The quarterly newsletter from Phoenix National Laboratories that focuses on quality, testing technology, and inspection trends
PNL is providing essential quality testing, inspection and engineering services for the ongoing I-10 Broadway Curve project-ADOT’s largest urban freeway reconstruction project, over the last 12 months. PNL has tested and inspected elastomeric bearing pads, steel reinforcing bars and 7 wire strand for multiple segments of the project, including the 48th St. underpass, Broadway Road underpass, and Guadalupe Road underpass widening. The Maricopa Association of Governments (MAG) initiative had been approved by voters in Maricopa County in 2004 through Proposition 400. The venture began July 23rd 2021-a 3 ½ year, 11-mile-long rebuilding and widening restoration of the freeway. MAG Regional Transportation Plan (RTP) identified the need for this project to reduce travel times on the I-10 during peak hours, improve airport access, support ridesharing (HOV-high occupancy vehicles) and transit as well as prepare the region for future growth projections by rebuilding and widening the freeway.
For those who are interested in staying “ahead of the curve” there is a downloadable app available for updates and information about the I-10 Broadway Curve Improvement Project. Everyone who drives, lives or works in or around the project area can learn about closures and restrictions; real-time traffic information and detour routes.
I-10 Broadway Curve construction in progress
There are several types of aerial lifts used to access work areas on construction sites where it is inconvenient or impractical to erect scaffolding. These lifts are vehicle mounted, boom supported platforms that are controlled by one or more operators. The six classifications for this type of equipment are Personnel Lifts, Towable Boom Lifts, Walkie Stackers, Bridge Inspection Booms, Scissor Lifts, and Aerial Boom Lifts. Scissor lifts and aerial boom lifts are the two most employed aerial lifts on construction sites. The major causes of injuries and fatalities while utilizing aerial lift machinery are falls, electrocution, collapses and tip overs. Operators must always follow the manufacturer’s recommendations for use. It is of paramount importance that the workers are properly trained, tested and certified. PNL provides training through United Rentals, a third-party organization, for lift training.
The guidelines that must be followed before using all aerial lift equipment include four basic steps: First a complete walk around inspection, assuring operational fire extinguishers and emergency controls, and checking leakages and tire inflation pressure is performed. Second, a work site assessment i.e., checking for bumps, floor or ground obstructions, debris, inadequate surface support for the load forces, weather conditions and power lines must be confirmed. Thirdly, the function test checks regarding functionality of the controls by starting in neutral, operating manually all functions and emergency stop controls are authorized. Finally, proper operation such as regulating travel speed according to ground conditions, maximum loads and the potential for hoses, ropes, or electrical wires to become entangled must be proven. All workers are to wear PPE: hard hats, safety glasses and harnesses at all times. One should never be positioned between overhead obstructions where the platform basket could be crushed by overhead beams. Always assume all power lines are energized and wheel chocks should be placed on brakes when the position is inclined.
Technician working on a scissor lift
While OSHA may not require a spotter in all circumstances, it is a good practice to designate a person as a spotter while the lift is in motion. When the aerial lift is in motion and the operator does not have full vision of their surroundings a spotter is required. The spotter can view a hole or uneven surface in the distance and alert the operator of the condition. Additionally, construction sites may have PVC, electrical conduit, post tension cables etc. extending upwards from the concrete which need to be avoided to prevent damage to both the vehicle and infrastructure.
Technician working on an aerial boom lift
Thomas Young a British scientist and Simeon Poisson, a French mathematician and physicist are the two theorists who devised the tensile concepts; Young’s Modulus is based on the principles of elasticity of materials, and Poisson’s ratio, the expansion or contraction of materials isometrically (in all directions). A universal test machine performs the most fundamental and common types of mechanical testing. PNL’s laboratory maintains three universal test machines, one customized hydraulic compression machine designed and engineered by PNL, and two bend test machines.
