EGCE430-02 Lecture Structural Steel Products PDF

Preview

Summary

Download EGCE430-02 Lecture Structural Steel Products PDF

Description

Dr. Uksun Kim

EGCE 430 Structural Steel Design Dept. of Civil and Environmental Engineering California State University, Fullerton

Lecture: STRUCTURAL STEEL PRODUCTS □ Steel Products used in Construction 1. Structural steel: plates, bars, pipes, structural shapes, etc. 2. Fastening products: structural connections including bolts, nuts, and washers. 3. Reinforcing steel: concrete reinforcement (rebars) 4. Miscellaneous products: forms, pans, etc. □ Steel Production * Overall process of steel production. 1. Reducing iron ore to pig iron (coke: charcoal made from coal, limestone, iron ore) 2. Refining pig iron to steel (removing excess carbon & other impurities) 3. Forming the steel into products

Figure 1: Conversion of raw material into different steel shapes

Uksun KIM

1

□ Steel Alloys * 250,000 different alloys of steel produced. * 200 different alloys may be used for CE applications. * Alloy agents are added to improve one or more of the following properties: 1. Hardenability; 2. Corrosion resistance; 3. Machineabiliby; 4. Ductility; 5. Strength

Table 1: Common Steel Alloying Agents

Uksun KIM

2

□ Structural Steel * Structural steel grades American Society for Testing and Materials (ASTM) specifications - A for ferrous materials, followed by an arbitrary serially assigned number. Ex.) ASTM A7 (Early 1900s) ~ ASTM A 992 (1999) - The terms grade, type, and class are used. Table 2: Designations, Properties, and Composition of ASTM Structural Steel

- ASTM A992 AISC Manual for Steel Construction - Excellent reference on the types of steel used for structural applications. □ Fastening Products □ Reinforcing Steel □ Mechanical Testing of Steel * Tension Test * Torsion Test * Charpy V-Notch Impact Test

Uksun KIM

3

◘ Mechanical Properties - Mechanical behavior of materials: response of the material to external loads * Stress-strain relations (σ – ε) * Elastic behavior - Modulus of elasticity or Young’s modulus E=

σ ε

- Poisson’s ratio: the rate of the lateral strain εl, to the axial strain, εa.

ν =−

εl εa

- Linear material vs. elastic material - Determination of E for nonlinear elastic behavior • Initial tangent modulus • Secant modulus

- Typical modulus and Poisson’s ratio values for materials

Uksun KIM

4

- Determination of yield strength

• Most materials do not display an abrupt change in behavior from elastic to plastic. • “Offset” method.

Uksun KIM

5

• Different offsets are used for different materials.

Uksun KIM

6...