Blast pressure capacities

Frame Loads. The window frame must develop the static design strength of the glass pane, r, given in Table II. Otherwise, the design is inconsistent with f rame assumptions, and the peak blast pressure capacity of the window assemblies will produce a failure rate in excess of the prescribed failure rate. This results... 

Figure 1. Peak blast pressure capacity for tempered glass panes a/b = 1.00, t = 1/4 and 5/16 in.

Figure 3. Peak blast pressure capacity for polycarbonate a/b =1.0 t = 1/2 and 1 in.

Figures 2 through 9 are design charts for ultraviolet stabilized polycarbonate under blast load. Charts are provided for pane thicknesses of 1/4, 3/8, 1/2, and 1 inch for pane areas up to 25 ft at pane aspect ratios (pane length to width ratios) of 1.00, 1.50, 2.00 and 4.00. The charts relate the peak experienced blast overpressure capacity, B, for convenient pane dimensions across the spectrum of encountered blast durations. Depending on the orientation of the window to the charge, the blast overpressure may either be incident or reflected. The pane dimensions (measured across the span from the gasket centerline) peak blast capacity at 1000 msec, B, static frame design pressure, r, and the required bite are printed to the right...

The blast resistance of conventional doors is generally limited by the rebound capacity in the unseating direction. A conventional unreinforced hollow metal door with a cylindrical latch may be adequate to withstand a rebound force of 50 psf (2.4 kPa). Door with a mortised latch may be adequate for a rebound force of 100 psf (4.8 kPa). If the blast pressure exceeds this, other alternatives may be considered. These include placing interior or externa barrier walls, or installation of blast resistant doors and frames. Unlike conventional doors, blast doors are typically provided as a complete assembly including the door, frame, hardware and accessories. This is because all the components are dependent on each other to provide the overall blast resistance. Refer to Chapter 9 for performance requirements and design details for blast resistant doors. 

Several methods are used to determine peak loads for the static design of the foundation. Such methods may be determined from the blast pressure applied to the building, the bending or shear capacities of supported structural elements, or dynamic reactions of supported elements. In this example, maximum loads from each of the components directly supported by the foundation are used,... 

These substances have been adopted to cover a wide range of variability of both the heat capacity ratio and the molecular weight (see Table 1). In all cases the calculations were carried out based on the heat capacity ratio at ambient conditions for Prugh s model the value deriving from Brown s equation (3) was used. Over all the investigated blast pressure ranges, the overpressure profiles calculated according to Baker s model remain... 

The Iron Bla.stFurna.ee, The reduction of iron oxides by carbon in the iron (qv) blast furnace is the most important of all extractive processes, and the cornerstone of all industrial economies. Better understanding of the reactions taking place within the furnace has made possible a more efficient operation through better preparation of the burden, higher blast temperature, and sometimes increased pressure. Furnace capacity has doubled since the 1800s, whereas coke consumption has been reduced by about half The ratio of coke to iron produced on a per weight basis is ca 0.5 to 1. 

It is worth noting that blast capacity of a polycarbonate pane is sensitive to the duration of the blast load. Because of this, the typical short overpressure duration testing of polycarbonate with small close-in charges with frame set-ups that permit a rapid pressure clearing time may give an unconservative estimate of blast capacity in many real world threat scenarios. 

In many cases, the dynamic amplification factor or the ratio of static load to dynamic load capacity will exceed two. This is because of the concave up shape of the resistance function and the mobilization of membrane resistance at large deflection to thickness ratios. Because of this phenomenon, it is unconservative to assume the blast capacity of polycarbonate glazing to be no less than one half of its static pressure load capacity. 

The experiments on the iodine separation were conducted as follows. A tubular vessel of pyrex glass, having at one end a plane window and at the other end a conical light-trap, was evacuated and then filled with iodine at about 0.17 mm. pressure, and then with hexene at about 6 mm. partial pressure. The tube was then subjected to the intense light from two Cooper-Hewitt glass mercury arcs, using a filter of 0.05 molal potassium dichromate 2 cm. in thickness to cut off all radiations on the violet side of the green mercury line. The lamps were rim at considerably below the rated capacity, and were cooled by a blast of air to keep the emission lines as narrow as possible. 

Some reduction of reflected overpressure results within a horizontal distance of about twice the barrier wall height. Beyond this distance, the effects of a barrier wail is virtually nil. Quantification of the pressure reduction is difficult and often times requires sophisticated computer modeling. Normally, it is more cost effective to upgrade the strength of the structure to be protected than it is to construct a barrier wall. This is especially true when the structure of interest does not have sufficient blast capacity in the roof to resist the blast load. 

Precast concrete piles will be used with an allowable compression force of 80 kips (356 kN) and an allowable tension force of 50 kips (222 kN), both with a safely factor of 3 against ultimate capacity. Because battered piles will resist all lateral forces without the need for passive soil pressure, a safety factor of 1.2 may be used. Permissible blast capacities will be adjusted accordingly. 

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