B&A : Corrosion Photos

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(click to zoom)	Some Bridges are Hard to Paint Some bridges present special challenges that make lead based paint removal and repainting with an expoxy zinc rich primers and expoxy/polyurethane topcoats most difficult. This bridge can not be taken out of service for more than 8 hours at night. Complete encapsulation/tenting of sand blast/paint areas must be done with care due to wind loading limitations. None the less,a forty year life, low maintenance system is to be applied to this bridge in 2002/2003.

(click to zoom)	Building_Foundation_Pile_Corrosion Building foundaton piles are often thought to be inherently resistant to corrosion. In this particular case, these solder piles had experienced as much as 20% web loss before the buiding was even fully erected. Special remediation using a unique impressed current cathodic protection design has completely mitigated this destructive corrosion.

(click to zoom)	MIC Corrosion on Heating Oil Tank Microbiological Induced Corrosion (MIC) resulted in penetration of this Steel Heating Oil Storage Tank within 4 years. Most commonly the microbes are found to be Sulfate Reducing Bacteria (SRB) which generate a highly acidic environment within and under the colony.

(click to zoom)	Commercial Hot Water Heat Tube Corrosion Fire Tube Hot Water Heaters are often used for heating domestic water in large industrial and commercial applications. Annual maintenance of the heater's corrosion control system(s) is often ignored resulting in premature failure such as in this unit after less than 5 years service.

(click to zoom)	Close-Up of Commercial Hot Water Heat Tube Corrosion

(click to zoom)	Galvanized Pipe Failure at Couplings Galvanized Pipe often suffers corrosion failure when installed underground since it is usually connected to more noble metals such as cast iron, steel or, most commonly, copper. In addition, the pipe often is assembled with threaded joints. It is often at the crevices formed between the pipe and couplings and at the threads themselves, where attack occurs after the pure zinc protective layer is consumed by the corrosion process.

(click to zoom)	Leaking Underground Storage Tank Leaking Underground Storage Tanks (USTs) usually result because they have inadequate or improperly designed and maintained corrosion control systems. The attack on buried and submerged metal structures is usually highly selective resulting in intensified corrosion attack at well defined pits.

(click to zoom)	Close-Up of Leaking Underground Storage Tank This is a classic example of normal galvanic corrosion experienced on USTs.

(click to zoom)	Prestressed Steel Cylinder Concrete Pipe Corrosion Failure Prestressed Concrete Pipe can suffer accelerated corrosion where either the cement mortar cover is damaged, the pipe is in contact with chloride contaminated or low pH soils or is influenced by stray DC currents. This form of corrosion can result in sudden, bursting failure of the pipe.

(click to zoom)	SRC Bridge Deck Corrosion Steel Reinforced Concrete (SRC) Bridge Deck Corrosion is all to common in the United States. Unfortunately, many of the repair and restoration procedures presently in use will not be effective in the long term. The problem is, primarily, caused by use of Sodium Chloride as a de-icing agent, the use of Calcium Chloride as a cure accelerator or by air borne and splash zone sea water contamination of the SRC.

(click to zoom)	Plastic Water Pipe Brittle Fracture This Plastic Water Transmission Pipe suffered numerous failures due to embrittlement with time. This type of brittle fracture of plastic pipe has reportedly occurred on pipe made from many different plastic pipe formulations.

(click to zoom)	Plastic Pipe Manufacturing Defect Failure Plastic Pipe manufacturing defects such as this void at the pipe bell made this section of water transmission pipeline fail prematurely.

(click to zoom)	Stainless Steel Band Clamp Failure This Stainless Steel Band Clamp failed because the screw fitting was made from a lower grade alloy SS than that of the band material. Lower grades of SS can suffer accelerated corrosion when placed underground as in this case while higher grades can suffer from stress corrosion cracking and hydrogen embrittlement in underground use. Special care must be taken when using SS materials underground.

(click to zoom)	Another AST Bacterial Corrosion Problem Another classic example of Microbialogical Corrosion Attack in a #2 Fuel Storage Tank. This form of attack is more common on above ground storage tanks where the ambient summer temperatures are ideal for bacterial colony growth.

(click to zoom)	Large Storm Sewer Culvert Pipe Corrosion Perforation This 12 to 18 foot diameter by more than a mile long Galvanized Culvert Storm Sewer provides critical drainage to the downtown area of a Southern City. This pipe has served well for more than 40 years and is in excellent condition except for the invert where erosion-corrosion has perforated the culvert at a number of locations. Ground water can be seen spurting up through a hole in the bottom of the culvert in this photo.

(click to zoom)	Condominium Steel Frame Failure The steel framework of this east coast condominijm complex had suffered severe corrosion after only 10 years. This bottom support sill had corroded so badly that it was no longer in contact with the column steel. There are four more units above this bottom unit.

(click to zoom)	Why Dry Cell Batteries Corrode All batteries are electro-chemical corrosion cells. This battery's outer case is made from a zinc cup which is filled with a gelled fluid of ammonium and zinc chlorides (electrolyte) wihin which is immersed a core rod made from carbon. Zinc and carbon have a natural energy imbalance of about 1.55 volts when they are are in contact with this electrolyte. The higher energy zinc is the anode (wants to corrode) while the carbon rod is the cathode and attracts the corrosion current provided by the zinc anode. When placed in an electrical appliance such as a flashlight, and the switch closed, energy in the form of electrons flows from the zinc through the switch, the light bulb filament and then enters the carbon rod core. For each two electrons so tranferred, one atom of zinc is corroded (dissolved). With time the case leaks as shown in this photo.

(click to zoom)	Copper Water Pipe Corrosion Copper water pipe can suffer accelerated corrosion if the water chemistry is particularly aggressive or if there is poor workmanship during the pipe installation. The poor workmanship in this case lead to pipe perforation in less than four years.

(click to zoom)	Ductile Iron Pipe Failure Ductile Iron Pipe generally suffers from pitting corrosion very much like any other ferrous metal pipe material. During this century, there has typically been a 60% to 80% reduction in wall thickness compared to the former cast iron material for the same class of service. This reduced wall has made the pipe much more susceptible to corrosion failure such as occurred on this 30" diameter water transmission pipeline.

(click to zoom)	Buried Propane Tank Failure Bacterial corrosion caused this buried propane storage tank to penetrate in less than 10 years even though it had a wall thickness of 3/8".

(click to zoom)	Ductile Iron Pipe Elbow Perforation Another example of Ductile Iron Corrosion Failure on this 12" diameter 45 degree flanged pipe elbow. Note the very selective pitting attack and complete perforation on the side of the elbow.

(click to zoom)	Parking Garage Corrosion Corrosion threatened to force demolition of this north eastern US parking garage. It was reportedly the first such structure constructed using pre-stressed, post-tensioned technology. Selective use of a passive galvanic anode cathodic protection system was able to overcome the corrosion after repairs were made. No power supplies are required and the output is somewhat self regulating. Complete repair and restoration cost less than 20% of costs to replace the srructure.

(click to zoom)	Parking Garage Structural Beam Almost Failed 2nd location in this same parking garage where the beam was in danger of collapse due to the heavy corrosion in the beam and adjacent support wall. As a result, temporary jacks and steel "I" beams had to be used to hold the column up until permanent repairs to the reinforcing and concrete could be completed.