Steel Design, or more specifically, Structural Steel Design, is an area of

structural engineering Structural engineering is a sub-discipline of civil engineering in which structural engineers are trained to design the 'bones and joints' that create the form and shape of human-made Structure#Load-bearing, structures. Structural engineers also ...

used to design steel structures. These structures include

schools A school is the educational institution (and, in the case of in-person learning, the building) designed to provide learning environments for the teaching of students, usually under the direction of teachers. Most countries have systems of ...

houses A house is a single-unit residential building. It may range in complexity from a rudimentary hut to a complex structure of wood, masonry, concrete or other material, outfitted with plumbing, electrical, and heating, ventilation, and air condi ...

bridges A bridge is a structure built to span a physical obstacle (such as a body of water, valley, road, or railway) without blocking the path underneath. It is constructed for the purpose of providing passage over the obstacle, which is usually somet ...

, commercial centers,

tall buildings A skyscraper is a tall continuously habitable building having multiple floors. Most modern sources define skyscrapers as being at least or in height, though there is no universally accepted definition, other than being very tall high-rise buil ...

warehouses A warehouse is a building for storing goods. Warehouses are used by manufacturers, importers, exporters, wholesalers, transport businesses, customs, etc. They are usually large plain buildings in industrial parks on the outskirts of cities, to ...

aircraft An aircraft ( aircraft) is a vehicle that is able to flight, fly by gaining support from the Atmosphere of Earth, air. It counters the force of gravity by using either Buoyancy, static lift or the Lift (force), dynamic lift of an airfoil, or, i ...

ships A ship is a large vessel that travels the world's oceans and other navigable waterways, carrying cargo or passengers, or in support of specialized missions, such as defense, research and fishing. Ships are generally distinguished from boats, ...

and

stadiums A stadium (: stadiums or stadia) is a place or venue for (mostly) outdoor sports, concerts, or other events and consists of a field or stage completely or partially surrounded by a tiered structure designed to allow spectators to stand or sit ...

. The design and use of

steel frame Steel frame is a building technique with a "skeleton frame" of vertical steel columns and horizontal I-beams, constructed in a rectangular grid to support the floors, roof and walls of a building which are all attached to the frame. The develop ...

s are commonly employed in the design of steel structures. More advanced structures include steel

plates Plate may refer to: Cooking * Plate (dishware), broad, mainly flat vessel commonly used to serve food * Plates, tableware, dishes or dishware used for setting a table, serving food and dining * Plate, the content of such a plate (for example: ...

and shells. In structural engineering, a structure is a body or combination of pieces of the rigid bodies in space that form a fitness system for supporting loads and resisting moments. The effects of loads and moments on structures are determined through

structural analysis Structural analysis is a branch of solid mechanics which uses simplified models for solids like bars, beams and shells for engineering decision making. Its main objective is to determine the effect of loads on physical structures and their c ...

. A steel structure is composed of structural members that are made of

steel Steel is an alloy of iron and carbon that demonstrates improved mechanical properties compared to the pure form of iron. Due to steel's high Young's modulus, elastic modulus, Yield (engineering), yield strength, Fracture, fracture strength a ...

, usually with standard cross-sectional profiles and standards of chemical composition and mechanical properties. The depth of steel beams used in the construction of bridges is usually governed by the maximum moment, and the cross-section is then verified for

shear strength In engineering, shear strength is the strength of a material or component against the type of yield or structural failure when the material or component fails in shear. A shear load is a force that tends to produce a sliding failure on a mater ...

near supports and lateral torsional buckling (by determining the distance between transverse members connecting adjacent beams). Steel column members must be verified as adequate to prevent

buckling In structural engineering, buckling is the sudden change in shape (Deformation (engineering), deformation) of a structural component under Structural load, load, such as the bowing of a column under Compression (physics), compression or the wrin ...

after axial and moment requirements are met. There are currently two common methods of steel design: The first method is the

Allowable Strength Design Allowable Strength Design and Allowable Stress Design (ASD) are terms used by the American Institute of Steel Construction (AISC) in the 14th Edition of the Manual of Steel Construction. Allowable Stress Design philosophy was left unsupported b ...

