-size excavators. The concept is the same as it is for backhoe-loaders.

“You don’t have to keep moving. You can just extend that stick out to get a little bit of extra reach,” says Wever. In some cases, it allows you to use a slightly smaller machine because you can get that extra 2 ft. of depth when needed. “We have found that once our customers have a telescoping dipper, the machine that doesn’t have it is the one that sits still.”

The extra reach with the extendible dipper depends on the carrier weight. It ranges from 5 ft. on a 40,000-lb. machine to 6 ft. on a 60,000-lb. machine.

Set for Success


With long reach attachments, setup is critical. For instance, consider the use of quick couplers. “A quick coupler will work,” says Heinneman. “I don’t like them because they usually weigh around 1,000 lbs. and that takes away from the lifting capacity of the machine. When you [extend the dipper] out there, it is desirable to have the least amount of weight possible.”

The operator is also key to success. “The operator has to have integrity in what he does,” says Heinneman. “A bad operator will do things that he isn’t supposed to do. The longer it gets, the better the operator that is required.”

The operator needs to consider the dynamics of the machine with the long reach arm. Swing speed at the end of the stick needs careful attention.

“The speed of the bucket at a farther distance away from the machine will dramatically change,” says Wever. “The operator needs to use caution when he slows down. Many operators in standard machines have no experience in long-front machines. You cannot stop as fast. The biggest issue that we have with operator error is the operators using the pile as a brake.”

Another issue is not slowing the bucket down before it enters water. “When you are reaching out with a long-reach front machine and slam that bucket in the water, it is like slamming it into a wall of concrete,” Wever points out. “Dynamically, it puts loads into the stick that will affect its life cycle.”

It is especially important to even out turret bearing wear. “To get normal wear on the turret bearings, you are supposed to reach over one side and then, after a certain number of hours, reach over the other side,” says Wever. “Let’s say your normal turret bearing wears in 10 years. You could easily take that down to three years if you never rotate your lower unit. That is one of the more expensive components.”

BY CURT BENNINK ON MAY 23, 2012

Rock grapple for excavator with long reach boom arm

In Dec. 2015, one of our old client ask us whether our  18m long reach boom arm (we provided) can grab and carry big boulders, in our experience, we think standard bucket is not suitable for material handling, we suggest rock grapple, which has two claws can open and close, one claw is fixed by a steel rod on bottom side of dipper, there are three adjusting holes, another claw is driven by bucket cylinder, maximum opening of this rock grapple is 1.9m that's wide enough to grab stone.

Rock grapple with two grab jaws , one jaw support by a rod pins on bottom side of arm, there are three position-adjusting holes. another jaw driven by hydraulic bucket cylinder, inner side of jaw with anti-skidding teeth, the rock grapple maximumly open 1.9m wide.

Mechanical Properties of Chinese low alloy steel: Q345B

Q345B steel is a Chinese standardized low alloy, medium tensile strength steel made with a hot-rolling process, and is used for a number of manufacturing purposes. It is a steel with less than 0.2 percent of its composition made up of carbon, less than 0.55 percent of its composition made of silicon and several impurities (mostly sulfur, chromium and nickel). This particular grade of steel is a 'general purpose' manufacturing steel in construction equipment field, such as Q345B is basic material of making excavator bucket and excavator boom arm attachments

The major benefit of this grade of steel is its mild temper. It's easy to form and easy to weld,

Mechanical Properties

1, Yield Strength

A yield strength or yield point is the material property defined as the stress at which a material begins to deform plastically. Prior to the yield point the material will deform elastically and will return to its original shape when the applied stress is removed, Yield strength of Q345B is 345 MegaPascals. Like most steels of its grade, it suffers elongation before it pulls apart, typically at 20-21 percent of its initial length.

2, Tensile strength

The tensile strength of a material is the maximum amount of tensile stress that it can take before failure, for example breaking. Steel tensile strength is expressed in units of force divided by cross sectional area; in the Metric system, this unit is known as the Pascal. One Pascal is a Newton (the force needed to accelerate a one kilogram object to a velocity of one meter per second) per square meter. The tensile strength of Q345B steel is rated at 470 to 660 MegaPascals (where mega is million)

3, Hardness (HB)

 Brinell scale hardness characterizes the indentation hardness of materials through the scale of penetration of an indenter, loaded on a material test-piece. It is one of several definitions of hardness in materials science, The typical test uses a 10 millimetres (0.39 in) diameter steel ball as an indenter with a 3,000 kgf (29.42 kN; 6,614 lbf) force, copper hardness is 35HB, Pure Aluminium is 15HB,

From Victory Construction Equipments Co., Ltd

repeat order of 18m excavator long boom arm for India customer

In end of March, 2015. our customer in India decides to re-place a order,customer still need 18m long reach boom arm for their EX350LC machine,

this time, customer just need us provide long reach boom arm, because they have a EX200 bucket and bucket cylinder, so we need to design the long reach arm that can fit EX200 bucket and cylinder. this long reach configuration is reasonable, after 20 days, we shipped the 18m long reach excavator booms to Mumbai port, below are finished product pictures

for more information, please visit our website:http://www.longreachboom.com

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