Structural Steel Restoration
TOPCOR Services, Inc. is suited for structural steel restoration in industrial and public applications. Structural steel restoration is required when the steel structural members are damaged or attacked by chemicals. Structural steel restoration is the rebuilding of the steel members using equivalent strength steel plates seal welded or stitch welded to the exposed and damaged flanges and webs.
Structural steel restoration will involve a design engineer. TOPCOR works with a number of design engineers and can contact them for your project. A design engineer is required to design the plates and determine the final load capacity of the restored member. The new steel plates can be undersized (thinner then the flange) or oversized (wider then the flange) to position the weld on the flange or on the edge of the flange on the existing steel member. The web plates are positioned in the center and have to have clearance for a properly sized weld to be effective. Structural steel restoration can be done during outages, turnarounds, and during the replacement of vessels or other members.
Structural steel restoration is done first by blasting or cleaning the steel mechanically. This initial step is done to remove as much contaminants on the surface as possible. It also serves to expose the extent of the damage. After cleaning the steel, an inspection documenting the damage and corrosion is completed (see our survey matrix). The results of the inspection are given to an engineer for analysis. The engineer will design the plating required. The plates are then welded into final position by TOPCOR.
For protection from chemical attack please see our coating page.
PILE JACKETS
TOPCOR is becoming known more and more for its expertise in bridge repair, especially in coastal areas where chlorides have had such a severe impact on the reinforcing steel in structural concrete Cathodic Protection.
One of the major items on any bridge repair project is pile restoration. Along the entire Gulf Coast and the southern East Coast, TOPCOR has specialized in the restoration of structural piles for bridges, docks, piers, ports, etc., through the use of Pile Jackets.
Pile Jackets are available in a wide variety of configurations and end uses, but basically they provide a permanent “form”, usually manufactured of FRP (Fiberglass Reinforced Plastic), within which a repair material can be applied or pumped to restore the piles.
Some examples:
 Cathodic Protection Pile Jackets – this is an FRP jacket with zinc mesh installed on the inside wall. This jacket is placed around a properly prepared concrete pile (round or square), the zinc is attached to the reinforcing steel to act as sacrificial cathodic protection, and a concrete mortar is pumped into the 2” annular space to fill the jacket. The FRP stays in place and provides corrosion protection. The zinc mesh protects the reinforcing steel from future corrosion. Cathodic Protection Structural Pile Jackets – Similar to those above, with this system, we build an entirely new reinforcing cage and create a 6” annular space, which is filled with structural concrete. These jackets not only cathodically protect the reinforcing steel, but they enhance the strength of the pile. Epoxy Filled Pile Jackets – This system seals and protects piles that have little existing damage. An FRP jacket is placed around a cleaned concrete pile and the annular space, only about ¾” is pumped with epoxy grout, which fully bonds to the concrete and the FRP jacket. Epoxy Puttied Pile Jackets – Similar to above, these FRP jackets are pre-applied on the inside with an epoxy material and the two half shells are then applied to the pile and compressed to force out water and air, forming fully bonded and sealed epoxy FRP jacket protection. Standard Concrete Filled Pile Jackets – These FRP jackets are formed similar to those above, but the annular space, which can vary, is simply filled with concrete to reinforce the pile. Extra reinforcing steel is often added. |
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TOPCOR employs a full team of OSHA certified divers who are cross-trained to apply these jackets, usually installed partially above and partially below the water line. The installation of Pile Jackets is usually accompanied by many of our other specialty services, such as:
Some examples of completed jobs:
TOPCOR Shotcrete Restorations Services:
Repair and Restoration of concrete structures is one of TOPCOR Services fastest growing market segments. Our customer base has come to rely on the quick, effective method of pneumatically applied concrete known worldwide as shotcrete. Shotcrete can be applied using a wet or dry process, and is used for new construction as well as repairs.
Shotcrete has often been described not as a material but as a process. Both wet and dry process produce a material that exhibits superior hardened properties to conventional concrete, such as high strength, low permeability and high durability. These properties allow shotcrete to be used as a structural rebuild material.
Shotcrete and gunite are two commonly used terms for sprayed concrete. Shotcrete is mortar or concrete conveyed through a hose and pneumatically projected at high velocity onto a surface. Shotcrete undergoes placement and compaction at the same time due to the force with which it is projected from the nozzle. It can be impacted onto any type or shape of surface, including vertical and overhead areas.
Shotcrete is today an all-inclusive term that describes spraying concrete or mortar with either a dry or wet process. However, it may also sometimes be used to distinguish from gunite as a wet mix. Shotcrete can be applied in either the dry mix process or the wet mix process. Job site logistics, material mix design, configuration of area to be sprayed and production rates are some factors that should be considered when choosing which process is most beneficial to the customers project needs. Both have advantages and disadvantages that may make one or the other more desirable for specific job requirements.
The dry-mix shotcrete method involves placing the dry ingredients into a hopper and then conveying them pneumatically through a hose to the nozzle. The nozzleman who holds the nozzle then controls the addition of water at the nozzle. The water and dry mixture is not completely mixed, but is completed as the mixture impinges on the receiving surface. This requires a highly skilled nozzleman, especially in the case of thick or heavily reinforced sections.
The wet-mix shotcrete method involves pumping of a previously prepared concrete, typically ready-mixed concrete, to the nozzle. Compressed air is introduced at the nozzle to propel the mixture onto the receiving surface. The wet-gun procedure generally produces less rebound, waste (when material falls to floor), and dusts compared to the dry process procedure.
As in regular concrete, shotcrete also uses admixture technologies to custom blend a mix design to meet the customer’s specific needs. (Silica fume, fibers, refractory blends, accelerators or retarders to name a few.) The versatility of the proven process of shotcrete has outstanding support from owners, architects, engineers, and contractors alike.
Common Applications for this technology:
TOPCOR Services is a member of the following organizations ACI (American Concrete Institute), ICRI (International Concrete Repair Institute), ASA (American Shotcrete Association), TOPCOR Services has 7 certified nozzleman that have been with us for over 10 years and some others to that are approaching there 5 year anniversary hire date.
The large diversity of shotcrete applications needs the very best combination of shotcreting experience and effective problem solving experience. This experience allows TOPCOR to provide correct material and mix design selection while at the same time allowing versatility to meet the job requirements and ways to save costs. TOPCOR is dedicated to deliver this experience on every project, no matter how large or small.
For further information or for a site survey or estimate, please go to our contact us page….
