Friday, March 9, 2018

STRUCTURAL REPAIR VERIFICATION


By: John W. Davis, P.E.

Crane surveyors are often faced with the problem of determining the sufficiency of structural repairs.  Some jurisdictions require that the surveyor declare that the crane is in “safe working condition” as a requirement for acceptance or certification.  In addition to the regulatory requirements, every surveyor is faced with the challenge of risk management.  In practical terms, the surveyor must consider and avoid the risk of accepting a structural repair the sufficiency of which cannot be determined by visible inspection or load testing as is offered by ASME B30 standards.

The first thing to consider is who authorized the repair.  The surveyor should require a copy of written directions by the authority that is qualified to allow and/or define the repair method.  Some jurisdictions require that the repairs be authorized by the crane manufacturer or a registered engineer.  The surveyor is left with the decision as to the validity of the authorizing agent.   
   
The surveyor should be satisfied that the material used in the repair is the same as or equivalent to the original material.  The material or the specification for the material may be supplied by the original equipment manufacturer.  Alternatively, the proper material can be determined by a laboratory analysis of the parent material together with a certified test report with a mill test report from the repair material supplier.

If welding is part of the repair, the welding process should be prequalified or the welding process should be certified in accordance with AWS D1.1 standard.  The joint design should be in accordance with the AWS D14.3 standard and the instructions of the authorizing authority.  The welding must be done by a welder certified for the process, material, and welding position(s) used. The electrode material must be compatible with the parent material.  The welds should be done in accordance with AWS D14.3 and be inspected in accordance with AWS D1.1 standard.

In general, the surveyor should require sufficient documentation to verify that the repair has been completed in accordance with the instructions of the authorizing agent.  This assurance should include a parent material specification, a material certification for the repair material, a welding procedure certification (if needed), a welder certification document, and a Non-Destructive Evaluation report.  The surveyor should load test the element(s) repaired and provide a document to attest to the satisfactory test results.

In summary, the crane surveyor should require sufficient documentation for his files to verify that the repair has been done in compliance with the instructions of the authorizing agency.  

Thursday, May 21, 2015

Crane Load Testing- From a Repairer’s point of view!

Load Testing- From a Repairer’s point of view!


By: Bruce MacPherson      Certified Boom Repair Service, Northeast


ASME B30.5-2011 5-2.2.2 guides decision making for Rated Load Testing “…… all cranes in which load-sustaining parts have been altered, replaced or repaired should be load tested by, or under the direction of qualified person.” We all know who a “qualified person” is because the description of a qualified person can be found in the definition section of the code. The question that comes to mind is how does OSHA or ASME define repairs to load-sustaining parts or structural repairs as it relates to load testing requirements?
Consider the following scenarios below. It is your customer and you are aware repairs have been made. How would you proceed?

If a picture frame lattice gets dented when the boom is being assembled and is then replaced in the field, is that a structural repair? Is the lattice a load sustaining part?

Equipment Manager notices a crater crack in an improper weld termination on an outrigger beam; the crack does not seem to be propagating. It is a small deficiency but he decides to repair it; you are doing the inspection. Is a load test required?

3. If (9) of the top lattice in a 20’ boom extension section are replaced because of wire rope wear, is this a structural repair?

4. What about a documented splice in a tubular chord done by a competent repair facility? Load Test?

5. A boom extension swings hard into the stow bracket of the base section of a truck crane causing a dent in the side plate. The deflection gets corrected using hydraulics with no heat applied? Do you load test?

6. Wire rope jumps a sheave at the boom point and saws into the axle shaft. The shaft and the rope get replaced. Is the shaft a load-sustaining part?

7. An operator doing an inspection of his machine finds (6) lattice have corrosion exceeding the OEM Manufacturer’s tolerance limit. There is 180’ of boom in the crane. The corroded lattice are dispersed over the length of the boom. The lattice are replaced. Do you require the owner to do a load test?

A crowd cylinder has leaking seals. The boom is disassembled, extend/ retract cables are inspected, the cylinder gets inspected, resealed and bench tested. The boom is reassembled. The machine is ready to go to work. Has the owner completed repairs to load sustaining components?

If you consider all (8) scenarios and strictly adhere to the Load Testing requirement as described in B30.5-2011, then you must say “YES” to load testing all of the above, BUT really…….are you going to require your customer to load test because he just replaced a Picture Frame lattice? OEM Manufacturers have procedures for lattice replacement. I have not seen an OEM requirement for Load Testing after one lattice has been replaced but it really is a structural repair. How do you feel about the (6) lattice in 180’ of boom, the (9) lattice in a single plane of a 20’ extension, a documented chord splice or the crowd cylinder work? If repairs are completed by an independent firm as opposed to OEM employees or through the OEM’s distributor network, would your Load Testing recommendations be any different?

An inspection with a Load Test is only a “snap shot” of a machine’s serviceability at one point in time. Load Testing after repairs, if done properly, is “cheap Insurance” for Crane Owners, Repairers, Insurance Companies, General Contractors and for any project that employs the machine; however there should be a common sense approach in the decision making process for Load Testing.

When the CCAA was in Baltimore many years ago, I had the opportunity to ask Paul Rossi of OSHA how he or his employer might define structural repair as it relates to Load Testing. His answer was, “We don’t define it. We leave it to the comfort level of the Certifier”. So there you have it…….”The ball is in your court”.