(ASD) method. The second is the

Load and Resistance Factor Design Limit State Design (LSD), also known as Load And Resistance Factor Design (LRFD), refers to a design method used in structural engineering. A limit state is a condition of a structure beyond which it no longer fulfills the relevant design criteri ...

(LRFD) method. Both use a strength, or ultimate level design approach.

Load combination equations

Allowable Strength Design

For ASD, the required strength, R_a, is determined from the following load combinations (according to the AISC SCM, 13 ed.) and: D + F
D + H + F + L + T
D + H + F + (L_r or S or R)
D + H + F + 0.75(L + T) + 0.75(L_r or S or R)
D + H + F ± (0.6W or 0.7E)
D + H + F + (0.75W or 0.7E) + 0.75L + 0.75(L_r or S or R)
0.6D + 0.6W
0.6D ± 0.7E where: * D = dead load, * D_i = weight of Ice, * E = earthquake load, * F = load due to fluids with well-defined pressures and maximum heights, * F_a = flood load, * H = load due to lateral earth pressure, ground water pressure, or pressure of bulk materials, * L = live load due to occupancy, * L_r = roof live load, * S = snow load, * R = nominal load due to initial rainwater or ice, exclusive of the ponding contribution, * T = self straining load, * W = wind load, * W_i = wind on ice.. Special Provisions exist for accounting flood loads and atmospheric loads i.e. D_i and W_i Note that Allowable Strength Design is NOT equivalent to Allowable Stress Design, as governed by AISC 9th Edition. Allowable Strength Design still uses a strength, or ultimate level, design approach.

Load and Resistance Factor Design

For LRFD, the required strength, R_u, is determined from the following factored load combinations: 1.4(D + F)
1.2(D + F + T) + 1.6(L + H) + 0.5(L_r or S or R)
1.2D + 1.6(L_r or S or R) + (L or 0.8W)
1.2D + 1.0W + L + 0.5(L_r or S or R)
1.2D ± 1.0E + L + 0.2S + 0.9D + 1.6W + 1.6H
0.9D + 1.6 H ± (1.6W or 1.0E) where the letters for the loads are the same as for ASD.

AISC Steel Construction Manual

The American Institute of Steel Construction (

AISC The American Institute of Steel Construction (AISC) is a not-for-profit technical institute and trade association for the use of structural steel in the construction industry of the United States. AISC publishes the Steel Construction Manual, a ...

), Inc. publishes the ''Steel Construction Manual'' (Steel construction manual, or SCM), which is currently in its 16th edition. Structural engineers use this manual in analyzing, and designing various steel structures. Some of the chapters of the book are as follows. *Dimensions and properties of various types of steel sections available on the market (W, S, C, WT, HSS, etc.) *General Design Considerations *Design of Flexural Members *Design of Compression Members *Design of Tension members *Design of Members Subject to Combined Loading *Design Consideration for Bolts *Design Considerations for Welds *Design of Connecting Elements *Design of Simple Shear Connections *Design of Flexure Moment Connections *Design of Fully Restrained (FR) Moment Connections *Design of Bracing Connections and Truss Connections *Design of Beam Bearing Plates, Column Base Plates, Anchor Rods, and Column Splices *Design of Hanger Connections, Bracket Plates, and Crane-Rail Connections *General Nomenclature *Specification and Commentary for Structural Steel Buildings *RCSC Specification and Commentary for Structural Joints Using High-Strength Bolts *Code of Standard Practice and Commentary for Structural Steel Buildings and Bridges *Miscellaneous Data and Mathematical Information

CISC Handbook of Steel Construction

Canadian Institute of Steel Construction publishes the "CISC Handbook of steel Construction". CISC is a national industry organization representing the structural steel, open-web steel joist and steel plate fabrication industries in Canada. It serves the same purpose as the AISC manual, but conforms with Canadian standards.

References