Crane Engineering / Our Services

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CP&A offers a wide variety of services tailored to your needs, including procurement, specification, design, design review, manufacturing review, voyage bracing, modifications and rehabilitation, accident investigation and repair, and condition surveys. With crane and material handling equipment design experience dating back to the 1960's, we can provide

you with fast, efficient and dependable service.

We have assisted crane manufacturers with both special projects and with generic design training to improve their own designs. This list includes DHI.DCW, Doosan, IMPSA, Paceco and ZPMC.

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Crane and Load Handling Equipment Purchase Specifications Design and Design Review

We bring our long history of design experience and automated computer analysis to quickly and efficiently review the proposed designs of equipment suppliers and show you definitively where, how and why a submitted design does or does not meet your requirements. If asked, we can also suggest cost effective modifications to help the supplier comply.

As professional engineers, our first love is original design for an owner or OEM client. From past years we have competent experience in that subject. However, the crane industry has matured to the level where OEM's rarely need design assistance and buyers are not interested in tendering a pre-engineered crane.

A complete OEM design of a new custom crane consists of several hundred drawings and several thousand pages of computer output. Mistakes, omissions, and internal conflicts are inevitable no matter how competent the OEM's engineers are. Most mistakes are of no consequence or are caught later during construction; but serious mistakes do occur that lead to structural failures, premature failure of mechanical components, and electrical malfunctions.

A competent peer review is statistically, without question, the most effective and most economical way to minimize serious engineering mistakes.

An entirely different issue is dishonest design to gain a competitive advantage when negotiating a tender. Few buyers have the expertise to catch deliberate under-design. Again, a competent peer review is the best and perhaps the only way for a buyer to counter dishonest design.

Simply looking for arithmetic mistakes in the OEM's calculations is not a competent peer review. A competent peer review should start with looking at the individual construction drawings and then, as much as practical, create independent calculations and independent reality checks to find deficiencies. These are the engineering deficiencies that matter most because, if not caught, they may become final product deficiencies.

Construction Inspection and Quality Audits
Crane Under Construction

Most purchase contracts stipulate that the OEM is responsible for Quality Assurance (QA) and Quality Control (QC). How do these differ? QA is the organization and procedures that set and audit QC activities. QC is the hands on every day inspection, such as weld inspection.

The reliability of an OEM's own QA and QC varies from excellent to superficial. Buyers with satisfactory long-term performance by a particular OEM can usually rely on such performance to continue. For new relationships or in dealing with OEM's that have a poor quality track record Caveat Emptor is the rule. The best defense is to conduct full time inspection and independent audits of both QA and QC that is being provided by the OEM.

We recommend that the buyer use a risk management approach to determine the level and expense for OEM audits. The most important consideration is the consequence of various forms of failure, and that consequence is magnified by the number of machines being ordered.

CP&A offers any level of inspection and QA/QC audits that the buyer deems appropriate. We also offer assistance with the buyer's risk management assessment of what is appropriate.

We can provide part-time or full-time presence to report on the quality of manufacturing and construction schedule. We use the internet to provide full weekly reports and updated schedules in a very timely manner. Potential problems are identified early and allow you to resolve them before they become headaches.

Our focus is on the entire crane as a complex system, not just on one aspect such as structural steel fabrication. Sure, the structure is important, but for a crane to be a profitable investment, the electrical and mechanical systems are where inspection services are most needed. Yet these are the areas where inspection requirements are usually minimal.

Commissioning and Acceptance Testing

This service is perhaps the most important aspect of any equipment purchase. This is the time when actual performance is measured and evaluated against specified requirements and unspecified industry standards.

We do not direct the OEM's erectors and vendors but we are available as advisors when a solution to a perplexing problem can benefit from our past experience and expertise. As with construction inspection, the appropriate level of our efforts depends on the buyer's judgment and authorization.

This is a specialty service where CP&A's multidiscipline expertise is particularly valuable. Major equipment such as a container crane is a complex system where electrical, computer science, mechanical, and structural engineering have to function together as a complete system. When there is a problem with one specialty it is important to be aware of how that problem can create secondary problems with any or all of the other specialties. One common example has been an overly flexible gantry frame that leads to malfunction of the mechanical anti-sway system that is electrically controlled by custom PLC software. Or a resonant mechanical vibration problem that will induce premature structural fatigue and risk of brittle fracture in a structural member.

Sea-fastening and Voyage Bracing

You need to make sure your equipment has the best chance to arrive safely.

What is Sea Fastening and Voyage Bracing?

When you need to ship a large crane or piece of material handling equipment across an ocean, the crane will be subjected to ship motions during the voyage. These motions are called heave (up and down), surge (fore and aft), sway (side to side), roll (tilting to the sides), pitch (tilting fore and aft), and yaw (spinning about a vertical axis). The crane will also be subjected to heel (tilting due to wind forces) and wind loads. The amount and magnitude of each motion depends on many factors like ship response characteristics, sea state, and heading. These voyage motions and heel translate into voyage loads on the crane. The magnitude of the loads will depend on where the crane is located relative to the vessel center of motion. The smallest loads are generated at locations close to the vessel's center of motion, like down in a cargo hold. If a crane will fit into a cargo hold, there is usually little need for special fastenings or bracing. Modern container cranes will not fit into a cargo hold, and are usually shipped on special heavy-transport vessels or barges. They are exposed to weather, and usually all or a majority of the crane is well above deck level. Because many of the crane's components are a significant distance from the vessel's center of motion, the voyage loads can be huge - well beyond the capacity of the crane to resist them.

Most large cranes are not designed for voyage loads, and can easily be damaged, destroyed or lost overboard if not properly strengthened and fastened to the transport vessel. The braces installed between the vessel and the crane are called sea fastenings, and any braces or strengthening internal to the crane (not connecting to the vessel) is called voyage bracing.

Experience

Casper, Phillips & Associates has over 20 years experience designing the voyage fastening and bracing for shipping cranes and large material handling equipment. Over 30 years ago Bill Casper, the founder of CP&A, designed the sea-fastenings and voyage bracing for the first ocean transport of a fully erected container crane. Recently we designed the sea-fastening and voyage bracing for a large continuous ship unloader. This was the first successful ocean shipment of a fully-erected continuous ship unloader.

Much of CP&A's voyage design expertise has also come from lessons learned. Acting as an expert witness for accident investigations, we have directly observed the consequences and damage that can occur if a crane is improperly secured and braced. This puts us in a unique position with an extremely valuable knowledge base.

Pitfalls

A common mistake made by many inexperienced designers is to assume the vessel is infinitely rigid. This is simply not true, especially for heavy seas. The vessel will undergo a significant amount of hog (bow & stern down, mid-ships up) and sag (bow & stern up, mid-ships down). If a crane (or cranes) are tied down along the length of the vessel at more than two points, or cranes are tied together (usually up high), when the ship hogs and sags, the crane (or cranes) will act like a strong-back, resisting the hog and sag. This amount of resistance can be large, and usually well in excess of either the crane, its bracing or sea fastenings. Something will fail - bend, break, part, or collapse. This failure can (and often does) lead to successive failures of other crane fastening or bracing components, until there is no more resistance to vessel hog and sag.

Condition Surveys

What is the condition of your material handling equipment?

What is it worth?

What would modification cost?

Is the modification worth the cost?

What are your options?

Let us answer any or all of these questions for you in a concise condition survey...

We can make brief or full investigation of your equipment's mechanical, electrical and structural condition, and provide you with a detailed report. We can work with you to provide projected maintenance guidelines, NDT inspections, equipment upgrades, and new equipment purchase based on your projected usage and growth.