A tensile test applies tensile (pulling) force to a material and measures the specimen's response to the stress. By doing this, tensile tests determine how strong a material is and how much it can elongate. A standard tensile test is a common destructive test that can measure multiple useful properties such as tensile and yield strength, ductility or elongation, the modulus of elasticity, strain hardening characteristics as well as other tensile properties. Tensile tests are typically conducted on electromechanical or universal testing machines, are simple to perform, and are fully standardized. ASTM provides several standards for determining tensile properties of materials. A tensile testing machine consists of a test frame that is equipped with a load cell, testing software, and application-specific grips and accessories, such as extensometers. The type of material being tested will determine the type of accessories needed, and a single machine can be adapted to test any material within its force range simply by changing the fixturing. Our largest Instron universal test machine which has a capacity of up to 450,000 pounds, is often used for multi strand wire and metal testing for highway bridge pylon infrastructure. Our hydraulic compression machine is used predominantly to inspect our elastomeric bearing pads with a compressive capacity of over 2 million pounds and simultaneous shear capacity of 300,000 pounds. We provide these tests for hundreds of U.S. and international cities’ highways and bridges projects.
An Instron universal test machine testing a 7-wire strand
A bend test is another type of destructive test used to evaluate the performance of a material. One method of bend testing is a guided bend test. Guided bend tests can be used as a method to evaluate the ductility of a material by checking the materials ability to resist cracking during one continuous bend operation. Guided bend tests are typically performed on specialized machines made specifically for bend testing. Our lab is equipped with two such bend test machines used for testing reinforcing steel (rebar) and welding qualification tests. Other types of bend tests can be configured using our universal machines.
PNL’s lab offers complete flexibility and capabilities for all your tensile and bend test projects. We utilize Instron universal testing equipment, a leading manufacturer of materials testing equipment. We offer a variety of different sizes and force capabilities ranging from 110 lbf to 450,000 lbf of tensile or compressive force and up to 2 million lbf of straight compressive force. We can perform tensile, compression, bend, peel, tear, shear, friction, puncture, and other mechanical tests.
For more information regarding our abilities email: Kyle Fleege at firstname.lastname@example.org.
A reinforced steel (rebar) bend test
This Quality Examiner’s Tech Talk issue explores PNL’s Mechanical Laboratory testing capabilities. Matt Sorce Advanced NDT Project Manager interviews Kyle Fleege, P.E., who has worked at PNL for 14 years and has managed the Mechanical Lab since 2012.
Most often reinforcing steel is joined using tie wires, specifically for cast-in-place concrete or where masonry is fully grouted. However, we encounter situations where reinforcing steel needs to be welded. Examples include where tilt-up concrete panels are connected and when lateral reinforcing extensions need to be made, or when welding rebar to anchor plates. When welding is required special welding procedures must be used. It is important to note that not all reinforcing steel is weldable. The welding of reinforcing steel shall be in accordance with a written WPS in accordance with AWS D1.4 Structural Welding Code - Steel Reinforcing Bars and shall be demonstrated by welding and testing a qualification sample called a PQR. Typically ASTM A615 are A706 are weldable, however, the carbon equivalent will determine the limits of welding. Welding of steels with carbon equivalents higher than that qualified is not allowed. The rules for qualification of Welding Procedure Specifications (WPS’s) is detailed in the D1.4 code. In summary, each welding process must be qualified as well as each groove type, bar diameter group, and electrode classification combination. PQR coupons must be tested and pass the requirements of the code. Testing involves tension tests as well as macroetch tests. Two specimens are to be tested per PQR qualification.
Once a welding procedure has been prepared and qualified, each welder who welds shall be qualified. Qualification consists of welding and testing coupons based on the type of grooves, diameter of bars and positions of welds to be welded in production. Testing depends on the type of joints to be made and include radiography, tension, macroetch, and/or bend testing. A minimum of 2 assemblies are to be tested per groove type and position to be welded.
Inspection and testing of production welding is required and includes 100% visual examination of all welds made and may include NDE, if specified by the Engineer of Record. Direct or indirect butt welds and multipass fillet welds will require continuous inspection per IBC: 2018.
Welding of reinforcing steel cannot be welding using procedures for normal structural steel welding in accordance with AWS D1.1. It is recommended that if welding of reinforcing steel is required, PNL, or another qualified third-party organization experienced in AWS D1.4 qualifications and inspections be consulted prior to making any production welds. The drawings below show typical weld joints used for anchorage and embed plates. Direct and indirect butt splice details can be found in the AWS D1.4.
To see a full list of our weld inspection services, click below to find out more.
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