Structural member design

Select low-temperature steels for fracture-critical structural members designed for tensile stress levels greater than a ksl (40 MPa) and specify a minimum Charpy V notch Impact energy absorption of 20 ft-lb (27 J) for base metal, heat-affected zones (HAZs), and welds when the structures are exposed to low-ambient temperatures. Fracture-critical members are those tension members whose failure would have a significant economic impact. 

Expansion joints for free-movement systems can be designed for axial or offset movement alone, or for combined axial and offset movements (see Fig. 10-171). For offset movement alone, the end load due to pressure and weight can be transferred across the joint by tie rods or structural members (see Fig. 10-172). For axial or combined movements, anchors must be provided to absorb the imbalanced pressure load and force bellows to deflect. 

The most commonly used warehouse chain conveyor is the tow chain. Chain may be mounted overhead or in the floor, and trucks being towed can be designed for automatic detachment at a specific point. While the overhead chain is often used and is usually easy to support from structural members in the ceihng, the in-floor chain is probably most common. Automatic disengagement is possible should trucks encounter an obstruction or accident ly strike warehouse personnel. The two-chain conveyor is, of course, most economical when large tonnages are moved over a fixed path. 

Design load The force or combination of forces that a structure is designed to withstand without exceeding the allowable stress in any member. 

With plastics to a greater extent than other materials, an opportunity exists to optimize product design by focusing on material composition and orientation to structural member geometry when required. The type of designer to produce a product depends on the product requirements. As an example in most cases an engineering designer is not needed... 

A snap joint is economical in two respects it allows the structural member to be molded simultaneously with the molded product, and it allows rationalizing the assembly, compared with such other joining processes as screws. Table 3-4 provides a comparison of its advantages and disadvantages. Some examples of the various types and their design considerations are shown in Figs. 3-23 to 3-25. 

In all blast-resistant structures (steel, concrete, or masonry) special attention should be given to the integrity of connections between structural elements up to the point of maximum response. For example, it is important to prevent premature brittle failure of welded connections to avoid stress concentrations or notches at joints in steel structures and to provide ductile reinforcement detailing in concrete/masonry structure connections. For all materials, it is recommended that connections be designed to be stronger than the connected structural members such that the more ductile member will govern the design over the more brittle connection. 

This chapter discusses various analysis methods for determining the dynamic response of structural members subjected to blast loading. In order to perform the dynamic analyses, it is necessary to have previously defined the loading as well as member properties such as stiffness and mass. The design of new structures sometimes involves several iterations of the analysis, where trial member sizes are used and the resulting response quantities are compared against the acceptance criteria defined in Chapter 5. 

AISI 1991, Load and Resistance Factor Design Specification for Cold-Formed Steel Structural Members, American Iron and Steel Institute, New York, NY, 1991... 

The basic analytical model used in most blast design applications is the single degree of freedom (SDOF) system. A discussion on the fundamentals of dynamic analysis methods for SDOF systems is given below which is followed by descriptions on how to apply these methods to structural members. 

Connections must be sized to transfer computed reaction forces and to assure that plastic hinges can be maintained in the assumed locations. For reinforced concrete design, splices and development lengths are provided for the full yield capacities of reinforcing. For structural steel design, connections are designed for a capacity somewhat greater than that of its supported member. Further information is provided in later sections of this chapter. Typical connection details are provided in Chapter 8. 

The design will proceed component by component. Each component will be designed as an independent uncoupled structural member. 

Ultimate Strength - A method of design in which structural members are proportioned by total section capacities rather than by extreme fiber allowable stresses. 

The bottom of the baseplate between structural members shall be open if the baseplate is designed to be installed and grouted to a concrete foundation. Accessibility shall be provided for grouting under all load-carrying members. The bottom of the baseplate shall be in one plane to permit use of a single level foundation. 

Raw sulfur has a high coefficient of thermal expansion. A value of 55 X 10 6/K at room temperature was found during the present work. If similar values were found in concretes, temperature differences between different parts of a single structural member would lead to high stress concentrations. Fillers reduce the value considerably in sulfur mortars values varied between 21 and 58 X 10"6/K and between 11 and 29 X 10 6/K in sulfur concretes depending on the composition of the fillers and mix design. 

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