Steel Jacketing Method

Keywords epoxy resin, seismic retrofit, steel jacketing method, carbon fiber sheet jacketing method, unseating prevention... 

Steel Jacketing Method. Concrete piers/columns are covered by steel plate in steel jacketing method as shown in Fig. 2 (b) and Fig. 4. The characteristics of this method [3] are represented by the following points. 

Liquid epoxy resin (for steel jacketing method and installation of anchor bar) Impregnating type epoxy resin (for fiber sheet jacketing method) Grease type epoxy resin (for fixing of anchor bolt)... 

Three types of jacketing methods using either reinforced concrete, steel or fiber as seismic retrofit to increase the flexural and shearing strength, and ductility of existing concrete piers are adopted. For steel jacketing method, liquid epoxy resin is effectively used for injection in the space between steel jacket and concrete piers. 

Another method of bomb dissolution involves placing the sample and digestion mixture in a sealed PTFE bomb and then encasing this in a stainless-steel jacket. This may then be placed in a conventional oven for a period of several hours. This technique, although cheaper, takes substantially longer. 

A real micro variant of the Kjeldahl process is described by Tolg and coworkers (11)(12) the sample - 80 to 200 mg - is digested under pressure at 120°C with 2 ml of a 10 to 1 mixture of hydrofluoric and perchloric acid in a PTFE vessel fitted with a steel jacket the duration is 2 to 6 hours. After adding sodium hydroxide solution, the ammonia formed is distilled off by recirculating steam in a special apparatus and is titrated in the distillation receiver with hypobromite produced by a coulometric method. This procedure excludes contamination during the digestion process... 

Strengthening of concrete columns can be achieved by reinforced concrete (RC) jackets. This is an intrusive and time-consuming procedure, but in some cases it is necessary. However, the effect of strengthening a column using RC jackets should be examined carefully as this method will increase column flexural strength and stiffness more than a steel jacket, FRP composite jacket, or wire wrap, with potentially undesirable effects on bridge performance. 

Strengthening method is to use external posttensioning as shown in Fig. 13a. Steel jackets bonded to the sides of the joint and anchored to the bent cap are also effective (Thewalt and Stojadinovic 1995). Finally, FRP jackets in the form of an ankle wrap have been tested (Gergely et al. 2000) and used to strengthen column to cap beam-colunm joints as shown in Fig. 13b (Pantelides et al. 2004). The nominal principal tensile stress developed in the beam-column joint is used to design the carbon FRP composite layers. When strengthening of these joints is required to improve the longitudinal response, transversely prestressed bolsters may be used. 

Heaters. The preferred methods for heating are a double-jacket heated tank, nonmetaUic heat exchangers, quartz heaters, or Teflon-coated low watt density stainless steel heaters. Localized overheating must be avoided. 

De Keen attempted to find the effect of pressure up to and above the critical point, on the specific heat. A steel cylinder enclosing the liquid was surrounded by a jacket of mercury vapour, and the time taken for heating through 50° compared with that when water was in the cylinder. The accuracy of this method is doubtful. He found that the specific heat decreased with increasing pressure near the critical point, and there was a sudden change of specific heat at the critical temperature. With ether ... 

The preparation of dichloroethyl sulphide by this method was carried out in a cylindrical vessel of sheet steel or cast-iron, lead-lined and jacketed, of about 100 cm. diameter and 130 cm. in height, fitted with an agitator. This vessel has a lid through which a pipe passes to within a short distance of the bottom in order to introduce the ethylene. 

The vacuum chamber (Fig. 2) is a 20 x 39-in. stainless steel cylinder of all heliarc-welded construction. The chamber is suspended in an insulated aluminum tank. The chamber volume after correction for the pump lines and cryosphere was calculated to be 202 liters. This chamber size makes possible the use of commercially available standard leaks, without introducing significant errors in the time measurement when calibrating the gas analyzer by the rate of pressure rise method. The 7-in.-diameter cryosphere has a calculated surface area of 995 cm . The coolant transfer lines to the cryosurface are vacuum-jacketed to prevent possible condensation. 

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